C12A7空心阴极发射体的失效研究

Failure Emitters of C12A7 Hollow Cathode

关键词:  电子化合物  空心阴极  微观分析  熔化  氧化

Key words:  Electride  Hollow cathode  Microscopic analysis  Melting  Oxidation

摘要:

为进一步提高新型C12A7空心阴极的工作性能与寿命，发射体失效形式的微观分析十分必要。本文利用SEM，EDS，XRD等技术对C12A7发射体的熔融和氧化问题进行研究，分析了失效发射体放电前后的表面形貌和组分变化。结果表明，C12A7发射体在放电后发射表面出现大量球形颗粒，不当工作条件下的发射体易过热，产生熔融再结晶形貌，且在高温下分解产生了不利于放电的CaAl₂O₄和Ca₃Al₂O₆。C12A7空心阴极虽有一定的抗氧化性，但在系统漏气状态下依然会被持续氧化，产生不可逆的中毒现象。

Abstract:

To further improve the performance and lifetime of the novel C12A7 hollow cathode， microscopic analysis of the failure samples of the C12A7 emitter is necessary. The surface morphology and component changes of C12A7 emitters with melting and oxidation problems before and after discharge were investigated by SEM， EDS and XRD. The results show that a large number of spherical particles appeared on the C12A7 emitter surface after discharge. Morphology of molten and recrystallization was detected on the melted emitter under improper working conditions. The C12A7 emitter also decomposed into CaAl₂O₄and Ca₃Al₂O₆ at high temperature which are unfavorable to the discharge. Although the C12A7 hollow cathode was reported with a certain oxidation resistance， it could also be oxidized in the leakage state of the system， resulting in an irreversible poisoning phenomenon.