Tribological behavior of sliding diamond-like carbon films under various environments

摘要

Tribological behaviors of amorphous diamond-like carbon (DLC) films were experimentallyevaluated under various environments using a steel ball-on-disk wear-rig at dry sliding surfaces. TheDLC films were prepared on Si wafer by r.f. PACVD method using benzene (C{sub}6H{sub}6).Every test was performed under the normal load 4.9 N and sliding velocity of 0.05 m/s, and thecoefficients of friction of DLC films were measured with the contact cycle. When the test wasperformed under a vacuum, the coefficient of friction of DLC films showed a significant fluctuationwith the contact cycles, remarkably accompanied with roll-shaped polymeric wear debris. Anothertest using thermally-baked DLC films showed that the friction was lower and more stable. Under ahumidity controlled air, friction of DLC films was also stable. Tests with dry O{sub}2 and N{sub}2gas were extended to find any other environmental factors which could affect the tribologicalbehavior of DLC films. It was found that tribological behavior of DLC films was dependent on theformation of friction layers which were mainly affected by the environment. In the final discussion ofthis work, effects of environment on the tribological behavior of DLC films were combined anddiscussed in terms of tribo-chemistry of DLC films.