Airborne wear particle emission from train brake friction materials with different contents of steel and copper fibres

This study investigated the influence of the amount of steel and copper fibres in a train brake friction material on the tribological performance, emission intensity and characteristics of airborne wear particles. The particles were generated on a pin-on-disc tribometer under controlled friction and environmental conditions. It was found that the steel fibre results in a more intensive emission of 0.3–10 μm particles compared to the copper fibre. The abrasive wear of the steel disc sample is a predominating source of iron in 1–10 μm particles. The content of iron in these particles is proportional to the relative wear of the disc sample, whilst the content of copper increases with that in the friction material.