SOME ASPECTS OF ELECTRODE EROSION IN ARC HEATERS

Very little information has been published on the erosion of electrodes occurring when the cathode and anode spots of arcs move over their surfaces for long periods. The results of measurements made during a study of an arc heater are reported herein. Operating an arc at 180A d. c. in argon at pressures between 2 and 73 atm has shown that the cathode erosion rate can vary by at least two orders of magnitude for relatively small changes in arc velocity. Phenomenological observation of electrode surfaces indicates that gas in the electrode material plays a very important role in electrode erosion.