Synergy between carbon fibers and copper-plated graphite on tribological performance of Cu-based composites

Various types of copper-based friction materials were prepared by blending different lubrication components in anticipation of improving the performance and reliability of high-speed train brake pads. The effects of copper-plated graphite (CG), carbon fiber (CF), MoS2 (MS), CG-CF (GF), and CG-MS (GM) on copper-based friction materials for high-speed braking were researched. The tribological properties were appraised on a pin-on-disk testing machine. The mechanical characteristics, micro morphology, element mapping, and tribo-layer were studied by the hardometer, densitometer, SEM, EDS, LSK, and XPS. GF sample has the best comprehensive performance. At 250–350 km/h, it exhibits the most consistent friction coefficient and lowest wear. Additionally, under water spray condition, the friction coefficient remains stable around 0.3 and the fluctuation range is the smallest. Through exploring the variations in element distribution, friction surface, section, and wear debris, the wear forms and mechanisms of materials were revealed. In addition, the synergistic action of copper-plated graphite and carbon fibers was elucidated.