Effect of Nickel Element Diffusion on the Tribological Properties of Cemented Carbide Materials under High Temperature Condition

An investigation was conducted in this study to clarify the effect mechanism of nickel element diffusion on the tribological properties of cemented carbide tools. An element diffusion experiment between cemented carbide inserts and nickel powder under high temperature condition was performed in a muffle furnace device. The surface morphology and chemical element content of the test samples were observed and measured with a white light interferometer and x-ray diffraction instruments. Tribological experiments were conducted on a friction and wear machine and the friction coefficient and wear scar were obtained. Experimental results show that the surface roughness value and element diffusion phenomenon of the test samples increase with increasing heating temperature. The same law applies to the friction coefficient and wear quantity. However, the change degree of these results varies under different heating mediums. The best surface quality and tribological properties of the test samples are obtained in nickel powder medium compared with those in air and iron powder mediums. The analysis results indicate that the infiltration of nickel element into the sample surface exhibits an alternative bonding action for the cobalt element that is leaching out. Moreover, the oxidative expansion phenomenon is reduced due to the good antioxidant properties of nickel, inducing better surface morphology and tribological properties. This study laid a theoretical foundation for the tool wear mechanism of cemented carbide materials under the nickel-based alloy manufacturing process.