Study on wear resistance of WC-Co and NiCr-Cr₂C₃ coatings sprayed by HVOF

WC-Co and NiCr-Cr₂C₃ coatings were prepared on 45 steel substrate by means of high velocity oxy-fuel spraying (HVOF). Coating porosity, micro-hardness and loss of coating in the sliding wear test with lubricant were studied. Profiles of the sliding wear coefficients were described and the wear mechanisms of coatings were discussed as well. The results show that both of coatings are compact and the porosities are 1.29% and 1.08%, the hardness of two coatings are 1140 HV and 950 HV under the press of 300 gram. Abrasion of two coatings are stable and friction coefficient are both 0.1 when the time is beyond 25 minutes. The main abrasion modes of WC-Co coatings are the fatigue desquamation and the micro-cutting and adhesive wear. Carbide flake and scratches of NiCr-Cr₂C₃ coating are serious and micro-cracks are enhanced greatly.