Tribological transfer of polytetrafluoroethylene onto a diamond-like carbon film

Abstract

The transfer of polytetrafluoroethylene (PTFE) onto a diamond-like carbon film (DLC) during dry sliding contact in the initial period, i.e. the first unidirectional traverse and the first ten unidirectional traverses, at a speed of 15 mm s -1 and a load of 1.5 MPa was investigated by determining the amount of PTFE transferred using the resonance of the 19F(p, αγ) 16O nuclear reaction at a proton energy of 340.4 keV. The amount of transferred PTFE on the DLC film was found to be much smaller than that on AISI 316 stainless steel. The friction and wear of PTFE and PTFE-based composites, i.e. carbon-reinforced and glass-reinforced PTFE, on DLC film were investigated at two sliding speeds of 7 and 79 mm s -1 under a load of 4.2 N (over a hemispherical pin with a radius of 4.9 mm). Generally, the lower friction coefficients for PTFE and PTFE-based composites in sliding contact with the DLC film compared with that for AISI 316 stainless steel occured only during a low number of sliding revolutions in the initial contact period. As a surface coating, the DLC film showed a considerable resistance to wear produced by reinforcing fillers.