Tribological studies on ultra-fine diamond composite coatings deposited on tungsten carbide

Ultra-fine diamond composite coatings were deposited onto the Co-cemented tungsten carbide (94 wt.% WC–6 wt.% Co) substrates via electron aided hot filament chemical vapor deposition (EAHFCVD). These diamond coatings have been tested in dry sliding against SiC particles reinforced aluminum-matrix composites materials (15% SiC PRAMC), metal copper wire core material (Cu-1) and metal aluminum wire core material (Al-0) by tribological pin-on-disc tests under a range of test conditions to evaluate the tribological performances of these ultra-fine diamond composite coatings. It was found that the friction coefficient of ultra-fine diamond composite coatings was remarkably decreased in comparison with that of uncoated carbides and normal diamond coatings after the initial period of rising rapidly. Furthermore, the friction coefficients between ultra-fine diamond composite coatings and SiC PRAMC, Cu-1, and Al-0 were measured as 0.122, 0.143, and 0.165 respectively during the steady-state period of friction, and these data were analyzed based on physical and chemical theory.