The behavior of vacuum arc discharges on hydrogen impregnated electrodes

This paper reports on experimental studies of the behavior of vacuum arcs at hydrogen impregnated electrodes. The arc discharges were analyzed by high speed photography, open shutter photography, measurement of arc voltage and current, and measurements of the erosion in dependence on the level of impregnation for a wide range of arc currents. The results show that impregnation of electrodes with hydrogen reduces the erosion rate, causes smaller crater dimensions, changes the macroparticle size, and decreases the current per spot. For a given current the arc voltage depends on the degree of impregnation. At low current it decreases with increasing impregnation. Furthermore, the arc discharge burns more stable on impregnated electrodes. The total erosion rate decreases significantly due to the reduction of the droplet fraction. The spot movement is faster than on nonimpregnated electrodes.