Friction and degradation of graphite: a nanotribological approach

Abstract

Abstract We investigated the friction and wear of graphite by atomic force microscopy in sliding contact with SiOx, Pt, and diamond tips with contact forces up to several micronewtons. Graphite’s tribology strongly depends on the chemistry of the counter body. With a SiOx tip, friction is governed by puckering. Wear initiates at surface steps by mechanical destabilization of folds. With a Pt tip, the adhesive effects lead to the exfoliation of graphite. At higher loads, friction crosses over from exfoliation to puckering. For SiOx and Pt, the wear rate is low in ambient conditions. In the case of diamond tips, we measured a friction coefficient and a wear rate of an order of magnitude larger than with SiOx or Pt tips.