Microstructure and Property of Four Typical WC-based Cermet Coatings by High Velocity Oxygen Fuel Flame Spraying

WC-based cermet coatings including WC-12Co, WC-10Co4Cr, WC-10Ni and WC-20Cr₃C₂-7Ni were prepared on surface of carbon steel by high velocity oxygen fuel flame spraying. The phase composition, hardness, wear resistance and corrosion resistance of different coatings were investigated and compared. The results show that a few W₂C decarburization phases were formed in WC-12Co, WC-10Co4Cr and WC-10Ni coatings. The four coatings were dense, and well bonded to the substrate. The hardness and wear resistance of WC-10Co4Cr and WC-12Co coatings were similar and the best, followed by those of WC-10Ni coating, and those of WC-20Cr₃C₂-7Ni coating were the worst. The corrosion resistance of WC-10Co4Cr coating was the best, that of WC-10Ni coating was slightly lower, and that of WC-20Cr₃C₂-7Ni coating was the worst. WC-10Ni coating had moderate wear resistance and slightly lower corrosion resistance comparing to WC-10Co4Cr coating, so was suitable to replace WC-10Co4Cr coating for wear and corrosion proof of mechanical part surface under normal service conditions.