Influence of post-treatment on the tribo-mechanical properties of cermet coatings

Whilst innovative advancements in thermal spray technology, especially in terms of characterization of starting powders, coating processes and optimisation of coating process parameters have resulted in coatings of improved quality, there is an ever increasing demand to push the frontiers of coating applications. Post-treatment of thermal spray coatings either by HIPing (Hot Isostatic Pressing) or vacuum heating can thus offer one such opportunity by presenting a combination of coating and substrate properties not achievable by individual processes. Hence the aim of this study was to investigate the potential of two integrated process technologies of thermal spraying and HIPing. Tribo-mechanical properties of WC-Co coatings deposited by the HVOF process in the as-sprayed and post-treated conditions were thus investigated in this study. Results are discussed in terms of coating microstructure, sliding wear resistance, elastic modulus, hardness, residual strain and rolling contact fatigue resistance. These results indicate that significant improvements in coating performance can be achieved by appropriate design of post-treated components.