日本金属学会誌

J. Japan Inst. Metals, Vol. 70, No. 7 (2006),
pp. 541-547

Local Lattice Distortion and Chemical Bond Change during Hydrogenation in Pure Niobium

Tomonori Nambu1, Hisakazu Ezaki1, Hiroshi Yukawa2 and Masahiko Morinaga2

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

Abstract:

The local lattice distortion and the chemical bond change in the course of hydrogenation in niobium metal were simulated using the pseudopotential method and the DV-Xα molecular orbital method. The calculated enthalpy changes, Δ H, of hydrogen solution into niobium indicated that hydrogen could be dissolved readily into niobium up to the hydrogen content (H/M) of about 0.7 at 673 K, but further dissolution became difficult, in agreement with the experiment. The local lattice distortion appeared to occur in the niobium lattice so as to suppress the large decrease in the Nb-Nb covalent interaction during hydrogen dissolution, while enhancing the Nb-H interaction.


(Received 2006/2/16)

Keywords:

pseudopotential method, DV-Xα cluster method, enthalpy of hydrogen solution, niobium, niobium hydride


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