Increasing the Hardness and Wear Resistance of Commercial-Purity Titanium by Anodic Plasma Electrolytic Carburizing

Abstract—The possibility of using the technology of anodic plasma electrolytic carburizing in a nontoxic electrolyte to increase the microhardness and wear resistance of commercial-purity titanium is considered. The surface morphostructure and roughness the material after saturation, the microhardness distribution in the surface layer, and the tribological behavior of the modified surface are studied. Wear resistance tests are carried out under dry friction conditions using quenched tool alloy steel as a counterbody. Plasma electrolytic carburizing in an aqueous electrolyte containing ammonium chloride and glycerin is found to increase the surface hardness by 3.5 times, up to 900 HV0.01, due to the formation of a diffusion layer. The tribological behavior is influenced by high-temperature surface oxidation (leading to the formation of an outer oxide layer), the formation of a modified layer, and the surface relief of titanium. The coefficient of friction after treatment increases by 1.2 times and the mass wear decreases by 3.4 times as compared to the untreated surface of titanium parts.