TRIBOLOGICAL BEHAVIOR OF SLIDING DIAMOND-LIKE CARBON-FILMS UNDER VARIOUS ENVIRONMENTS

Tribological behaviors of amorphous diamond-like carbon (DLC) films we re experimentally evaluated under various environments using a steel b all-on-disk wear-rig at dry sliding surfaces. The DLC films were prepa red on Si wafer by r.f. PACVD method using benzene (C,H,). Every test was performed under the normal load 4.9 N and sliding velocity of 0.05 m/s, and the coefficients of friction of DLC films were measured with the contact cycle. When the test was performed under a vacuum, the co efficient of friction of DLC films showed a significant fluctuation wi th the contact cycles, remarkably accompanied with roll-shaped polymer ic wear debris. Another test using thermally-baked DLC films showed th at the friction was lower and more stable. Under a humidity controlled air, friction of DLC films was also stable. Tests with dry 0, and N, gas were extended to find any other environmental factors which could affect the tribological behavior of DLC films. It was found that tribo logical behavior of DLC films was dependent on the formation of fricti on layers which were mainly affected by the environment. In the final discussion of this work effects of environment on the tribological beh avior of DLC films were combined and discussed in terms of tribe-chemi stry of DLC films. (C) 1998 Elsevier Science S.A. All rights reserved.