A study on carburized La–Mo cathode material

Abstract The effect of carburization on the thermionic electron-emission properties of the La 2 O 3 -doped molybdenum (La–Mo) cathode has been systematically studied, and the optimal carburizing technology has been obtained. The optimal carburizing technology is that the La–Mo cathode is exposed to benzene vapour for 8 min at about 1500°C, and the pressure of benzene vapour is about 8.5–9.5 Pa. The thermionic electron-emission capacity of the La–Mo cathode has reached the level of the traditional thoriated tungsten (Th–W) cathode, and the service lifetime of the 6T51-type electron tube equipped with the La–Mo cathode has been about 1657 h under on–off working conditions. So it is possible that the La–Mo cathode will replace the Th–W cathode with the problems of radioactive pollution and drastic brittleness as cathode material of some powerful electron tubes, and this is also the purpose of the study.