Friction and Wear Behavior of Diamond-Like Carbon Film Prepared by Plasma Enhanced Chemical Vapor Deposition

Diamond-like carbon films were prepared on single crystal silicon substrate using direct current radio frequency plasma enhanced chemical vapor deposition (DC-RFPECVD). The structure and morphology of the films were analyzed by means of Raman spectroscopy and atomic force microscopy. The hardness of the film was determined using a nano-indenter. The friction and wear behaviors of the DLC film sliding against Al_2O_3 ball or GCr15 steel ball under dry- and water-lubricated conditions were evaluated using a UMT test rig. The morphology of the wear scar of the counterpart steel ball was observed sing a scanning electron microscope. It was found that the diamond-like carbon film formed on the Si surface was smooth and compact. The DLC film showed good friction-reducing and antiwear behavior as it slid against the ceramic and steel counterparts under unlubricated condition, which was ascribed to the graphitization of the DLC film and the formation of a DLC transferred layer on the counterpart surface. However, the DLC film showed poor friction-reducing and antiwear ability as it slid against the ceramic under water-lubricated condition. This was because water as the lubricant acted to restrain the graphitization of the DLC film and the formation of its transferred layer on the counterpart surface.