Components of cathode erosion in vacuum arcs

Abstract

The composition of cathode mass loss was analysed for cadmium, copper and molybdenum vacuum arcs. It showed that two dominant flows are present, one consisting of ions, the other of molten droplets which have sizes in the order of microns to tens of microns. The droplet flow is mainly oriented along the cathode plane and is strongly dependent on the fusion temperature of the cathode metal and the charge transfer by the arc. The cathode mass loss in vapour form is considered to be small.