Effects of aluminosilicate particles on tribological performance and friction mechanism of Cu-matrix pads for high-speed trains

The effects and mechanism of mullite and kyanite on the friction and wear of copper-based brake pads for high-speed trains were studied. The braking performance was tested at different speeds using a pin-disc tester. The physical properties, element distribution and tribo-film formation were investigated using the hardness tester, density meter, SEM, EDS and XRD. The results showed that the braking performance of materials with 1% kyanite was optimal. The friction coefficient was the most stable and the wear rate reduces over 30%. Kyanite can promote the formation of primary platform and mechanical mixing layer, thus accelerating the tribo-film generation to protect the surface. Moreover, the wear mechanism was elucidated by characterizing the changes of worn surface, wear debris and tribo-film.