日本金属学会誌

J. Japan Inst. Metals, Vol. 70, No. 6 (2006),
pp. 467-472

In-Situ X-ray Diffraction Measurement for Pure Niobium Metal in High Temperature Hydrogen Atmosphere

Tomonori Nambu1, Nobue Shimizu1,, Hisakazu Ezaki1, Hiroshi Yukawa2, Masahiko Morinaga2 and Nobuhiko Takeichi3

1Department of Materials Science and Engineering, Suzuka National College of Technology, Suzuka 510-0294
2Department of Materials Science and Engineering, Graduate School of Engineering, Nagoya University, Nagoya 464-8603
3Research Institute for Ubiquitous Energy Devices, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda 563-8577

Abstract:

The Lattice constants of pure niobium metal were measured by in-situ X-ray diffraction method at the temperature of 293 K to 673 K and the hydrogen pressure below 0.3 MPa. The deformation and fracture of niobium metal membrane during hydrogen permeation were treated by the measured lattice strain. The membrane was deformed and fractured easily when about 10% lattice contraction was introduced to it by lowering the hydrogen pressure at 673 K, at which the dehydrogenation reaction progressed smoothly. However, neither deformation nor fracture took place at the temperature lower than 473 K, because the dehydrogenation reaction hardly occurred in such a temperature range. Thus, the principal reason for the deformation or fracture of niobium metal membrane was attributable to the large volumetric contraction during dehydrogenation, the easiness of which, however, depended largely on the temperature.


(Received 2005/12/15)

Keywords:

lattice constant, volumetric strain, niobium, niobium hydride, hydrogen permeation, X-ray diffraction


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