Effect of Matrix Alloying on Braking Performance of Copper-Based Brake Pad Under Continuous Emergency Braking

Abstract

The continuous emergency braking performance of copper-based brake pads alloyed with different Ni contents were tested. The results showed that the copper-based brake pad with high Ni content exhibits improved stability of friction coefficient during the whole emergency braking process, which indicates that Ni helps to reduce the sensitivity of the brake pad to the change of braking conditions. Moreover, the fade phenomenon of friction coefficient is obviously alleviated as the increase in Ni content under high-pressure and high-speed braking conditions. The introduction of Ni enhances the plastic deformation resistance of friction surface and promotes the formation of high-strength mechanical mixed layer and thick tribo-oxide film. This stable tribo-film remained on the contact interface is responsible for the steady mean friction coefficient under different braking conditions. Excessive addition of Ni reduces the plasticity of the friction surface, leading to the change of the main wear mechanism from adhesive wear to delamination