Experimental study of the transition to high-current regime of discharge with a hollow self-heated titanium cathode in nitrogen

Abstract

It is established that rapid formation of a nitride layer on the surface of a self-heated hollow titanium cathode in arc discharge in nitrogen leads to an increase in the thermal stability and emissive properties of the cathode. Optimum regimes of cathode training that ensures rapid Ti → TiN transition over the entire cathode wall thickness in the active zone are determined, which allows the operation temperature to be increased above 2200 K at a discharge current of up to 50 A for the cathode with an inner diameter of 8 mm and a wall thickness of 1 mm. Results of measurements of the current-voltage characteristics of discharge, thermal regimes of operation, and chemical composition of the cathode are presented. The rates of erosion of the cathode operating in nitrogen and argon have been determined.