Wear of Gadfield steel-base sintered composite at current collection sliding

Abstract

Model copper-matrix MMCs reinforced by high manganese steel particles have been characterized for me-chanical strength and conductivity in comparison to com- 59 mercially available current collection material. The com-mercial material is intended for current collection while sliding over a copper trolley. As shown, solid phase sinter-ing allows obtaining composites of high bulk strength. Friction coefficient and wear rate of so obtained compos-ites in sliding over steel counterbody while passing alter-nating electric current have been determined. It was found that high-manganese steel facilitates the formation of so-called secondary structures on the sliding surfaces. These structures consist of mixed oxides, which increase the slid-ing contact resistance. Most intense oxidizing occurs at current density 50 A/cm2. The results of comparison car-ried out between the model and commercially available materials show that model MMC has somewhat higher electrical resistance at current densities above 25 A/cm2. However, the wear rate of the model material in the ab-sence of intense oxidation is lower than that of commercial one. To complete the picture, we determined also the wear rate of carbon graphite material under the same experimen-tal conditions. As shown, carbon graphite fails to pass the current of densities above 25 A/cm2.