The concept of incorporating a solid lubricant, Ag, within a hard carbide film for vacuum tribology applications is investigated in this paper. SiC/Ag and HfC/Ag films were deposited by magnetron co-sputtering at 200 deg C onto Si and 440C steel substrates. The composition, phase structure and morphology in these films was examined using x-ray diffraction, scanning electron microscopy and x-ray photoelectron spectroscopy. The microstructural analysis showed that Ag was incorporated both within and on the surface of the films. There was a strong tendency for Ag to segregate to the film surface. Vacuum tribology tests were conducted using a ball-on-disk test in a vacuum of 1.33 mu Pa with a 1 N load for 10,000 cycles. For both the SiC/Ag and HfC/Ag films, the average friction coefficients were reduced when sufficient Ag was present. These tests show that caribde-silver composite films hold promise for vacuum tribology applications.
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