Surface Characterization and Blood Compatibility of Diamond-Like Carbon (DLC) Films on the NiTi Alloys

Diamond-like carbon (DLC) films are fabricated on the NiTi alloys at room temperature using plasma immersion ion implantation and deposition (PIIID). The effects of the substrate bias on the characteristics of the DLC films are systematically examined to correlate to the blood compatibility. The results show both the ID/IG ratio (inverse trend in the sp^3/sp^2 ratio) and the G peak position first decrease and then increase, while the nano-hardness first increases and then decreases with the increase of the substrate bias, and the blood compatibility of the coated sample is better than that of the uncoated sample and the DLC films on the NiTi alloys deposited at the substrate bias of 25 kV possesses better blood compatibility than the films deposited at other substrate bias. It can be concluded that the blood compatibility of the DLC films on the NiTi alloys is influenced by the sp^3/sp^2 ratio.