Influence of Electropolishing Cu and Al Electrodes on Predischarge Phenomena and Breakdown of Vacuum Gaps

Results of an experimental investigation of predischarge charge phenomena and electrical strength of a vacuumgap between copper and aluminum electropolished electrodes are presented. The optimal technological parameters of the electropolishing process and some criteria of electrode surface evaluation have been determined. It is shown that the electropolishing of electrodes improves the electrical strength and significantly reduces the number of the microdischarges. It is postulated that the improvement in electrical strength is due to elimination of microneedles during the electropolishing process.