Mechanical properties of WC-Co coatings with different decarburization levels

In this study, two kinds of WC-Co coatings with different decarburization levels were deposited by high-velocity oxy-fuel（HVOF） spraying using the ultrafine WC-Co composite powder and commercial micronsized powder, respectively. The hardness and elastic modulus were measured on the top surface and cross sections of the prepared coatings by the nanoindentation method. The results show that the ultrafine-structured coating has much higher density and inhibited decarburization than the conventional coating, which thus results in higher hardness and elastic modulus values than the micronsized coating. The wear resistance of thermal-sprayed cermet coatings greatly depends on the cross-sectional hardness and elastic modulus which reflects the bond strength between splats to some extent. Based on the analysis, a better understanding of the microstructure and properties in cermet coating materials was obtained.