Structural and hydriding properties of the Mg-Ni-H system with nano-and/or amorphous structures

Kazutaka Ikeda, Yuko Nakamori, Shin Ichi Orimo

Research output: Contribution to journalArticle

Abstract

Structural properties of the Mg-Ni alloys have been extensively investigated to improve their hydriding properties. The alloys Mg-x at.%Ni (x = 33, 38, 43 and 50) with different nanometer-scale structures were successively synthesized by mechanical grinding of Mg2Ni with Ni. Nanostructured Mg2Ni (w-Mg2Ni) was obtained by grinding only Mg 2Ni (x = 33). Amorphous MgNi (a-MgNi) was partially formed by grinding of Mg2Ni with additional Ni (x = 38 and 43), and was homogeneously formed in equivalent composition (x = 50). The hydriding temperatures decrease from 440 K for x = 33 to 373 K for x = 50 with increasing the Ni amounts. The electrochemical p-c isotherm measurements revealed that there is obviously the miscibility gap (plateau) pressure higher than 10 -4 MPa at ambient temperature even in the amorphous phase. The coordination numbers and interatomic distances of the Mg-D and Ni-D correlations in the a-MgNi-D show that deuterium occupies the interstitial tetrahedral site composed of nearly 2Mg-2Ni. The interatomic distances continuously decrease with increasing Li amounts in LixMg1-xNi-H (x = 0,0.25 and 0.50).

Original languageEnglish
Pages (from-to)415-418
Number of pages4
JournalJournal of Metastable and Nanocrystalline Materials
Volume24-25
DOIs
Publication statusPublished - 2005 Dec 1

Keywords

  • Amorphous
  • Magnesium-nickel-hydrogen
  • Nanostructure
  • Substitution

ASJC Scopus subject areas

  • Materials Science (miscellaneous)
  • Materials Science(all)
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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