Optimized Coatings/Substrate Combinations Under Contact Loadings Through a Combined Experimental and Numerical Methodology

For a long time the search of suitable coatings/substrate combinations was mainly based on empirical approaches using results issued from scratch, hardness, wear tests or extrapolating previous experiences to different configurations. There is an increasing need to understand and to be able to predict the performance of the coatings To reach these objectives a methodology encompassing the development of coatings, the complete characterization, the testing and the modeling must be carried out, requiring a multi-disciplinary approach implying collaborations. Concerning the characterization, the number of parameters to be addressed is huge, spanning from micro-structural, materials, physical, mechanical and surface properties to the behavior of complex coatings/substrate systems under representative loading conditions. Further these properties may be thickness dependant. In addition, there is a serious lack in fundamental resistance, fatigue data of the coatings and the interfaces. The choice is all the more difficult since many coating combinations are feasible, from single layer to multilayered coatings or graded coatings over a substrate. A review of the different 2D and 3D numerical models developed will be presented with some applications.