Abstract
Friction and wear tests were conducted for two kinds of material combinations: a DLC-coated and sintered-graphite-carbon material combination, and a non-coated and sintered-graphite-carbon material combination, for comparison. DLC showed a higher friction coefficient than non-DLC materials. Carbon transfer films were only observed at certain places on the DLC surfaces, while most non-DLC surfaces were coated with those films. However, for DLC specimens, the high friction was found to be attributable to the transfer-film area but not non-transfer-film area (i.e. DLC itself). The sintered-graphite-carbon specimens having slid on DLC had little oriented surface layers due to anti-adhesion and amorphous properties of DLC while those having slid on non-DLC were strongly oriented to the sliding direction. Thus, the surface orientation was necessary for sintered carbon graphite to indicate low friction when sliding on its transfer film, and the high friction of DLC was due to the sliding between the little oriented sintered graphite carbon and the transfer film.
