Electroless Plating of Ni Nanoparticles on WC to Assist Its Pressureless Sintering of WC-Ni Cemented Carbide with Enhanced Mechanical and Corrosion-resistant Performance

Ni nanoparticles were coated uniformly on the surface of WC powder via a facile electroless plating method (abbreviated as WCN-EP), and then consolidated for mechanical and corrosion resistance performance characterization, in comparison with hand mixed WC-Ni (WCN-H). Under the optimized electroless plating parameters, Ni particles, less than 1 µm in average diameter, were found to be uniformly and densely wrapped on the surface of the tungsten carbide matrix of WCN-EP. In comparison, in WCN-H, the Ni particles about 1.8 µm in average diameter, were randomly distributed together with irregular WC particles. The uniform coating of Ni was found to assist the densification process of WCN-EP effectively, with higher densities and less pores than those of WCN-H at the Ni content of 10.6wt%, 25.5wt%, and 30.3 wt%. However, at the Ni content of 18.8wt%, the relative densities of WCN-EP and WCN-H both increased to the maximum value of 98%. The maximum hardness of the consolidated WCN-EP was 82.6 HRA, about 1.2 HRA higher than that of WCN-H. In addition, the consolidated WCN-EP also exhibits a superior corrosion resistance by the polarization curve analysis at an electrochemical workstation..