Thermal Oxidized Coating on Surface of Titanium Alloy for Improvement of Tribological Properties in Vacuum

A hardened layer possessing good bonding strength with substrate has been prepared on the surface of aTi-6Al-4V alloy using the process of thermal oxidation followed by vacuum diffusion. The friction and wear tests are performed in vacuum. The results show that the hardened layer, which thickness can reach 180μm, comprises a thin surface oxide layer and an oxygen diffusion zone. After vacuum diffusion at 820°C, it is found that the decrease rate of the hardness becomes slower with increasing the depth within the diffusion layer,resulting from the formation of the Ti3Al phase. The friction coefficient and the wear rate of the thermal oxidation/vacuum diffusion treated Ti-6Al-4V alloy against AISI 52100 steel are efficiently reduced.