In situ x-ray diffraction study of phase transformation of Mg 2-xPr xNi 4 during hydrogenation and dehydrogenation (x = 0.6 and 1.0)

K. Sakaki, N. Terashita, S. Tsunokake, Y. Nakamura, E. Akiba

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Abstract

The phase transformations of Mg 1.4Pr 0.6Ni 4 and Mg 1.0Pr 1.0Ni 4 during hydrogenation and dehydrogenation were investigated using in situ X-ray diffraction (XRD). Both alloys showed the cubic MgCu 4Sn type structure with space group F4̄3m before hydrogenation. The hydride β-Mg 1.4Pr 0.6Ni 4H ∼3.6 had the same crystal structure as the starting alloy, and its lattice was expanded by 4.3% by hydrogenation. Mg 1.0Pr 1.0Ni 4 was initially transformed to an orthorhombic β-Mg 1.0Pr 1.0Ni 4H ∼4 with space group Pmn2 1. By further hydrogenation, the orthorhombic hydride changed to β-Mg 1.0Pr 1.0Ni 4H ∼6 with a cubic structure with space group F4̄3m. The lattice constant of β-Mg 1.0Pr 1.0Ni 4H ∼6 was 7.6% larger than that of the starting alloy. Through dehydrogenation, all hydride phases returned to the alloy phase without any amorphization or disproportionation.

Original languageEnglish
Pages (from-to)1401-1407
Number of pages7
JournalJournal of Physical Chemistry C
Volume116
Issue number1
DOIs
Publication statusPublished - Jan 12 2012

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All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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