The anodic vacuum arc. I. Basic construction and phenomenology

Abstract

A new type of vacuum arc is described, the anodic vacuum arc at low currents. This arc discharge is ignited in vacuum and generates a pure metal vapor plasma by evaporating anodic material, which continuously sustains the discharge. By proper construction of the electrodes a steady arc can be maintained at low currents (20–40 A). Basic electrode phenomena are the formation of cathode and anode spots. Metallic coatings produced by means of the anodic vacuum arc show promising features: the coatings are homogeneous, the deposition rates are high (8 nm/s for a 0.7-kW Al arc), and the thermal stress of the substrates being coated is low.