Hydrogen adsorption characteristics of Zr57V36Fe7 non-evaporable getters at low operating temperatures. (August 2018)

• Record Type: Journal Article
• Authors: Feng, Tianyou; Cheng, Yongjun; Chen, Lian; Xi, Zhenhua; Zhu, Jianbing; Li, Yali
• Is Part Of: Vacuum. Volume 154(2018)
• Page Start: 6
• Page End: 10
• Publication Date: 2018-08
• Subjects: Non-evaporable getters -- Hydrogen sorption capacity -- Hydrogen adsorption rate -- Adsorption isotherm -- Low temperature; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2018.04.038
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: Non-evaporable getter is commonly used to remove active gases in vacuum chambers, especially H2 at ambient temperature. In this work, the getter was applied to low operating temperatures where a vacuum chamber is cooled to a temperature of 100 K, and maintained under a pressure of approximately 1 × 10 −3 Pa, in which the residual gas is mainly hydrogen. The test temperatures ranged from 100 K to 293 K. Using constant volume method, the hydrogen sorption capacity of Zr57 V36 Fe7 at different temperatures and equilibrium pressures are determined. In addition, the corresponding adsorption isotherms of the getter from 10 −4 Pa to 10 Pa are obtained. In contrast with its properties at ambient temperature, Zr57 V36 Fe7 displays a lower hydrogen adsorption rate but a higher hydrogen sorption capacity at low temperature conditions. From that, it is reasonable to recommend the use of Zr57 V36 Fe7 for hydrogen degassing of vacuum chambers at low temperatures. Highlights: H2 adsorption characteristics of St707 are measured at 173 K and 100 K first time. Adsorption isotherms at corresponding temperatures are obtained. Adsorption and diffusion theories are used to analyze the results. St707 has larger H2 sorption capacity at low temperature.