[2E01-08] Vaccuum Science and Technology (VST)

10:45 AM - 11:00 AM JST(1:45 AM - 2:00 AM UTC)

[2E04] Analysis of degradation mechanisms in Ti-Zr-V NEG coating by X-ray photoelectron spectroscopy

*junichiro kamiya¹, kazuma koarai¹, tatsuo fukuda¹, masaaki kobata¹, yuko morohashi¹, kaoru wada², ippei yamada¹ (1. Japan Atomic Energy Agency (Japan), 2. Tokyo Electronics Co., Ltd. (Japan))

TiZrV non evaporable getter (NEG) coatings are widely used for ultra-high and extreme-high vacuum systems in particle accelerators and are expected to be applied to quantum devices in the near future. Their gas sorption relies on thermal activation, which reduces surface oxides; however, repeated air exposure and activation cycles degrade performance. In this study, NEG films from fresh to 20 exposure and activation cycles were analyzed by XPS with Ar sputter depth profiling. Zr was found to be oxidized deep into the coating, Ti to an intermediate depth, and V only near the surface, with oxide depth increasing with cycle number. HAXPES revealed suboxide formation beneath the surface and incomplete reduction after activation. These results indicate that progressive bulk oxidation of Zr and Ti suppresses oxygen migration and surface metallization, leading to degradation of NEG performance.

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