Friction and Wear Responses with Metallic Composite Materials to Replace Copper and Copper Alloys in Brake Pad Formulations

Copper and copper alloys are widely used in friction materials such as brake pad formulations as one of key ingredients by providing good thermal conductivity and high temperature friction stability to achieve desired friction performance, fade and wear resistance. However, the use of copper or copper containing material is being restricted in brake pads due to environment and health concerns. Extensive works have been made to explore the copper substitutes but most of these efforts became ineffective and failed with issues either thermal fade or excessive pad/rotor wear. In this paper, friction and wear responses were examined when a metallic composite material was used as the copper substitute in NAO and Low-met brake formulations where the copper and copper alloys were added 8% and 22% respectively. Full scale automotive brake dynamometer tests were performed based on the SAE J2430 test procedure to compare the metallic composite containing friction samples with the baseline friction samples. The studies in this paper demonstrated the potential opportunity of using the metallic composite material as copper substitute to manufacture Cu-free brake pad formulation with good thermal resistance and low rotor/pad wear.