Effect of disc material on particulate matter emissions during high-temperature braking

Abstract

Brake emissions during high-temperature brake applications were investigated using four different brake discs—FC170 and FC250 Gy iron discs, oxynitride-coated gray iron discs, and ceramic discs. The brake emission tests were performed with a low-steel brake pad using a 1/5 scale brake dynamometer with a high resolution electrical low-pressure impactor. The highest number concentration was observed using ceramic discs, whereas the gray iron discs produced higher mass concentrations than others. The effect of the disc material on brake emissions at elevated temperatures was primarily determined by the thermal conductivity of the disc and the time- and temperature-dependent variations of contact plateaus on the pad surface.