TY - JOUR
T1 - Improved pumping speeds of oxygen-free palladium/titanium nonevaporable getter coatings and suppression of outgassing by baking under oxygen
AU - Miyazawa, Tetsuya
AU - Kano, Yu
AU - Nakayama, Yasuo
AU - Ozawa, Kenichi
AU - Iga, Toshiharu
AU - Yamanaka, Misao
AU - Hashimoto, Ayako
AU - Kikuchi, Takashi
AU - Mase, Kazuhiko
N1 - Publisher Copyright:
© 2019 Author(s).
PY - 2019/3/1
Y1 - 2019/3/1
N2 - 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 H 2 and CO have been reported to be improved by baking under an O 2 atmosphere, the authors investigated oxygen-free Pd/Ti samples heated in an ultrahigh vacuum (UHV) or under an O 2 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 O 2 . Pressure-curve measurements in an oxygen-free Pd/Ti-coated chamber show that pumping speeds for H 2 and CO were considerably improved after baking the chamber under an O 2 pressure of 1.3 × 10 -4 Pa (O 2 baking) in comparison with baking in UHV. Furthermore, partial-pressure measurements suggested that O 2 baking removes adsorbed carbon and hydrogen, and consequently suppresses the formation of H 2 , CO, H 2 O, and CH 4 . 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 H 2 and CO were measured by using the orifice method and were found to be improved after O 2 baking. O 2 baking is therefore useful for improving pumping speeds for H 2 and CO and for reducing the partial pressures of H 2 , CO, H 2 O, and CH 4 .
AB - 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 H 2 and CO have been reported to be improved by baking under an O 2 atmosphere, the authors investigated oxygen-free Pd/Ti samples heated in an ultrahigh vacuum (UHV) or under an O 2 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 O 2 . Pressure-curve measurements in an oxygen-free Pd/Ti-coated chamber show that pumping speeds for H 2 and CO were considerably improved after baking the chamber under an O 2 pressure of 1.3 × 10 -4 Pa (O 2 baking) in comparison with baking in UHV. Furthermore, partial-pressure measurements suggested that O 2 baking removes adsorbed carbon and hydrogen, and consequently suppresses the formation of H 2 , CO, H 2 O, and CH 4 . 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 H 2 and CO were measured by using the orifice method and were found to be improved after O 2 baking. O 2 baking is therefore useful for improving pumping speeds for H 2 and CO and for reducing the partial pressures of H 2 , CO, H 2 O, and CH 4 .
UR - http://www.scopus.com/inward/record.url?scp=85059954661&partnerID=8YFLogxK
U2 - 10.1116/1.5074160
DO - 10.1116/1.5074160
M3 - Article
AN - SCOPUS:85059954661
SN - 0734-2101
VL - 37
JO - Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
JF - Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
IS - 2
M1 - 021601
ER -