An experimental study on the degradation of the C12A7 hollow cathode  

作　　者：Zhiwei HUA Pingyang WANG Zhuang LUO Xin ZHANG Leichao TIAN 华志伟;王平阳;骆壮;张忻;田雷超(School of Mechanical Engineering,Shanghai Jiao Tong University,Shanghai 200240,People's Republic of China;College of Materials Science and Engineering,Beijing University of Technology,Key Laboratory of Functional Materials,Beijing 100124,People's Republic of China;Shanghai Institute of Space Propulsion,Shanghai 201112,People's Republic of China;Shanghai Space Engine Engineering and Technology Research Center,Shanghai 201112,People's Republic of China)

机构地区：[1]School of Mechanical Engineering,Shanghai Jiao Tong University,Shanghai 200240,People's Republic of China [2]College of Materials Science and Engineering,Beijing University of Technology,Key Laboratory of Functional Materials,Beijing 100124,People's Republic of China [3]Shanghai Institute of Space Propulsion,Shanghai 201112,People's Republic of China [4]Shanghai Space Engine Engineering and Technology Research Center,Shanghai 201112,People's Republic of China

出　　处：《Plasma Science and Technology》2022年第7期90-101,共12页等离子体科学和技术（英文版）

基　　金：supported by the Joint Fund for Equipment Pre-research and Aerospace Science and Technology (No. 6141B061203)。

摘　　要：Emitter overheating is by far the greatest problem limiting the performance of novel C12A7 hollow cathodes. To explore the failure operating point and degradation mechanism of the C12A7 hollow cathode, microscopic analyses of a degraded electride emitter after 10 h of thermal electron emission are presented in this paper. The morphology and composition variation of overheated electride emitters by scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction indicate the melting and decomposition of electride of the surface layer. The monitored temperature of the electride emitter during the C12A7 hollow cathode operation shows that to avoid overheating the electride emitter, the average current density allowed should be about 64 m A mm^(-2) for the C12A7 hollow cathode in its current configuration. Experimental results of the heaterless C12A7 hollow cathode demonstrate that xenon(Xe) ion bombardment can remove the insulating layer and restore the thermionic emission capability for less degraded emitters. Based on experimental results and microscopic characterization, the depletion and degradation mechanisms of electride emitters during the hollow cathode operation are discussed.

关 键 词：C12A7 electride DEGRADATION micro characterization hollow cathode 

分 类 号：O462.1[理学—电子物理学]