Tribochemical Degradation of Polytetrafluoroethylene Catalyzed by Copper and Aluminum Surfaces

Abstract

The tribochemical reaction of polytetrafluoroethylene (PTFE) resin sliding against a metallic surface was investigated for a purpose of improving its tribological performance. The tribochemical reaction between PTFE and aluminum surface has been investigated experimentally and theoretically [Onodera et al., J. Phys. Chem. C 2015, 119, 15954−15962]. One of the important results is that the wear and self-lubrication properties can be controlled by the catalytic activity of the oxidized aluminum surfaces with different crystal structures (α- and γ-alumina). In particular, the amount of wear was higher on the γ-alumina surface because it easily activates tribochemical degradation of PTFE and suppresses the formation of transfer film (a necessary phenomenon for reducing wear). Accordingly, for controlling catalytic activity a copper surface was tested as a model surface exhibiting a weaker reactivity than an aluminum surface. A thermogravimetric analysis proved that the copper surface showed a weaker catalytic...