Determination of high-pressure Phase equilibria of Fe2O 3 using the Kawai-type apparatus equipped with sintered diamond anvils

Eiji Ito, Hiroshi Fukui, Tomoo Katsura, Daisuke Yamazaki, Takashi Yoshino, Yosh Itaka Aizawa, Atsushi Kubo, Sho Yokoshi, Kazuyoki Kawabe, Shuangmeng Zhai, Anton Shatzkiy, Maki Okube, Akifumi Nozawa, Ken Ichi Funakoshi

    Research output: Contribution to journalArticlepeer-review

    27 Citations (Scopus)

    Abstract

    Phase equilibria of Fe2O3 have been studied up to 58 GPa and 1400 K using the Kawai-type multi anvil apparatus equipped with sintered diamond anvils. Identification of phases and pressure determination has been carried out by means of in situ X-ray observation using synchrotron radiation at SPring-8. Hematite (phase I) successively transforms to the Rh 2O3(II)-type structure (phase II) and then to an orthorhombic structure (phase III) with increasing pressure. The transformations of hematite into high-pressure phases have been observed only at temperatures higher than 500 K, which is not concordant with previous results obtained by using the diamond anvil cell. Volume changes accompanied by the I-II and II-III transformations are calculated to be -2.8 and -5.0%, respectively. The phase boundary between I and II phases and that between II and III have been proposed to be P (GPa) = -0.015 T (K) + 44.2 and P (GPa) = -0.005 T (K) + 48.7, respectively. Possible correlation between a Mott transition and the phase stabilities may be concealed at room temperature due to slow reaction kinetics of the structural transformations.

    Original languageEnglish
    Pages (from-to)205-209
    Number of pages5
    JournalAmerican Mineralogist
    Volume94
    Issue number2-3
    DOIs
    Publication statusPublished - 2009

    Keywords

    • FeO
    • High-pressure phase equilibria
    • In situ X-ray observation
    • Kawai-cell
    • Sintered diamond

    ASJC Scopus subject areas

    • Geophysics
    • Geochemistry and Petrology

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