Tribological behaviors of copper modified carbon/carbon composites for pantograph strip under electric current conditions

Copper fiber reinforced carbon/carbon composite (C/C-Cuf) and copper alloy impregnating carbon/carbon (C/C-Cu) composite as promising materials of pantograph strip were fabricated and investigated for tribological behaviors and relevant mechanisms, comparing results with pure carbon strip currently used in high-speed railway. C/C-Cuf composite and C/C-Cu composite have more advantage than the pure carbon strip in terms of electric conductivity and mechanical performances. During current-carrying friction tests, C/C-Cu composite has the lowest arc discharge energy and smoothest worn surface. It is attributed that suitable heat treatment decreases the interlaminar defects (Covalent cross-bonds and sp3 structure) of amorphous carbon, and the tribolayer with grapheme-like structure is formed through the processes of rehybridization, rearrangement and reorganization on the worn surface of C/C-Cu composite.