Effect of grinding on surface characteristics of HVOF-sprayed WC-10Co-4Cr coatings

摘要

The aim of this research was to investigate the effect of the grinding depth of cut on surface quality and corrosion behaviour of WC-10Co-4Cr cermet coatings. Accordingly, a WC-10Co-4Cr coating with 400 mu m thickness was deposited on the carbon steel substrate using a High-Velocity Oxygen Fuel (HVOF) process. Consequently, the effect of different depths of cut on the coating properties was evaluated. Porosity, surface roughness and microhardness of as-sprayed and ground coatings were measured in order to investigate the effect of grinding on the coating characteristics. The corrosion behaviour of the coatings was evaluated using open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarisation tests. The results indicated that after grinding, the porosity and microhardness of the coatings were increased and the surface roughness was decreased. Furthermore, the increase in the depth of cut increased the coating porosity and microcracks. Therefore, the corrosion resistance of the coating was decreased.