Authors: Gang Qian Yi Feng FanYan Chen WenHong Liu XueBin Zhang YanFang Liu
Publish Date: 2013/09/25
Volume: 56, Issue: 11, Pages: 2839-2846
Abstract
In this paper CuWS2graphiteWS2 nanotube composites were fabricated by powder metallurgy hot pressing method The effect of current polarity on the wear rates and contact voltage drops of the composites were investigated using a brushonslip ring tribometer rubbing against Cu5 wt Ag alloy ring in air and vacuum respectively The worn surfaces of the composites were analyzed by scanning electron microscopy SEM and Xray photoelectron spectroscopy XPS Surface profile curves of the worn tracks were measured using the surface profiler The results demonstrated that the current polarity has a significant effect on the wear rates and contact voltage drops of the composites in both air and vacuum conditions Positive brush possesses a higher wear rate compared with the negative brush in the air atmosphere since the electrical field direction activates oxidation at the positive brush surface while inhibits oxidation at the negative brush surface Except for the regular wear losses the combined effect of molten metal bridge erosion and arc erosion cause the positive brush to lose extra material and the negative brush to gain extra material so the positive brush shows a higher wear rate in the vacuum condition The contact voltage drop of the positive brush is lower than that of the negative brush in the air atmosphere but contrarily the positive brush shows a higher contact voltage drop in the vacuum condition
Keywords: