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Science 12 July 1991:
Vol. 253. no. 5018, pp. 421 - 424
DOI: 10.1126/science.253.5018.421
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Articles

High-Pressure Chemistry of Hydrogen in Metals: In Situ Study of Iron Hydride

J. V. BADDING 1, R. J. HEMLEY 1, and H. K. MAO 1

1 Geophysical Laboratory and Center for High Pressure Research, Carnegie Institution of Washington, 5251 Broad Branch Road, N.W., Washington, DC 20015

Optical observations and x-ray diffraction measurements of the reaction between iron and hydrogen at high pressure to form iron hydride are described. The reaction is associated with a sudden pressure-induced expansion at 3.5 gigapascals of iron samples immersed in fluid hydrogen. Synchrotron x-ray diffraction measurements carried out to 62 gigapascals demonstrate that iron hydride has a double hexagonal close-packed structure, a cell volume up to 17% larger than pure iron, and a stoichiometry close to FeH. These results greatly extend the pressure range over which the technologically important iron-hydrogen phase diagram has been characterized and have implications for problems ranging from hydrogen degradation and embrittlement of ferrous metals to the presence of hydrogen in Earth's metallic core.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
High-Pressure Geoscience Special Feature: Dynamical stability of Fe-H in the Earth's mantle and core regions.
E. I. Isaev, N. V. Skorodumova, R. Ahuja, Y. K. Vekilov, and B. Johansson (2007)
PNAS 104, 9168-9171
   Abstract »    Full Text »    PDF »
Hydrogen Partitioning into Molten Iron at High Pressure: Implications for Earth's Core.
T. Okuchi (1997)
Science 278, 1781-1784
   Abstract »    Full Text »


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