LAUSR

Abstract Hydrogenated amorphous carbon (a-C: H) films show high friction and wear in aqueous solution, especially in simulated acid rain, which restrict their application. This problem can be solved by doping Si in the film. Therefore, the influence of the Si content on the composition, structure, mechanical and tribological properties were investigated by various methods in this work. Results show that the contents of Si C bonds and sp3C, including sp3CH and sp3CH2 as well as the surface roughness increase with increasing Si content in the film. Furthermore, films with higher Si content (>8.33 at.%) show better tribological properties in the simulated acid rain. The self-lubricated behaviors are attributed to the adequate content of Si can form silicic acid at the counterface under low applied load and short sliding time in the simulated acid rain. Additionally, the tribological behaviors of the film are mainly depended on the formation of silicic acid instead of graphitization of the film.