High temperature and current-carrying friction and wear properties of resin-coated graphite/copper composites
FANG Huachan1, SUN Zhen1, XU Yongxiang3, ZHANG Zhuo2, WANG Jiayu1, ZHU Jiamin1, CHEN Zhuo1
1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China; 2. Advance Research Center, Central South University, Changsha 410083, China; 3. CRRC Qishuyan Institute Co., Ltd., Changzhou 213011, China
Abstract：Resin-coated graphite/copper composites and copper-plated graphite/copper composites were prepared by cold pressing-pressure sintering process using phenolic resin powder, graphite powder, copper-plated graphite powder and electrolytic copper powder as raw materials, respectively, the friction and wear properties of two kinds of graphite/copper composites at room temperature, high temperature and current-carrying were studied, and compared with overseas Roland grounding brush; the effects of resin decomposition on the conductivity, mechanical and friction and wear properties of the composites were analyzed based on the crystal structure of copper matrix and the variation of composite conductivity and mechanical properties at high temperature (200-600 ℃). The results show that the mechanical properties of resin-coated graphite/copper composites at high temperature are better than that of copper-plated graphite/copper composites. When the ambient temperature reaches 600 ℃, the shear strength of resin-coated graphite/copper composites decreases by only 6%, while that of copper-plated graphite/copper composites decreases by 24%. The high temperature (250 ℃) wear resistance and friction stability of resin-coated graphite/copper composites are much better than those of copper-plated graphite/copper composites and Roland brush, the current-carrying friction factor of the resin-coated graphite/copper composites is lower than that of Roland brush. The resin coating of graphite can improve the friction and wear properties of copper matrix composites at high temperature and current-carrying, due to the protection of the resin layer, a continuous and stable graphite lubricating film can be formed even under the conditions of high temperature oxygen and current-carrying, thus reducing the friction contact micro-gap; the carbonized resin breaks into fine hard particles during the friction, which hinder the adhesion and wear between composite and disc; the Cu matrix softening at high temperature is not obvious, so the occurrence of arc decreases.
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2023, Vol. 28 
