Microstructure and corrosion behaviour of WC-Co coating fabricated by plasma arc welding

Abstract

The WC-Co composite coating was prepared on SS 316L by plasma arc welding technology. The microstructure, phase composition, and microhardness of the WC-Co composite coating were thoroughly studied. The corrosion behaviour including electrochemical corrosion, cavitation erosion, and erosion corrosion was tested. The results showed that the WC-Co coating exhibited a good metallurgical bond with the substrate. The average microhardness of the WC-Co coating reached 1785 HV, which was 9.4 times that of the SS 316L. The corrosion current density of the WC-Co composite coating was one order of magnitude lower than that of the substrate. Meanwhile, the cumulative mass loss of cavitation erosion and erosion corrosion of the WC-Co composite coating was much lower than that of the SS 316L.