纯石墨和铜-石墨的阴极斑点与截流值研究

Cathode Spot Movements and Chopping Current of Pure Graphite and Copper-Graphite in Vacuum

摘要:

研究了纯石墨和铜-石墨材料的阴极斑点的特性及真空电弧截流现象。发现纯石墨的阴极斑点呈现随机运动的特点，斑点的直径小于3 μm，阴极斑点每次运动的距离约为阴极斑点的半径。而铜-石墨的阴极斑点的运动与Cu相息息相关，它选择性的发生在Cu相上，阴极斑点的大小取决于Cu相的大小，阴极斑点的运动距离为Cu相之间的距离。同时，铜-石墨的真空电弧截流值1.18 A，远远大于纯石墨的截流值，这主要是由于两种材料不同的阴极斑点运动特性引起的

Abstract:

In the paper, the cathode spot movements and chopping current of pure graphite and copper-impregnated metallized graphite (Cu-C) in vacuum were investigated. It can be found that cathode spot movements produce an arc erosion pattern composed of a large number of craters with varying distances between them. The size of the craters is less than 3 μm in diameter. This pattern indicates that the cathode spot walk randomly on the surface. Whereas, cathode spots initiated selectively on the Cu phases in Cu-C materials. The diameter of the cathode spots depends on the dimension of the Cu phases and the displacement of a cathode spot moving is equal to the distance between the Cu phases. Meanwhile, the chopping current of Cu-C is 1.18 A, far larger than that of pure graphite. The phenomenon can be explained by the different characteristics of the cathode spot movement