Tribological properties of amorphous carbon in hydrochloric acid with ta-C for counterpart

In this paper, the chromium doped diamond-like carbon film (Cr-DLC) and tetrahedral-amorphous carbon (ta-C) were prepared through Magnetron sputtering and Arc ion plating, respectively. Microstructures, mechanical and tribological properties of Cr-DLC film and ta-C were systematically investigated. Results showed that when the GCr15/Cr-DLC as a tribo-pair was exposed to an aggressive solution, it exhibited a high friction coefficient and wear rate. Tribo-chemical reaction and mechanical action played significant roles during sliding. However, the ta-C/Cr-DLC as the tribo-pair could present superior tribological performances in an aggressive solution. It is not only attributed to the dangling bonds of carbon atoms on the sliding interface that is sufficiently passivated by -OH or -H groups, which weaken the strong covalent bond between the sliding interfaces, as well as the formed low-adhesion water layer plays a role of lubrication and protection in a certain extent. It also related to the graphitization transfer layer formed in the sliding process. This investigation has a progressive significance for the practical application of Cr-DLC in HCl.