Final Report Summary - IPACTS (International Partnership for Advanced Coatings by Thermal Spraying) Introduction The seventh framework programme “International Partnership for Advanced Coatings by Thermal Spraying” (IPACTS), Marie Curie Actions with grant number 268696 involves initially four universities: two European universities: the University of Technology of Belfort-Montbeliard, (UTBM), France, Nottingham University (NTHU), UK, and two Chinese universities: Tsinghua University (TU) and Xi’an Jiaotong University (XJU). During the programme another European university joined in: Cranfield University, UK. This programme covered four years from 2011 September 1st to 2015 August 31st. The main objectives of this program are to establish close relationships between these universities, to execute an innovative exchange and training programme, to gather the very best research teams in this field. Research efforts have been made to create a platform for research training and transfer of knowledge, both within the network domain and towards the public domain. A key element of this project is to provide researchers, young researchers in particular, intensive training via research programmes as well as a complementary skills training in order to become trainers of the future in a pluri-disciplinary field of academic, industrial and societal issues. This project lays the foundation to establish collaborative mechanisms for long-term partnerships between the EU and China researchers and institutes on surface engineering technologies and other challenges of the 21st century.Scientific highlights and research achievementsThe main scientific objectives of this project were obtained,5 software were established for modelling different new thermal spray processes: plasma spraying, cold spraying and HVOF flame spraying. The model of HVOF was established and some results were obtained. In this report the effects of solid nanoparticles percentage, loading on liquid feedstock trajectory in high velocity suspension flame spray process are investigated. It is found out that small droplets with high concentrations have high surface tension and initialization of fragmentation process is difficult. Vaporization is the dominant factor controlling the process for small drops and it will result in leaving nanoparticles in the middle of barrel with prior evaporation of solvent. However, larger droplets undergo sever fragmentation inside the combustion chamber and release nanoparticles in the middle of barrel and while with higher concentration of nanoparticles they may leave the gun before complete evaporation. For cold Spray process, the critical velocity is the most important parameter, only if impact velocity is over the critical velocity, a transition from erosion to deposition occurs. This study used an Eulerian formulation available in ABAQUS software to show particle deformation processes at different impact velocities for materials. Results show that the jet composed of both the particle and substrate materials or one of them could prove the critical velocity and the onset of adiabatic shear instability. Based on the morphology and strain characteristics of the six materials, their deposition models can be classified as coordinated deformation and uncoordinated deformation patterns. In conclusion, the present model can provide abundant information involved in cold praying.Arc behaviour in plasma gun for plasma spraying was also simulated. The three-dimensional steady-state non transferred plasma arc was investigated using computational fluid dynamics (CFD) with user defined functions. It is found that the temperature and velocity inside the plasma column reduce as the deviation distance increases, but the temperature near the arc-root attachment shows an increasing trend. Besides, it is also found that the arc length decreases with increasing the deviation distance.Several new processes were developed in this programme for example, the suspension plasma spraying in very low pressure. This method was employed to deposit nanostructured YSZ coating at low pressure down to 100 Pa. The axial injection mode was adopted to improve the enthalpy exchange between the plasma jet and sprayed material. The relatively dense coatings were obtained due to the higher velocity of particles accelerated by the relatively higher velocity of the plasma jet at low pressure. It is revealed that the crystallite size of as-sprayed coating is reduced from 30 nm for the feedstock to about 20 nm after the thermal spray process at low pressure. It is also found that the mean value of elastic moduli shows a decreasing tendency whereas the hardness shows a mean value up to 5.77 GPa at a stand-off distance of 200 mm. The hardness and the elastic moduli increase by 61% and 31% in comparison with the obtained values by SPS at atmospheric ambient.High performance coatings are developed for industry. Dry ice treatment in plasma spraying was proposed to a French industry (Radiance, Albertville, France) for improving their productions. Solid CO2 (dry ice at a temperature of -78.5°C), as a blasting medium, is accelerated and carried to the substrate by compressed air through a gun. It is also believed that dry-ice blasting can potentially clean the substrate surface, reduce the oxide and porosity, increase the deposition efficiency and even increase the adhesive strength and reduce the pollution in the spray booth by the cryogenic, mechanical effect. The most commonly used metallic, alloy and ceramic coatings, such as, FeSiB, aluminium, Al2O3 and Cr2O3 coatings, were investigated in this study. High quality nano-deposition rate is achieved for TiO2. Nanocrystalline dye-sensitized solar cell (DSC) has been attracting increasing attention owing to its low cost, high stability and colorful decorative appearance, since a high energy conversion efficiency of 7.1% was reported by Gratzel in 1991. The recently reported efficiency of 13% makes it a strong competitor against silicon based solar cells. A nano-porous TiO2 coating, the important part in DSC, serves as the support of dye molecules and the electron transport route as well. In this program, room temperature cold spray technique is utilized to produce nano-TiO2 coatings for high efficiency DSC. The feedstock preparation, coating deposition, microstructure characterization, assemble of solar cells and photovoltaic performance characterization are examined towards the development of high quality nano-deposit of TiO2.Teaching and Training activities (workshops...)Thanks to the Marie-Curie IPACTS program, extensive exchanges between European universities and Chinese universities were performed. A large number of researchers have been trained with fruitful experiences. A significant number of articles issued from collaboration works were published in international journals.An EU-China network was formed. Under the support of the French embassy in China, a joint laboratory (Franco-Chinese joint laboratory of Surface Engineering) has been created between LERMPS-Technology University of Belfort-Montbeliard, TSL-Xi’an Jiaotong University, Guangdong Institute of Industrial Technologies in October 2013. The third workshop of IPACTS program was organised by this joint laboratory in September 2014. Several real collaboration programs will be carried out. This research platform will become a permanent bridge between EU and China. A joint Franco-Chinese laboratory was established, some projects were approved by Chinese local government. 4 workshops were organised, two in China and two in France (see reports in annexes), one of them was co-organised with a European Cold Spray club, one of them was co-organised with Guangdong Institute of Industrial Technologies supported by France Embassy in China. The 83 person-months of exchanges are executed between partner universities.Dissemination of results (conferences, publications...)The research works were carried out in the participated laboratories with the planned tasks achieved. More than 30 papers are published in international journals from this programme and about ten oral presentations are delivered in international conferences. More articles will be published in the future. The scientific results are very encouraging and many of them need to be further investigated. Some of them, like dry ice during plasma spraying can be explored to other thermal spray process. IPACTS program comes to an end but future collaborations between Europe universities and Chinese universities will continue over the years to come. Website : http://web.utbm.fr/ipact/
