Cathodic contact erosion due to short-duration gas breakdown arcs

Abstract

The erosion of palladium contacts due to gas breakdown arcs in air and in an activating environment (naphthalene vapour) has been studied. The rate of erosion in air was not constant with arc energy but increased almost linearly from about 0·1 to 1·5 cm 3 erg −1 over an energy range of about 100 to 500 erg per discharge. Beyond this energy range a slower increase was observed. Under the activated conditions the erosion rate was much lower than in air (eg at 2000 erg the erosion rate in air was 1·65×10 −14 cm 3 erg −1 and with naphthalene activation the rate was 1·1×10 −14 cm 3 erg −1 ); however, a variation in the erosion rate with energy was also observed. The variation with energy is considered to be caused by part of the available erosion energy being used up in surface film decomposition.