Tribological properties of HVOF sprayed WC-10Ni coating in corrosive environments

WC-Ni coating possesses superior wear and corrosion resistance and it can be widely used on the surface of pump shafts in the petrochemical field, crusher hammers and liners in mining machinery to prevent the base metal from being damaged. In this study, microstructure, mechanical properties of HVOF sprayed WC-10Ni coating and its systematically properties of friction and wear under different combinations of counterparts and test environments were examined. The primary phase of the coating was WC, accompanied by only traces of W2C and NiO. The coating had a porosity as low as 0.74 %, the surface hardness of approximately 1264 HV0.3, and the bonding strength as high as 68 MPa between coating and substrate. WC-10Ni coating/ceramic tribo-pairs exhibited lower friction coefficients in corrosive environments than in dry condition. WC-10Ni/Al2O3 and WC-10Ni/SiC tribo-pairs showed friction coefficients below 0.15 in NaOH and HCl environments, while the wear rates of WC-10Ni coating after sliding against Al2O3 was (3.36–11.9) × 10-8 mm3/N⋅m. On the whole, WC-10Ni/SiC tribo-pair possessed excellent tribological properties in NaOH environment, while WC-10Ni/Al2O3 tribo-pair was more suitable for applicating in NaCl and HCl tribo-corrosive environments.