Low-friction carbon-based tribofilm from poly-alpha-olefin oil on thermally oxidized Ti6Al4V

Titanium alloy shows a poor tribological performance even under lubrication. In this paper, we report the formation of carbon-based tribofilms from poly-alpha-olefin (PAO) base oil molecules on Ti6Al4V (Ti64) samples after thermal oxidization treatment, where PAO enabling base oils to provide not only the fluid but also the solid tribofilm. Ball-on-disk tests at contact pressures of 2.0 GPa reveal that these carbon-based tribofilms on thermally oxidized Ti64 samples decrease the friction coefficient by about 3 times and wear rate by up to 2 orders magnitude as comparing to untreated one.