Frictional Performance of Brake Pads against Al Metal Matrix Composites with Different Sizes of SiC Particles

Two drums suitable for a Chase Machine were made of Al metal matrix composites containing 25vol.% SiCp with 3.5 μm and 34 μm in nominal diameter respectively. The same brake pads were measured on the Chase Machine installing each individual drum. It has been found that the brake pads had better frictional performance and wear resistance against the drum with the large-size SiCp than against the drum with the small-size ones. Friction fade took place at elevated temperatures - above 316 oC, but the original level of friction coefficient could be regained rapidly upon cooling with regard to the latter. The minor level of friction coefficient was attributable to soft Al crystal structure characteristics and thick tribofilms during the testing stages.