Leyu Lin, Yuxiao Zhao, Chi Hua, Alois K. Schlarb

• In the present study, effects of the sliding velocity sequences on the friction and wear properties of pure polyetheretherketone (PEEK) and a PEEK hybrid composite were studied. It is demonstrated that the tribological properties of pure PEEK and its composite show a complex nature of the dependence on the velocity sequences in the studied range. The friction coefficient of PEEK is independent on previous velocity histories. In contrast, the testing sequence of the velocity exerts obvious impact on the friction coefficient of the PEEK composite at slow sliding velocities. With respect to the wear performance, the specific wear rate of pure PEEK exhibits a strong dependence on the sequences of the velocity only at the initial pv-levels. For the PEEK composite, its specific wear rate exhibits an obvious dependence on the previous velocity levels at a low nominal pressure of 1 MPa. When the pressure is increased to 8 MPa, the impact of the velocity sequences on the wear performance becomes insignificant. In addition, the tribological properties clearly correlate with the temperature of the tribosystem.