Tribological Characteristics of Binder Resins for Brake Friction Materials at Elevated Temperatures

The heat resistance of the multiphase friction materials made with straight phenolic resin (ST), boron–phosphorous (B–P)-modified phenolic resin (BP), or polyimide (PI) was investigated using a Krauss-type friction tester. Thermal analysis of the cured resins was also carried out to examine the chemical and mechanical properties of the resin and their effects on the wear rate and the coefficient of friction. The results showed that the fade and wear of the friction materials were closely related to the thermal decomposition of the binder resin and durability of the contact plateaus, which were produced by the compaction of wear debris around hard ingredients on the rubbing surface. The friction material containing the B–P modified resin was more resistant to wear and fade than the other binder resins. On the other hand, the friction material with polyimide showed good fade resistance but exhibited excessive wear despite its good thermal resistance.