Thermally sprayed cobalt-bonded tungsten carbide coatings have been widely used as various wear resistant materials in dry environment. However, generally they have poor corrosion resistance against aqueous solution. The WC-20 mass%Cr3C2-7 mass%Ni (WC-Cr3C2-Ni) spray material, which is a typical WC cermet with non-cobalt binding phase, is sprayed by means of the high velocity oxygen-fuel flame process. Substantial factors that are controlling the coating properties such as microstructure, electrochemical characteristics and abrasive wear resistance are evaluated compared with WC-12 mass%Co(WC-12Co) sprayed coatings. The diameter of the carbide particle, 2.80 mu m, and the length of the mean free path, 4.01 mu m, determined for WC-Cr3C2-Ni sprayed coatings are almost comparable to those for WC-12Co coatings, respectively. This results suggest that both coatings are almost equivalent in mechanical properties. The passive current density for sprayed WC-Cr3C2-Ni coating is about ten times less than that for WC-12Co coatings. The corrosion resistance of WC-Cr3C2-Ni sprayed coating in aqueous solution is superior to that of WC-12Co coatings. Microhardness and abrasive wear resistance of sprayed WC-Cr3C2-Ni coatings are comparable to those of WC-12Co sprayed coatings.
