Experimental Investigation of Electrode Erosion of Trigatron in Microsecond Arc Discharge Process

Abstract

Trigatrons have been widely used in many fields. However, the performance of trigatrons typically degrades as operational time increases. Among many influence factors, electrode erosion is a primary cause of trigatrons failure. In this paper, the peak current and pulsewidth of trigatrons are in the order of kiloampere (kA) and microsecond (μs), respectively, with an electrode size in the order of millimeters (mm). The discharge images show that the arc appearance looks filamentary in shape during the early period of the discharge. As the discharge process progresses, the arc expands and moves radially to the side surface of the anode. Simultaneously, electrode erosion experiments are conducted on the trigatrons in an atmospheric environment. Experimental results show that the erosion level becomes more serious with an increase of gap distance and discharge current. The weight loss of Mo and W electrodes with erosion times are very close to a linear distribution, however, weight loss rate of W-Cu electrodes increases more dramatically with an increase of erosion times. The erosion of WCu electrode is more pronounced than Mo and W electrodes the volume erosion rate of W is smaller than Mo, but the mass erosion rate of W is higher than Mo. Many cracks always appear on the W and Mo electrode surfaces, which are due to frequent and intensive interaction between the expansion and shrinkage of the electrode material.