Mapping of friction, wear and particle emissions from high-speed train brakes

Abstract

This study reports contact pressure-sliding speed maps for friction, wear and particle emissions from high-speed train brakes. Two particle spectrometers measured the airborne wear particles generated with a pin-on-disc tribometer. Particles were characterized with transmission electron microscopy and energy dispersive X-ray fluorescence. The results indicate that both the friction and wear of brake pads and discs gradually decreased as sliding speed increased, which showed less dependence on contact pressure. Particle concentrations gradually increased with increasing sliding speed. Low contact pressure and sliding speed tended to generate particles smaller than 2.5 μm. The train brake emitted particles had higher average geometric mean diameters than the car brake emitted particles, which were primarily composed of iron, copper and chromium and were oxidized.