Design of low-friction and anti-corrosion a-C:H:SiOx films

Some properties of hydrogenated amorphous carbon (a-C:H) film are effectively improved via silicon (Si) and oxygen (O) incorporation, such as high friction coefficient (0.1–0.4) in the atmospheric environment and serious pitting corrosion caused by pores in the film. In this study, the Si and O incorporated a-C:H (a-C:H:SiOx) films were deposited by plasma-assisted chemical vapor deposition (PACVD) technology using acetylene (C2H2) and hexamethyldisiloxane (HMDSO) as precursors, and then studied their tribological and anti-corrosion properties in the atmospheric environment. The a-C:H:SiOx films exhibited impressive friction coefficient (0.05–0.07) and wear rate (1.8–5.6 × 10−7 mm3/Nm) owing to silicon oxide formed on surface of wear scar during friction process. Compared to pure a-C:H film, Si and O incorporated greatly increased the deposition rate of films. Therefore, a slightly increased wear rates of a-C:H:SiOx films are acceptable as long as the films are thick. In addition, the incorporation of Si and O makes the film have high resistance, thereby improving the corrosion resistance of the film. This excellent pitting corrosion resistance of the film can make up for the defects of the a-C:H film such as pinholes. The a-C:H:SiOx film with excellent tribological properties and corrosion resistance will have a good application prospect under the combined action of corrosion and mechanics.