Microstructure and tribological properties of cold sprayed WC_p/Ti composite coatings on Ti6Al4V titanium alloy

In this study, WC_p/Ti composite coatings with the WC proportions of 30.1–44.1 vol% were cold sprayed using powders with WC proportions of 40–80 vol%. Coatings are well bonded to Ti6Al4V substrates, with a thickness of more than 3.8 mm, and have dense microstructure with a porosity of lower than 1.0% despite the high proportion of ceramics. The wear testing shows that coatings exhibit excellent tribological behavior with wear rates reduced by an order of magnitude compared with Ti6Al4V substrate. WC particles help develop more stable mechanically-mixed layers, obtaining a stable coefficient of friction and lower wear. The significance of crack extension resistance and plastic deformation resistance of Ti matrix reflected by H/E and H³/E², respectively, in determining tribological behavior is also discussed.