EFFECTS OF STEEL COUNTERFACE ROUGHNESS AND TEMPERATURE ON THE FRICTION AND WEAR OF PE(E)K COMPOSITES UNDER DRY SLIDING CONDITIONS

The friction and wear behavior of virgin polyetheretherketone (PEEK) and of polyetherketone (PEK) and PEEK composites, including different types and amounts of fiber reinforcement and/or lubricating agents, was studied as a function of steel counterface roughness and testing temperature. Roughness effects were more pronounced in the non-reinforced PEEK than in the fiber-filled versions. An increase in testing temperature resulted in higher specific wear rates and in lower coefficients of friction for the different materials tested. The incorporation of carbon fibers proved to be more beneficial than glass fibers with respect to both friction and wear performance. The composition with the highest resistance to wear at elevated temperatures (e.g. 220-degrees-C) and a low coefficient of friction (mu < 0.1 at a pressure-velocity condition of p = 1 MPa and upsilon = 1 m s-1 respectively) was a PEEK version containing 15 wt.% polytetrafluoroethylene (PTFE) particles and 15 wt.% graphite lubricant.