ISSN:
1662-8985
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Hydrogen storage materials are attracting much attention as media of storing hydrogen.High-pressure synthesis has been widely used for exploration of novel materials. We have reportedthat many new Mg-based hydrides or alloys have been synthesized by anvil-type apparatus underthe pressure of GPa-order. In Mg - TM ( TM = Nb, Ta ) - H systems, it was reported that novelFCC-type hydride which is similar in crystal structure and composition to Mg7TiH13-16 wassynthesized under 8 GPa. On the other hand, there is few reports of novel Ca-based hydrides to besynthesized under high pressure. However, the compressibility of calcium is higher than that ofmagnesium. Thus, there is a tendency for Ca compounds to be synthesized by lower pressure thanMg ones.This study describes the synthesis of new Ca-based hydrides by this high-pressure techniques. InCa - TM ( TM = Ti, Hf, V, Nb and Ta ) systems, the influence of applied pressure on present phaseswere investigated. For the composition of CaH2 - 14.3 mol%ZrH2 in Ca - Zr - H system, novelhydride was synthesized at 1073 K for 2 h under 5 GPa. Crystal structure of the novel hydride wasfound to be FCC-type with a lattice parameter of a = 0.531 nm. In addition, the thermal stability andhydrogen contents of this novel hydride were investigated.In Ca - Hf - H system, the unknown phase was observed in the sample of CaH2 - 12.5 mol%HfH2prepared 1073 K for 2 h under 5 GPa. This unknown phase is FCC structure with lattice parameterof a = 0.528(2) nm
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/40/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.26-28.885.pdf
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