日本金属学会誌

J. Japan Inst. Met. Mater, Vol. 79, No. 3 (2015),
pp. 124-130

Observation of Transient Structural Changes on Hydrogen Absorption Process of LaNi4.75Sn0.25 by Time Resolved X-Ray Diffraction

Akihiko Machida1, Kensuke Higuchi1, Yoshinori Katayama1, Kouji Sakaki2, Hyunjeong Kim2 and Yumiko Nakamura2

1Quantum Beam Science Center, Japan Atomic Energy Agency, Sayo-gun, Hyogo 679-5148
2Hydrogen Energy Technology Group, Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8565

Abstract:

Structural changes on hydrogen absorption process of hydrogen absorbing alloy LaNi4.75Sn0.25 have been investigated by time-resolved X-ray diffraction measurements using synchrotron radiation source. We have found the transient intermediate phase between the solid solution and hydride phases of LaNi4.75Sn0.25 under non-equilibrium hydrogen pressure condition at room temperature. LaNi4.75Sn0.25 has transformed into the hydride through three phase co-existing state. The hydrogen content of the intermediate phase estimated from the unit cell volume is independent of the induced hydrogen gas pressure. The variation of lattice constants indicate that the hydrogen atoms are located at the La2Ni2(Ni, Sn)2 octahedron and La2(Ni, Sn)2 tetrahedron in the intermediate phase. [doi:10.2320/jinstmet.JC201407]


(Received 2014/9/18)

Keywords:

hydrogen storage materials, synchrotron radiation X-rays, in-situ measurements, X-ray diffraction


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