High Temperature Electrical Breakdown in Sodium Chloride

Abstract

Doubt exists as to the mechanism responsible for electrical breakdown in alkali halide crystals at temperatures where the breakdown strength has generally been found to fall with rise in temperature. As thermal breakdown may be involved, experiments designed to examine this possibility in sodium chloride at 350 °0 have been conducted. It is shown that when linearly rising voltage transients are applied the dependence of breakdown strength on electrical conductivity, time, and energy input is in agreement with the impulse thermal theory for times to breakdown of the order of milliseconds. Conduction of heat is found to be an important factor as the time to breakdown is increased. Effects, such as dendrite growth, which are seen after breakdown with 10-second transients, are also discussed.