Tribological Properties and Mechanisms of PTFE Matrix Composites Under Wide‐Temperature‐Range and Long‐Term Friction Conditions

To address the challenges of using polytetrafluoroethylene (PTFE) in practical applications, it is crucial to develop PTFE matrix composites with enhanced wear resistance and prolonged service life. In this study, the effects of filler materials and testing temperatures on the tribological behavior of PTFE composites were systematically investigated, and the performance under prolonged friction (0.5–15 h) at 0.33 and 0.66 m/s was thoroughly evaluated. Results indicate that the PTFE/Kevlar fibers (KF)/Polyimide (PI) composite exhibited a low coefficient of friction (COF) of only 0.09 at 250°C, with a wear rate ranging from 0.65 × 10 −5 to 1.8 × 10 −5 mm 3 /Nm. During the extended tests (1–15 h), the composite maintained a low wear rate at both 0.33 m/s (0.89–7.67 × 10 −6 mm 3 /Nm) and 0.66 m/s (1.43–7.43 × 10 −6 mm 3 /Nm). Examination of the worn surfaces reveals that the wear mechanism transfer from abrasive wear to fatigue wear with the increasing of testing temperature and sliding speed/time.