Final Report Summary - HIGRAPH (Incorporation of solid lubricants into surface of friction parts engineered for high-temperature applications)
Executive Summary:
Since traditional lubricants fail when friction is combined with high temperature, it is either impossible or impractical to use these materials in many industrial applications and numerous small and medium-sized enterprises (SMEs) seek the competitive edge new technologies that could solve existing wear problems.
The goal of the HIGRAPH project was to provide participating SMEs and the machinery industry with novel technologies for manufacturing sliding and rotating components that enhances dry-friction performance under high temperatures, increases durability, and extends the service lifetime of parts.
The Project goal was reached by: the surface modification of the porous sliding bushings, bearings and forging tools with high temperature solid lubricant (HTSL) micro- and nanoparticles and formation of the surface layers providing the quasi-hydrodynamic lubrication regime at the sliding contact at high temperature; modification of the surface layer of thermal spray (TS) coatings by encapsulation of HTSL particles in micro-reservoirs fabricated by micromachining. These approaches maintain operational integrity of friction parts at high temperatures and enables slow release of solid lubricant generating a lubricating film at the frictional interface allowing to considerably diminish friction coefficient and wear rate.
The database on wear mechanisms of parts subjected to wear at high temperatures was created at the first stage of the Project. A widespread exploration was executed first, aiming the selection of the most promising HTSL materials. Further activities were the thorough specification of the required HTSL powders, and research and analysis of the market to determine the potential suppliers of the materials of further HIGRAPH needs. The economic aspects (cost of HTSL depending on particle size and suppliers) were also carefully analysed that is very important for successful integration of the developed technology in industry. The tribological tests allowed choosing the HTSL that are the most suitable for desired applications.
To imitate the real exploitation conditions various friction tests in wide temperature range were applied (using ball-on-disk high temperature testers and special bushing-shaft test bench). Tests of samples modified with HTSL powders demonstrated an important decrease of a friction coefficient and wear rate under temperature up to 700C.
The process control system was developed and integrated with Gazela equipment for coating deposition. The process control system allows to ensure coating quality (ensure stability of coating properties and to decrease the number of rejected parts) and to decrease the production cost.
Testing of self-lubricating prototypes manufactured by compacting-sintering-repressing-HTSL impregnation powder metallurgy technology and technology of TS coating modification with HTSL enabled optimisation of tribological parameters to maximise lubrication performance of parts demonstrators: sliding/rotating components and forging tools.
SME real self-lubricating friction parts were finally fabricated using novel technologies and pilot tests of their exploitation properties were carried out in wide temperature range and they demonstrate the lifetime increases at least in 3-4 times in comparison with untreated friction parts.
HIGRAPH developed novel solid lubricant technologies for high-temperature applications. It allows increasing service lifetime and reducing the need for replacement while decreasing the energy consumed by the machines to do their jobs. The slight increase in unit price (<2-10%) will be completely offset by the enhanced service lifetimes for a 40 to 60 % cost savings within 2 to 3 years. The developed methods could be effectively applied not only for high temperature friction parts, but also for other ones applied at ambient temperature and the exploitable results are expected to reach new markets including various industrial sectors.
Project Context and Objectives:
The main goal and concept of the Projects are presented below. Since traditional lubricants fail when friction is combined with high temperature, it is either impossible or impractical to use these materials in many industrial applications. The need for improved lubricating technologies is critical when trying to solve tribological problems concerning dry friction under high temperatures. The goal of the HIGRAPH project is to provide participating SMEs and the machinery industry with novel technologies for manufacturing of sliding, rotating components and forging tools with enhanced dry-friction performance (low friction coefficient) under high temperatures (up to 700C), increased durability, and extended in 2-3 times the lifetime.
The main goal of the Project was to develop technologies: for the surface modification of the porous sliding bushings, bearings and forging tools with High Temperature Solid Lubricant (HTSL) micro- and nanoparticles and formation of the surface layers providing the quasi-hydrodynamic lubrication regime at the sliding contact at high temperature; modification of the surface layer of thermal spray (TS) coatings by encapsulation of HTSL particles in micro-reservoirs fabricated by micromachining.
The Project goals were attained through the solution of the following RTD problems (Project objectives):
-Analyses of SME’s wear problems, definition of critical components and study of their damage mechanisms. Collection of the data on critical friction parts, their operation parameters and definition of main wear mechanisms. Choice of critical components for further improvement and definition of their specification;
-Definition of requirements for high temperature coatings and selection of type of coatings to be applied. Definition of the most suitable manufacturing routes fro chosen components. The following groups of components were considered: P/M sliding bearings and bushings; forging tools; friction parts of annealing furnaces;
-Develop of methodologies to evaluate the tribological properties of high-temperature surface layers and related testing benches and testers;
-Development of database including: specification of SME’s friction parts; general information on HTSL materials and their properties; data on HTSL materials available on the market, their cost and manufacturers; data on high temperature thermal spray coatings and their properties; data on testing results of HTSL and surfaces modified with HTSL;
-Development of the model of mixed lubrication based on non-Newtonian behaviour of HTSL and knowledge-based engineering calculation package. The calculation model validation during the SME components tests and accumulation of experimental data;
-HTSL market analysis, definition of suppliers providing lower cost and high quality of HTSL for wide industrial applications, estimation of influence of powder particle size on the cost;
-Ordering and characterisation of HTSL powders from various selected suppliers;
-Tribological characterisation of ordered HTSL at ambient and high temperature to define the most suitable ones for desired SMEs application both in terms of friction coefficient, thermal stability and the cost;
-Choice of powder materials and optimisation of HVOF spraying parameters to get desired coating quality for SME friction parts;
-Development of micro-machining method for modification of sprayed coating surface in order to create micro-sized reservoirs to be filled with HTSL without changes in mechanical integrity of the base coating and taking into account economic feasibility of modified coated parts fabrication;
-Specification of the process diagnostic and control system to for SME coating technologies. Development of hardware and software, building of process control system prototype. Test of the system under laboratory conditions, Integration of the developed system with coating SME equipment and its’ test under conditions of industrial equipment;
-The development of new pressure impregnation/filtering technology for formation of surface layer containing HTSL providing the quasi-hydrodynamic regime of lubrication. Study of HTSL flow in porous network, determination of conditions of impregnation. Development of nitriding technology;
-According to specification of testing machines fabrication of: lab-samples by method of TS coating modification with HTSL; P/M prototypes by nitriding, pressure impregnation/filtering method;
- Characterization of microstructure, density, porosity of lab-samples and P/M part prototypes using, preliminary tribological tests using ball-on-disk and shaft-sleeve tests, technologies optimisation and definition of necessity of post operation;
-Choice of the most representative and marketable components of SME for application of the developed technologies;
-Development of complex technology prototypes to manufacture coated and P/M components for SME industrial sectors: (1) design of part prototypes; (2) design of tooling; (3) devise and implement component-manufacturing technologies; (4) Coating modification and nitriding/pressure impregnation/filtering technologies application; (5) elaboration post-processing technologies;
-Fabrication of component prototypes for further characterisation and testing in wide temperature range;
-Test the friction and wear of prototype components under conditions that are closed to real conditions of SMEs components operation. To imitate the real exploitation conditions the bushing-shaft test bench was specially developed by INOP and applied for testing of porous sliding bearing sleeves with HTSL in wide temperature range. The real geometry and contact conditions (contact stresses, sliding speed, temperature, etc.) are achieved by use of test benches that ensure the above parameters for end-user applications;
-Analysis of the structure of worn parts and friction test results. Optimisation of coating modification and nitriding/pressure impregnation/filtering technology for SME applications;
-Select the most promising HTSL and coatings and base materials for SMEs applications;
-Estimation of potential harmful and environmental influence of the developed technologies, establishing of contacts with European Safety cluster;
-The completion of the development of the final database on the most promising HTSL, coatings and testing results;
-Pilot tests of surface modification technologies in the industrial environment for SME components from related industrial sectors: annealing furnace; sliding bearings and bushings; forging tools;
-Pilot tests of exploitation properties of real component prototypes and assessment of: geometry, shape and dimension accuracy, surface quality, component failure and lifetime. Quality assessment of the test results;
-Optimisation of novel surface modification technologies in terms of quality, economic efficiency, and productivity;
-Identification of competitors, suppliers, customers, and substitute products within the target markets, patent search and analysis, market watch in related industrial sectors;
-Demonstration that the developed technology increases a friction part lifetime, evaluation of the cost of component production using the developed technologies and the estimation of the market potential. Estimation of economic benefits for SME partners and potential social and economic benefits for EU industry;
-Elaboration and signing of an Exploitation Agreement;
-Realisation of measures for training of SME partners on the use of the Project results;
-Elaboration of Plan for the Use and Dissemination of knowledge (PUDK) and measures for IPR protection;
-Realization of specific measures for results exploitation and dissemination: newsletters; flyer; creation and continuous update of the Project website; publications, presentation on conferences, workshops, trade fairs and exhibitions; organisation of Workshop on coating technologies; creation of the Project video presentation and DVD.
Project Results:
The HIGRAPH Projects generated the following exploitable results (foreground):
1) Database for friction part wear mechanisms under high temperature
Relevant Sectors: Thermal spraying, Powder Metallurgy, Tribology, Mechanical Engineering
Description of the main S&T Results:
The database on high temperature wear mechanism, TS coatings and HTSL materials is designed to help determine the correlation between material properties, surface layers, manufacturing technology and tribological conditions of friction parts operating at high temperatures. Based on the project partners’ feedbacks the database were developed and integrated with the Project website. Representative friction parts of SMEs with description if their wear problems and wear mechanisms, the most promising HTSL, coating and P/M matrix materials selected for SMEs applications and test results were included in the database. The Consortium processed and imported into the web application provided content of the database. Project partners can update the database continuously and further content (such as new products, testing results etc.) can be easily added.
Based on discussion with the SME and RTD partners on the demands and requirements the structure and elements of HIGRAPH database were defined. The database is divided into the following main subunits, as follows:
-High temperature solid lubricant (HTSL) materials and their properties;
-High temperature HTSL powders, their manufacturers, suppliers and cost evaluation;
-High temperature TS coatings and related powder materials and their manufacturers;
-High temperature industrial problems of SMEs (PMR, Gazela and J-VST);
-Results of tests of HTSL materials and SMEs components prototypes.
-Supportive, general database tables.
The database was designed in such a way so that it could help to determine the correlation between material properties, surface layers, manufacturing technology and tribological conditions of friction pairs operating at high temperatures. As a result, it could provide an ultimate tool for designers of machine parts by providing recommendation. The base of recommendations is to propose the selection of materials, the properties of the surface layers, manufacturing technologies of the selected operating conditions. Sub-modules of the database were implemented and tested. A web application was developed to provide frontend for the database and it is the part of the project website. The database was designed as MySQL database and utilizing a PHP web application frontend. Feedbacks from partners were collected and related modifications were implemented. Populating the database with data collected during the project was realised. Preparing technical and economic assessment of new technologies was carried out. Experimentally analysed friction and wear, and the structure/topography of worn out parts were carried out for PMR, JVST and Gazela applications.
One of the main tasks of the Project is to select and order those HTSL materials, which have the highest potential to be applied at the applications outlined in HIGRAPH project. Regarding this goal, a widespread exploration was executed first (including literature and market research), aiming the selection of the most promising HTSL materials. Further activities were the thorough specification and technical analysis of the required HTSL powders, and the research and analysis of the market to determine the potential suppliers of the materials of further HIGRAPH researches and choosing the material to be ordered. The economic aspects (cost of HTSL depending on particle size and suppliers) were also carefully analysed that is very important for successful integration of the technology to be developed in industry. It was shown that the difference in cost for various suppliers could reach 10-100 times for powders with parameters that are very closed. Considering the possible differences (morphology, particle size distribution etc.) between the powders of different suppliers, similar powders were ordered from different sources – when it was justifiable. Wide range of HTSL powders (h-BN, MoS2, WS2, WSe2, CaF2, BaF2 and Graphite) were ordered from various selected suppliers taking into account economic aspects and quality.
Selection of coatings type for PMR applications was realised by IfU based on analysis of PMR friction units (ball-on-rail support and mesh-belt-on-roller). Analysis of TS powders was based on technical data of leading manufacturers of these powder materials and developers of related TS technologies. The results of analysis (more than 50 various types of TS coatings were analysed) were included in the database and could be for engineering selections by end-users depending.
Analysis and classification of J-VST, which work at the harsh friction and wear conditions is made taking into consideration: part geometry, applied materials and operating conditions (temperature range, contact stress, environment, type of solid lubricant, sliding speed). Based on analysis and classification the use of self- lubricating effect was planned to consider for the following groups of J-VST components: forging tools; P/M porous bearing and chain bushing.
Study the mechanisms that underlie friction and damage of surface layers of P/M parts modified with HTSL was performed by INOP. The most difficult problem to solve is the control of local contact phenomena during the sliding process. Two research strategies were applied: (1) Experimentally determine the effects of HTSL on friction and wear under high temperatures, and (2) Develop a new mixed and quasi-hydrodynamic model (which will describe the friction parameters of contacts, and the conditions that cause surface wear) will be used to establish lifetime criteria. To ensure accuracy, computations were performed at the contact level to determine the relevant contact parameters, and to define the friction conditions. As a result, knowledge-based engineering calculation package was developed to analyse the influence of HTSL on actual friction and wear mechanisms. Friction conditions outputs are comprehensive requirements for surface layer parameters.
Task statement. The available experimental data exhibit that effective lubrication of boundary and mixed lubricated system such as sliding bearings, sliding components, and others, is ensured by two processes: i) the formation of very thin films in the contact as a result of interaction between chemical components of solid lubricant with the lubricated surface and ii) flow of the powder body at the interface.
The model of mixed lubrication based on non-Newtonian behaviour of powder solid lubricant was developed and validated based on the experimental results. Based on the model knowledge-based engineering calculation package is developed to analyse the influence of HTSL on actual friction and wear mechanisms and to establish lifetime criteria.
Types of testers and testing parameters to be applied for evaluation of tribological properties were chosen: ball-on-disc high temperature testers; specially developed by INOP high-temperature shaft-sleeve test bench.
2) Optimal selection of technological parameters of PM process
Relevant Sectors: Powder Metallurgy
Description of the main S&T Results:
Summary: The surface modification of the high temperature porous sliding bearings with solid lubricant nanoparticles allows to considerably diminish its’ friction coefficient and wear rate. The surface modification technology of powder-sintered bearings was developed. It consists of nitriding, pressure impregnation and sizing operations that allow to solid lubricant particulate layer at the sliding surface. It is found the solid lubricant micro- and nanoparticle layer provides the quasi-hydrodynamic lubrication regime at the sliding contact at high temperature.
In order to realize the quasi hydrodynamic lubrication regime the sliding bearing needs to be supplied with the powder lubricant layer of definite thickness. The thickness of this layer is defined by solid lubrication third body concept. Therefore, the simple vacuum impregnation of porous sliding bearing is not effective for the case of high temperature dry lubrication, and sufficient amount of solid lubricant nano- and micro-particles seems to be required at the sliding interface. The pressure impregnation technology based on a filtration approach may solve the problem of powder layers formation.
Often, the particulate layers (coatings) on the various surfaces are conveniently built by self-assembly through various deposition techniques. One option to produce these coatings directly from the liquid based suspension is the filtration onto a porous substrate, which is a rapid and convenient method of deposition yielding homogeneous films of a controlled thickness and a high degree of reproducibility. The structure of the solid lubricant particulate layer together with the particle functionality determines its performance, and therefore the thickness of the powder layer, its density and morphology are fundamental parameters that require an accurate control. First, however, characterization tools are needed, as classic methods for determination of morphological properties, such as pore-size distributions in porous materials, which are based on capillary condensation, cannot be applied for these physically bonded highly porous layers.
Thus the aim of the pressure impregnation technology development is to characterise the phenomena encountered in pressure filtration operation, and to define the parameters of pressure impregnation technology.
In order to increase the loading parameters of the bearings, the solid lubricants like WS2 and MoS2 are usually used as additions to powders under a sintering. However an effectiveness of WS2 and MoS2 is very low for this case because of its thermal degradation during sintering. In the case of high temperature friction it seems to be better to apply a compacting-sintering-impregnation-drying PM route. A pressure impregnation fixture consists of impregnation cylinder made in a bottom plate, pressing piston, and matrix with porous sleeve. A carrier liquid-solid lubricant suspension was employed to impregnate real PM porous self-lubricating bearing samples (porous sleeves) made of stainless steel AISI 316L powder. The filtering process of nano- and micro-particle suspension through the porous sleeve wall is being controlled impregnation pressure, wall porosity and, consequently, permeability of the porous sleeve with certain wall thickness.
Main pressure impregnation parameters controlled during impregnation step are followings: Pressure in the impregnation chamber; Concentration of MoS2 particles in carrier liquid; Piston movement distance; Nanoparticle suspension volume; Impregnation (filtration) time .
The filtration process is being performed at different pressures. Other parameters were kept constant.
Determination of filtration/impregnation effect was made on the sleeve samples with certain level of initial porosity. The weight of MoS2 deposited layer was determined after drying of the samples. The MoS2 layer thickness was measured with SEM FEI during fracture topography examination. Microstructure of porous sleeves was examined with optical microscope Nikon Eclipse 150L and porosity was calculated with software NIS Elements AR (Nikon Imaging Software). The micro/nano-particle suspension of MoS2 were prepared on the base of cooling liquid FC111 by mixing. The MoS2 micro/nano-particle powder mixture was made of natural MoS2 powder by rolling cleavage technology.
The three main stages of the process were quantitatively determined: pore deposition (deep bed filtration), pore clogging and cake growth. These regimes affect the deposit morphology, as the initial deposit is much porous than that which grows during cake filtration. The experimental results of pressure impregnation process examination reveal the MoS2 particle suspension behavior. The filtration experiment allows defining the pressure gradient dependences on the punch travelling distance. These data were analyzed to obtain the filtering parameters and to calculate porosity of deposited layer. The main task of filtration analysis is the determination of cake porosity. The authors Elmoe et al developed the method of determination of the cake porosity for the aerosol case. The similar relationships may be used for filtration analysis of micro/nano-particle suspension. Because a flow-rate through the porous sleeve during deposition depends on filtering time, the mass deposited can be calculated from a mass-balance as the total liquid mass-concentration is known. Based on these parameters the deposited mass may be defined. The following results were achieved as a result of this Task execution:
-The new pressure impregnation/filtering technology is developed for deposition of micro/nano-particles on the surface of sliding bearings to achieve the quasi-hydrodynamic regime of lubrication;
-The aerosol-filtering model is verified for the case of suspension filtering, and it is shown that the behaviour of the particles during deposition is similar to that of aerosol suspensions;
-The classical filtering theory equations are used for analysis for the deposition process of the porous sleeves;
-The pressure impregnation/filtering technology is applied for preparation of impregnated P/M lab-samples and modification of the real parts demonstrators: chain bushing and sliding bearing.
A porous structure of the fabricated sleeves was studied by SME. The substrate consists of large Stainless Steel particles, while the MoS2 deposited layer consists of primary agglomerated MoS2 nano-sized flakes forming a lace-like structure. From the cross-sectional cut the cake thickness was measured and the porosity calculated, as the deposited mass is known. The thickness dependence on the pressure gradient is clearly observed. Results of characterisation reveal influence of pressure gradient on the MoS2 layer thickness and density. Study of dependences of MoS2 layer mass, thickness and porosity on pressure gradient were carried out. The results reveal that change of the pressure gradient results in change of the flow-rate through the porous sleeve during deposition, and, consequently, to kinetics of layer deposition. Increase of the pressure gradient leads to additional densification of the MoS2 powder layer due to increase of flow rate.
Quantitative analysis was carried out on the basis of the impregnation process (vacuum/pressure impregnation). The aim of this study was to determine the amount of impregnated particles of solid lubricants in porous structure of certain parts. On this basis, it’s possible to specify the size and proportion of lubricant particles in the modified surface layer. An important element is adequate and continuous supply of lubricant in the working zone of specified pair of friction.
On the basis of the study it can be concluded that the mixture of MoS2 with graphite and WS2 with graphite particles allows collecting and covering in the porous structure the sufficient amount of lubricant. This is the result of change of the flow of the various particles during suspension filtration through the porous channel. The addition of the graphite particles, which is characterized by layered structures greatly facilitates the accumulation of lubricant on either of the mating surface (lubricating film formation) and favors the accumulation of lubricant in the surface reservoirs of the porous structure. It is the promising phenomenon that will facilitate the longer operational life of certain friction pair as well as reducing wear and friction coefficient.
Preliminary tests were carried out to characterise tribological properties of impregnated surface layers and to optimise process parameters.
Nitriding development. Ion nitriding is one of the newer methods of increasing the durability of tools and machine parts.
In comparison with other methods of thermo-chemical surface ion nitriding has an important advantages.
For the analyzed tools the ion nitriding was performed in a furnace JONIMP 900/500.
The nitriding takes place under an atmosphere of nitrogen - hydrogen under reduced pressure 5-10 mbar. The gas was ionized in an electric field, the stem and the input i s the cathode, and the casing (base and cap) is the anode. During the ion bombardment the cathode get hot, and the heat generated is enough to heat the workpieces to the required temperature. The nitriding process was carried out on tools at 580C during 20 hours. Measurement of the thickness of nitrided layer is determined on the metallographic specimens etched. Treated in this way bushing has be en tested on a microscope Nikon Eclipse 150L. The nitride layer with thickness of 122 to 133μm was obtained. Hardness analysis of the P/M samples was conducted as a function of distance from the surface. Results of preliminary study of friction and wear parameters of the sleeves were obtained and analysed to optimize the technological parameters.
After optimal selection of process parameters the technology prototype was developed to manufacture J-VST components.
3) Choice of HTSL powders and coating type to be used under specified operating conditions
Relevant Sectors: Thermal Spraying
Description of the main S&T Results:
Selection of HTSL powder was based on market, cost and properties analysis. It was found that WS2 powder from some selected suppliers is the most suitable for high temperature applications. Selection of coatings type for PMR applications was realised based on analysis of PMR friction units. Analysis of TS powders was based on technical data of leading manufacturers of these powder materials and developers of related TS technologies. Analysis shows that the most suitable for PMR applications are Co-based Tribaloy-type high temperature coatings.
Purchased HTSL (h-BN, MoS2, WS2, WSe2, CaF2, BaF2, and mixture of MoS2+graphite, WS2+graphite) were characterised by modern high-resolution instrumentation (FESEM/EDS/EBSD, X-ray). Real particle parameters (shape, size, purity) were defined. It was found that composed of nano- particles and micro- particles and in some cases the particle size distributions are in some cases different from specification of suppliers. It was found that for WS2 powder two groups of particles are observed: smooth plates and porous fibrous granules. WSe2 powder consists of large granules (micron range) and rough plates (sub-micron range). The table was created to summarize the results of commercial HTSL study (powders that are the most suitable for application taking into account both their cost and quality): shape of particles and their size, purity, specific features of each powder. Powders from different manufacturers have practically similar parameters. The cost of powder from some manufacturers is much less (~6 times) that makes application of powders from these manufacturers very attractive. These companies specialize on production of materials for tribological applications that ensure high quality of related products. Parameters of WSe2 powder differ from specification of manufacturer (large size of particles). This material is much more expensive (in ~6,8 times) in comparison with WS2.
Two types of sliding tests were performed to characterise tribological properties of ordered powders: i) ball-on-disc tests at ambient temperature and ii) ball-on-disc tests at high temperature (up to 700C). Officially manufacturer declares that WS2 can be applied up to 650C. WSe2 is less resistant for high temperature: oxidation starts at 350C. Preliminary tribological tests show that the most promising solid lubricants for SME applications are: i) MoS2, MoS2+Graphite (up to 300C; ii) WS2, WS2+Graphite (up to 650-700C) due to demonstration of low friction coefficient (0.1-0.4). The process of high temperature behaviour of the most promising candidates was studied taking into account that HTSL will be encapsulated into micro-reservoirs that could slow or prevent oxidation process. During the further development stages, the thermal resistance analyses of selected powders were carried out to define their resistance to oxidation and detailed tribological study were performed under conditions imitated real operating conditions.
To increase the nanoparticle content in some commercial MoS2 and WS2 powders a special cleavage milling procedure was developed by INOP.
There are wide ranges of powder materials intended for deposition of coatings for high temperature applications by PS and HVOF. Each material (powder) is intended for specific exploitation conditions. The analysis of nomenclature of high temperature coatings deposited by PS and HVOF, their key properties and application areas were carried out for more than 50 types of TS coatings. The analysis is based on specification of powder of leading TS powder manufactures and leading TS companies. The main parameters of coating that determine their exploitation properties (abrasion, heat, impact, wear and corrosion resistance) are: chemical composition and porosity. According to the state-of-the-art: Cobalt base coatings have maximum abrasion resistance at high temperatures and moderate impact resistance; A superior abrasive wear performance was exhibited by the Co based coatings, which did not show a change on the wear rate after temperature exposure, and confirmed the stability of the microstructure after exposure at 600C in an air furnace. Properties and application areas of Cobalt-based Tribaloy-type coatings are the most suitable for PMR applications were considered in details. Coatings exhibit coefficient of friction near 0.6-0.7. This is the main drawback of the coating that was improved though the modification of the coating with HTSL in the frame of HIGRAPH Project.
All available data allows determining the requirements for coatings for PMR application: surface layer structure, composition, microstructure features, and critical material properties, manufacturing routes. Real Co based powders to be applied for HVOF coating deposition and supplier were defined. The first economic assessment of industrialization of new technology for coating modification with HTSL shows that total expected increase of the cost of average part with modified coating would be less than 2-10%.
4) Optimal selection of technological parameters of coating surface modification
Relevant Sectors: Thermal Spraying, Laser Micromachining
Description of the main S&T Results:
Laser micro-machining method was developed for modification of sprayed HVOF coating surface in order to create micro-sized reservoirs to be filled with HTSL without changes in mechanical integrity of the base coating and taking into account economic feasibility of modified coated parts fabrication.
Thermal Spraying (TS) is an effective and low cost method to apply thick coatings to change surface properties of the component. HVOF spraying are the most potential methods for producing a good adherent coating with low porosity. Through high kinetic energy of particles (particle velocity can reach 900 m/s in HVOF process) and heating in the jet particles are ductile and, as a result, after impact on the target they form lamellar structure. According to study of the particle substrate interaction using the digital CCD camera the following typical parameters for particle interaction with the substrate were defined: the time of lamella formation and particle solidification time; the time between 2 impacts. Particles therefore arrive one after the other on particles already solidified; therefore the coating has a lamellar structure and the final coating contains about 4-40 layers (depending on the initial particle size) and the typical coating thickness is a few hundreds microns.
Normally, powder manufacturers and leading spraying companies propose recommendation of optimal parameters for spraying of various commercial powder materials. Nevertheless, these parameters should be strictly control in real time to ensure process stability and coating quality and the developed diagnostic system allows to solve this problem.
In spite of good exploitation properties the majority of wear resistant coatings have relatively high friction coefficient. There are two ways for modification of surface layers of commercial TS coatings with HTSL to decrease friction coefficient:
(1) Use residual pores like reservoirs for HTSL particles;
(2) Fabrication by micromachining special grooves and cavities that could be used like reservoirs for HTSL.
The HVOF and PS coatings deposited under optimal conditions normally have residual porosity: <3-12% for PS coatings and <0.5-1% for HVOF coatings. Increase of the porosity leads to decrease of coating mechanical properties that is why the first way (use of residual porosity) cannot be applied for modification of commercial HVOF coatings with HTSL. During the Project execution the deposition parameters were adjusted for three types of HVOF coatings that are the most promising for solution of SME problems: two types of Co-based and WC-based. The adjusted parameters for deposition of related TS powders from leading suppliers by HVOF spraying system were defined. Digital CCD camera system was applied for spraying parameters optimisation. The optimal HVOF spraying parameters were defined for Co-based coatings: Oxygen flow rate; Fuel flow rate; Carrier gas flow rate (Ar); Powder flow rate; spraying distance. The adjusted spraying parameters allow to reach low porosity (<1%) and high Macrohardness (55-57 HRC for Co-based coatings) that ensure high mechanical and exploitation coating properties.
The technology of solid lubrication has advanced rapidly in the past four decades, responding primarily to the needs of the automobile and aerospace industry. One of the effective ways of application of solid lubricants is surface micromachining for creation of micro-reservoirs for solid lubricant particles. According to the state-of-the-art laser surface texturing is effectively applied for increase life-time and decrease of friction coefficient for such friction parts like SiC sliding cylinders, bearing rings, DLC thin films on friction pairs, piston rings, tools, etc.. In spite of the fact that surface micro-texturing methods are developed for some specific applications, each new application requires full development stages including: choice of laser source; optimisation of laser treatment parameters (pulse duration, energy, etc.); structure of network of micro-reservoirs, tribological tests, etc.. Laser micro-machining of TS coating to improve wear resistance was not developed yet. This method was developed in the frame of HIGRAPH Project.
In the frame of the Project laser ultra shot pulses micromachining method was chosen like a basic one for fabrication of micro-reservoirs to be filled with HTSL. The micromachining of bulk material (thick TS coating could be considered like a bulk material for ultrashot laser action) was historically a difficult task using nanosecond (or longer) pulse lasers due to issues to do with melting effects around the machined site, recast material and general edge quality of the microstructure. The fine control that was required for precision microstructures could not be obtained with such lasers. Recently, pico- and femtosecond lasers have overcome these problems and high quality micromachining is now possible in a range of bulk metals. So-called “cold ablation” is the main mechanism of material removal in this case. This mechanism allows avoiding: micro-cracking; material re-melting; formation of recast layer and heat affected zone. It is very important to keep initial integrity and strength of TS coatings. Recent achievements in laser micro-machining open new ways for tool surface structuring at relatively low treatment cost.
Development of micro-machining method for modification of TS coating surface in order to create micro-sized reservoirs to be filled with HTSL without changes in mechanical integrity of the base coating was realised through the following steps:
-Existing laser cutting, drilling and engraving technologies was studied and their behaviour physical features understood so the knowledge gained was used for the development of the technology. Efforts were directed at pico- femtosecond laser, as it has been identified as the most suitable method for this application. Economic aspects was taken into account: the cost of 1 minute of laser system operation, presence on the modern market of companies offering laser micromachining service;
-Experimental study of process of formation of microchannels and their geometry after laser treatment in material ablation mode. Optimisation of microchannel network structure;
-Fabrication of coated samples and SME components with micro-reservoirs filled with solid lubricant.
The study of laser micromachining was realised on disk sample that were fabricated from heat resisting steel X12CrNi23-13. The disks were coated with HVOF Co-based coating. The choice of the ultrafast laser system was justified by its availability on the market and offering of micromachining service by companies. The parameters of laser treatment were chosen. The width and depth of micro-reservoirs (concentric micro-channels) and distance between them were defined.
In the case of macro products (rolls, support guides, etc.), the parameters of reservoirs for HTSL are different (larger width, depth, distance between micro reservoirs) from other applications (cutting and forging tools) discussed in recent publications. That is why micromachining laser system with higher pulse frequency and longer pulse was chosen to ensure high productivity of micro-reservoirs fabrication.
The structure of HVOF coatings and fabricated micro-grooves were characterised by SEM. Study of micro-channel structure by SEM and optical microscopy was carried out study of process of formation of microchannels and their geometry after laser treatment in material ablation mode and optimisation of microchannel network structure. Application of short pulse laser allows to reach rectangular-like structure of micro-grooves with ration ~1:4 and absence of splashes of liquid material near the grove border due to realisation of ablation regime of laser treatment. The optimal parameters of laser system were defined: wavelength; Average power; Energy density; Pulse duration range; Pulse frequency range; Material removal rate; Focal spot size. The operational cost of chosen system is near 0,2-0,3 € per minutes.
Alternative methods (micro-EDM63, mechanical micromachining) of micro-machining will be also considered taking into account economic aspects.
Based on results of optimisation of TS and laser micromachining parameters, the lab-samples (disks for CSM high temperature tester) were fabricated for further tribological tests. The disk dimensions was: diameter 54 mm; thickness 12 mm. Co-based coating was deposited by HVOF on the disk surfaces under optimal deposition parameters. The coating surface was grinded to reach surface roughness Ra<4 microns. Special micro reservoirs (concentric micro grooves) were fabricated by micromachining to encapsulate HTSL powder. HTSL powders were rubbed into these grooves. The total number of fabricated disks allowed to realise 125 tribological tests
5) Coated parts and P/M sliding and other components
Relevant Sectors: Thermal Spraying, Laser Micromachining
Description of the main S&T Results:
Fabrication of engineered surfaces by novel coating modification technologies and P/M parts using end user’s facilities.
In the frame of execution of the Project analysis of PMR and Gazela industrial problem, classification of related friction parts and development of combined Thermal Spraying/Laser Micromachining technology were carried out. Two main friction units are considered: (1) Ball on guide rail; (2) Mesh-belt-roller. The configuration and dimension of rollers could be different for various types of conveyer furnaces and other similar applications. Calculation of contact stress was done with the help of on-line engineering software. Hertzian stress and subsurface stresses are calculated for point and line contact. The real friction parts have cylindrical and flat friction surfaces and the developed technology of TS coating modification with HTSL was adapted for these two types of prototype surfaces taking into account calculated dimension of contact areas. This data allows to define real geometry of micro-channels to be fabricated on the flat surface of rail and on the cylindrical surface of rollers. According to preliminary tribological evaluation of coating with micro-channels filled with HTSL, it was found that the optimum ratio of the microchannel surface to the total surface within the contact area is near 15-20%. Based on this result the configuration of micro-channels was chosen for fabrication of prototypes. The chosen number of micro-channels per millimeter is four. The width and depth of individual microchannel were defined. The ratio of micro-channel surface to total surface of contact area was also defined. Application of modern laser system allows easy adjustment of the microchannel depth using the typical width to depth ratio 1:5 and even 1:10. It allows to reach optimal treatment cost and to apply this method for modification of other types of friction units where requirements for geometrical accuracy are strict. HVOF spraying parameters were adjusted and optimized and these parameters were used for deposition of coating of flat and cylindrical surfaces of prototypes. The optimal HVOF coating deposition parameters using GTV HVOF K2 system were applied for prototype fabrication. In parallel with coating deposition, process diagnostics was also applied to ensure stable spraying parameters and the final coating quality.
The parameters of laser micro-fabrication of micro-channels were adapted for flat and cylindrical surface taking into account optimized structure of microchannel network. Additional study of the modern market of laser micromachining service shows that new generation of laser systems appears on the market. This system is based on so-called fiber lasers that are characterised by short pulses in nanosecond range with rectangular shape and high pulse energy allowing also to realise high quality machining. These systems are much less expensive in sale and exploitation. Some prototypes were fabricated using this type of system. The optimal laser treatment parameters of deposited TS coatings were also defined for this system: wavelength; pulse duration; pulse frequency; Focal spot size. The scanning unit was used in both laser system providing high scanning speed (up to 8 m/s) and high treatment positioning (~2 microns).
Friction parts prototypes were fabricated in the form of disks that were coated by HVOF Co-based coatings (both cylindrical and flat surfaces), laser engraved and filled with various types of HTSL (WS2, WSe2). The technologies were adjusted for the considered types of parts and their geometry. The full range of tribological testing was performed using disks with concentric micro-channels fabricated on flat surface of the disk in accordance with the requirements of high temperature CSM tester. The width of the area of microchannels filled with HTSL is is 5 times more than the contact area in real parts (ball-on-rail). The width of treated area on cylindrical surface was defined to be suitable for tests. For real rollers (Mesh-belt-roller units) a few areas (depending on the roller length) with this dimension were fabricated.
Pilot tests of surface modification technologies in the industrial environment were carried out and fabrication of real end-users friction parts were realised using developed technologies. Gazela like a coating company has wide range of parts operating both at high temperature and at normal temperature conditions and the developed technology for modification of friction part surface with HVOF coating and HTSL could be effectively applied to a variety of products. Among them are: tension and guide rolls for steel industry; vanes and driving shaft for Aeronautics; valves for petrochemistry and others. To demonstrate the maximum impact it was decided to reduce the set of possible products and to focus the technology optimisation efforts and testing on two types of PMR and Gazela friction parts: rail guide and rollers.
The complete technological chain was developed for deposition of HFOV high temperature coatings, coating surface texturing using laser micromachining and filling of micro-grooves with HTSL. The technological route was realised under industrial environment of coating company through the following steps: HVOF coating deposition (quality was supported by process monitoring and control); surface finishing; laser micromachining and filling micro-grooves with HTSL. The main technological parameters were specified in details for HVOF coating deposition (specification of applied initial powder; HVOF process parameters: oxygen and fuel flow rate, spraying distance, etc.).
The required parameters for desired applications of deposited Co-based coating were defined (hardness, density, porosity, thickness, etc.). Generally coating roughness is suitable for further laser micro-machining, nevertheless additional coating finishing was applied according to recommendations of powder manufacturer. The main parameters of final finishing were also specified (grinding conditions, final roughness).
Modern fiber-based lasers allow to drill deep holes (15 microns width and 200 microns depth) with a low number of pulses. Due to high pulse repetition rate this system can make 1500-1800 holes per second or 3000 mm/s in line scanning. It should be note that high power fiber-based lasers are small and they could be used for design of portable laser marking machines that recently appear on the market. It open a wide way for application of the developed technology for surface modification with HTSL in various industrial sectors, because laser texturing in certain cases could be done on place especially in combination of portable spraying systems that also appearing on the market.
Preliminary friction tests that were carried out in the Project and results of other author applied laser surface texturing for modification of surface with MoS2 show that optimum holes/microgrooves surface coverage is near 5-10%. This value was used for creation of treatment algorithm both for rail and roller treatment. Optimized laser micromachining parameters were defined and applied in industrial environment.
A part of the supporting rail guide was fabricated with length 500 mm and width 90 mm. Microreservoirs were created on the surface of HVOF coating with a margin within a zone in the central part of the rail guide to ensure good solid lubrication. The rollers for small annealing furnace were chosen for tests. The roller has length 300 mm and diameter 50 mm. Three various types of microreservoirs networks were chosen for further testing and optimisation: (1) annular microgrooves that are fabricated perpendicular to the roller axis; (2) Longitudinal microgroove lines that are fabricated along the roller axis); (3) the set of microholes located that cover the roller cylindrical surface. The real friction parts and some special samples were fabricated for further testing.
Pilot tests of surface modification technologies in the industrial environment were carried out. SME real self-lubricating friction parts and special samples were fabricated for pilot testing of exploitation properties. The real cost of full range of pilot tests of exploitation properties with full replacement of friction parts is very expensive for PMR due to the necessity to stop production. That is why it was decided integrate only one rollers and a part of supporting guide into the furnaces (for wear monitoring during a few months of exploitation) and in parallel to make full range of high temperature tribological tests using samples and high temperature tribometer under conditions that fully reproduce exploitation conditions of real friction parts in temperature range 25-700C. In parallel study of thermal stability of applied High Temperature Solid Lubricants (HTSL) was carried out with the help of Simultaneous Differential Technics (SDT) in wide temperature range (up to 700C).
Heating of WS2 up to 700C causes a small weight loss (4,33%) and relatively small exothermic effect. This effect can be due to prime disulfide decomposition into tungsten and sulfur with subsequent oxidation of the latter and sulphur oxides loss. Results of the test confirm that WS2 is characterised by good thermal stability and good tribological performance are expected in the desired temperature range up to 700C. The loss of weight due to oxidation is very important for WSe2 and it reaches 28% at 470C. The results of thermal stability test show that WSe2 can be effectively applied only up to 350C.
Tribological tests were carried out on air (temperature 25-700C, pressure 22 atm, humidity 40% at room temperature) at loads that well reproduce the real operating parameters of considered friction pairs (PMR and Gazela applications). Initial HVOF Co-based TS coating is characterised by high friction coefficient (0,69-0,79) and intensive wear. At relatively low loads, some spalled particles of the coating play a role of abrasive media that causes intensive coating abrasive wear. Under higher loads occurs wear mostly caused by plastic deformation that is confirmed by microscopic images.
Application of laser engraving of surface of TS coatings and filling of micro-grooves with HTSL (WS2) allows decreasing significantly the friction coefficient. As a result, wear is very low (under the same testing conditions that were close to real operating conditions of friction parts). During the testing (especially within run-in period) HTSL powder was pressed completely into the microgrooves and its continuous release into the contact area ensure low friction coefficient and low wear intensity. The friction coefficient decreases to 0,13 (statistical mean values). The coefficient is quite stable during the test. Noticeable wear is absent. Special experiment was dome when the test track only partially (5-30%) passed through the area with microchannels. Nevertheless, due to intensive release of HTSL from microchannel and transfer it on un-treated area, the friction coefficient remains low and did not exceed 0,22. It allows covering only part of the friction surface (near 5-10%) by microchannel network and, as a result, makes the developed method more effective from economic point of view. Friction coefficient remains low while increasing the temperature to 300C. This test is characterised by a transition period in which the coefficient of friction decreases from 0,23 down to 0,09. There is practically no wear track as a result of application of WS2, only slight decrease of surface roughness within contact area is observed on profilogram of the tested area.
Tests of TS coating modified with HTSL with the help of HIGRAPH method at 700C demonstrated also very low friction coefficient. At the beginning of the test a short transition period is observed. During this period the friction coefficient dropped down to 0,095 as a result of solid lubricant transfer and distribution on the surface. The value of the friction coefficient remains very low at 700C due to encapsulation of solid lubricant powders inside of micro-channels. That prevents from oxidation of the whole HTSL volume and continuous release of WS2 into the contact surface. As it was shown WS2 is very stable for oxidation at high temperature. More over, oxidation rate is relatively low, because WS2 can build up compact WO3 covering layer by slow oxidation to inhibit further oxidation, and WO3 has also low friction factor and can prevent the glue happened between metal surfaces as well. These factors explain the fact that low friction coefficient remains practically stable during the testing time with only slow growth. Perceptible wear is also absent in this case like at the same testing conditions at 300C.
Monitoring of wear for roller and part of supporting guide (that were integrated into pilot furnaces of PMR) was also performed in parallel with wide range of tribological tests under conditions that are closed to industrial ones. After 6 months of testing only slight wear was observed both for roller and supporting guide with TS coating modified with HTSL and for all three types of applied configuration of microreservoirs networks. Normally, wear tracks are observed for PMR friction parts after 1 month from the beginning of exploitation of new parts that were replaced in the frame of periodic annual maintenance of the equipment. The friction coefficient is decreased in more than 7 times in comparison with TS coating without application of HTSL that allow to increase the wear resistance of such type of coating and enhance their application areas and potential. At least 3 times of the increase of lifetime of friction parts of PMR and Gazela is achieved.
The economic estimation of each stage of technology of TS coating modification with HTSL was done to define expected cost of the final products and technology economic efficiency. Totally, the increase of the cost will not exceed 3-10% of the cost of untreated friction parts (depending on their geometry and size).
The analysis made it possible to define two groups of parts of J-VST. The first group consists of parts intended to forging and trimming, which were coating deposited. The second group consists of sliding parts (P/M), which has undergone a modification of the surface layer (infiltration). The first group includes: stock die for forging (matrix and punch); punching tools. The second group includes: self-lubricating porous bearing; porous self-lubricating chain bushing. Prototypes were fabricated and ready for testing.
A compaction-sintering-impregnation-sizing Powder Metallurgy (PM) route was applied to obtain the porous sleeve. The samples were made of water atomized AISI 316L austenitic stainless steel powder. The powder with zinc stearate as a lubricant were mixed and compacted to obtain sleeves. They were preheated to take off the zinc stearate. Sintering was performed at defined temperature in a tubular furnace, in a vacuum. After the sintering process, the samples were slowly cooled until room temperature, under vacuum. Afterwards they were nitrided in the furnace JONIMP 900/500. A conventional d.c. glow discharge (DGW) was applied, under a gas mixture of H2+N2 between the workpiece (cathode) and the furnace walls (anode). This gaseous mixture was applied under a pressure for defined hours. The voltage and current density were adjusted to maintain the temperature at defined level. After the nitriding process, the samples were submitted to slow cooling down under vacuum inside the treatment chamber. As a result of pressure impregnation, following drying, and sizing we obtained the porous sliding bearings with MoS2 solid lubricant powder layer of thickness about 80-100μm. MoS2 layer consists of micro- and nanoparticles obtained by method described in detail in [H.Wisniewska-Weinert Powder Metallurgy and Metal Ceramics, 52/11, (2013) 24-430]. To study microstructure and microhardness the samples were cross-sectioned, mechanically polished and then they were slightly etched. The nitride layer depth was measured optically.
A real sliding bearing prototype of a hot air valve unit was chosen for experiment. The sliding bearing is supported on housing, and shaft-bearing interface is sealed by spacer and washer that allows to prevent a leakage of solid lubricant powder outside sliding area. MoS2 solid lubricant powder layer is incorporated onto internal surface of a sliding bearing. Operating temperatures of the sliding bearing assembling are in the range of 20-500C. For this reason the counterparts were made of AISI 316L stainless steel (sleeve) and EZ6NCT25 (shaft).
The sliding bearing samples with MoS2 powder layer were tested on a home made (INOP) friction tester TWT 500N which allows to define the friction and wear parameters at the conditions similar to those of real bearing unit used in valve control systems. The counterpart is the shaft made of EZ6NCT25 steel. The test bench allows to make friction tests of the friction pair shaft-sleeve in real exploitation conditions: speed up to 120rpm, max normal load 500N, test temperature up to 600C. The parameters to be registered are followings: friction moment, normal load, temperature. Friction coefficient is also calculated. The two sliding schemes were examined with TWT-500N friction tests: i) conventional sliding without sealing of sliding contact, and ii) sliding of counterparts with the sealing of the sliding contact to prevent the leakage of solid lubricant from the sliding interface. A friction diagrams of tests at 300 and 500C of sliding bearing with MoS2, WS2 and MoS2+Graphite and WS2+Graphite solid lubricants with sealing of sliding interface reveal considerable improvement of friction coefficient and wear resistance for sliding bearing with sealing of the interface because of presence of nanoparticles. Friction diagrams of tests at 300 and 500C of chain bushings with MoS2, WS2 and MoS2+Graphite and WS2+Graphite solid lubricants confirms that at temperature 300C, MoS2 has better lubricating properties than MoS2 + graphite. This is confirmed by the results of initial testing of lubricants that have been made using tester T-21 at T = 300C. This is also confirmed, for which the friction coefficient in the final phase of the test for MoS2 + graphite has reached a value close to 0.1 whereas the friction coefficient of MoS2 on the same friction distance is about 0.05. Test results show that, at 500C, WS2 has better lubricating properties than WS2 + graphite. WS2 operates over a distance of 200-250m, while the WS2 + graphite over a distance of 150-250m. In the case of WS2 lubricated sleeve friction coefficient value 0,025-0,075 has been observed for a distance equal to 0-100m, and to WS2 with the addition of graphite 0.05-0.15. The results of initial tests of additional lubricants that have been made using T-21 do not confirm that. In the initial test, the value of friction coefficient for graphite additive WS2 was smaller compared to friction coefficient for WS2. Test results also show that over a distance of 0-400m the value of friction coefficient for graphite additive WS2 is lower than friction coefficient WS2. At a distance of 400-600m this ratio was the opposite.
Pilot tests of P/M technology in the industrial environment were carried out. A constant pressure-drop is applied by a compression machine thus forcing the flow through the porous substrate and leading to the formation of a filter cake on the inside of the sleeve substrate. The axial flow-inside the pressure impregnation chamber depends on the chamber pressure. The flow calculations reveals the Reynolds number (Re) inside the sleeve confirming that the flow is laminar so no enhanced deposition rate is expected. Pressure impregnation was carried out for various times to study the effect of deposited mass on the filter cake morphology. The flow-rate through the substrate during filtration is measured while the experiment is running, and the amount of deposited material is calculated from the total suspension mass-concentration. The flow curve was obtained during constant pressure-drop filtration. Two of the three impregnation regimes are clearly distinguishable. The first, pore deposition, is not observed, as it is typically finished within seconds after the beginning of filtration and is likely obscured by any time-delays in the setup. The second regime (pore clogging), contributed to pore clogging, is characterized by a fast decreasing flow-rate. Finally, in the third regime, cake growth, occurs that is characterized by near-linear decrease in flow-rate. A size distribution of MoS2 particles in the cake was measured on the base of SEM images. The distribution is lognormal and narrow. The experimental data illustrate the wide opportunities of pressure impregnation operation from the viewpoint of control of thickness and porosity of the obtained solid lubricant powder cake. However, the density of the formed porous layer is about 75%. Thus, the deposited layer needs to be densified to increase its mechanical properties and decrease the porosity.
The set of bearings was fabricated for further testing using the developed technology that consists of nitriding, pressure impregnation and sizing operations that allow to solid lubricant particulate layer at the sliding surface.
The three types of forging matrixes Matrix 1,2 and 3 HLAVICNIK) were fabricated (nitriding and modification with HTSL) for further testing. The surface modification of forging tool was performed by nitriding and rubbing of working surfaces with solid lubricant micro/nano particles. Additionally PVD coatings made by Gazela were applied in the separate cases. Solid lubricant reservoirs such as microgrooves and cavities were made on the tool surface in the areas of minimal shear contact stresses defined by FEM analysis. A trajectory of the microgrooves was chosen on the base of shear strains calculation results. Incorporation of solid lubricant micro/nano particles into the lubricant reservoirs network on the working surface of the nitrided forging tool was performed by burnishing process with special burnishing tool installed at CNC milling machine. The surface treatment hard roller burnishing was chosen to optimize the tool surface of die at the critical region. Thus, the positive influence of the compressive residual stress and the flattening of the topography can extend lifetime of die by closing micro cracks on the surface. Several tools with the surface treatment hard roller burnishing were used in production. After a certain amount of parts die has to be polished in order to work precisely. The average tool life of untreated tools is standardized to a relative tool life of 100%. In this case, the amount of parts was extended up to 160% with hard roller burnished tools. In the end, the failure reason of the surface treated tools was a fatigue crack in the radius above the die shoulder.
For testing under actual working conditions (JVST facility) three types of forging dies were selected. The dies were modified according to the developed nitriding-solid lubrication technology. Nitriding process results in the hardness increase of modified templates. Dies after nitriding process has been modified with nanoparticles HTSL. The prepared tools have been tested in real conditions of use (real production of pieces by J-VST). The data on working hours (number of completed cycles in pieces production) were obtained. The collected data show that nitriding and surface modification with HTSL substantially increase of working hours (average number of produced pieces) of the forging tool.
The friction tests of sliding bushings in exploitation conditions were carried out using the new test bench TWT-500N which models real friction and wear exploitation parameters. The variation of lubrication regime was reached by increase of normal load that changed the Sommerfeld parameter. Obtained results present the dependence of coefficient of friction versus sliding distance for various tribological conditions:
-316L sleeve (not impregnated) – counterpart (shaft made of steel E-Z6NCT25) at ambient temperature;
-316L steel sleeve (impregnated with oil NT100) – counterpart (shaft made of steel E-Z6NCT25) at ambient temperature;
-316L steel sleeve (modified with MoS2 particles) - counterpart (shaft made of steel E-Z6NCT25) at the temperature 300oC (real sliding bearings);
-316L steel sleeve (modified with WS2 particles) - counterpart (shaft made of steel E-Z6NCT25) at the temperature 300oC (real sliding bearings);
-316L steel sleeve (modified with WS2 particles) - counterpart (shaft made of steel E-Z6NCT25) at the temperature 500oC (real sliding bearings);
The wear coefficient was measured for real sliding bearings made of 316L stainless steel: without impregnation of the porous tube; impregnated with MoS2 particles (at temperature 300C); impregnated with WS2 (at temperature 500C).
The Striebeck analysis of exploitation results demonstrates that lubrication behavior with application of solid lubricant is similar to that of oil lubricated sliding contact. The stages of boundary, hydrodynamic and mixed lubrication are clearly seen. Thus, the quasi-lubrication regime of high temperature sliding contact is achieved. Moreover, sealed sliding interface exhibits better load bearing capacity than that of open sliding contact. It is defined that oil lubrication regime is less stable than that of solid lubrication. It reveals that the solid lubricant film has superior strength than that of oil lubricant that results in increase of wear resistance of the sealed high temperature sliding couple.
The surface modification of the high temperature porous sliding bearings with solid lubricant nanoparticles allows to considerably diminish its’ friction coefficient and wear rate. The surface modification technology of sintered bearings was developed and optimized. It consisted of nitriding, pressure impregnation and sizing operations that allowed obtaining solid lubricant particulate layer at the sliding surface. It is found the solid lubricant micro/nano particle layer provides the quasi-hydrodynamic lubrication regime at the sliding contact at high temperature.
The surface modification of forging tool was performed by rubbing of working surfaces with solid lubricant micro/nano particles. Solid lubricant reservoirs such as microgrooves and cavities were made on the tool surface in the areas of low contact stresses. Incorporation of solid lubricant micro/nano particles into the lubricant reservoirs working surface of the forging tool was performed by rubbing process with special rubbing device.
For testing under actual working conditions three types of forging dies were selected. The dies were modified according to the developed technology combined with nitriding. Nitriding process affects the hardness increase of modified templates. Dies after nitriding process has been modified with nanoparticles HTSL. Thus prepared tools have been tested in real conditions of use (real production of pieces by J-VST). The data on working hours (number of completed cycles in pieces production) were obtained. The collected data show that nitriding and surface modification with HTSL increase of working hours (average number of produced pieces) of the tribological system based on criteria of change in tool geometry (diameter ~1 microns): for upper forging tool (matrix 1) from 19 770 to 67 060 pieces; for bottom forging tool (matrix 2) from 36 500 to 115 600 pieces; for matrix 3 (HLAVICNIK) from 41 030 to 155 700 and from 49 900 to 168 200 pieces.
Economic parameters assessment, Cost comparison: It is well known that in a tool unit cost decreases when the tool service life increases. Knowing the average price of the forging tools (punch and die) on the base of JVST data, it is possible to calculate the Tool Unit Cost (TUC). Since the operating principles of the equipment compared are similar, no other costs originating from the use are taken into account in the calculations. The other costs can result from pressurized air, maintenance, service and electricity. The 6 types of the tool were chosen for calculation: (1) Bending Tool of lock component; (2) Matrix of heading (Hlavickar); (3) Heading matrix of the screw; (4) Bottom forging tool for steel insert; (5) Upper forging tool for steel insert; (6) Extrusion die for steel insert. Estimated average cost of P/M modification of the tool surface per 1 cm2 is ~0.05 that will allow to get profit on sales or J-VST. The use of this technology should significantly affect the economic benefits to companies that will implement it. The effects of implementation of the MoS2/WS2 will are followings: i) increase of tool lifetime, ii) resources save and iii) reduction of costs associated with the replacement of worn parts and repairs. Economic benefits will result from the reduction of operating costs compared to conventional methods of machine parts manufacturing. It is estimated that the cost of operation will be reduced from 25 to 50%. Despite the higher price of the product, the economic balance will be better of 25% to the end user. This is due to the 2 - 3 times longer working time of the forging tool modified with technology developed and elaborated in the Project. This can reduce maintenance costs and downtimes.
The Quality assessment of the test results were carried out. For quality control of new technology for coating deposition Ateknea in cooperation with IfU and Gazela developed the process control system for the automation of the manufacturing equipment used by Gazela.
Inspection certificates. Sliding bearings and forging tool manufacturing process require constant monitoring geometric characteristics of manufactured products. The permanent control and monitoring of the geometric characteristics of manufactured products was performed by the instruments of Gauge and Standards Room. The Gauge and Standards Room has done quality assessment work, and certificates of compliance checks dimensions of fits (tolerance) were issued for each tested part. The following technical documentation was obtained: functionality designed and manufactured product; mounting interchangeability (technology) and operating; durability and reliability of the product; safety (protection of health and life of humans, the environment and others).
Research of the Rockwell hardness was carried out by INOP accredited testing laboratory. The management system in the laboratory is improving continuously under the supervision of the Polish Centre for Testing and Certification, and since 2002 - Polish Centre for Accreditation. In 2006 the system was implemented in accordance with PN-EN ISO / IEC 17025: 2005 - General requirements for the competence of testing and calibration laboratories.
Market overview. Porter's model was applied like a tool for analyzing the competitive conditions prevailing in the market and allows us to estimate the degree of influence that each of the five forces have on SME and, accordingly, how one or another branch of interest to the company: (1) New competitors (new players in the market); (2) The existing competitors in the industry; (3) Companies that offer substitute products; (4) The impact of suppliers; (5) The impact of customers.
The following market segments were analysed: Thermal Spraying (TS) - coating companies and coating end-users); Powder Metallurgy (P/M); Forging Industry (FI). For each market sectors potential suppliers and end-users were analysed.
The potential environmental impact was estimated. The developed technologies (technology of modification of TS coatings with HTSL using laser micromachining and nitriding/pressure impregnation/filtering P/M technology) are green technologies. In machining industry solid lubricants could in some application replace cooling liquids and decrease its’ influence on environment. The application of solid lubricant allows decreasing oil lubricants and grease consumption. The project greatly contributes to environment-friendly production and maintenance. In the Project, practically green production processes for materials are used. The increase of friction parts life-time allows decrease of raw material and energy consumption.
During the tests of exploitation properties under SME real industrial conditions (PMR-furnace exploitation, Gazela – coating deposition, J-VST – production of pieces by forging) the improved tribological properties of friction part and tools were demonstrated: the friction coefficient decreased in more than 7 times (from 0.74 to 0.095 in temperature range 25-700C) and the lifetime of PMR and Gazela parts increased at least in 3 times; forging tools in real production demonstrated the increase of lifetime in 3-4 times. The slight increase in unit price (<2-10%) will be completely offset by the enhanced service lifetimes for a 40 to 60 % cost savings within 2 to 3 years. The results were analysed by SMEs and marketing and sale departments of SME partners confirmed the efficiency of the developed technologies.
Final Plan for the Use and Dissemination of Knowledge (PUDK) was developed and Joint Ownership and Exploitation Agreement was elaborated and signed.
Wide dissemination activity (publications; presentations on conferences, workshops and trade fairs, Video presentation of the Project results, and others) were realised.
6) On-line process control system for coating deposition technologies
Relevant Sectors: Thermal Spraying, Coating Technologies
Description of the main S&T Results:
The prototype of process control system was developed for process diagnostics and control in coating technologies. The system consists of sensor (background of IfU), digital interface and process control software allowing to control in real time the coating deposition process. The process control system was developed and integrated with Gazela equipment for coating deposition. The process control system allows to ensure coating quality (ensure stability of coating properties and to decrease the number of rejected parts) and to decrease the production cost. It could be also applied for the development of new coating processes.
Instability of spraying process parameters and/or initial powder quality influence strongly on particle-in-flight parameters: velocity and temperature. Variation of these parameters leads to deviation of coating properties from the desired values. The following benefits due to application of diagnostic system in TS are expected:
-Quality: typically spraying SME has 8-10% rejection of a final product. With the normal price of a single substrate of 1000€ and 300€ cost of the sprayed powder, the total savings can be estimated as 20 000€ for a 150 set of samples (normal monthly production for SME);
-Maintenance: At present, the regular Plasma Spraying workstation is out for maintenance for 50 hours in 250 hours, i.e. 25% of the total time. With the systematic control of operation parameters, the reduction of 50% for maintenance time may be expected;
-Energy, water and gas consumption: the energy consumption for Plasma Spraying device is ~10-100 kW/h, cooling water debit is 400-600 l/h and debit of plasma gases (Ar, H2, N2) is measured by hundreds m. cub. per hour. This consumable contribute in production cost between 350 and 600€/h. Consequently, 10% economy in this item will bring ~40 k€ of savings;
-Wastes treatment: on average 2% of the turnover of a thermal spraying company is devoted to scrap recovery. On-line diagnostic and control system can diminish these costs.
The universal process control system includes two parts: alarm control in thermal spraying (TS) and process control system in High-power Impulse Magnetron Sputtering (HIPIMS).
The system for TS is based on the optical particle-in-flight sensor previously developed by IfU (IfU background). The main steps that were realised to develop alarm process control system are the following: study of TS process for deposition of powders chosen for PMR and Gazela applications and some others that will be important for dissemination; Definition of optimal parameters for deposition of the coating with desired properties/quality; Analysis of particle-in-flight parameters corresponding to optimal deposition conditions; Development of software for data averaging and presentation of mean values in real time and alarm signal generation for operator in the case if desired particle-in-flight parameters come out the optimal level. The system was integrated with industrial spraying equipment. System allows measurements of particle-in-flight temperature in the range 1000 – 2800C and velocity in the range 30 – 900 m/s. Statistical analysis of particles histograms was carried out to define optimal values of mean particle temperature and velocity. The alarm signal generated when mean temperature (or mean velocity) go beyond the optimal values (red borders). After that operator should stop the process to define the reason of mean value important deviation.
Another part of the system is intended to control HIPIMS that is also very important for Gazela like a coating company. The machine features four magnetrons, two of which (Silicon, Zr/Nb/Si) can be power controlled. Currently 3 types of gas (N2, Argon and O2) are used in the process. The control software running on a PC was also developed for this application. Power supplies and VAT valves are connected to the PC via serial interface. In order to extend the number of the available serial ports up to 8, National Instrument’s PCI-232/8 serial interface card was applied. The data acquisition field instrument is a National Instrument SCXI 1000 chassis with 4 modules. National Instruments SCXI is a signal conditioning and switching platform for measurement and automation systems. SCXI data acquisition (DAQ) hardware provides a single, integrated platform for all of your signal conditioning and switching needs. An SCXI system consists of multichannel signal conditioning modules installed in one or more rugged chassis. The system equipped with 32 channels analogue and digital input/outputs models. The software provides the basic SCADA features for the machine, including: Manual control of components / Automated process control based on recipe files; Recipe file handling; Trending and monitoring the process; Alarm and error handling; User Access Control; Maintenance and service menu. These features are accessible through dedicated screens. The main features of the control software are working and thus the system can be used, however there are some parts that were corrected and also some new features that were added. The prototype of the system was improved by adding some extra features: adding extra power supplies; adding vacuum sensors; new spectroscopic sensors AOS (IfU background) for monitoring of plasma intensity and control process via O2 and N2 mass flow controllers; new HW components (heaters); chamber temperature and cooling management; valves and mass flow controllers for monitoring the use of krypton. The Control Software has been upgraded to more up-to-date version. Gazela updated its’ coating system with new components. The prototype of process control system was integrated with Gazela equipment and successfully tested.
Potential Impact:
Potential economic impact resulting from results exploitation.
The Project helps to solve one the most complicated tribological problems related to fast wear under conditions of dry friction and high temperatures. The main goal of the Project is the industrial implementation of self-lubricating materials with improved tribological properties. Developed technologies (TS coating and forging tool modification with HTSL; P/M manufacturing of self-lubricating sliding parts) will be first applied in the business areas of the project SMEs then diffused in further industries. Prior to starting the project the partners have investigated the aspects of commercializing the Higraph technologies taking into account the individual business interest of each company. The business plan was developed like a part of Plan for the Use and Dissemination of knowledge (PUDK). The results will have direct impact on the following market sectors:
-Thermal spraying (TS): In spite of the fact that the developed technology could be effectively applied for various types of Thermal Spray coatings (HVOF, APS, VPS and others) that are intended for application both at normal and elevate temperatures, Gazela will better focus exploitation activity on Co-based and WC coatings modified with solid lubricants for various industrial sectors: furnaces, steel industry, aeronautics, petrochemistry and metal forming. Some parts to be considered are: tension rolls; furnace rolls; skin pass rolls; leveler rolls; valves; pump parts; driving shaft. These parts have similar cylindrical or spherical geometry and the developed technological approach could be transferred for all these friction parts treatment. Gazela estimates that for them the largest markets for Higraph T/S coated parts will be represented by the steel industry (64.8%), followed by industrial furnace users and manufacturers (cc.21.3%), aeronautic industry (9.3%), petrochemistry (5,3%) and metal forming (0.3%). PMR will benefit directly from exploitation of novel furnace friction part (decrease economic losses for part replacement from 4-5% to 2-2,5% of annual turnover), licensing of the developed technology and opening of new market niche in parallel with the main company activity. PMR also expects additional benefits from reducing the volume of faulty products and also cut the energy consumption in the manufacturing process. By these the company assumes an annual saving of approximately 5-8% of annual turnover;
-Powder Metallurgy (P/M): The largest end-user segment for P/M is automotive representing over 70% of the market. Approximately 75% of the automotive components are used in transmissions (eg. bushing, thrust washer etc.) and engines (eg. turbocharger thrust bearing, valve guide, valve seats, bearings, bearing caps etc.), most of which are impacted by high-temperature. J-VST through realisation of new technology will deeply penetrate its’ activity in this segment;
-Forging industry (FI): Forged parts are mostly demanded in the automotive industry (58%), mechanical engineering and metal wear. In case of forging tools wear and heat resistance on the surface is critical as tool life and quality of production can greatly influence the profitability of production. Thus material improvement has a high priority on the industry’s technology innovation agenda. Improved performance of forging tools can contribute to increase return on investments for J-VST that are producing forged parts. J-VST estimation indicates that the highest production volume will be associated with Heading matrix of the screw (43%) followed by Bending Tool of lock component (21%) and upper forging tool for steel insert (21%).
In case of TS coating technology estimated 2-10% increase in costs expected compared to state of the art coated parts by using WS2 at a costs of 87€/kg. Estimated average cost of P/M modification of the tool surface per 1 cm2 is near 0.05€. The forecast of total profit for companies directly involved in the Project resulting from the cost saving, licensing and profit on sales will reach ~1 850 000€ after the results commercialisation.
Longer lifetime will result in lower amortization costs in industry-wide. Self-lubricating parts will have 2-3 times longer lifetime, with only 2-10% increase in unit prices. The direct cost of replacement of friction parts in production lines in industries that use furnaces is around 70-90k€ per year for a normal-sized SMEs according to information of partners of PMR. In the direct network of the Consortium there are a few thousands companies with similar activity that face the very same problems. Tribological components resulting from the HIGRAPH project could cut these costs by 50% resulting in a total saving of 55-70M€ per year just for these companies. the HIGRAPH technology can pave the way for the use of similar coatings in other industrial areas outside the businesses’ scope of the consortium partners, through licensing and dissemination activities. The estimated total market growth of SMEs involved in P/M, TS and machine building indystries could reach 120 million EUR.
It is estimated that wear causes losses to industries in the order of magnitude of 1% of a nation’s GDP20. For the EU this can mean an annual loss of 12 billion EUR (0.01×12 300 billion EUR). Even a marginal improvement in this figure would amount to several hundreds of millions EUR annually. For example, new components could be effectively applied in aircraft industry for production of sliding components operating under high temperatures. If sliding aircraft bearings reliability can be multiplied by a factor 2 or 3, reduction of maintenance costs for aircraft systems is estimated to 10-15%. It will result in ~3M€ saving gained just for one single components.
The Project objectives require a European approach because commercialization efforts in Europe in the area are of high temperature self-lubricating materials are relatively weak. The patent search and the market watch have shown that the main activities in this field are concentrated in USA, China and Japan. In the global marketplace, commercialization efforts in the United States are most advanced: about 63 % of all companies manufacturing solid lubricant materials/components, whereas 25 % are in European countries. This indicates a relative weakness of the commercialization efforts in the EU in this sector with currently the highest market potential. Cooperation in the frame of the Project will open new markets for SME partners and will improve their competitiveness on International market.
European Technology Platforms (ETP) define emergency technological needs and roadmaps for considered industrial sectors. RTD partners of the Project participate in the following ETP: EuMaT “Advanced Engineering Materials and Technologies”; MANUFUTURE “Future Manufacturing Technologies”; MINAM “Micro- Nanomanufacturing” and NANOFUTURE “European initiative for sustainable development by Nanotechnologies”. Tribological problems and antifriction materials are among the most important ones defined by these platforms. The Project results will be disseminated through these ETP that ensure their wide future exploitation.
Contributions to standards.
HIGRAPH contributions to standards will not be immediate. However, through some of the results, HIGRAPH may influence some future standards like slef-lubricating component for high temperature applications.
Contribution to EU policy objectives.
Independence of the European industry.
The project will ensure the availability of a critical technology on European market. It will guarantee a competitive European supply chain having better quality standards in design and development than Japan or US suppliers. The transfer process from research to industrials is generally seen as a very slow process. The project will exploit directly high level and recent research in several domains: tribology, P/M, coatings and processes. The project will be a clear demonstration that the transfer process can be improved if both industrials and researchers share common interests for high quality and innovative technologies.
Transnational approach.
Tribology problems are common for all European companies. That is why manufacturers of high temperature bearings should cooperate with leading RTD partners with important background in high temperature tribology, coating and P/M technologies.
Acceleration of integration of partners from Poland, the Czech Republic, Slovenia and Hungary in the European Research Area is very important. Cooperation in the frame of the Project will open new markets for SMEs partners.
Project training program to be realized by IfU (Germany), INOP (Poland) and ATEKNEA (Hungary) through hosting of engineers from SMEs partners for “training in tribology”. It will help successful dissemination of the novel technologies in all European countries.
Environmental impact.
The project will greatly contribute to environment-friendly production and maintenance. In the Project, a green production process are applied.
Decreased use of liquid lubricants and greases. The world demand of lubricant oils in 2010 was ~40 million tons. Western Europe and the CEE region accounted for 25% of the world consumption. Industrial demand represents 32% of the total demand for lubricants, which amounts ~3 million tons of industrial lubricants consumed each year. The average price of industrial lubricants is 1–1.5 €/kg. HIGRAPH based technologies have the potential to reduce lubricant consumption by 80–85% resulting in a potential for saving in the range of 2.5–3.8 billion EUR per year for the industry.
Decreased energy consumption. The significantly lower coefficients of friction for HIGRAPH solid lubricants would result in 10–15% lower energy consumption for machines. An average SME in the forging industry has an annual power bill of 200 000 €, where the decreased power consumption would result in a yearly saving of 30000€. Industry-wide this creates a potential for saving 100 M€/year.
Decrease of raw material and fuel consumption.
As a result of increased in 2-3 times the life-time of friction parts, the consumption of steel will be decreased. The powder metallurgy manufacturing is certified as ecological. The waste of materials is low and material are used efficiently due to direct fabrication of parts with required shape and dimensions. Powdered materials are as usual by 5-25% lighter than parts produced by traditional machining.
Reduction of systems weight (turbo machines, valves, etc.) will decrease fuel consumption. Any change of such type will help EU countries fulfil the Kyoto summit commitments of an 8% reduction in greenhouse gases relative to 1990 levels. For example, the thermal efficiency of turbo machines can be increased when the temperature of hot gases entering the axial turbine is heightened. Increasing the operating temperature of turbo machines only by 50°C will result in the increase of thermal efficiency by 0,7–2% points and the reduction of fuel consumption by 4–13%.
Contribution to societal objectives.
Growth in this market area requires a lot of technical work resulting in the creation of new jobs at suppliers of HTSL, sliding bearings and other friction units. For the project SME partners the expected increase of employment will be 10% for 2018. The demands for documentation of technical and quality aspects are extremely high, mainly affecting the technical sales department and quality assurance. At least ten additional employees with technical background will be needed for SMEs within one year after project completion.
Education and training programs will solve the following tasks: to form education/training network integrating all the partners and the interested parties outside the Consortium; to link project S&T activity with EC education program ERASMUS; to promote new forms of education: full cycle of e-education, e-learning, interactive e-training, remote learning; introduction of a new M.Sc. specialization: “High Temperature Tribological Engineering”.
Improving safety and security will be reached though developing highly reliable friction units. Special attention will be paid on safety of all cycles of operation with HTSL powder. During the Project execution the contacts with European Safety cluster was established.
The application of solid lubricant will allow decreasing oil lubricants and grease consumption. The main reasons of liquid (oil vapours) and gaseous (COx and NOx) carcinogen generation are high temperature between friction surfaces. The application of solid lubricants will greatly reduce this problem. As a results, new standard for air pollution in heavy industry could be introduced (<35 micorg/m3 for aerosols; <20 ml/m3 for CO; <50 microg/m3 for NOx; <80 microg/m3 for hydrocarbons ). Better working conditions will lead to decreased dangerous and mortal illnesses.
Dissemination of the project and the results.
The consortium acknowledged that communicating the importance of research and development and its contribution to economic competitiveness is an essential dimension of achieving project objectives but also an opportunity to increase the visibility for European companies in coating and P/M technologies. During the runtime of the project partners performs a range of dissemination activities as set forth by Work Package 6 with the aim to facilitate the commercialization plans of SMEs and ease the way to market. It will also promote further research in this field and contribute to strengthening the European knowledge infrastructure on high temperature operating problems.
Objectives of dissemination. In light of the project relevance the main dissemination objectives were:
-Raise awareness on high temperature operation problems and provide an insight on the solutions that the Higraph technology can offer;
-Emphasise the economic and environmental aspects and the potential impacts;
-Provide appropriate information to parties in industry and academia that are potentially impacted or interested in the work performed in the Higraph projects;
-Promote the results to potential customers and third party collaborators and highlight the differences from conventional processes to improve high temperature friction and wear resistance;
-Network with synergetic projects/research initiatives;
-Provide evidence based findings such as publishable results of testing and pilot production and involve relevant stakeholders in discussion.
These objectives were achieved and were taken into consideration during the whole project period. The results were published and presented at several workshops, conferences and trade fairs.
Targeted audience. In choosing the most relevant selected dissemination platforms and means to reach out the following specific audiences were considered:
-Relevant industry segments;
-Potential end-users, third party collaborators, manufacturers, and distributors etc. in Powder metallurgy, Thermal spaying, Surface coating, Furnace manufacturers, Machine Tools, Automotive, Aerospace, and Energy sector;
-Interest groups: associations and technology platforms such as the European Powder Metallurgy Association, etc.;
-Research community: researchers, scientists, engineers and students in the domain of tribology, material science, surface and coating technologies, powder metallurgy;
-Other project initiatives implementing research and development in related fields;
-General public: all other parties interested in collaborative R&D, industry and academia partnership and novel technologies with potential wider impact on everyday life.
Dissemination channels and instruments. The list below depicts the groupings of dissemination platforms and instruments that are most suitable for delivering targeted massages for different the different audiences. However some of these are interrelated and potentially can raise attention in all stakeholder domains.
-General Public: Project website, Project Visual Identity, Digital Media, Articles on popular websites, Mass Media, Oral and printed presentations;
-Relevant industry segments: Trade Fairs, Exhibitions, Industry events, Networking events, Partnership brokerage events, Market relevant project presentation, Workshops, Business Meetings, Direct Mailing;
-Research Community: Scientific Publications, Technical papers, Scientific thematic conferences, Networking events, use of research forums.
The following dissemination actions were completed:
-Creation of the Project visual identity: Project Logo, Presentation template, Typical images used in public materials, Project flyer and posters, General Project presentation for Trade fairs, Conferences and Workshops;
-Creation of the Project website (http://higraph.eu) with confidential and public parts;
-Creation of Newsletters: Several issues were prepared during the project introducing the aims and general objectives of the project and provide a short description of the consortium members with links to their websites and logos;
-Presentation of the Project results on Conferences, Workshop and Trade Fairs: 9 Reports on International Conferences (2 presentation are planned for 2016), 4 presentations on Workshops, 3 presentations on Trade Fairs (3 planned for 2016);
-Publications of articles: 9 articles were submitted for publications.
-Organisation of International Workshop: The International Workshop “Diagnostic Systems for Plasma Processing” was organised by IfU on 29 September 2015;
-Creation of Video presentation of the Project including the following main parts: The Goal, The Applied Solutions, The Consortium, The main Project Results, The Project contact details. The video file was uploaded on YouTube and website of the Project. DVD was issued and distributed using the contacts list of RTD and SME partners.
List of Websites:
http://higraph.eu
The Coordinating organization:
IfU Private Research Institute GmbH (IfU)
Gottfried-Schenker-Str. 18
Phone: +49-37208 889 0
E-mail: higraph@ifu.de
Since traditional lubricants fail when friction is combined with high temperature, it is either impossible or impractical to use these materials in many industrial applications and numerous small and medium-sized enterprises (SMEs) seek the competitive edge new technologies that could solve existing wear problems.
The goal of the HIGRAPH project was to provide participating SMEs and the machinery industry with novel technologies for manufacturing sliding and rotating components that enhances dry-friction performance under high temperatures, increases durability, and extends the service lifetime of parts.
The Project goal was reached by: the surface modification of the porous sliding bushings, bearings and forging tools with high temperature solid lubricant (HTSL) micro- and nanoparticles and formation of the surface layers providing the quasi-hydrodynamic lubrication regime at the sliding contact at high temperature; modification of the surface layer of thermal spray (TS) coatings by encapsulation of HTSL particles in micro-reservoirs fabricated by micromachining. These approaches maintain operational integrity of friction parts at high temperatures and enables slow release of solid lubricant generating a lubricating film at the frictional interface allowing to considerably diminish friction coefficient and wear rate.
The database on wear mechanisms of parts subjected to wear at high temperatures was created at the first stage of the Project. A widespread exploration was executed first, aiming the selection of the most promising HTSL materials. Further activities were the thorough specification of the required HTSL powders, and research and analysis of the market to determine the potential suppliers of the materials of further HIGRAPH needs. The economic aspects (cost of HTSL depending on particle size and suppliers) were also carefully analysed that is very important for successful integration of the developed technology in industry. The tribological tests allowed choosing the HTSL that are the most suitable for desired applications.
To imitate the real exploitation conditions various friction tests in wide temperature range were applied (using ball-on-disk high temperature testers and special bushing-shaft test bench). Tests of samples modified with HTSL powders demonstrated an important decrease of a friction coefficient and wear rate under temperature up to 700C.
The process control system was developed and integrated with Gazela equipment for coating deposition. The process control system allows to ensure coating quality (ensure stability of coating properties and to decrease the number of rejected parts) and to decrease the production cost.
Testing of self-lubricating prototypes manufactured by compacting-sintering-repressing-HTSL impregnation powder metallurgy technology and technology of TS coating modification with HTSL enabled optimisation of tribological parameters to maximise lubrication performance of parts demonstrators: sliding/rotating components and forging tools.
SME real self-lubricating friction parts were finally fabricated using novel technologies and pilot tests of their exploitation properties were carried out in wide temperature range and they demonstrate the lifetime increases at least in 3-4 times in comparison with untreated friction parts.
HIGRAPH developed novel solid lubricant technologies for high-temperature applications. It allows increasing service lifetime and reducing the need for replacement while decreasing the energy consumed by the machines to do their jobs. The slight increase in unit price (<2-10%) will be completely offset by the enhanced service lifetimes for a 40 to 60 % cost savings within 2 to 3 years. The developed methods could be effectively applied not only for high temperature friction parts, but also for other ones applied at ambient temperature and the exploitable results are expected to reach new markets including various industrial sectors.
Project Context and Objectives:
The main goal and concept of the Projects are presented below. Since traditional lubricants fail when friction is combined with high temperature, it is either impossible or impractical to use these materials in many industrial applications. The need for improved lubricating technologies is critical when trying to solve tribological problems concerning dry friction under high temperatures. The goal of the HIGRAPH project is to provide participating SMEs and the machinery industry with novel technologies for manufacturing of sliding, rotating components and forging tools with enhanced dry-friction performance (low friction coefficient) under high temperatures (up to 700C), increased durability, and extended in 2-3 times the lifetime.
The main goal of the Project was to develop technologies: for the surface modification of the porous sliding bushings, bearings and forging tools with High Temperature Solid Lubricant (HTSL) micro- and nanoparticles and formation of the surface layers providing the quasi-hydrodynamic lubrication regime at the sliding contact at high temperature; modification of the surface layer of thermal spray (TS) coatings by encapsulation of HTSL particles in micro-reservoirs fabricated by micromachining.
The Project goals were attained through the solution of the following RTD problems (Project objectives):
-Analyses of SME’s wear problems, definition of critical components and study of their damage mechanisms. Collection of the data on critical friction parts, their operation parameters and definition of main wear mechanisms. Choice of critical components for further improvement and definition of their specification;
-Definition of requirements for high temperature coatings and selection of type of coatings to be applied. Definition of the most suitable manufacturing routes fro chosen components. The following groups of components were considered: P/M sliding bearings and bushings; forging tools; friction parts of annealing furnaces;
-Develop of methodologies to evaluate the tribological properties of high-temperature surface layers and related testing benches and testers;
-Development of database including: specification of SME’s friction parts; general information on HTSL materials and their properties; data on HTSL materials available on the market, their cost and manufacturers; data on high temperature thermal spray coatings and their properties; data on testing results of HTSL and surfaces modified with HTSL;
-Development of the model of mixed lubrication based on non-Newtonian behaviour of HTSL and knowledge-based engineering calculation package. The calculation model validation during the SME components tests and accumulation of experimental data;
-HTSL market analysis, definition of suppliers providing lower cost and high quality of HTSL for wide industrial applications, estimation of influence of powder particle size on the cost;
-Ordering and characterisation of HTSL powders from various selected suppliers;
-Tribological characterisation of ordered HTSL at ambient and high temperature to define the most suitable ones for desired SMEs application both in terms of friction coefficient, thermal stability and the cost;
-Choice of powder materials and optimisation of HVOF spraying parameters to get desired coating quality for SME friction parts;
-Development of micro-machining method for modification of sprayed coating surface in order to create micro-sized reservoirs to be filled with HTSL without changes in mechanical integrity of the base coating and taking into account economic feasibility of modified coated parts fabrication;
-Specification of the process diagnostic and control system to for SME coating technologies. Development of hardware and software, building of process control system prototype. Test of the system under laboratory conditions, Integration of the developed system with coating SME equipment and its’ test under conditions of industrial equipment;
-The development of new pressure impregnation/filtering technology for formation of surface layer containing HTSL providing the quasi-hydrodynamic regime of lubrication. Study of HTSL flow in porous network, determination of conditions of impregnation. Development of nitriding technology;
-According to specification of testing machines fabrication of: lab-samples by method of TS coating modification with HTSL; P/M prototypes by nitriding, pressure impregnation/filtering method;
- Characterization of microstructure, density, porosity of lab-samples and P/M part prototypes using, preliminary tribological tests using ball-on-disk and shaft-sleeve tests, technologies optimisation and definition of necessity of post operation;
-Choice of the most representative and marketable components of SME for application of the developed technologies;
-Development of complex technology prototypes to manufacture coated and P/M components for SME industrial sectors: (1) design of part prototypes; (2) design of tooling; (3) devise and implement component-manufacturing technologies; (4) Coating modification and nitriding/pressure impregnation/filtering technologies application; (5) elaboration post-processing technologies;
-Fabrication of component prototypes for further characterisation and testing in wide temperature range;
-Test the friction and wear of prototype components under conditions that are closed to real conditions of SMEs components operation. To imitate the real exploitation conditions the bushing-shaft test bench was specially developed by INOP and applied for testing of porous sliding bearing sleeves with HTSL in wide temperature range. The real geometry and contact conditions (contact stresses, sliding speed, temperature, etc.) are achieved by use of test benches that ensure the above parameters for end-user applications;
-Analysis of the structure of worn parts and friction test results. Optimisation of coating modification and nitriding/pressure impregnation/filtering technology for SME applications;
-Select the most promising HTSL and coatings and base materials for SMEs applications;
-Estimation of potential harmful and environmental influence of the developed technologies, establishing of contacts with European Safety cluster;
-The completion of the development of the final database on the most promising HTSL, coatings and testing results;
-Pilot tests of surface modification technologies in the industrial environment for SME components from related industrial sectors: annealing furnace; sliding bearings and bushings; forging tools;
-Pilot tests of exploitation properties of real component prototypes and assessment of: geometry, shape and dimension accuracy, surface quality, component failure and lifetime. Quality assessment of the test results;
-Optimisation of novel surface modification technologies in terms of quality, economic efficiency, and productivity;
-Identification of competitors, suppliers, customers, and substitute products within the target markets, patent search and analysis, market watch in related industrial sectors;
-Demonstration that the developed technology increases a friction part lifetime, evaluation of the cost of component production using the developed technologies and the estimation of the market potential. Estimation of economic benefits for SME partners and potential social and economic benefits for EU industry;
-Elaboration and signing of an Exploitation Agreement;
-Realisation of measures for training of SME partners on the use of the Project results;
-Elaboration of Plan for the Use and Dissemination of knowledge (PUDK) and measures for IPR protection;
-Realization of specific measures for results exploitation and dissemination: newsletters; flyer; creation and continuous update of the Project website; publications, presentation on conferences, workshops, trade fairs and exhibitions; organisation of Workshop on coating technologies; creation of the Project video presentation and DVD.
Project Results:
The HIGRAPH Projects generated the following exploitable results (foreground):
1) Database for friction part wear mechanisms under high temperature
Relevant Sectors: Thermal spraying, Powder Metallurgy, Tribology, Mechanical Engineering
Description of the main S&T Results:
The database on high temperature wear mechanism, TS coatings and HTSL materials is designed to help determine the correlation between material properties, surface layers, manufacturing technology and tribological conditions of friction parts operating at high temperatures. Based on the project partners’ feedbacks the database were developed and integrated with the Project website. Representative friction parts of SMEs with description if their wear problems and wear mechanisms, the most promising HTSL, coating and P/M matrix materials selected for SMEs applications and test results were included in the database. The Consortium processed and imported into the web application provided content of the database. Project partners can update the database continuously and further content (such as new products, testing results etc.) can be easily added.
Based on discussion with the SME and RTD partners on the demands and requirements the structure and elements of HIGRAPH database were defined. The database is divided into the following main subunits, as follows:
-High temperature solid lubricant (HTSL) materials and their properties;
-High temperature HTSL powders, their manufacturers, suppliers and cost evaluation;
-High temperature TS coatings and related powder materials and their manufacturers;
-High temperature industrial problems of SMEs (PMR, Gazela and J-VST);
-Results of tests of HTSL materials and SMEs components prototypes.
-Supportive, general database tables.
The database was designed in such a way so that it could help to determine the correlation between material properties, surface layers, manufacturing technology and tribological conditions of friction pairs operating at high temperatures. As a result, it could provide an ultimate tool for designers of machine parts by providing recommendation. The base of recommendations is to propose the selection of materials, the properties of the surface layers, manufacturing technologies of the selected operating conditions. Sub-modules of the database were implemented and tested. A web application was developed to provide frontend for the database and it is the part of the project website. The database was designed as MySQL database and utilizing a PHP web application frontend. Feedbacks from partners were collected and related modifications were implemented. Populating the database with data collected during the project was realised. Preparing technical and economic assessment of new technologies was carried out. Experimentally analysed friction and wear, and the structure/topography of worn out parts were carried out for PMR, JVST and Gazela applications.
One of the main tasks of the Project is to select and order those HTSL materials, which have the highest potential to be applied at the applications outlined in HIGRAPH project. Regarding this goal, a widespread exploration was executed first (including literature and market research), aiming the selection of the most promising HTSL materials. Further activities were the thorough specification and technical analysis of the required HTSL powders, and the research and analysis of the market to determine the potential suppliers of the materials of further HIGRAPH researches and choosing the material to be ordered. The economic aspects (cost of HTSL depending on particle size and suppliers) were also carefully analysed that is very important for successful integration of the technology to be developed in industry. It was shown that the difference in cost for various suppliers could reach 10-100 times for powders with parameters that are very closed. Considering the possible differences (morphology, particle size distribution etc.) between the powders of different suppliers, similar powders were ordered from different sources – when it was justifiable. Wide range of HTSL powders (h-BN, MoS2, WS2, WSe2, CaF2, BaF2 and Graphite) were ordered from various selected suppliers taking into account economic aspects and quality.
Selection of coatings type for PMR applications was realised by IfU based on analysis of PMR friction units (ball-on-rail support and mesh-belt-on-roller). Analysis of TS powders was based on technical data of leading manufacturers of these powder materials and developers of related TS technologies. The results of analysis (more than 50 various types of TS coatings were analysed) were included in the database and could be for engineering selections by end-users depending.
Analysis and classification of J-VST, which work at the harsh friction and wear conditions is made taking into consideration: part geometry, applied materials and operating conditions (temperature range, contact stress, environment, type of solid lubricant, sliding speed). Based on analysis and classification the use of self- lubricating effect was planned to consider for the following groups of J-VST components: forging tools; P/M porous bearing and chain bushing.
Study the mechanisms that underlie friction and damage of surface layers of P/M parts modified with HTSL was performed by INOP. The most difficult problem to solve is the control of local contact phenomena during the sliding process. Two research strategies were applied: (1) Experimentally determine the effects of HTSL on friction and wear under high temperatures, and (2) Develop a new mixed and quasi-hydrodynamic model (which will describe the friction parameters of contacts, and the conditions that cause surface wear) will be used to establish lifetime criteria. To ensure accuracy, computations were performed at the contact level to determine the relevant contact parameters, and to define the friction conditions. As a result, knowledge-based engineering calculation package was developed to analyse the influence of HTSL on actual friction and wear mechanisms. Friction conditions outputs are comprehensive requirements for surface layer parameters.
Task statement. The available experimental data exhibit that effective lubrication of boundary and mixed lubricated system such as sliding bearings, sliding components, and others, is ensured by two processes: i) the formation of very thin films in the contact as a result of interaction between chemical components of solid lubricant with the lubricated surface and ii) flow of the powder body at the interface.
The model of mixed lubrication based on non-Newtonian behaviour of powder solid lubricant was developed and validated based on the experimental results. Based on the model knowledge-based engineering calculation package is developed to analyse the influence of HTSL on actual friction and wear mechanisms and to establish lifetime criteria.
Types of testers and testing parameters to be applied for evaluation of tribological properties were chosen: ball-on-disc high temperature testers; specially developed by INOP high-temperature shaft-sleeve test bench.
2) Optimal selection of technological parameters of PM process
Relevant Sectors: Powder Metallurgy
Description of the main S&T Results:
Summary: The surface modification of the high temperature porous sliding bearings with solid lubricant nanoparticles allows to considerably diminish its’ friction coefficient and wear rate. The surface modification technology of powder-sintered bearings was developed. It consists of nitriding, pressure impregnation and sizing operations that allow to solid lubricant particulate layer at the sliding surface. It is found the solid lubricant micro- and nanoparticle layer provides the quasi-hydrodynamic lubrication regime at the sliding contact at high temperature.
In order to realize the quasi hydrodynamic lubrication regime the sliding bearing needs to be supplied with the powder lubricant layer of definite thickness. The thickness of this layer is defined by solid lubrication third body concept. Therefore, the simple vacuum impregnation of porous sliding bearing is not effective for the case of high temperature dry lubrication, and sufficient amount of solid lubricant nano- and micro-particles seems to be required at the sliding interface. The pressure impregnation technology based on a filtration approach may solve the problem of powder layers formation.
Often, the particulate layers (coatings) on the various surfaces are conveniently built by self-assembly through various deposition techniques. One option to produce these coatings directly from the liquid based suspension is the filtration onto a porous substrate, which is a rapid and convenient method of deposition yielding homogeneous films of a controlled thickness and a high degree of reproducibility. The structure of the solid lubricant particulate layer together with the particle functionality determines its performance, and therefore the thickness of the powder layer, its density and morphology are fundamental parameters that require an accurate control. First, however, characterization tools are needed, as classic methods for determination of morphological properties, such as pore-size distributions in porous materials, which are based on capillary condensation, cannot be applied for these physically bonded highly porous layers.
Thus the aim of the pressure impregnation technology development is to characterise the phenomena encountered in pressure filtration operation, and to define the parameters of pressure impregnation technology.
In order to increase the loading parameters of the bearings, the solid lubricants like WS2 and MoS2 are usually used as additions to powders under a sintering. However an effectiveness of WS2 and MoS2 is very low for this case because of its thermal degradation during sintering. In the case of high temperature friction it seems to be better to apply a compacting-sintering-impregnation-drying PM route. A pressure impregnation fixture consists of impregnation cylinder made in a bottom plate, pressing piston, and matrix with porous sleeve. A carrier liquid-solid lubricant suspension was employed to impregnate real PM porous self-lubricating bearing samples (porous sleeves) made of stainless steel AISI 316L powder. The filtering process of nano- and micro-particle suspension through the porous sleeve wall is being controlled impregnation pressure, wall porosity and, consequently, permeability of the porous sleeve with certain wall thickness.
Main pressure impregnation parameters controlled during impregnation step are followings: Pressure in the impregnation chamber; Concentration of MoS2 particles in carrier liquid; Piston movement distance; Nanoparticle suspension volume; Impregnation (filtration) time .
The filtration process is being performed at different pressures. Other parameters were kept constant.
Determination of filtration/impregnation effect was made on the sleeve samples with certain level of initial porosity. The weight of MoS2 deposited layer was determined after drying of the samples. The MoS2 layer thickness was measured with SEM FEI during fracture topography examination. Microstructure of porous sleeves was examined with optical microscope Nikon Eclipse 150L and porosity was calculated with software NIS Elements AR (Nikon Imaging Software). The micro/nano-particle suspension of MoS2 were prepared on the base of cooling liquid FC111 by mixing. The MoS2 micro/nano-particle powder mixture was made of natural MoS2 powder by rolling cleavage technology.
The three main stages of the process were quantitatively determined: pore deposition (deep bed filtration), pore clogging and cake growth. These regimes affect the deposit morphology, as the initial deposit is much porous than that which grows during cake filtration. The experimental results of pressure impregnation process examination reveal the MoS2 particle suspension behavior. The filtration experiment allows defining the pressure gradient dependences on the punch travelling distance. These data were analyzed to obtain the filtering parameters and to calculate porosity of deposited layer. The main task of filtration analysis is the determination of cake porosity. The authors Elmoe et al developed the method of determination of the cake porosity for the aerosol case. The similar relationships may be used for filtration analysis of micro/nano-particle suspension. Because a flow-rate through the porous sleeve during deposition depends on filtering time, the mass deposited can be calculated from a mass-balance as the total liquid mass-concentration is known. Based on these parameters the deposited mass may be defined. The following results were achieved as a result of this Task execution:
-The new pressure impregnation/filtering technology is developed for deposition of micro/nano-particles on the surface of sliding bearings to achieve the quasi-hydrodynamic regime of lubrication;
-The aerosol-filtering model is verified for the case of suspension filtering, and it is shown that the behaviour of the particles during deposition is similar to that of aerosol suspensions;
-The classical filtering theory equations are used for analysis for the deposition process of the porous sleeves;
-The pressure impregnation/filtering technology is applied for preparation of impregnated P/M lab-samples and modification of the real parts demonstrators: chain bushing and sliding bearing.
A porous structure of the fabricated sleeves was studied by SME. The substrate consists of large Stainless Steel particles, while the MoS2 deposited layer consists of primary agglomerated MoS2 nano-sized flakes forming a lace-like structure. From the cross-sectional cut the cake thickness was measured and the porosity calculated, as the deposited mass is known. The thickness dependence on the pressure gradient is clearly observed. Results of characterisation reveal influence of pressure gradient on the MoS2 layer thickness and density. Study of dependences of MoS2 layer mass, thickness and porosity on pressure gradient were carried out. The results reveal that change of the pressure gradient results in change of the flow-rate through the porous sleeve during deposition, and, consequently, to kinetics of layer deposition. Increase of the pressure gradient leads to additional densification of the MoS2 powder layer due to increase of flow rate.
Quantitative analysis was carried out on the basis of the impregnation process (vacuum/pressure impregnation). The aim of this study was to determine the amount of impregnated particles of solid lubricants in porous structure of certain parts. On this basis, it’s possible to specify the size and proportion of lubricant particles in the modified surface layer. An important element is adequate and continuous supply of lubricant in the working zone of specified pair of friction.
On the basis of the study it can be concluded that the mixture of MoS2 with graphite and WS2 with graphite particles allows collecting and covering in the porous structure the sufficient amount of lubricant. This is the result of change of the flow of the various particles during suspension filtration through the porous channel. The addition of the graphite particles, which is characterized by layered structures greatly facilitates the accumulation of lubricant on either of the mating surface (lubricating film formation) and favors the accumulation of lubricant in the surface reservoirs of the porous structure. It is the promising phenomenon that will facilitate the longer operational life of certain friction pair as well as reducing wear and friction coefficient.
Preliminary tests were carried out to characterise tribological properties of impregnated surface layers and to optimise process parameters.
Nitriding development. Ion nitriding is one of the newer methods of increasing the durability of tools and machine parts.
In comparison with other methods of thermo-chemical surface ion nitriding has an important advantages.
For the analyzed tools the ion nitriding was performed in a furnace JONIMP 900/500.
The nitriding takes place under an atmosphere of nitrogen - hydrogen under reduced pressure 5-10 mbar. The gas was ionized in an electric field, the stem and the input i s the cathode, and the casing (base and cap) is the anode. During the ion bombardment the cathode get hot, and the heat generated is enough to heat the workpieces to the required temperature. The nitriding process was carried out on tools at 580C during 20 hours. Measurement of the thickness of nitrided layer is determined on the metallographic specimens etched. Treated in this way bushing has be en tested on a microscope Nikon Eclipse 150L. The nitride layer with thickness of 122 to 133μm was obtained. Hardness analysis of the P/M samples was conducted as a function of distance from the surface. Results of preliminary study of friction and wear parameters of the sleeves were obtained and analysed to optimize the technological parameters.
After optimal selection of process parameters the technology prototype was developed to manufacture J-VST components.
3) Choice of HTSL powders and coating type to be used under specified operating conditions
Relevant Sectors: Thermal Spraying
Description of the main S&T Results:
Selection of HTSL powder was based on market, cost and properties analysis. It was found that WS2 powder from some selected suppliers is the most suitable for high temperature applications. Selection of coatings type for PMR applications was realised based on analysis of PMR friction units. Analysis of TS powders was based on technical data of leading manufacturers of these powder materials and developers of related TS technologies. Analysis shows that the most suitable for PMR applications are Co-based Tribaloy-type high temperature coatings.
Purchased HTSL (h-BN, MoS2, WS2, WSe2, CaF2, BaF2, and mixture of MoS2+graphite, WS2+graphite) were characterised by modern high-resolution instrumentation (FESEM/EDS/EBSD, X-ray). Real particle parameters (shape, size, purity) were defined. It was found that composed of nano- particles and micro- particles and in some cases the particle size distributions are in some cases different from specification of suppliers. It was found that for WS2 powder two groups of particles are observed: smooth plates and porous fibrous granules. WSe2 powder consists of large granules (micron range) and rough plates (sub-micron range). The table was created to summarize the results of commercial HTSL study (powders that are the most suitable for application taking into account both their cost and quality): shape of particles and their size, purity, specific features of each powder. Powders from different manufacturers have practically similar parameters. The cost of powder from some manufacturers is much less (~6 times) that makes application of powders from these manufacturers very attractive. These companies specialize on production of materials for tribological applications that ensure high quality of related products. Parameters of WSe2 powder differ from specification of manufacturer (large size of particles). This material is much more expensive (in ~6,8 times) in comparison with WS2.
Two types of sliding tests were performed to characterise tribological properties of ordered powders: i) ball-on-disc tests at ambient temperature and ii) ball-on-disc tests at high temperature (up to 700C). Officially manufacturer declares that WS2 can be applied up to 650C. WSe2 is less resistant for high temperature: oxidation starts at 350C. Preliminary tribological tests show that the most promising solid lubricants for SME applications are: i) MoS2, MoS2+Graphite (up to 300C; ii) WS2, WS2+Graphite (up to 650-700C) due to demonstration of low friction coefficient (0.1-0.4). The process of high temperature behaviour of the most promising candidates was studied taking into account that HTSL will be encapsulated into micro-reservoirs that could slow or prevent oxidation process. During the further development stages, the thermal resistance analyses of selected powders were carried out to define their resistance to oxidation and detailed tribological study were performed under conditions imitated real operating conditions.
To increase the nanoparticle content in some commercial MoS2 and WS2 powders a special cleavage milling procedure was developed by INOP.
There are wide ranges of powder materials intended for deposition of coatings for high temperature applications by PS and HVOF. Each material (powder) is intended for specific exploitation conditions. The analysis of nomenclature of high temperature coatings deposited by PS and HVOF, their key properties and application areas were carried out for more than 50 types of TS coatings. The analysis is based on specification of powder of leading TS powder manufactures and leading TS companies. The main parameters of coating that determine their exploitation properties (abrasion, heat, impact, wear and corrosion resistance) are: chemical composition and porosity. According to the state-of-the-art: Cobalt base coatings have maximum abrasion resistance at high temperatures and moderate impact resistance; A superior abrasive wear performance was exhibited by the Co based coatings, which did not show a change on the wear rate after temperature exposure, and confirmed the stability of the microstructure after exposure at 600C in an air furnace. Properties and application areas of Cobalt-based Tribaloy-type coatings are the most suitable for PMR applications were considered in details. Coatings exhibit coefficient of friction near 0.6-0.7. This is the main drawback of the coating that was improved though the modification of the coating with HTSL in the frame of HIGRAPH Project.
All available data allows determining the requirements for coatings for PMR application: surface layer structure, composition, microstructure features, and critical material properties, manufacturing routes. Real Co based powders to be applied for HVOF coating deposition and supplier were defined. The first economic assessment of industrialization of new technology for coating modification with HTSL shows that total expected increase of the cost of average part with modified coating would be less than 2-10%.
4) Optimal selection of technological parameters of coating surface modification
Relevant Sectors: Thermal Spraying, Laser Micromachining
Description of the main S&T Results:
Laser micro-machining method was developed for modification of sprayed HVOF coating surface in order to create micro-sized reservoirs to be filled with HTSL without changes in mechanical integrity of the base coating and taking into account economic feasibility of modified coated parts fabrication.
Thermal Spraying (TS) is an effective and low cost method to apply thick coatings to change surface properties of the component. HVOF spraying are the most potential methods for producing a good adherent coating with low porosity. Through high kinetic energy of particles (particle velocity can reach 900 m/s in HVOF process) and heating in the jet particles are ductile and, as a result, after impact on the target they form lamellar structure. According to study of the particle substrate interaction using the digital CCD camera the following typical parameters for particle interaction with the substrate were defined: the time of lamella formation and particle solidification time; the time between 2 impacts. Particles therefore arrive one after the other on particles already solidified; therefore the coating has a lamellar structure and the final coating contains about 4-40 layers (depending on the initial particle size) and the typical coating thickness is a few hundreds microns.
Normally, powder manufacturers and leading spraying companies propose recommendation of optimal parameters for spraying of various commercial powder materials. Nevertheless, these parameters should be strictly control in real time to ensure process stability and coating quality and the developed diagnostic system allows to solve this problem.
In spite of good exploitation properties the majority of wear resistant coatings have relatively high friction coefficient. There are two ways for modification of surface layers of commercial TS coatings with HTSL to decrease friction coefficient:
(1) Use residual pores like reservoirs for HTSL particles;
(2) Fabrication by micromachining special grooves and cavities that could be used like reservoirs for HTSL.
The HVOF and PS coatings deposited under optimal conditions normally have residual porosity: <3-12% for PS coatings and <0.5-1% for HVOF coatings. Increase of the porosity leads to decrease of coating mechanical properties that is why the first way (use of residual porosity) cannot be applied for modification of commercial HVOF coatings with HTSL. During the Project execution the deposition parameters were adjusted for three types of HVOF coatings that are the most promising for solution of SME problems: two types of Co-based and WC-based. The adjusted parameters for deposition of related TS powders from leading suppliers by HVOF spraying system were defined. Digital CCD camera system was applied for spraying parameters optimisation. The optimal HVOF spraying parameters were defined for Co-based coatings: Oxygen flow rate; Fuel flow rate; Carrier gas flow rate (Ar); Powder flow rate; spraying distance. The adjusted spraying parameters allow to reach low porosity (<1%) and high Macrohardness (55-57 HRC for Co-based coatings) that ensure high mechanical and exploitation coating properties.
The technology of solid lubrication has advanced rapidly in the past four decades, responding primarily to the needs of the automobile and aerospace industry. One of the effective ways of application of solid lubricants is surface micromachining for creation of micro-reservoirs for solid lubricant particles. According to the state-of-the-art laser surface texturing is effectively applied for increase life-time and decrease of friction coefficient for such friction parts like SiC sliding cylinders, bearing rings, DLC thin films on friction pairs, piston rings, tools, etc.. In spite of the fact that surface micro-texturing methods are developed for some specific applications, each new application requires full development stages including: choice of laser source; optimisation of laser treatment parameters (pulse duration, energy, etc.); structure of network of micro-reservoirs, tribological tests, etc.. Laser micro-machining of TS coating to improve wear resistance was not developed yet. This method was developed in the frame of HIGRAPH Project.
In the frame of the Project laser ultra shot pulses micromachining method was chosen like a basic one for fabrication of micro-reservoirs to be filled with HTSL. The micromachining of bulk material (thick TS coating could be considered like a bulk material for ultrashot laser action) was historically a difficult task using nanosecond (or longer) pulse lasers due to issues to do with melting effects around the machined site, recast material and general edge quality of the microstructure. The fine control that was required for precision microstructures could not be obtained with such lasers. Recently, pico- and femtosecond lasers have overcome these problems and high quality micromachining is now possible in a range of bulk metals. So-called “cold ablation” is the main mechanism of material removal in this case. This mechanism allows avoiding: micro-cracking; material re-melting; formation of recast layer and heat affected zone. It is very important to keep initial integrity and strength of TS coatings. Recent achievements in laser micro-machining open new ways for tool surface structuring at relatively low treatment cost.
Development of micro-machining method for modification of TS coating surface in order to create micro-sized reservoirs to be filled with HTSL without changes in mechanical integrity of the base coating was realised through the following steps:
-Existing laser cutting, drilling and engraving technologies was studied and their behaviour physical features understood so the knowledge gained was used for the development of the technology. Efforts were directed at pico- femtosecond laser, as it has been identified as the most suitable method for this application. Economic aspects was taken into account: the cost of 1 minute of laser system operation, presence on the modern market of companies offering laser micromachining service;
-Experimental study of process of formation of microchannels and their geometry after laser treatment in material ablation mode. Optimisation of microchannel network structure;
-Fabrication of coated samples and SME components with micro-reservoirs filled with solid lubricant.
The study of laser micromachining was realised on disk sample that were fabricated from heat resisting steel X12CrNi23-13. The disks were coated with HVOF Co-based coating. The choice of the ultrafast laser system was justified by its availability on the market and offering of micromachining service by companies. The parameters of laser treatment were chosen. The width and depth of micro-reservoirs (concentric micro-channels) and distance between them were defined.
In the case of macro products (rolls, support guides, etc.), the parameters of reservoirs for HTSL are different (larger width, depth, distance between micro reservoirs) from other applications (cutting and forging tools) discussed in recent publications. That is why micromachining laser system with higher pulse frequency and longer pulse was chosen to ensure high productivity of micro-reservoirs fabrication.
The structure of HVOF coatings and fabricated micro-grooves were characterised by SEM. Study of micro-channel structure by SEM and optical microscopy was carried out study of process of formation of microchannels and their geometry after laser treatment in material ablation mode and optimisation of microchannel network structure. Application of short pulse laser allows to reach rectangular-like structure of micro-grooves with ration ~1:4 and absence of splashes of liquid material near the grove border due to realisation of ablation regime of laser treatment. The optimal parameters of laser system were defined: wavelength; Average power; Energy density; Pulse duration range; Pulse frequency range; Material removal rate; Focal spot size. The operational cost of chosen system is near 0,2-0,3 € per minutes.
Alternative methods (micro-EDM63, mechanical micromachining) of micro-machining will be also considered taking into account economic aspects.
Based on results of optimisation of TS and laser micromachining parameters, the lab-samples (disks for CSM high temperature tester) were fabricated for further tribological tests. The disk dimensions was: diameter 54 mm; thickness 12 mm. Co-based coating was deposited by HVOF on the disk surfaces under optimal deposition parameters. The coating surface was grinded to reach surface roughness Ra<4 microns. Special micro reservoirs (concentric micro grooves) were fabricated by micromachining to encapsulate HTSL powder. HTSL powders were rubbed into these grooves. The total number of fabricated disks allowed to realise 125 tribological tests
5) Coated parts and P/M sliding and other components
Relevant Sectors: Thermal Spraying, Laser Micromachining
Description of the main S&T Results:
Fabrication of engineered surfaces by novel coating modification technologies and P/M parts using end user’s facilities.
In the frame of execution of the Project analysis of PMR and Gazela industrial problem, classification of related friction parts and development of combined Thermal Spraying/Laser Micromachining technology were carried out. Two main friction units are considered: (1) Ball on guide rail; (2) Mesh-belt-roller. The configuration and dimension of rollers could be different for various types of conveyer furnaces and other similar applications. Calculation of contact stress was done with the help of on-line engineering software. Hertzian stress and subsurface stresses are calculated for point and line contact. The real friction parts have cylindrical and flat friction surfaces and the developed technology of TS coating modification with HTSL was adapted for these two types of prototype surfaces taking into account calculated dimension of contact areas. This data allows to define real geometry of micro-channels to be fabricated on the flat surface of rail and on the cylindrical surface of rollers. According to preliminary tribological evaluation of coating with micro-channels filled with HTSL, it was found that the optimum ratio of the microchannel surface to the total surface within the contact area is near 15-20%. Based on this result the configuration of micro-channels was chosen for fabrication of prototypes. The chosen number of micro-channels per millimeter is four. The width and depth of individual microchannel were defined. The ratio of micro-channel surface to total surface of contact area was also defined. Application of modern laser system allows easy adjustment of the microchannel depth using the typical width to depth ratio 1:5 and even 1:10. It allows to reach optimal treatment cost and to apply this method for modification of other types of friction units where requirements for geometrical accuracy are strict. HVOF spraying parameters were adjusted and optimized and these parameters were used for deposition of coating of flat and cylindrical surfaces of prototypes. The optimal HVOF coating deposition parameters using GTV HVOF K2 system were applied for prototype fabrication. In parallel with coating deposition, process diagnostics was also applied to ensure stable spraying parameters and the final coating quality.
The parameters of laser micro-fabrication of micro-channels were adapted for flat and cylindrical surface taking into account optimized structure of microchannel network. Additional study of the modern market of laser micromachining service shows that new generation of laser systems appears on the market. This system is based on so-called fiber lasers that are characterised by short pulses in nanosecond range with rectangular shape and high pulse energy allowing also to realise high quality machining. These systems are much less expensive in sale and exploitation. Some prototypes were fabricated using this type of system. The optimal laser treatment parameters of deposited TS coatings were also defined for this system: wavelength; pulse duration; pulse frequency; Focal spot size. The scanning unit was used in both laser system providing high scanning speed (up to 8 m/s) and high treatment positioning (~2 microns).
Friction parts prototypes were fabricated in the form of disks that were coated by HVOF Co-based coatings (both cylindrical and flat surfaces), laser engraved and filled with various types of HTSL (WS2, WSe2). The technologies were adjusted for the considered types of parts and their geometry. The full range of tribological testing was performed using disks with concentric micro-channels fabricated on flat surface of the disk in accordance with the requirements of high temperature CSM tester. The width of the area of microchannels filled with HTSL is is 5 times more than the contact area in real parts (ball-on-rail). The width of treated area on cylindrical surface was defined to be suitable for tests. For real rollers (Mesh-belt-roller units) a few areas (depending on the roller length) with this dimension were fabricated.
Pilot tests of surface modification technologies in the industrial environment were carried out and fabrication of real end-users friction parts were realised using developed technologies. Gazela like a coating company has wide range of parts operating both at high temperature and at normal temperature conditions and the developed technology for modification of friction part surface with HVOF coating and HTSL could be effectively applied to a variety of products. Among them are: tension and guide rolls for steel industry; vanes and driving shaft for Aeronautics; valves for petrochemistry and others. To demonstrate the maximum impact it was decided to reduce the set of possible products and to focus the technology optimisation efforts and testing on two types of PMR and Gazela friction parts: rail guide and rollers.
The complete technological chain was developed for deposition of HFOV high temperature coatings, coating surface texturing using laser micromachining and filling of micro-grooves with HTSL. The technological route was realised under industrial environment of coating company through the following steps: HVOF coating deposition (quality was supported by process monitoring and control); surface finishing; laser micromachining and filling micro-grooves with HTSL. The main technological parameters were specified in details for HVOF coating deposition (specification of applied initial powder; HVOF process parameters: oxygen and fuel flow rate, spraying distance, etc.).
The required parameters for desired applications of deposited Co-based coating were defined (hardness, density, porosity, thickness, etc.). Generally coating roughness is suitable for further laser micro-machining, nevertheless additional coating finishing was applied according to recommendations of powder manufacturer. The main parameters of final finishing were also specified (grinding conditions, final roughness).
Modern fiber-based lasers allow to drill deep holes (15 microns width and 200 microns depth) with a low number of pulses. Due to high pulse repetition rate this system can make 1500-1800 holes per second or 3000 mm/s in line scanning. It should be note that high power fiber-based lasers are small and they could be used for design of portable laser marking machines that recently appear on the market. It open a wide way for application of the developed technology for surface modification with HTSL in various industrial sectors, because laser texturing in certain cases could be done on place especially in combination of portable spraying systems that also appearing on the market.
Preliminary friction tests that were carried out in the Project and results of other author applied laser surface texturing for modification of surface with MoS2 show that optimum holes/microgrooves surface coverage is near 5-10%. This value was used for creation of treatment algorithm both for rail and roller treatment. Optimized laser micromachining parameters were defined and applied in industrial environment.
A part of the supporting rail guide was fabricated with length 500 mm and width 90 mm. Microreservoirs were created on the surface of HVOF coating with a margin within a zone in the central part of the rail guide to ensure good solid lubrication. The rollers for small annealing furnace were chosen for tests. The roller has length 300 mm and diameter 50 mm. Three various types of microreservoirs networks were chosen for further testing and optimisation: (1) annular microgrooves that are fabricated perpendicular to the roller axis; (2) Longitudinal microgroove lines that are fabricated along the roller axis); (3) the set of microholes located that cover the roller cylindrical surface. The real friction parts and some special samples were fabricated for further testing.
Pilot tests of surface modification technologies in the industrial environment were carried out. SME real self-lubricating friction parts and special samples were fabricated for pilot testing of exploitation properties. The real cost of full range of pilot tests of exploitation properties with full replacement of friction parts is very expensive for PMR due to the necessity to stop production. That is why it was decided integrate only one rollers and a part of supporting guide into the furnaces (for wear monitoring during a few months of exploitation) and in parallel to make full range of high temperature tribological tests using samples and high temperature tribometer under conditions that fully reproduce exploitation conditions of real friction parts in temperature range 25-700C. In parallel study of thermal stability of applied High Temperature Solid Lubricants (HTSL) was carried out with the help of Simultaneous Differential Technics (SDT) in wide temperature range (up to 700C).
Heating of WS2 up to 700C causes a small weight loss (4,33%) and relatively small exothermic effect. This effect can be due to prime disulfide decomposition into tungsten and sulfur with subsequent oxidation of the latter and sulphur oxides loss. Results of the test confirm that WS2 is characterised by good thermal stability and good tribological performance are expected in the desired temperature range up to 700C. The loss of weight due to oxidation is very important for WSe2 and it reaches 28% at 470C. The results of thermal stability test show that WSe2 can be effectively applied only up to 350C.
Tribological tests were carried out on air (temperature 25-700C, pressure 22 atm, humidity 40% at room temperature) at loads that well reproduce the real operating parameters of considered friction pairs (PMR and Gazela applications). Initial HVOF Co-based TS coating is characterised by high friction coefficient (0,69-0,79) and intensive wear. At relatively low loads, some spalled particles of the coating play a role of abrasive media that causes intensive coating abrasive wear. Under higher loads occurs wear mostly caused by plastic deformation that is confirmed by microscopic images.
Application of laser engraving of surface of TS coatings and filling of micro-grooves with HTSL (WS2) allows decreasing significantly the friction coefficient. As a result, wear is very low (under the same testing conditions that were close to real operating conditions of friction parts). During the testing (especially within run-in period) HTSL powder was pressed completely into the microgrooves and its continuous release into the contact area ensure low friction coefficient and low wear intensity. The friction coefficient decreases to 0,13 (statistical mean values). The coefficient is quite stable during the test. Noticeable wear is absent. Special experiment was dome when the test track only partially (5-30%) passed through the area with microchannels. Nevertheless, due to intensive release of HTSL from microchannel and transfer it on un-treated area, the friction coefficient remains low and did not exceed 0,22. It allows covering only part of the friction surface (near 5-10%) by microchannel network and, as a result, makes the developed method more effective from economic point of view. Friction coefficient remains low while increasing the temperature to 300C. This test is characterised by a transition period in which the coefficient of friction decreases from 0,23 down to 0,09. There is practically no wear track as a result of application of WS2, only slight decrease of surface roughness within contact area is observed on profilogram of the tested area.
Tests of TS coating modified with HTSL with the help of HIGRAPH method at 700C demonstrated also very low friction coefficient. At the beginning of the test a short transition period is observed. During this period the friction coefficient dropped down to 0,095 as a result of solid lubricant transfer and distribution on the surface. The value of the friction coefficient remains very low at 700C due to encapsulation of solid lubricant powders inside of micro-channels. That prevents from oxidation of the whole HTSL volume and continuous release of WS2 into the contact surface. As it was shown WS2 is very stable for oxidation at high temperature. More over, oxidation rate is relatively low, because WS2 can build up compact WO3 covering layer by slow oxidation to inhibit further oxidation, and WO3 has also low friction factor and can prevent the glue happened between metal surfaces as well. These factors explain the fact that low friction coefficient remains practically stable during the testing time with only slow growth. Perceptible wear is also absent in this case like at the same testing conditions at 300C.
Monitoring of wear for roller and part of supporting guide (that were integrated into pilot furnaces of PMR) was also performed in parallel with wide range of tribological tests under conditions that are closed to industrial ones. After 6 months of testing only slight wear was observed both for roller and supporting guide with TS coating modified with HTSL and for all three types of applied configuration of microreservoirs networks. Normally, wear tracks are observed for PMR friction parts after 1 month from the beginning of exploitation of new parts that were replaced in the frame of periodic annual maintenance of the equipment. The friction coefficient is decreased in more than 7 times in comparison with TS coating without application of HTSL that allow to increase the wear resistance of such type of coating and enhance their application areas and potential. At least 3 times of the increase of lifetime of friction parts of PMR and Gazela is achieved.
The economic estimation of each stage of technology of TS coating modification with HTSL was done to define expected cost of the final products and technology economic efficiency. Totally, the increase of the cost will not exceed 3-10% of the cost of untreated friction parts (depending on their geometry and size).
The analysis made it possible to define two groups of parts of J-VST. The first group consists of parts intended to forging and trimming, which were coating deposited. The second group consists of sliding parts (P/M), which has undergone a modification of the surface layer (infiltration). The first group includes: stock die for forging (matrix and punch); punching tools. The second group includes: self-lubricating porous bearing; porous self-lubricating chain bushing. Prototypes were fabricated and ready for testing.
A compaction-sintering-impregnation-sizing Powder Metallurgy (PM) route was applied to obtain the porous sleeve. The samples were made of water atomized AISI 316L austenitic stainless steel powder. The powder with zinc stearate as a lubricant were mixed and compacted to obtain sleeves. They were preheated to take off the zinc stearate. Sintering was performed at defined temperature in a tubular furnace, in a vacuum. After the sintering process, the samples were slowly cooled until room temperature, under vacuum. Afterwards they were nitrided in the furnace JONIMP 900/500. A conventional d.c. glow discharge (DGW) was applied, under a gas mixture of H2+N2 between the workpiece (cathode) and the furnace walls (anode). This gaseous mixture was applied under a pressure for defined hours. The voltage and current density were adjusted to maintain the temperature at defined level. After the nitriding process, the samples were submitted to slow cooling down under vacuum inside the treatment chamber. As a result of pressure impregnation, following drying, and sizing we obtained the porous sliding bearings with MoS2 solid lubricant powder layer of thickness about 80-100μm. MoS2 layer consists of micro- and nanoparticles obtained by method described in detail in [H.Wisniewska-Weinert Powder Metallurgy and Metal Ceramics, 52/11, (2013) 24-430]. To study microstructure and microhardness the samples were cross-sectioned, mechanically polished and then they were slightly etched. The nitride layer depth was measured optically.
A real sliding bearing prototype of a hot air valve unit was chosen for experiment. The sliding bearing is supported on housing, and shaft-bearing interface is sealed by spacer and washer that allows to prevent a leakage of solid lubricant powder outside sliding area. MoS2 solid lubricant powder layer is incorporated onto internal surface of a sliding bearing. Operating temperatures of the sliding bearing assembling are in the range of 20-500C. For this reason the counterparts were made of AISI 316L stainless steel (sleeve) and EZ6NCT25 (shaft).
The sliding bearing samples with MoS2 powder layer were tested on a home made (INOP) friction tester TWT 500N which allows to define the friction and wear parameters at the conditions similar to those of real bearing unit used in valve control systems. The counterpart is the shaft made of EZ6NCT25 steel. The test bench allows to make friction tests of the friction pair shaft-sleeve in real exploitation conditions: speed up to 120rpm, max normal load 500N, test temperature up to 600C. The parameters to be registered are followings: friction moment, normal load, temperature. Friction coefficient is also calculated. The two sliding schemes were examined with TWT-500N friction tests: i) conventional sliding without sealing of sliding contact, and ii) sliding of counterparts with the sealing of the sliding contact to prevent the leakage of solid lubricant from the sliding interface. A friction diagrams of tests at 300 and 500C of sliding bearing with MoS2, WS2 and MoS2+Graphite and WS2+Graphite solid lubricants with sealing of sliding interface reveal considerable improvement of friction coefficient and wear resistance for sliding bearing with sealing of the interface because of presence of nanoparticles. Friction diagrams of tests at 300 and 500C of chain bushings with MoS2, WS2 and MoS2+Graphite and WS2+Graphite solid lubricants confirms that at temperature 300C, MoS2 has better lubricating properties than MoS2 + graphite. This is confirmed by the results of initial testing of lubricants that have been made using tester T-21 at T = 300C. This is also confirmed, for which the friction coefficient in the final phase of the test for MoS2 + graphite has reached a value close to 0.1 whereas the friction coefficient of MoS2 on the same friction distance is about 0.05. Test results show that, at 500C, WS2 has better lubricating properties than WS2 + graphite. WS2 operates over a distance of 200-250m, while the WS2 + graphite over a distance of 150-250m. In the case of WS2 lubricated sleeve friction coefficient value 0,025-0,075 has been observed for a distance equal to 0-100m, and to WS2 with the addition of graphite 0.05-0.15. The results of initial tests of additional lubricants that have been made using T-21 do not confirm that. In the initial test, the value of friction coefficient for graphite additive WS2 was smaller compared to friction coefficient for WS2. Test results also show that over a distance of 0-400m the value of friction coefficient for graphite additive WS2 is lower than friction coefficient WS2. At a distance of 400-600m this ratio was the opposite.
Pilot tests of P/M technology in the industrial environment were carried out. A constant pressure-drop is applied by a compression machine thus forcing the flow through the porous substrate and leading to the formation of a filter cake on the inside of the sleeve substrate. The axial flow-inside the pressure impregnation chamber depends on the chamber pressure. The flow calculations reveals the Reynolds number (Re) inside the sleeve confirming that the flow is laminar so no enhanced deposition rate is expected. Pressure impregnation was carried out for various times to study the effect of deposited mass on the filter cake morphology. The flow-rate through the substrate during filtration is measured while the experiment is running, and the amount of deposited material is calculated from the total suspension mass-concentration. The flow curve was obtained during constant pressure-drop filtration. Two of the three impregnation regimes are clearly distinguishable. The first, pore deposition, is not observed, as it is typically finished within seconds after the beginning of filtration and is likely obscured by any time-delays in the setup. The second regime (pore clogging), contributed to pore clogging, is characterized by a fast decreasing flow-rate. Finally, in the third regime, cake growth, occurs that is characterized by near-linear decrease in flow-rate. A size distribution of MoS2 particles in the cake was measured on the base of SEM images. The distribution is lognormal and narrow. The experimental data illustrate the wide opportunities of pressure impregnation operation from the viewpoint of control of thickness and porosity of the obtained solid lubricant powder cake. However, the density of the formed porous layer is about 75%. Thus, the deposited layer needs to be densified to increase its mechanical properties and decrease the porosity.
The set of bearings was fabricated for further testing using the developed technology that consists of nitriding, pressure impregnation and sizing operations that allow to solid lubricant particulate layer at the sliding surface.
The three types of forging matrixes Matrix 1,2 and 3 HLAVICNIK) were fabricated (nitriding and modification with HTSL) for further testing. The surface modification of forging tool was performed by nitriding and rubbing of working surfaces with solid lubricant micro/nano particles. Additionally PVD coatings made by Gazela were applied in the separate cases. Solid lubricant reservoirs such as microgrooves and cavities were made on the tool surface in the areas of minimal shear contact stresses defined by FEM analysis. A trajectory of the microgrooves was chosen on the base of shear strains calculation results. Incorporation of solid lubricant micro/nano particles into the lubricant reservoirs network on the working surface of the nitrided forging tool was performed by burnishing process with special burnishing tool installed at CNC milling machine. The surface treatment hard roller burnishing was chosen to optimize the tool surface of die at the critical region. Thus, the positive influence of the compressive residual stress and the flattening of the topography can extend lifetime of die by closing micro cracks on the surface. Several tools with the surface treatment hard roller burnishing were used in production. After a certain amount of parts die has to be polished in order to work precisely. The average tool life of untreated tools is standardized to a relative tool life of 100%. In this case, the amount of parts was extended up to 160% with hard roller burnished tools. In the end, the failure reason of the surface treated tools was a fatigue crack in the radius above the die shoulder.
For testing under actual working conditions (JVST facility) three types of forging dies were selected. The dies were modified according to the developed nitriding-solid lubrication technology. Nitriding process results in the hardness increase of modified templates. Dies after nitriding process has been modified with nanoparticles HTSL. The prepared tools have been tested in real conditions of use (real production of pieces by J-VST). The data on working hours (number of completed cycles in pieces production) were obtained. The collected data show that nitriding and surface modification with HTSL substantially increase of working hours (average number of produced pieces) of the forging tool.
The friction tests of sliding bushings in exploitation conditions were carried out using the new test bench TWT-500N which models real friction and wear exploitation parameters. The variation of lubrication regime was reached by increase of normal load that changed the Sommerfeld parameter. Obtained results present the dependence of coefficient of friction versus sliding distance for various tribological conditions:
-316L sleeve (not impregnated) – counterpart (shaft made of steel E-Z6NCT25) at ambient temperature;
-316L steel sleeve (impregnated with oil NT100) – counterpart (shaft made of steel E-Z6NCT25) at ambient temperature;
-316L steel sleeve (modified with MoS2 particles) - counterpart (shaft made of steel E-Z6NCT25) at the temperature 300oC (real sliding bearings);
-316L steel sleeve (modified with WS2 particles) - counterpart (shaft made of steel E-Z6NCT25) at the temperature 300oC (real sliding bearings);
-316L steel sleeve (modified with WS2 particles) - counterpart (shaft made of steel E-Z6NCT25) at the temperature 500oC (real sliding bearings);
The wear coefficient was measured for real sliding bearings made of 316L stainless steel: without impregnation of the porous tube; impregnated with MoS2 particles (at temperature 300C); impregnated with WS2 (at temperature 500C).
The Striebeck analysis of exploitation results demonstrates that lubrication behavior with application of solid lubricant is similar to that of oil lubricated sliding contact. The stages of boundary, hydrodynamic and mixed lubrication are clearly seen. Thus, the quasi-lubrication regime of high temperature sliding contact is achieved. Moreover, sealed sliding interface exhibits better load bearing capacity than that of open sliding contact. It is defined that oil lubrication regime is less stable than that of solid lubrication. It reveals that the solid lubricant film has superior strength than that of oil lubricant that results in increase of wear resistance of the sealed high temperature sliding couple.
The surface modification of the high temperature porous sliding bearings with solid lubricant nanoparticles allows to considerably diminish its’ friction coefficient and wear rate. The surface modification technology of sintered bearings was developed and optimized. It consisted of nitriding, pressure impregnation and sizing operations that allowed obtaining solid lubricant particulate layer at the sliding surface. It is found the solid lubricant micro/nano particle layer provides the quasi-hydrodynamic lubrication regime at the sliding contact at high temperature.
The surface modification of forging tool was performed by rubbing of working surfaces with solid lubricant micro/nano particles. Solid lubricant reservoirs such as microgrooves and cavities were made on the tool surface in the areas of low contact stresses. Incorporation of solid lubricant micro/nano particles into the lubricant reservoirs working surface of the forging tool was performed by rubbing process with special rubbing device.
For testing under actual working conditions three types of forging dies were selected. The dies were modified according to the developed technology combined with nitriding. Nitriding process affects the hardness increase of modified templates. Dies after nitriding process has been modified with nanoparticles HTSL. Thus prepared tools have been tested in real conditions of use (real production of pieces by J-VST). The data on working hours (number of completed cycles in pieces production) were obtained. The collected data show that nitriding and surface modification with HTSL increase of working hours (average number of produced pieces) of the tribological system based on criteria of change in tool geometry (diameter ~1 microns): for upper forging tool (matrix 1) from 19 770 to 67 060 pieces; for bottom forging tool (matrix 2) from 36 500 to 115 600 pieces; for matrix 3 (HLAVICNIK) from 41 030 to 155 700 and from 49 900 to 168 200 pieces.
Economic parameters assessment, Cost comparison: It is well known that in a tool unit cost decreases when the tool service life increases. Knowing the average price of the forging tools (punch and die) on the base of JVST data, it is possible to calculate the Tool Unit Cost (TUC). Since the operating principles of the equipment compared are similar, no other costs originating from the use are taken into account in the calculations. The other costs can result from pressurized air, maintenance, service and electricity. The 6 types of the tool were chosen for calculation: (1) Bending Tool of lock component; (2) Matrix of heading (Hlavickar); (3) Heading matrix of the screw; (4) Bottom forging tool for steel insert; (5) Upper forging tool for steel insert; (6) Extrusion die for steel insert. Estimated average cost of P/M modification of the tool surface per 1 cm2 is ~0.05 that will allow to get profit on sales or J-VST. The use of this technology should significantly affect the economic benefits to companies that will implement it. The effects of implementation of the MoS2/WS2 will are followings: i) increase of tool lifetime, ii) resources save and iii) reduction of costs associated with the replacement of worn parts and repairs. Economic benefits will result from the reduction of operating costs compared to conventional methods of machine parts manufacturing. It is estimated that the cost of operation will be reduced from 25 to 50%. Despite the higher price of the product, the economic balance will be better of 25% to the end user. This is due to the 2 - 3 times longer working time of the forging tool modified with technology developed and elaborated in the Project. This can reduce maintenance costs and downtimes.
The Quality assessment of the test results were carried out. For quality control of new technology for coating deposition Ateknea in cooperation with IfU and Gazela developed the process control system for the automation of the manufacturing equipment used by Gazela.
Inspection certificates. Sliding bearings and forging tool manufacturing process require constant monitoring geometric characteristics of manufactured products. The permanent control and monitoring of the geometric characteristics of manufactured products was performed by the instruments of Gauge and Standards Room. The Gauge and Standards Room has done quality assessment work, and certificates of compliance checks dimensions of fits (tolerance) were issued for each tested part. The following technical documentation was obtained: functionality designed and manufactured product; mounting interchangeability (technology) and operating; durability and reliability of the product; safety (protection of health and life of humans, the environment and others).
Research of the Rockwell hardness was carried out by INOP accredited testing laboratory. The management system in the laboratory is improving continuously under the supervision of the Polish Centre for Testing and Certification, and since 2002 - Polish Centre for Accreditation. In 2006 the system was implemented in accordance with PN-EN ISO / IEC 17025: 2005 - General requirements for the competence of testing and calibration laboratories.
Market overview. Porter's model was applied like a tool for analyzing the competitive conditions prevailing in the market and allows us to estimate the degree of influence that each of the five forces have on SME and, accordingly, how one or another branch of interest to the company: (1) New competitors (new players in the market); (2) The existing competitors in the industry; (3) Companies that offer substitute products; (4) The impact of suppliers; (5) The impact of customers.
The following market segments were analysed: Thermal Spraying (TS) - coating companies and coating end-users); Powder Metallurgy (P/M); Forging Industry (FI). For each market sectors potential suppliers and end-users were analysed.
The potential environmental impact was estimated. The developed technologies (technology of modification of TS coatings with HTSL using laser micromachining and nitriding/pressure impregnation/filtering P/M technology) are green technologies. In machining industry solid lubricants could in some application replace cooling liquids and decrease its’ influence on environment. The application of solid lubricant allows decreasing oil lubricants and grease consumption. The project greatly contributes to environment-friendly production and maintenance. In the Project, practically green production processes for materials are used. The increase of friction parts life-time allows decrease of raw material and energy consumption.
During the tests of exploitation properties under SME real industrial conditions (PMR-furnace exploitation, Gazela – coating deposition, J-VST – production of pieces by forging) the improved tribological properties of friction part and tools were demonstrated: the friction coefficient decreased in more than 7 times (from 0.74 to 0.095 in temperature range 25-700C) and the lifetime of PMR and Gazela parts increased at least in 3 times; forging tools in real production demonstrated the increase of lifetime in 3-4 times. The slight increase in unit price (<2-10%) will be completely offset by the enhanced service lifetimes for a 40 to 60 % cost savings within 2 to 3 years. The results were analysed by SMEs and marketing and sale departments of SME partners confirmed the efficiency of the developed technologies.
Final Plan for the Use and Dissemination of Knowledge (PUDK) was developed and Joint Ownership and Exploitation Agreement was elaborated and signed.
Wide dissemination activity (publications; presentations on conferences, workshops and trade fairs, Video presentation of the Project results, and others) were realised.
6) On-line process control system for coating deposition technologies
Relevant Sectors: Thermal Spraying, Coating Technologies
Description of the main S&T Results:
The prototype of process control system was developed for process diagnostics and control in coating technologies. The system consists of sensor (background of IfU), digital interface and process control software allowing to control in real time the coating deposition process. The process control system was developed and integrated with Gazela equipment for coating deposition. The process control system allows to ensure coating quality (ensure stability of coating properties and to decrease the number of rejected parts) and to decrease the production cost. It could be also applied for the development of new coating processes.
Instability of spraying process parameters and/or initial powder quality influence strongly on particle-in-flight parameters: velocity and temperature. Variation of these parameters leads to deviation of coating properties from the desired values. The following benefits due to application of diagnostic system in TS are expected:
-Quality: typically spraying SME has 8-10% rejection of a final product. With the normal price of a single substrate of 1000€ and 300€ cost of the sprayed powder, the total savings can be estimated as 20 000€ for a 150 set of samples (normal monthly production for SME);
-Maintenance: At present, the regular Plasma Spraying workstation is out for maintenance for 50 hours in 250 hours, i.e. 25% of the total time. With the systematic control of operation parameters, the reduction of 50% for maintenance time may be expected;
-Energy, water and gas consumption: the energy consumption for Plasma Spraying device is ~10-100 kW/h, cooling water debit is 400-600 l/h and debit of plasma gases (Ar, H2, N2) is measured by hundreds m. cub. per hour. This consumable contribute in production cost between 350 and 600€/h. Consequently, 10% economy in this item will bring ~40 k€ of savings;
-Wastes treatment: on average 2% of the turnover of a thermal spraying company is devoted to scrap recovery. On-line diagnostic and control system can diminish these costs.
The universal process control system includes two parts: alarm control in thermal spraying (TS) and process control system in High-power Impulse Magnetron Sputtering (HIPIMS).
The system for TS is based on the optical particle-in-flight sensor previously developed by IfU (IfU background). The main steps that were realised to develop alarm process control system are the following: study of TS process for deposition of powders chosen for PMR and Gazela applications and some others that will be important for dissemination; Definition of optimal parameters for deposition of the coating with desired properties/quality; Analysis of particle-in-flight parameters corresponding to optimal deposition conditions; Development of software for data averaging and presentation of mean values in real time and alarm signal generation for operator in the case if desired particle-in-flight parameters come out the optimal level. The system was integrated with industrial spraying equipment. System allows measurements of particle-in-flight temperature in the range 1000 – 2800C and velocity in the range 30 – 900 m/s. Statistical analysis of particles histograms was carried out to define optimal values of mean particle temperature and velocity. The alarm signal generated when mean temperature (or mean velocity) go beyond the optimal values (red borders). After that operator should stop the process to define the reason of mean value important deviation.
Another part of the system is intended to control HIPIMS that is also very important for Gazela like a coating company. The machine features four magnetrons, two of which (Silicon, Zr/Nb/Si) can be power controlled. Currently 3 types of gas (N2, Argon and O2) are used in the process. The control software running on a PC was also developed for this application. Power supplies and VAT valves are connected to the PC via serial interface. In order to extend the number of the available serial ports up to 8, National Instrument’s PCI-232/8 serial interface card was applied. The data acquisition field instrument is a National Instrument SCXI 1000 chassis with 4 modules. National Instruments SCXI is a signal conditioning and switching platform for measurement and automation systems. SCXI data acquisition (DAQ) hardware provides a single, integrated platform for all of your signal conditioning and switching needs. An SCXI system consists of multichannel signal conditioning modules installed in one or more rugged chassis. The system equipped with 32 channels analogue and digital input/outputs models. The software provides the basic SCADA features for the machine, including: Manual control of components / Automated process control based on recipe files; Recipe file handling; Trending and monitoring the process; Alarm and error handling; User Access Control; Maintenance and service menu. These features are accessible through dedicated screens. The main features of the control software are working and thus the system can be used, however there are some parts that were corrected and also some new features that were added. The prototype of the system was improved by adding some extra features: adding extra power supplies; adding vacuum sensors; new spectroscopic sensors AOS (IfU background) for monitoring of plasma intensity and control process via O2 and N2 mass flow controllers; new HW components (heaters); chamber temperature and cooling management; valves and mass flow controllers for monitoring the use of krypton. The Control Software has been upgraded to more up-to-date version. Gazela updated its’ coating system with new components. The prototype of process control system was integrated with Gazela equipment and successfully tested.
Potential Impact:
Potential economic impact resulting from results exploitation.
The Project helps to solve one the most complicated tribological problems related to fast wear under conditions of dry friction and high temperatures. The main goal of the Project is the industrial implementation of self-lubricating materials with improved tribological properties. Developed technologies (TS coating and forging tool modification with HTSL; P/M manufacturing of self-lubricating sliding parts) will be first applied in the business areas of the project SMEs then diffused in further industries. Prior to starting the project the partners have investigated the aspects of commercializing the Higraph technologies taking into account the individual business interest of each company. The business plan was developed like a part of Plan for the Use and Dissemination of knowledge (PUDK). The results will have direct impact on the following market sectors:
-Thermal spraying (TS): In spite of the fact that the developed technology could be effectively applied for various types of Thermal Spray coatings (HVOF, APS, VPS and others) that are intended for application both at normal and elevate temperatures, Gazela will better focus exploitation activity on Co-based and WC coatings modified with solid lubricants for various industrial sectors: furnaces, steel industry, aeronautics, petrochemistry and metal forming. Some parts to be considered are: tension rolls; furnace rolls; skin pass rolls; leveler rolls; valves; pump parts; driving shaft. These parts have similar cylindrical or spherical geometry and the developed technological approach could be transferred for all these friction parts treatment. Gazela estimates that for them the largest markets for Higraph T/S coated parts will be represented by the steel industry (64.8%), followed by industrial furnace users and manufacturers (cc.21.3%), aeronautic industry (9.3%), petrochemistry (5,3%) and metal forming (0.3%). PMR will benefit directly from exploitation of novel furnace friction part (decrease economic losses for part replacement from 4-5% to 2-2,5% of annual turnover), licensing of the developed technology and opening of new market niche in parallel with the main company activity. PMR also expects additional benefits from reducing the volume of faulty products and also cut the energy consumption in the manufacturing process. By these the company assumes an annual saving of approximately 5-8% of annual turnover;
-Powder Metallurgy (P/M): The largest end-user segment for P/M is automotive representing over 70% of the market. Approximately 75% of the automotive components are used in transmissions (eg. bushing, thrust washer etc.) and engines (eg. turbocharger thrust bearing, valve guide, valve seats, bearings, bearing caps etc.), most of which are impacted by high-temperature. J-VST through realisation of new technology will deeply penetrate its’ activity in this segment;
-Forging industry (FI): Forged parts are mostly demanded in the automotive industry (58%), mechanical engineering and metal wear. In case of forging tools wear and heat resistance on the surface is critical as tool life and quality of production can greatly influence the profitability of production. Thus material improvement has a high priority on the industry’s technology innovation agenda. Improved performance of forging tools can contribute to increase return on investments for J-VST that are producing forged parts. J-VST estimation indicates that the highest production volume will be associated with Heading matrix of the screw (43%) followed by Bending Tool of lock component (21%) and upper forging tool for steel insert (21%).
In case of TS coating technology estimated 2-10% increase in costs expected compared to state of the art coated parts by using WS2 at a costs of 87€/kg. Estimated average cost of P/M modification of the tool surface per 1 cm2 is near 0.05€. The forecast of total profit for companies directly involved in the Project resulting from the cost saving, licensing and profit on sales will reach ~1 850 000€ after the results commercialisation.
Longer lifetime will result in lower amortization costs in industry-wide. Self-lubricating parts will have 2-3 times longer lifetime, with only 2-10% increase in unit prices. The direct cost of replacement of friction parts in production lines in industries that use furnaces is around 70-90k€ per year for a normal-sized SMEs according to information of partners of PMR. In the direct network of the Consortium there are a few thousands companies with similar activity that face the very same problems. Tribological components resulting from the HIGRAPH project could cut these costs by 50% resulting in a total saving of 55-70M€ per year just for these companies. the HIGRAPH technology can pave the way for the use of similar coatings in other industrial areas outside the businesses’ scope of the consortium partners, through licensing and dissemination activities. The estimated total market growth of SMEs involved in P/M, TS and machine building indystries could reach 120 million EUR.
It is estimated that wear causes losses to industries in the order of magnitude of 1% of a nation’s GDP20. For the EU this can mean an annual loss of 12 billion EUR (0.01×12 300 billion EUR). Even a marginal improvement in this figure would amount to several hundreds of millions EUR annually. For example, new components could be effectively applied in aircraft industry for production of sliding components operating under high temperatures. If sliding aircraft bearings reliability can be multiplied by a factor 2 or 3, reduction of maintenance costs for aircraft systems is estimated to 10-15%. It will result in ~3M€ saving gained just for one single components.
The Project objectives require a European approach because commercialization efforts in Europe in the area are of high temperature self-lubricating materials are relatively weak. The patent search and the market watch have shown that the main activities in this field are concentrated in USA, China and Japan. In the global marketplace, commercialization efforts in the United States are most advanced: about 63 % of all companies manufacturing solid lubricant materials/components, whereas 25 % are in European countries. This indicates a relative weakness of the commercialization efforts in the EU in this sector with currently the highest market potential. Cooperation in the frame of the Project will open new markets for SME partners and will improve their competitiveness on International market.
European Technology Platforms (ETP) define emergency technological needs and roadmaps for considered industrial sectors. RTD partners of the Project participate in the following ETP: EuMaT “Advanced Engineering Materials and Technologies”; MANUFUTURE “Future Manufacturing Technologies”; MINAM “Micro- Nanomanufacturing” and NANOFUTURE “European initiative for sustainable development by Nanotechnologies”. Tribological problems and antifriction materials are among the most important ones defined by these platforms. The Project results will be disseminated through these ETP that ensure their wide future exploitation.
Contributions to standards.
HIGRAPH contributions to standards will not be immediate. However, through some of the results, HIGRAPH may influence some future standards like slef-lubricating component for high temperature applications.
Contribution to EU policy objectives.
Independence of the European industry.
The project will ensure the availability of a critical technology on European market. It will guarantee a competitive European supply chain having better quality standards in design and development than Japan or US suppliers. The transfer process from research to industrials is generally seen as a very slow process. The project will exploit directly high level and recent research in several domains: tribology, P/M, coatings and processes. The project will be a clear demonstration that the transfer process can be improved if both industrials and researchers share common interests for high quality and innovative technologies.
Transnational approach.
Tribology problems are common for all European companies. That is why manufacturers of high temperature bearings should cooperate with leading RTD partners with important background in high temperature tribology, coating and P/M technologies.
Acceleration of integration of partners from Poland, the Czech Republic, Slovenia and Hungary in the European Research Area is very important. Cooperation in the frame of the Project will open new markets for SMEs partners.
Project training program to be realized by IfU (Germany), INOP (Poland) and ATEKNEA (Hungary) through hosting of engineers from SMEs partners for “training in tribology”. It will help successful dissemination of the novel technologies in all European countries.
Environmental impact.
The project will greatly contribute to environment-friendly production and maintenance. In the Project, a green production process are applied.
Decreased use of liquid lubricants and greases. The world demand of lubricant oils in 2010 was ~40 million tons. Western Europe and the CEE region accounted for 25% of the world consumption. Industrial demand represents 32% of the total demand for lubricants, which amounts ~3 million tons of industrial lubricants consumed each year. The average price of industrial lubricants is 1–1.5 €/kg. HIGRAPH based technologies have the potential to reduce lubricant consumption by 80–85% resulting in a potential for saving in the range of 2.5–3.8 billion EUR per year for the industry.
Decreased energy consumption. The significantly lower coefficients of friction for HIGRAPH solid lubricants would result in 10–15% lower energy consumption for machines. An average SME in the forging industry has an annual power bill of 200 000 €, where the decreased power consumption would result in a yearly saving of 30000€. Industry-wide this creates a potential for saving 100 M€/year.
Decrease of raw material and fuel consumption.
As a result of increased in 2-3 times the life-time of friction parts, the consumption of steel will be decreased. The powder metallurgy manufacturing is certified as ecological. The waste of materials is low and material are used efficiently due to direct fabrication of parts with required shape and dimensions. Powdered materials are as usual by 5-25% lighter than parts produced by traditional machining.
Reduction of systems weight (turbo machines, valves, etc.) will decrease fuel consumption. Any change of such type will help EU countries fulfil the Kyoto summit commitments of an 8% reduction in greenhouse gases relative to 1990 levels. For example, the thermal efficiency of turbo machines can be increased when the temperature of hot gases entering the axial turbine is heightened. Increasing the operating temperature of turbo machines only by 50°C will result in the increase of thermal efficiency by 0,7–2% points and the reduction of fuel consumption by 4–13%.
Contribution to societal objectives.
Growth in this market area requires a lot of technical work resulting in the creation of new jobs at suppliers of HTSL, sliding bearings and other friction units. For the project SME partners the expected increase of employment will be 10% for 2018. The demands for documentation of technical and quality aspects are extremely high, mainly affecting the technical sales department and quality assurance. At least ten additional employees with technical background will be needed for SMEs within one year after project completion.
Education and training programs will solve the following tasks: to form education/training network integrating all the partners and the interested parties outside the Consortium; to link project S&T activity with EC education program ERASMUS; to promote new forms of education: full cycle of e-education, e-learning, interactive e-training, remote learning; introduction of a new M.Sc. specialization: “High Temperature Tribological Engineering”.
Improving safety and security will be reached though developing highly reliable friction units. Special attention will be paid on safety of all cycles of operation with HTSL powder. During the Project execution the contacts with European Safety cluster was established.
The application of solid lubricant will allow decreasing oil lubricants and grease consumption. The main reasons of liquid (oil vapours) and gaseous (COx and NOx) carcinogen generation are high temperature between friction surfaces. The application of solid lubricants will greatly reduce this problem. As a results, new standard for air pollution in heavy industry could be introduced (<35 micorg/m3 for aerosols; <20 ml/m3 for CO; <50 microg/m3 for NOx; <80 microg/m3 for hydrocarbons ). Better working conditions will lead to decreased dangerous and mortal illnesses.
Dissemination of the project and the results.
The consortium acknowledged that communicating the importance of research and development and its contribution to economic competitiveness is an essential dimension of achieving project objectives but also an opportunity to increase the visibility for European companies in coating and P/M technologies. During the runtime of the project partners performs a range of dissemination activities as set forth by Work Package 6 with the aim to facilitate the commercialization plans of SMEs and ease the way to market. It will also promote further research in this field and contribute to strengthening the European knowledge infrastructure on high temperature operating problems.
Objectives of dissemination. In light of the project relevance the main dissemination objectives were:
-Raise awareness on high temperature operation problems and provide an insight on the solutions that the Higraph technology can offer;
-Emphasise the economic and environmental aspects and the potential impacts;
-Provide appropriate information to parties in industry and academia that are potentially impacted or interested in the work performed in the Higraph projects;
-Promote the results to potential customers and third party collaborators and highlight the differences from conventional processes to improve high temperature friction and wear resistance;
-Network with synergetic projects/research initiatives;
-Provide evidence based findings such as publishable results of testing and pilot production and involve relevant stakeholders in discussion.
These objectives were achieved and were taken into consideration during the whole project period. The results were published and presented at several workshops, conferences and trade fairs.
Targeted audience. In choosing the most relevant selected dissemination platforms and means to reach out the following specific audiences were considered:
-Relevant industry segments;
-Potential end-users, third party collaborators, manufacturers, and distributors etc. in Powder metallurgy, Thermal spaying, Surface coating, Furnace manufacturers, Machine Tools, Automotive, Aerospace, and Energy sector;
-Interest groups: associations and technology platforms such as the European Powder Metallurgy Association, etc.;
-Research community: researchers, scientists, engineers and students in the domain of tribology, material science, surface and coating technologies, powder metallurgy;
-Other project initiatives implementing research and development in related fields;
-General public: all other parties interested in collaborative R&D, industry and academia partnership and novel technologies with potential wider impact on everyday life.
Dissemination channels and instruments. The list below depicts the groupings of dissemination platforms and instruments that are most suitable for delivering targeted massages for different the different audiences. However some of these are interrelated and potentially can raise attention in all stakeholder domains.
-General Public: Project website, Project Visual Identity, Digital Media, Articles on popular websites, Mass Media, Oral and printed presentations;
-Relevant industry segments: Trade Fairs, Exhibitions, Industry events, Networking events, Partnership brokerage events, Market relevant project presentation, Workshops, Business Meetings, Direct Mailing;
-Research Community: Scientific Publications, Technical papers, Scientific thematic conferences, Networking events, use of research forums.
The following dissemination actions were completed:
-Creation of the Project visual identity: Project Logo, Presentation template, Typical images used in public materials, Project flyer and posters, General Project presentation for Trade fairs, Conferences and Workshops;
-Creation of the Project website (http://higraph.eu) with confidential and public parts;
-Creation of Newsletters: Several issues were prepared during the project introducing the aims and general objectives of the project and provide a short description of the consortium members with links to their websites and logos;
-Presentation of the Project results on Conferences, Workshop and Trade Fairs: 9 Reports on International Conferences (2 presentation are planned for 2016), 4 presentations on Workshops, 3 presentations on Trade Fairs (3 planned for 2016);
-Publications of articles: 9 articles were submitted for publications.
-Organisation of International Workshop: The International Workshop “Diagnostic Systems for Plasma Processing” was organised by IfU on 29 September 2015;
-Creation of Video presentation of the Project including the following main parts: The Goal, The Applied Solutions, The Consortium, The main Project Results, The Project contact details. The video file was uploaded on YouTube and website of the Project. DVD was issued and distributed using the contacts list of RTD and SME partners.
List of Websites:
http://higraph.eu
The Coordinating organization:
IfU Private Research Institute GmbH (IfU)
Gottfried-Schenker-Str. 18
Phone: +49-37208 889 0
E-mail: higraph@ifu.de