Tribological properties of modified carbon fabric/polytetrafluoroethylene composites

Various modified carbon fabric (CF)/polytetrafluorothylene (PTFE) composites were prepared by means of CF surface treatment, i.e. air-plasma treatment and HNO3 etching, introduction of nano-TiO2 and combined methods. The composites were evaluated for their tribological behaviors and the worn surfaces were observed by a scanning electron microscope (SEM) to understand the mechanism. The water contact angle and the surface topography of the untreated and surface-treated CF were also analyzed. It was found that the surface treatment improved the surface hydrophilicity and changed the surface topography of CF, which contributed to improve the interfacial adhesion of the composites and hence the tribological behaviors. The inclusion of 4 wt% nano-TiO2 provided the optimum wear resistance among the nano-TiO2 modified composites. There was a cooperating effect of CF air-plasma treatment and 4 wt% nano-TiO2 modification to the wear-reduction of the composites.