국내 최대 기계 및 로봇 연구정보

기술보고서

기술보고서 게시판 내용
타이틀	Destructive Evaluation of a Xenon Hollow Cathode After a 28,000 Hour Life Test
저자	Timothy R. Sarver-Verhey
Keyword	Hollow cathode; Electron emission; Plasma contactor; Dispenser cathode;
URL	http://gltrs.grc.nasa.gov/reports/1998/CR-1998-208678.pdf
보고서번호	NASA CR-1998-208678
발행년도	1998
출처	NASA Glenn Research Center
ABSTRACT	The International Space Station (ISS) plasma contactor system requires a hollow cathode assembly (HCA) with a lifetime of at least 18,000 hours. In order to demonstrate the lifetime capability of the HCA, a series of hollow cathode wear tests was performed which included a life test operated at the maximum current of the HCA. This test sought to verify hollow cathode lifetime capability and contamination control protocols. This hollow cathode accumulated 27,800 hours of operation before it failed during a restart attempt. The cathode was subsequently destructively analyzed in order to determine the failure mechanism. Microscopic examination of the cathode interior determined that relatively small changes in the cathode physical geometry had occurred and barium tungstates, which are known to limit the emission process, had formed over a majority of the electron emitter surface. Because the final state of the insert was consistent with expected impregnate chemistry, the hollow cathode was believed to have reached the end of its usable life under the test conditions.