日本金属学会誌

J. Japan Inst. Metals, Vol. 73, No. 9 (2009),
pp. 742-746

Mechanical Properties in Hydrogen Atmosphere and Hydrogen Permeability of Nb-W-Ta Alloys for Hydrogen Permeable Membrane

Naoshi Watanabe1, Hiroshi Yukawa1, Tomonori Nambu2, Yoshihisa Matsumoto3, Guoxing Zhang1 and Masahiko Morinaga1

1Department of Materials Science and Engineering, Graduate School of Engineering, Nagoya University, Nagoya 464-8603
2Department of Materials Science and Engineering, Suzuka National College of Technology, Suzuka 510-0294
3Department of Mechanical Engineering, Oita National College of Technology, Oita 870-0152

Abstract:

Pressure-Composition-Isotherm (PCT) measurements, in-situ small punch (SP) tests in hydrogen gas atmosphere and hydrogen permeation tests are conducted for Nb-W-Ta ternary alloys in order to investigate the alloying effects of tantalum on the hydrogen solubility, the mechanical properties and hydrogen permeability of Nb-5 mol%W alloy. It is found that the hydrogen solubilities of Nb-5 mol%W-Xmol%Ta (X = 5, 10) alloys are very similar with that of Nb-5 mol%W alloy. Also, the mechanical properties in hydrogen gas atmosphere and hydrogen permeability of the alloys are comparable with Nb-5 mol%W alloy. Therefore, the addition of tantalum scarcely modifies the properties of Nb-5 mol%W alloys. Thus, it is not necessary to take into account the amount of tantalum in Nb-W alloys for hydrogen permeable membrane. In other words, it is not needed to remove tantalum impurity from niobium mineral ores in the course of the refinery process of niobium metal. This means that niobium mineral ore containing high tantalum impurity can be used to reduce the material cost of Nb-W-based hydrogen permeable membranes.


(Received 2009/5/22)

Keywords:

hydrogen permeable membrane, hydrogen purification, niobium-based alloy, hydrogen solubility, hydrogen permeability, mechanical property


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