Wear mechanism of multiphase friction materials with different phenolic resin matrices

Wear of the brake friction materials with straight phenolic resin, silicon modified phenolic resin, or boron–phosphorous (B–P) modified phenolic resin was investigated. A simple formulation was used to produce friction material specimens and wear tests were carried out using a Krauss type friction tester. Friction stability and wear rate of the three friction materials were compared as a function of temperature up to 400 °C and the mechanisms associated with the wear processes at different temperature ranges were analyzed using Arrhenius type plots and worn surface morphology after tests. The results showed that the wear process below the critical temperature was mainly attributed to the gradual stripping of the heat affected surface layers of the friction material, while the wear rate at elevated temperatures was determined by the detachment of subsurfaces that was caused by the thermal decomposition of the resin. Among the three friction materials investigated in this study, the friction material containing B–P modified resin showed the best wear resistance and friction stability.