The correlation between the type of abrasive particles in the brake friction material and brake emission was studied. Brake emission tests with the friction materials with four different abrasive particles such as silicon carbide, alumina, zircon, and magnesia were performed using a sealed 1/5 scale dynamometer with a high-resolution electrical low-pressure impactor (HR-ELPI+). Results showed that the particle abrasivity, which comprises hardness, fracture toughness, size, and spike parameter, strongly affected the brake emission. In particular, fracture toughness of the abrasive particle showed more influence on the wear rates and brake emissions than the spike parameter and hardness. The analysis of the sliding surfaces suggested that the disc-induced particulate matter was directly related to the abrasivity of the hard particles in the friction material. In contrast, the brake emission induced by the brake pad was determined by the strength of the friction films on the pad surface that were affected by the iron compounds transferred from the grey iron disc.

Korea University: Mr. Wansu Song, Mr. Jinsoo Choi, Prof. Ho Jang; Sangshin Brake: Dr. Jungju Lee