High-pressure and high-temperature phase diagram for Fe0.9Ni0.1-H alloy

Yuki Shibazaki; Hidenori Terasaki; Eiji Ohtani; Ryuji Tateyama; Keisuke Nishida; Ken ichi Funakoshi; Yuji Higo

doi:10.1016/j.pepi.2013.12.013

High-pressure and high-temperature phase diagram for Fe_0.9Ni_0.1-H alloy

Yuki Shibazaki, Hidenori Terasaki, Eiji Ohtani, Ryuji Tateyama, Keisuke Nishida, Ken ichi Funakoshi, Yuji Higo

Research output: Contribution to journal › Article › peer-review

20 Citations (Scopus)

Abstract

Planetary cores are considered to consist of an iron-nickel (Fe-Ni) alloy and light elements and hydrogen is one of plausible light elements in the core. Here we have performed in situ X-ray diffraction experiments on an Fe_0.9Ni_0.1-H system up to 15.1GPa and 1673K, and investigated the effect of Ni on phase relations of FeH_x under high pressure and high temperature. The experimental system in the present work was oversaturated with hydrogen. We found a face-center-cubic (fcc) phase (with hydrogen concentration up to x~1) and a body-center-cubic (bcc) phase (x<0.1) as stable phases. The partial melting was observed below 6GPa. We could not observe a double-hexagonal-close-packed (dhcp) phase because of limitations in pressure and temperature conditions. The stability field of each phase of Fe_0.9Ni_0.1H_x was almost same as that of FeH_x. The solidus of Fe_0.9Ni_0.1H_x was 500-700K lower than the melting curve of Fe and its liquidus was 400-600K lower than that of Fe in the pressure range of this study. Both the solidus and liquidus of Fe_0.9Ni_0.1H_x were depressed at around 3.5GPa, as was the solidus of FeH_x. The hydrogen contents in fcc-Fe_0.9Ni_0.1H_x just below solidus were slightly lower than those of fcc-FeH_x, which suggests that nickel is likely to prevent dissolution of hydrogen into iron. Due to the lower hydrogen solubilities in Fe_0.9Ni_0.1 compared to Fe, the solidus of Fe_0.9Ni_0.1H_x is about 100-150K higher than that of FeH_x.

Original language	English
Pages (from-to)	192-201
Number of pages	10
Journal	Physics of the Earth and Planetary Interiors
Volume	228
DOIs	https://doi.org/10.1016/j.pepi.2013.12.013
Publication status	Published - Mar 2014
Externally published	Yes

Keywords

High pressure
Hydrogen
Iron hydride
Iron-nickel alloy
Melting temperature
Planetary core

ASJC Scopus subject areas

Astronomy and Astrophysics
Geophysics
Physics and Astronomy (miscellaneous)
Space and Planetary Science

Access to Document

10.1016/j.pepi.2013.12.013

Cite this

@article{e4480ce930b74bc7a3dbae100d3c2a24,

title = "High-pressure and high-temperature phase diagram for Fe0.9Ni0.1-H alloy",

abstract = "Planetary cores are considered to consist of an iron-nickel (Fe-Ni) alloy and light elements and hydrogen is one of plausible light elements in the core. Here we have performed in situ X-ray diffraction experiments on an Fe0.9Ni0.1-H system up to 15.1GPa and 1673K, and investigated the effect of Ni on phase relations of FeHx under high pressure and high temperature. The experimental system in the present work was oversaturated with hydrogen. We found a face-center-cubic (fcc) phase (with hydrogen concentration up to x~1) and a body-center-cubic (bcc) phase (x<0.1) as stable phases. The partial melting was observed below 6GPa. We could not observe a double-hexagonal-close-packed (dhcp) phase because of limitations in pressure and temperature conditions. The stability field of each phase of Fe0.9Ni0.1Hx was almost same as that of FeHx. The solidus of Fe0.9Ni0.1Hx was 500-700K lower than the melting curve of Fe and its liquidus was 400-600K lower than that of Fe in the pressure range of this study. Both the solidus and liquidus of Fe0.9Ni0.1Hx were depressed at around 3.5GPa, as was the solidus of FeHx. The hydrogen contents in fcc-Fe0.9Ni0.1Hx just below solidus were slightly lower than those of fcc-FeHx, which suggests that nickel is likely to prevent dissolution of hydrogen into iron. Due to the lower hydrogen solubilities in Fe0.9Ni0.1 compared to Fe, the solidus of Fe0.9Ni0.1Hx is about 100-150K higher than that of FeHx.",

keywords = "High pressure, Hydrogen, Iron hydride, Iron-nickel alloy, Melting temperature, Planetary core",

author = "Yuki Shibazaki and Hidenori Terasaki and Eiji Ohtani and Ryuji Tateyama and Keisuke Nishida and Funakoshi, {Ken ichi} and Yuji Higo",

note = "Funding Information: We thank T. Sakai, T. Sakamaki, Y. Nishihara, and N. Tsujino for their useful suggestions. We appreciate to anonymous reviewers for their constructive comments. Y.S was supported by a Research Fellow of the Japan Society for the Promotion of Science . This work was supported by the Grants-in-aid of Scientific Research from the Ministry of Education, Culture, Science, Sport, and Technology of the Japanese Government (Nos. 18104009 and 22000002) to E.O and conducted as a part of the Global COE Program at Tohoku University, “Global Education and Research Center for Earth and Planetary Dynamics” . The synchrotron radiation experiments were performed at the BL04B1 beamline at the SPring-8 facility with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal Nos. 2009B1696 and 2009B1184). ",

year = "2014",

month = mar,

doi = "10.1016/j.pepi.2013.12.013",

language = "English",

volume = "228",

pages = "192--201",

journal = "Physics of the Earth and Planetary Interiors",

issn = "0031-9201",

publisher = "Elsevier",

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TY - JOUR

T1 - High-pressure and high-temperature phase diagram for Fe0.9Ni0.1-H alloy

AU - Shibazaki, Yuki

AU - Terasaki, Hidenori

AU - Ohtani, Eiji

AU - Tateyama, Ryuji

AU - Nishida, Keisuke

AU - Funakoshi, Ken ichi

AU - Higo, Yuji

N1 - Funding Information: We thank T. Sakai, T. Sakamaki, Y. Nishihara, and N. Tsujino for their useful suggestions. We appreciate to anonymous reviewers for their constructive comments. Y.S was supported by a Research Fellow of the Japan Society for the Promotion of Science . This work was supported by the Grants-in-aid of Scientific Research from the Ministry of Education, Culture, Science, Sport, and Technology of the Japanese Government (Nos. 18104009 and 22000002) to E.O and conducted as a part of the Global COE Program at Tohoku University, “Global Education and Research Center for Earth and Planetary Dynamics” . The synchrotron radiation experiments were performed at the BL04B1 beamline at the SPring-8 facility with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal Nos. 2009B1696 and 2009B1184).

PY - 2014/3

Y1 - 2014/3

N2 - Planetary cores are considered to consist of an iron-nickel (Fe-Ni) alloy and light elements and hydrogen is one of plausible light elements in the core. Here we have performed in situ X-ray diffraction experiments on an Fe0.9Ni0.1-H system up to 15.1GPa and 1673K, and investigated the effect of Ni on phase relations of FeHx under high pressure and high temperature. The experimental system in the present work was oversaturated with hydrogen. We found a face-center-cubic (fcc) phase (with hydrogen concentration up to x~1) and a body-center-cubic (bcc) phase (x<0.1) as stable phases. The partial melting was observed below 6GPa. We could not observe a double-hexagonal-close-packed (dhcp) phase because of limitations in pressure and temperature conditions. The stability field of each phase of Fe0.9Ni0.1Hx was almost same as that of FeHx. The solidus of Fe0.9Ni0.1Hx was 500-700K lower than the melting curve of Fe and its liquidus was 400-600K lower than that of Fe in the pressure range of this study. Both the solidus and liquidus of Fe0.9Ni0.1Hx were depressed at around 3.5GPa, as was the solidus of FeHx. The hydrogen contents in fcc-Fe0.9Ni0.1Hx just below solidus were slightly lower than those of fcc-FeHx, which suggests that nickel is likely to prevent dissolution of hydrogen into iron. Due to the lower hydrogen solubilities in Fe0.9Ni0.1 compared to Fe, the solidus of Fe0.9Ni0.1Hx is about 100-150K higher than that of FeHx.

AB - Planetary cores are considered to consist of an iron-nickel (Fe-Ni) alloy and light elements and hydrogen is one of plausible light elements in the core. Here we have performed in situ X-ray diffraction experiments on an Fe0.9Ni0.1-H system up to 15.1GPa and 1673K, and investigated the effect of Ni on phase relations of FeHx under high pressure and high temperature. The experimental system in the present work was oversaturated with hydrogen. We found a face-center-cubic (fcc) phase (with hydrogen concentration up to x~1) and a body-center-cubic (bcc) phase (x<0.1) as stable phases. The partial melting was observed below 6GPa. We could not observe a double-hexagonal-close-packed (dhcp) phase because of limitations in pressure and temperature conditions. The stability field of each phase of Fe0.9Ni0.1Hx was almost same as that of FeHx. The solidus of Fe0.9Ni0.1Hx was 500-700K lower than the melting curve of Fe and its liquidus was 400-600K lower than that of Fe in the pressure range of this study. Both the solidus and liquidus of Fe0.9Ni0.1Hx were depressed at around 3.5GPa, as was the solidus of FeHx. The hydrogen contents in fcc-Fe0.9Ni0.1Hx just below solidus were slightly lower than those of fcc-FeHx, which suggests that nickel is likely to prevent dissolution of hydrogen into iron. Due to the lower hydrogen solubilities in Fe0.9Ni0.1 compared to Fe, the solidus of Fe0.9Ni0.1Hx is about 100-150K higher than that of FeHx.

KW - High pressure

KW - Hydrogen

KW - Iron hydride

KW - Iron-nickel alloy

KW - Melting temperature

KW - Planetary core

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U2 - 10.1016/j.pepi.2013.12.013

DO - 10.1016/j.pepi.2013.12.013

M3 - Article

AN - SCOPUS:84897093809

SN - 0031-9201

VL - 228

SP - 192

EP - 201

JO - Physics of the Earth and Planetary Interiors

JF - Physics of the Earth and Planetary Interiors

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