ENHANCEMENT OF ADHESION STRENGTH AND TRIBOLOGICAL PERFORMANCE OF CVD DIAMOND FILMS ON TUNGSTEN CARBIDE SUBSTRATES WITH HIGH COBALT CONTENT VIA AMORPHOUS SiC INTERLAYERS

摘要

In this study, the diamond films are deposited on tungsten carbide substrates with 10 wt.% Co via hot filament chemical vapor deposition (HFCVD). Amorphous SiC (a-SiC) interlayers with various thicknesses are fabricated between the diamond films and tungsten carbide substrates via precursor pyrolysis to promote the adhesion and friction performance of diamond films. Indentation tests are performed to evaluate the adhesion of the as-fabricated diamond films, which show that the a-SiC interlayers can greatly improve the adhesive strength between diamond films and tungsten carbide substrates with 10 wt.% Co. Moreover, the thickness of a-SiC interlayer is of great importance for the effectiveness on the film-substrate adhesion enhancement. The optimum thickness of a-SiC interlayer is 1 mu m. Afterwards, ball-on-disc experiments are chosen to check the tribological properties of the as-fabricated a-SiC interlayered diamond film specimen with the optimum interlayer thickness, which exhibits lower friction coefficient than the conventional diamond film with no interlayer.