The influences of high temperature on tribological properties of Cu-based friction materials with a friction phase of SiO2/SiC/Al2O3

Abstract

Cu-based friction materials have better tribological properties, high mechanical strength, and excellent thermal conductivity; therefore, they are widely used as friction materials in high-speed rail brake systems. However, with the remarkable increase in running speed of high-speed trains, a great amount of energy and high temperature are induced in the brake system; therefore, new challenges are generated for brake pad materials. In this paper, Cu-based friction materials were prepared with the addition of various hard particles as the friction phase, in order to obtain a good high temperature tribological performance. The experimental results showed that the Cu-based friction materials with addition of hard particles have moderate mechanical strengths and proper tribological properties. The temperature effects on the tribological behaviors of friction materials were investigated. The coefficient of friction (COF) for friction materials with addition of hard particles increased with temperature, resulting from the integrated effects of friction film, graphite, and material softening. The variation trends of the wear loss and wear rate with temperatures are similar to those of COFs, which are significantly reduced with the addition of hard particles.