Friction and Degradation of Graphite: A Nanotribological Approach

We investigated the friction and wear of graphite by atomic force microscopy in sliding contact with SiO x , 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 SiO x 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 SiO x 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 SiO x or Pt tips. Graphical Abstract