Regensburg 2007 – wissenschaftliches Programm
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AKE: Arbeitskreis Energie
AKE 3: Solar and Hydrogen Technology, Fuel Cells
AKE 3.2: Vortrag
Montag, 26. März 2007, 17:00–17:15, H45
Hydrogen Permeability of Nb Membrane Annealed Under Ultra High Vacuum — •Helmut Takahiro Uchida1, Yoshihiro Yamazaki2, Atsunori Kamegawa3, Hitoshi Takamura3, Junichi Koike3, Masuo Okada3, Astrid Pundt1, and Reiner Kirchheim1 — 1Institut für Materialphysik, Göttingen, Germany — 2California Institute of Technology, California, USA — 3Department of Materials Science, School of Engineering, Tohoku University, Sendai, Japan
In this research, hydrogen permeability of Pd-free Nb membrane using hydrogen annealing process by ultra high vacuum equipment was investigated. Pure Nb (99.85 percent) was used as membrane. The hydrogen permeation experiment was carried out in the temperature range of 773-1173K, and the H2 pressure range of 1-3.5 atm in the inlet side. Hydrogen flux and hydrogen pressures in the inlet side and outlet side of chamber were measured using mass flow meter and capacitance manometer, respectively. Hydrogen permeability was determined by Fick’s first low.
Effects of annealing conditions and heat treatment under hydrogen atmosphere on hydrogen permeability were investigated. It is supposed that the surface oxidation of Nb is reduced by the hydrogen annealing. Moreover, it is found that the value of hydrogen permeability becomes almost equivalent to the theoretical value when the sample preparation was optimized by an extension of the evacuating time. The best hydrogen permeability is obtained in metal membranes using the annealing under ultra-high vacuum and pure hydrogen atmosphere.