Improved pumping speeds of oxygen-free palladium/titanium nonevaporable getter coatings and suppression of outgassing by baking under oxygen
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- Tetsuya Miyazawa
- Department of Materials Structure Science, SOKENDAI 1 , 1-1 Oho, Tsukuba 305-0801, Japan
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- Yu Kano
- Department of Pure and Applied Chemistry, Tokyo University of Science 2 , 2641 Yamazaki, Noda 278-8510, Japan
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- Yasuo Nakayama
- Department of Pure and Applied Chemistry, Tokyo University of Science 2 , 2641 Yamazaki, Noda 278-8510, Japan
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- Kenichi Ozawa
- Department of Chemistry, Tokyo Institute of Technology 3 , 2-12-1 Ookayama, Meguro 152-8551, Japan
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- Toshiharu Iga
- Osaka Vacuum, Ltd. 4 , 7-775 Ohtori-higashi-machi, Nishi-ku, Sakai 593-8324, Japan
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- Misao Yamanaka
- National Institute for Materials Science 5 , 1-2-1 Sengen, Tsukuba 305-0047, Japan
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- Ayako Hashimoto
- National Institute for Materials Science 5 , 1-2-1 Sengen, Tsukuba 305-0047, Japan
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- Takashi Kikuchi
- Institute of Materials Structure Science 7 , KEK, 1-1 Oho, Tsukuba 305-0801, Japan
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- Kazuhiko Mase
- Department of Materials Structure Science, SOKENDAI 1 , 1-1 Oho, Tsukuba 305-0801, Japan
抄録
<jats:p>Oxygen-free palladium/titanium (Pd/Ti) is a new nonevaporable getter material with an activation temperature as low as 133 °C. Because pumping speeds of oxygen-free Pd/Ti for H2 and CO have been reported to be improved by baking under an O2 atmosphere, the authors investigated oxygen-free Pd/Ti samples heated in an ultrahigh vacuum (UHV) or under an O2 pressure of 1.3 × 10−4 Pa by x-ray photoelectron spectroscopy. The authors found that carbon contamination decreased to an extent on heating in UHV, but decreased considerably on heating in O2. Pressure-curve measurements in an oxygen-free Pd/Ti-coated chamber show that pumping speeds for H2 and CO were considerably improved after baking the chamber under an O2 pressure of 1.3 × 10−4 Pa (O2 baking) in comparison with baking in UHV. Furthermore, partial-pressure measurements suggested that O2 baking removes adsorbed carbon and hydrogen, and consequently suppresses the formation of H2, CO, H2O, and CH4. Catalytic chemical reactions on the Pd surface appear to be responsible for the removal of adsorbed carbon and hydrogen. The pumping speeds of the oxygen-free Pd/Ti-coated chamber for H2 and CO were measured by using the orifice method and were found to be improved after O2 baking. O2 baking is therefore useful for improving pumping speeds for H2 and CO and for reducing the partial pressures of H2, CO, H2O, and CH4.</jats:p>
収録刊行物
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- Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films
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Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 37 (2), 02160-, 2019-01-09
American Vacuum Society
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詳細情報 詳細情報について
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- CRID
- 1360004235870002944
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- ISSN
- 15208559
- 07342101
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- データソース種別
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- Crossref
- KAKEN