Research on erosion resistance of rare earth tungsten electrode in electric propulsion

Abstract:

As the "heart" of the Arcjet, cathode is responsible for heating the gaseous propellant to produce propulsion. Due to the long service cycle and frequent ignition times of satellite, high requirements are put forward for the service life and erosion resistance of cathode materials. Based on W-La-Ce-Y and W-La-Y-Zr electrodes, W-La-Ce-Y-Re and W-La-Y-Zr-Re electrode materials were prepared by hydrogen reduction-median frequencySsintering. By simulating the actual working condition of the Arcjet, the arcing test was carried out at 250A current, the erosion resistance of each electrode material was studied, and the morphology of the electrode tip after arcing was observed. The results show that the rhenium electrode has less burning loss quality, better tip morphology stability, and better burning loss resistance after 2 hours of arc burning. Under SEM, it was observed that the rhenium inhibited the growth of dendrites and weakened the recrystallization degree of tungsten matrix grains. The grain orientation on the surface of rhenium electrode was more conducive to the migration of rare earth oxides; Under the metallographic microscope, it was observed that the grains at the tip of the rhenium electrode are finer, and rhenium plays a role in refining the recrystallized grains. The cathode voltage drop of rhenium electrode is lower at different currents. The addition of rhenium improves the electron emission performance of electrode materials.

Key words:Rare earth tungsten electrodes; Erosion resistance; Rhenium; electric propulsion.