Abstract: The traditional barium tungsten hollow cathode has the advantages of low working temperature and high emission efficiency, but its antipoisoning ability is poor. The life of electric thruster is mainly limited by hollow cathode. To ensure the longterm onorbit working of thruster, a new kind of modified barium tungsten cathode with a strong antipoisoning ability was developed. The cathode was exposed to environment of 90% humidity, 60℃ and accumulated 240h.The discharge voltage variation before and after test was less than 1V, satisfing the requirement of criterion. The test results also show that the steady working temperature of the modified barium tungsten cathode is 1050℃, 250℃ lower than that of lanthanum hexaboride type cathode. The componentlevel anode voltage is 21V, 4~5V lower than the lanthanum hexaboride hollow cathode. The thrusterlevel anode voltage is 35V, 8~10V lower than the lanthanum hexaboride hollow cathode. The experimental results show that the modified barium tungsten cathode has strong antipoisoning ability and excellent performance, and the application of the cathode can effectively meet the long life requirement of the thruster.

Key words: hollow cathode, barium tungsten emitter, lanthanum hexaboride, antitoxicity, moisture and heat test