High-Temperature Tribological Behavior and Thermal Recovery of Resin-Based Friction Materials Modified by PEEK Powder

Traditional resin-based friction materials (RBFMs) suffer from severe friction coefficient (COF) fade and aggressive wear under continuous high-temperature braking loads. To mitigate these limitations, five multi-component RBFMs reinforced with systematically varied polyether ether ketone (PEEK) powder contents (0-4 wt%) were fabricated via direct step mixing and hot pressing. The physical, mechanical and temperature-dependent tribological properties of the composites were systematically characterized. The results revealed that density (2.25-2.33 g/cm 3 ) varied non-monotonically due to multi-component structural packing. Hardness and impact strength peaked at the addition of 2 wt% and 3 wt% PEEK, respectively, with the latter showing a 3.5% enhancement over the PEEK-free control. During non-isothermal heating (100-350 °C), the incorporating PEEK lowered the overall COF by releasing self-lubricating molecules to the interface. Throughout the subsequent cooling cycle, and it manifested a distinct “heat fade memory” effect; however, the presence of PEEK effectively stabilized the COF trajectory and mitigated fluctuations. Crucially, PEEK-containing samples achieved significantly higher thermal recovery ratios (92.8%-95.5%) than the unmodified sample (84.4%). The total wear rate followed a non-linear decreasing trend, optimized at 3 wt% PEEK with a 29.3% volume reduction. Worn surface morphology demonstrated that the in-situ activation of PEEK powder promoted the establishment of a uniform, resilient transfer film, which effectively transformed aggressive solid-to-solid abrasion into low-energy shear deformation within the tribo-film. This study provides a vital design paradigm for evolving highly stable, wear-resistant friction components for automotive braking systems.