Experimental investigation of electrode erosion of triggered spark gap

Abstract

Electrode erosion and particulate sputtering would be inevitable in gas spark gap, which could affect its dielectric performance and reliability. To analyze the process of electrode-to-electrode sputtering in gas spark gap, this paper conducted discharge experiments between Mo and W electrodes and analyzed the results with scanning electron microscopy (SEM). Results indicated that main electrodes began sputtering particles to each other after 10 shots, and its distribution range extended with larger sputtering velocities and angles. However, even after only one shot, W particulates are sputtered and found on the surface of opposite electrode, its diameters being 1.5μm or so. And clear erosion cracks, pits and sputtered particulates for tungsten are observed more early than molybdenum. After 500 or even more shots, craters and cracks of the erosion that appear on the Mo electrode surface become more and more significant, and finally more heavy than W electrodes. It is reasonable that electrodes erosion (cracks, craters, sputtered particulates etc.) could be related to fatigue life of electrode materials.