Influence of Ag on the microstructure, mechanical and tribological properties of SiC-Ag composite film deposited by the industrial DC magnetron sputtering system

Industrial synthesis and application of green self-lubricant hard film have been considering as a hot spot in the field of surface engineering. In this paper, the Ag was added into the amorphous SiC matrix to deposit a series of Ag-SiC composite film with various Ag content using an industrial DC magnetron sputtering system, to enhancing the tribological properties for the real self-lubricant applications. Results showed that a dual-phase of fcc-Ag and amorphous SiC co-existed into the films regardless of Ag content. The accumulation of nano-particles of Ag could be detected in the amorphous matrix. The addition of soft Ag into the matrix gradually decreased the hardness from 21 +/- 1 GPa for the binary SiC film to 7 +/- 1 GPa for the composite film at 15.3 +/- 0.8 at.% Ag, whilst it also dropped room temperature the average friction coefficient. Both the enhanced anti-friction property and the degradation of hardness attributed to the wear rate first dropping and then rising as a function of increase of Ag content and the lowest wear rate could be detected for the film at 4.3 +/- 0.2 at.% Ag.