Effect of Graphite Particle Size on Friction and Wear Performance of Paper-based Friction Material

Paper-based friction materials containing four different graphite particle sizes were prepared using the wet paper-making process. The effects of graphite particle size on friction performance such as friction torque curves, dynamic friction coefficient, static friction coefficient and wear rate were studied by using an inertia friction tester. Meanwhile, the sensitivity of friction coefficient to braking pressure and rotating speed was also investigated. Worn surfaces of samples were analyzed by using scanning electron microscope. The results show that with graph- ite particle size decreasing, braking time increases and torque curves become more stable, while friction coefficient and wear rate decrease. The dynamic friction coefficient declines as braking pressure and rotating speed increase. Samples with proper particle size exhibit more stable friction coefficient in the continuous braking process. Lubri- cating film is formed to lower wear rate in the worn surface as the graphite particles size decreases.