Elevated temperature tribological properties of a-C:Si films sputtered from SiC target in the presence of C2H2 gas

The study investigated the tribological behavior of the a-C:Si films sputtered from SiC target in the presence of C2H2 gas at elevated temperatures. The results showed that the a-C:Si films exhibited excellent tribological property until 450 degrees C, with a friction coefficient (COF) below 0.09, and a low wear rate in the 10(-7) mm(3)/N<middle dot>m order of magnitude. The friction mechanisms of the films varied depending on the test temperature. At temperatures below 200 degrees C, the films show low COF and excellent anti-wear performance due to their unique composite structure of thin films, which had weak interactions with Al2O3 ball. At 300 degrees C, the films showed good tribological properties attributed to the formation of transfer layer consisting of Si, C and O. This transfer layer contributed to reduce COF and wear rate. At temperatures of 400-450 degrees C, the dominant wear mechanism changed to oxidation wear, and the presence of SiO2 tribo-film resulted in low COF and wear rate.