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Enhancing mechanisms of arc-erosion resistance for copper tungsten electrical contact using reduced graphene oxides in situ modified by copper nanoparticles
International Journal of Refractory Metals & Hard Materials ( IF 4.2 ) Pub Date : 2022-06-17 , DOI: 10.1016/j.ijrmhm.2022.105934
LongLong Dong , Liang Li , Xiang Li , Wei Zhang , YongQing Fu , Ahmed Elmarakbi , YuSheng Zhang

To solve critical issues of premature failure for copper tungsten (CuW) based electrical contacts during arc erosion at the moment of arc breakdown, we proposed a new strategy of using metal doped reduced graphene oxides (rGOs) and in-situ formed tungsten carbides to inhibit movements of cathode spots during the arc ablation process. CuW composites were reinforced with Cu modified rGO nanopowders (i.e. Cu@rGO) using combined processes of chemical co-reduction, ball milling and spark plasms sintering (SPS). Effects of Cu@rGO addition on microstructure, arc erosion resistance and arc ablation resistance of the CuW composites were systematically investigated. Results showed that tungsten carbides with irregular shapes were formed through in-situ reactions of rGO and tungsten during the SPS process. Arc erosion resistance of CuW composites was significantly improved owing to introduction of nanostructured Cu@rGO. Compared with those of CuW composites, the ablation areas of Cu@rGO/CuW ones were much smaller and the ablation craters were shallower, and the average strengths of dielectric vacuum breakdowns of the CuW composites with 3 wt% Cu@rGO were increased by 28.9%. The arc breakdown mechanisms of Cu@rGO/CuW composites were identified as: (1) The nanostructured Cu@rGO increases the viscosity of molten metal Cu, thus inhibiting its fast flow and splashing; (2) Lower work functions of carbon (i.e. rGO) and tungsten carbide restrain the electron emissions during arc breakdown; and (3) The tungsten carbides with their good stability and high melting point shorten the solidification time of molten copper liquid and extend the service life time of the Cu@rGO/CuW composites.



中文翻译:

铜纳米粒子原位修饰还原氧化石墨烯增强钨铜电触点的耐电弧侵蚀机制

为了解决在电弧击穿瞬间电弧侵蚀期间基于铜钨 (CuW) 的电触点过早失效的关键问题,我们提出了一种使用金属掺杂的还原氧化石墨烯 (rGO) 和原位形成的碳化钨来抑制电弧烧蚀过程中阴极点的移动。使用化学共还原、球磨和火花等离子体烧结 (SPS) 的组合工艺,用 Cu 改性的 rGO 纳米粉末(即Cu@rGO)增强 CuW 复合材料。系统研究了添加Cu@rGO对CuW复合材料微观结构、耐电弧侵蚀性和耐电弧烧蚀性能的影响。结果表明,原位形成了形状不规则的碳化钨。SPS过程中rGO和钨的反应。由于引入了纳米结构的 Cu@rGO,CuW 复合材料的抗电弧侵蚀性显着提高。与CuW复合材料相比,Cu@rGO/CuW复合材料的烧蚀面积更小,烧蚀坑更浅,3 wt% Cu@rGO的CuW复合材料的介电真空击穿平均强度提高了28.9 %。Cu@rGO/CuW复合材料的电弧击穿机理确定为:(1)纳米结构的Cu@rGO增加了熔融金属Cu的粘度,从而抑制了其快速流动和飞溅;(2) 碳的低功函数(rGO)和碳化钨抑制电弧击穿期间的电子发射;(3)碳化钨具有良好的稳定性和高熔点,缩​​短了熔融铜液的凝固时间,延长了Cu@rGO/CuW复合材料的使用寿命。

更新日期:2022-06-17
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