Friction and Wear of Nitrogen Incorporated Diamond-like Carbon Films under a Vacuum

 Tribological behaviors of nitrogen incorporated amorphous diamond-like carbon films were experimentally measured under a vacuum (3x10-5 Torr) using a ball (AISI 52100)-on-disk wear-rig. Nitrogen incorporated DLC films were deposited by r.f. plasma assisted chemical vapor depositionmethod. Mixtures of benzene and ammonia or nitrogen gases were used as the reaction gases for the r.f. PACVD, and Si (100) wafer was used as the substrate. In the tribo-test, effects of DLC film thickness and normal load in friction were measured and discussed. Results showed that friction of nitrogen incorporated DLC films from a mixture gas of benzene and ammonia was lower than tat of 100% benzene, specially in the measurement of minimum coefficient of friction. Differences in frictional characteristics of nitrogen incorporated DLC films wre explained with the changes in chemical structures of the films. Results also showed that friction of DLC films increased with the sliding contact cycle, which remarkably accompanied with roll-shaped wear debris. Mechanism and roles of the polymer-like wear debris were presented and discussed.