On the nature of tribological contact in automotive brakes

The tribological contact in automotive brakes involves dry sliding contact at high speeds and high contact forces. The commonly used organic binder-type brake pad friction materials are extremely inhomogeneous and exhibit very low bulk strengths. Despite the low strength, the specific contact surfaces that form during the use render the pads very good friction and wear characteristics. This paper gives a general view of the contact situation of organic binder brake friction materials against cast iron discs, with special emphasis on many mechanisms for contact surface variations and the corresponding variations of the coefficient of friction.