Comparative study of the current-carrying tribological properties of carbon graphite composites with different hardnesses

To investigate the effect of sliding speed and electrical current on the current-carrying friction performance of carbon brushes with different hardnesses. In this paper, two carbon-graphite material samples with different hardnesses manufactured by a powder metallurgical process were prepared. And a pin-disc current-carrying friction tester was used for testing. The results showed that the difference in hardness has a noticeably different effect on the sliding contact resistance and interface temperature rise of the material. As the electric current changes, the material with low hardness exhibited good adaptability. Then, the adhesive wear occurred for all materials of different hardnesses, and it changed to abrasive wear mainly with increasing electrical current. As the sliding speed increased, the wear rate of low-hardness material dropped, while the opposite trend was observed for high-hardness material. The increased sliding speed does not generate remarkable damage to the contact surface of the high-hardness material, which demonstrated good resistance to mechanical shocks.