Corrosion resistance enhancement of WC cermet coating by carbides alloying

A new type of WC-based coating was prepared using a specially designed WC-Co2Cr3 powder. The microstructure and corrosion resistance of the present coating were examined and compared with those of the conventional WC-10Co-4Cr coating. It was found that Cr dissolved homogeneously in Co, WC and W2C phases in the WC-Co2Cr3 coating. However, in the conventional coating Cr mainly exists in Co. The potential difference between the carbides and metallic binder was significantly decreased in the WC-Co2Cr3 coating owing to Cr dissolution in carbides. The resistance against the micro-galvanic corrosion is then remarkably enhanced compared to the conventional WC-based coating.