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Development of engineering surface coatings obtained by advanced, cost effective and environmentally friendly technologies

Exploitable results

The SHS process is a process, coming originally from the ex-Soviet Union, allowing the sintering of materials a low temperature. The intrinsic character of "Self Propagating Synthesis" leads to an easy, versatile and very low cost process for the sintering of ceramics, cermets and over kind of materials. At the start of the project in 1998, only three European articles referred to this process. The university of Cagliari, partner of DESCO, was the unique European institute working extensively on this subject. The introduction of the SHS technology within the project was of the highest innovation and its introduction in the field of Thermal Spray was completely new, and as a consequence, very risky. The research undertaken (INSTM, IAM, Flametal) turns out to prove and demonstrate that SHS powder are usable for Thermal Spray and presents a real cost effectiveness attraction. It must be mentioned that at the end of the project, some articles about thermal sprayed SHS powders have been published in the most academic thermal spray reviews, demonstrating the highest interest of this process.
The modelling and prediction of wear is something that has proved extremely difficult to achieve, and usually experimentally fitted relationships and empirical methods are employed to predict wear rates and component lifetimes. This is especially true for new generation high performance surface coatings now seen more commonly in industrial applications. This result, a modelling methodology based on a fracture mechanism approach for the prediction of the propagation of cracks i.e. of the life-time of the coating, is innovative. The result has significant relevance to the research community, in that new scientific methods have been developed, and to industry, in that a predictive methodology now exists to aid in coating selection and assessment. Currently the methodology is being disseminated through journal and conference.
A formulation of a model that establishes a link between a local and global friction coefficient for the tested AlSiMo coatings on synchronizer rings has been developed. Synchronizer engagement has been modelled using various friction coefficient to determine the effects that the wear of the coating has on the surface geometry and subsequently on the computed friction coefficients. This computer code will be of extremely relevance for the understanding of physics laws that govern the behaviour of the synchronizer rings.