High-pressure synthesis of novel hydrides in Mg-RE-H systems (RE = Y, La, Ce, Pr, Sm, Gd, Tb, Dy)

A. Kamegawa, Y. Goto, H. Kakuta, H. Takamura, M. Okada

Research output: Contribution to journalConference articlepeer-review

37 Citations (Scopus)

Abstract

The high-pressure synthesis of new hydrides of Mg-RE-H systems, where RE = Y, La, Ce, Pr, Sm, Gd, Tb and Dy, were conducted by using a cubic-anvil-type apparatus, and their crystal structure, thermal stabilities and hydrogen contents were investigated. In Mg-Y-H system, newly found MgY2H y with a FCC-type structure has been prepared. In MgH2-x mol% REH (REH = LaH3, CeH2.5 and PrH3), new hydrides with primitive tetragonal structure were synthesized around x = 25-33 under GPa-order high pressures. The lattice constants were a = 0.8193 nm, c = 0.5028 nm, a = 0.8118 nm, c = 0.4979 nm and a = 0.8058 nm, c = 0.4970 nm at x = 25 in Mg-La, Ce and Pr systems, respectively. The hydrogen contents of the novel compounds were 4.1, 3.7 and 3.9 mass% in Mg-La, Ce and Pr systems, respectively, and the chemical formulae were found to correspond to Mg 3LaH9, Mg3CeH8.1 and Mg 3PrH9. The new hydrides decomposed into Mg and rare-earth hydride at about 600 K (Mg3LaH9: 614 K, Mg 3CeH8.1: 609 K, Mg3PrH9: 630 K) with an endothermic reaction. In MgH2-x mol% hREH (hREH = GdH 3, TbH3 and DyH3), new hydrides with FCC-type structure were synthesized around x = 67.

Original languageEnglish
Pages (from-to)284-287
Number of pages4
JournalJournal of Alloys and Compounds
Volume408-412
DOIs
Publication statusPublished - 2006 Feb 9
EventProceedings of the Rare Earths'04 in Nara, Japan -
Duration: 2004 Nov 72004 Nov 12

Keywords

  • High pressure
  • Hydride
  • Magnesium
  • Rare earth
  • Thermal stability

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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