Effect of pv factor on sliding friction and wear of copper-impregnated metallized carbon

In this paper, the effect of pv factor on the tribological behavior of a copper-impregnated metallized carbon brush sliding against a CuCrZr ring was investigated. Friction and wear tests were conducted on a brush-on-slip ring type wear tester. The tests were performed at two electrical currents (0 and 20 A) and seven different combinations of contact pressure (p) and sliding velocity (v), herein referred to as the pv factor to study the relationship between electrical and mechanical wear. The results show that mechanical wear aggravates electrical wear. Higher interfacial temperatures appear to be responsible for the higher wear rate. Worn surfaces of brush specimens were observed and analyzed by scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDS). It is apparent that the degree of tribo-oxidation at the brush increases with an increase in pv, which has a significant influence on the tribological behavior of the brush specimen.