Oxygen boost diffusion for the deep-case hardening of titanium alloys

In order to withstand the high stresses encountered in such general engineering components as bearings and gears, deep case hardening is necessary. In the present investigation, oxygen boost diffusion of titanium alloys has been explored and a new oxygen boost diffusion technique has been developed for deep case hardening of titanium and its alloys. The oxygen boost diffusion process essentially consists of thermal oxidation in air followed by diffusion in vacuum. A total hardened case of about 300 μm can be successfully achieved following the oxygen boost diffusion treatment. It has also showed that the oxygen boost diffusion treated titanium alloys exhibited significantly improved abrasive wear resistance. Based on the experimental results, the boost diffusion and hardening mechanisms are discussed.