Dry sliding friction and wear of short carbon-fiber-reinforced polyetheretherketone (PEEK) at elevated temperatures

This paper describes the results from an experimental investigation of the effects of operating temperature on the dry sliding friction and wear performance of a short carbon-fiber-reinforced (SCFR) polyetheretherketone (PEEK) composite. The sliding experiments were carried out on a pin-on-disc tribometer at selected temperatures in the range of 20-225 degrees C. The contact configuration used was a stationary steel ball on a rotating polymer flat. As test temperatures increased from below to above the glass transition temperature (T-g) of the composite, wear and friction transitions were seen to occur. These transitions were, however, opposite in nature. In effect, a wear intensification was accompanied by a sharp drop in friction. Particularly interesting was the fact that in the sliding regime above T-g, SCFR-PEEK exhibited coefficients of friction that were lower than those exhibited by neat PEEK by factors of about two to three. The tribological behavior of SCFR-PEEK is discussed in terms of the impact of temperature on structure and mechanical properties. Additionally, the active friction and wear mechanisms of SCFR-PEEK across the range of test temperatures are identified and discussed in relation to those of neat PEEK.