A novel bronze-impregnated carbon strip containing Al2O3 particles for subway current collectors

Bronze-impregnated carbon matrix composites with different mass percentages of Al2O3 particulate reinforcement were prepared through compression molding, carbonization and impregnation. Effect of Al2O3 particle content on the electrical performance, tribological and mechanical properties of composites was studied. The results showed that the electrical resistivity of composites was enhanced with increasing the amount of alumina. The bending strength and compressive strength of composites increased as the content of Al2O3 increased and reached a maximum of 66.98 and 262.62 MPa at 8 wt.% of Al2O3 reinforcement, respectively. The micro-hardness of composites increased with an increase in the mass percentage of alumina. The friction coefficient of composites increased monotonously, but the wear rate decreased with increasing the content of alumina. The wear mechanism of composites was mainly adhesive wear accompanied by abrasive wear. The lubricating film on the worn surface of the composite with 8 wt.% of Al2O3 reinforcement was smooth and uniform, showing less signs of scuffing.

Research highlights
► The electrical resistivity was enhanced with increasing the amount of Al2O3.
► The bending strength and compressive strength reached a maximum at 8 wt.% of Al2O3.
► The micro-hardness of composites increased with increase in the content of Al2O3.
► The wear rate decreased monotonously with increasing the content of Al2O3.
► The wear mechanism of composites was adhesive wear and abrasive wear.