Microstructure and wear resistance of HVOF sprayed WC-10Co-4Cr coating on Ti-6Al-4V

WC-10Co-4Cr coating was deposited on Ti-6Al-4V by the high velocity oxygen fuel spray process to improve the surface hardness and wear resistance. The results show that the porosity of the coating is 2.0%, the microhardness is 1300 HV0.2, the surface roughness Ra is about 6.0 μm, and the bonding strength is 70 MPa. SEM and XRD analyses show that the coating is composed of WC, W2C, and Co phases. Under the condition of dry sliding with a load of 20 N and frequency of 10 Hz, the volume wear rate of the WC-10Co-4Cr coating is 9.2 × 10−6 mm3/N·m, while the wear rate of the Ti-6Al-4V is 4.6 x10−4 mm3/N·m, which means that the coating significantly improves the wear resistance of Ti-6Al-4V. With the load increased from 20 N to 50 N, the wear rate of the coating changes little. The analysis of the worn coating surface shows that the dominant wear mechanism of WC-10Co-4Cr coating was abrasive wear.