DIAMOND-LIKE CARBON COATINGS ON TI-6AL-4V

Diamondlike carbon (DLC) was deposited onto Ti-6Al-4V, using a non-mass analyzed ion beam of methane, for subsequent coating characterization. Prior to successful deposition of DLC, a bond layer development study was required which resulted in the selection of SiC as an effective bond layer material. The DLC/SiC coating exhibited an extremely smooth surface finish, similar to the polished Ti-6Al-4V substrate. Tribology tests, conducted in room temperature air, showed a frictional dependence on load similar to that observed for solid lubricant films, and relatively low friction values, such as 0. 1-0.2. No DLC delamination and minor polishing wear was observed for loads up to 1 kg, which corresponds to an initial Hertz stress above the yield strength of the substrate material DLC failure at the SiC bond layer-Ti-6Al-4V interface was eventually observed at an extremely high load of 2.5 kg.