Sliding friction and wear behaviour of polytetrafluoroethylene and its composites under dry conditions

In this paper, we studied and explored the influence of test speed and load values on the friction and wear behaviour of pure polytetrafluoroethylene (PTFE), glass fibre reinforced (GFR) and bronze and carbon (C) filled PTFE polymers. Friction and wear experiments were run under ambient conditions in a pin-on-disc arrangement. Tests were carried out at sliding speed of 0.32-, 0.64-, 0.96- and 1.28-m s(-1) and under a nominal load of 5-, 10-, 20- and 30-N. The results showed that, for pure PTFE and its composites used in this investigated, the friction coefficient decrease with the increase in load. The maximum reductions in wear rate and friction coefficient were obtained by reinforced PTFE + 17% glass fiber. The wear rate for pure PTFE was in the order of 10(-7) mm(2)/N, while the wear rate values for PTFE composites were in the order of 10(-8) and 10(-9) mm(2)/N. Adding glass fiber, bronze and carbon fillers to PTFE were found effective in reducing the wear rate of the PTFE composite. In addition, for the range of load and speeds used in this investigation, the wear rate showed very little sensitivity to test speed and large sensitivity to the applied load, particularly at high load values. (C) 2003 Elsevier Ltd. All rights reserved.