Effects of abrasive filler size and crosslinking treatment on airborne particle emissions of brake composites

Vehicle brake wear particles significantly contribute to urban airborne pollution. Understanding the effect of abrasive fillers on the wear particle characteristics of brake composites is vital in curbing brake wear particle emissions. In this study, we investigated the effects of alumina filler size and crosslinking treatment on the tribology and airborne particle emissions of brake composites. Our findings revealed that the use of larger abrasive fillers effectively reduces < 10 mu m particle emissions without compromising tribological performance. Crosslinking the filler minimizes wear but has a limited effect on particle emissions. Mechanistic investigations show a direct correlation between wear-induced airborne particle size and composite surface properties: particle average size aligns with composite surface roughness and is inversely related to its hardness. This study sheds light on strategies to mitigate vehicle brake airborne particle emissions.