Gra./Cu和CNTs/Cu复合材料的截流值与阴极斑点研究

Chopping Current and Cathode Spot Movements of Gra./Cu and CNTs/Cu Composites

采用粉末冶金方法制备石墨铜复合材料(Gra./Cu)和碳纳米管铜复合材料(CNTs/Cu),研究2种铜基复合材料的真空电弧截流现象和阴极斑点特性。结果表明,与Gra./Cu相比,CNTs/Cu在真空放电过程中电弧更加稳定,且分散性好,截流值小;在正对阳极处CNTs/Cu的真空电弧烧蚀坑明显比Gra./Cu的细小,灼痕直径约为0.1～5μm,分布面积也较小,而Gra./Cu的灼痕直径为10～100μm;两者的相同之处在于,在电击穿过程中阴极斑点的运动呈一种随机的、突变式的跳跃,而且选择性发生在Cu相上,Cu相被消耗。总之,CNTs/Cu比Gra./Cu具有更高的耐电弧烧蚀能力,CNTs的加入可以有效地增加铜基复合材料的电弧稳定性和降低截流值。

Gra./Cu composites and CNTs/Cu composites were prepared by powder metallurgy. Chopping current and cathode spot movements of the 2 kinds of Cu matrix composites in vacuum were investigated. The results show that the vacuum arc of CNTs/Cu is more stable and dispersive,and the chopping current is less than that of Gra./Cu. For CNTs/Cu the size of cathode spot craters is 0.1-5 μm in diameter,while for Gra./Cu is between 10 and 100 μm. The common characteristics are that cathode spot initiates selectively on the Cu phases and walks randomly on the surface of the Cu matrix composites. It is concluded that CNTs/Cu has an higher arc erosion resistance than Gra./Cu,and CNTs can effectively increase stability and lower chopping current of the Cu matrix composites.