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.
[1] LIU X L, CAI Z B, XIAO Q, et al.Fretting wear behavior of brass/copper-graphite composites as a contactor material under electrical contact[J]. International Journal of Mechanical Sciences, 2020, 184: 1879-2162. [2] HAN X M, YANG J Y, NONG W H, et al.Tribological behavior of copper and graphite of layered friction materials[J]. Tribology Transactions, 2020, 63(5): 906-912. [3] GRANDIN M, WIKLUND U.Wear phenomena and tribofilm formation of copper/copper-graphite sliding electrical contact materials[J]. Wear, 2018, 398: 227-235. [4] TANG Z M, XU L, WANG Z M, et al.Effect of microwave-activated sintering on microstructure and properties of graphite/copper composites[J]. ACS Applied Electronic Materials, 2021, 3(5): 2268-2276. [5] HU Z L, CHEN Z H, XIA J T, et al.Properties of electric brushes made with Cu-coated graphite composites and with copper powders[J]. Transactions of Nonferrous Metals Society of China, 2007, 17: 1060-1064. [6] ZHU J M, LI J W, LIU T, et al.Differences in mechanical behaviors and characteristics between natural graphite/ copper composites and carbon-coated graphite/copper composites[J]. Materials Characterization, 2020, 162: 1873-4189. [7] 张国玺. 石墨含量及粒度对铜-镀铜石墨复合材料性能的影响[J]. 粉末冶金技术, 2016, 34(3): 196-198, 204. ZHANG Guoxi.Effects of copper-coated graphite content and particle size on properties of the Cu/copper-coated graphite composite[J]. Powder Metallurgy Technology, 2016, 34(3): 196-198, 204. [8] YANG Z H, GE Y X, XU Z, et al.Effect of carbon content on friction and wear properties of copper matrix composites at high speed current-carrying[J]. Materials, 2019, 12(18): 1996-1944. [9] KOVACIK J, EMMER S, BIELEK J, et al.Effect of composition on friction coefficient of Cu-graphite composites[J]. Wear, 2008, 265(3/4): 417-421. [10] XING L L, LIN J C, HUANG M, et al.Joining of graphite to copper with Nb interlayer: microstructure and mechanical properties[J]. Advanced Engineering Materials, 2019, 21(2): 1527-2648. [11] WANG H B, TAO Z C, LI X F, et al.Graphite fiber/copper composites prepared by spontaneous infiltration[J]. Applied Surface Science, 2018, 439: 488-493. [12] 赖远腾, 甘雪萍, 肖柱, 等. 石墨表面镀镍对石墨/铜复合材料微观结构和力学性能的影响[J]. 粉末冶金材料科学与工程, 2018, 23(5): 495-506. LAI Yuanteng, GAN Xueping, XIAO Zhu, et al.Effects of Ni-coated graphite particles on microstructure and properties of graphite/copper composites[J]. Materials Science and Engineering of Powder Metallurgy, 2018, 23(5): 495-506. [13] 秦笑, 王娟, 林高用, 等. 镀铜石墨/铜复合材料的组织和摩擦磨损性能[J]. 材料导报, 2020, 34(S1): 380-384. QIN Xiao, WANG Juan, LIN Gaoyong, et al.Microstructure, friction and wear properties of copper-coated graphite/copper composites[J]. Materials Reports, 2020, 34(S1): 380-384. [14] BARA A, LUNGU P, BONDAR A M.Copper-coated graphite composites for sliding electrical contacts[J]. Revista Romana de Materiale-Romanian Journal of Materials, 2008, 38(2): 130-133. [15] ZHAN Y Z, ZHANG G D, WU Y Y.Effect of surface metallization of graphite on the tribological properties of copper hybrid composites[J]. Scandinavian Journal of Metallurgy, 2004, 33(2): 80-84. [16] TAO Z C, GUO Q G, GAO X Q, et al.The wettability and interface thermal resistance of copper/graphite system with an addition of chromium[J]. Materials Chemistry and Physics, 2011, 128(1/2): 228-232. [17] SLAVIC J, BOLTEZAR M.Measuring the dynamic forces to identify the friction of a graphite-copper contact for variable temperature and current[J]. Wear, 2006, 260(9/10): 1136-1144. [18] LIU R T, CHENG K, CHEN J, et al.Friction and wear properties of high temperature and low temperature sintered copper-graphite brushes at different ambient temperatures[J]. Journal of Materials Research and Technology, 2020, 9(4): 7288-7296. [19] JIANG X, FANG H C, XIAO P, et al.Influence of carbon coating with phenolic resin in natural graphite on the microstructures and properties of graphite/copper composites[J]. Journal of Alloys and Compound, 2018, 744: 165-173. [20] 佟立国. 高速动车组接地回流装置用电刷的制备[J]. 炭素, 2019(3): 12, 28-30. TONG Liguo. Preparation of brush for high speed ERCU device[J]. Carbon, 2019(3): 12, 28-30. [21] 赵彦文, 孙乐民. 浸金属碳材料载流质量与摩擦学性能的关系[J]. 特种铸造及有色合金, 2022, 42(5): 559-564. ZHAO Yanwen, SUN Lemin.Relationship between current- carrying quality and tribological properties of metal-impregnated carbon materials[J]. Special Casting and Nonferrous Alloys, 2022, 42(5): 559-564. [22] YAMASHITA Y, OUCHI K.A study on carbonization of phenol-formaldehyde resin labelled with deuterium and 13C[J]. Carbon, 1981, 19(2): 89-94.