Effect of chlorine doping on tribological properties of amorphous carbon films deposited by plasma-based ion implantation and deposition

Many efforts to improve the tribological properties of amorphous carbon films have been reported. We used chlorine doping to reduce the friction coefficient of amorphous carbon films under non-lubricated conditions. This forms chlorine compounds, such as chlorinated tribofilm, at the sliding interface between films and counter parts. A friction test indicated a lower friction coefficient and lower attackability for chlorine-containing amorphous carbon films compared with hydrogenated amorphous carbon films. Time-of-flight secondary-ion mass spectroscopy (TOF-SIMS) confirmed the existence of chlorine-bonded ions along the wear track of chlorine-containing amorphous carbon films suggesting that chlorinated compounds improve the friction properties of these films.