Abrasive wear of friction materials and brake disc rotor is mainly responsible for non-exhaustive particle emission from transportation. In this work, we investigated the effect of friction and disc materials on airborne particle emission from NAO and low-steel (L/S) materials for automobiles. First, the evolution of brake emission factor (BEF) upon raw materials of friction materials was studied, which shows that particle size of raw materials affects the BEF of NAO significantly, in contrast to small changes of BEF for L/S brake. According to microscopic analysis on collected airborne particles, the majority of PM10 is found to be originated from gray cast iron(GCI), which means abrasive wear of disc rotor is crucial to airborne particle emission. Disc materials with enhanced surface hardness such as ceramic coated GCI shows significantly improved particle emission characteristics, however nitride-coated GCI disc exhibits deteriorated emission characteristics due to tribo-characteristics of nitride layer.

Dr. Jung-Ju Lee, Chief Research Engineer, SANGSIN BRAKE; Dr.-Ing. Jong-Young Kim, Chief researcher, Korea Institute of Ceramic Engineering and Technology; Dipl.-Ing. Sanghun Sung, Principal research engineer, SANGSIN BRAKE; Dipl.-Ing. Sungwook Kwon, Principal research engineer, SANGSIN BRAKE