Arc discharges with gas-impregnated cathodes in vacuum

Cathode material and surface conditions control parameters of the cathode spot (CS), and thus have an influence on properties of the vacuum arc discharge as a whole. A great number of various alloys and compositions have been developed to provide for improvement of operating characteristics of electrodes and arc properties due to selection of CS parameters. Some metals can be impregnated by hydrogen (H) up to an impregnation degree /spl alpha//spl sim/1 (H atom per metal atom) which corresponds to a very high concentration of H in metal matrix (up to C/spl sim/10/sup 23//spl middot/m/sup -3/). The impregnation of the cathode of the vacuum arc by H opens up new opportunities for influence upon CS parameters. The paper reflects the present state of research into vacuum are with H-impregnated cathodes. The introductory sections discuss the basic characteristics of the Me-H system and techniques of impregnation of different metals with H. The subsequent sections present the results of investigations of CS parameters and arc characteristics at various Ti cathode impregnation degrees. A comparison with characteristics of degassed cathodes demonstrated marked differences: using impregnation of a cathode with H, the velocity of CS motion grows, the current per spot falls off, erosion diminishes and droplet size decreases. A high-current arc burns steadily and at a lower voltage. The critical current for anode spot formation grows significantly. The use of H-impregnated cathodes is promising for various applications including switching apparatus, coating technique, plasma accelerators, and so on.