Review of the mechanisms of electrode and insulator erosion and degradation in high current arc environments

The mechanisms responsible for the erosion and degradation of electrode and insulator materials in high current arc discharge environments such as electromagnetic launchers are reviewed. The review represents the experimental results obtained from several studies and are from investigations into materials performance in high current closing switches such as spark gaps and surface discharge switches. Parameters of interest that affect electrode and insulator material erosion and degradation include peak current, charge transfer, mass erosion, the surface voltage holdoff recovery, and arc velocity. Other parameters that have been shown to affect materials performance include the synergistics produced by certain electrodes, insulators, and gas combinations. Models that describe the erosion and degradation processes are presented and compared to the experimental results.<>