TY - JOUR
T1 - Static compression of Fe0.83Ni0.09Si0.08 alloy to 374GPa and Fe0.93Si0.07 alloy to 252GPa
T2 - Implications for the Earth's inner core
AU - Asanuma, Hidetoshi
AU - Ohtani, Eiji
AU - Sakai, Takeshi
AU - Terasaki, Hidenori
AU - Kamada, Seiji
AU - Hirao, Naohisa
AU - Ohishi, Yasuo
N1 - Funding Information:
This work was supported by grants-in-aid for scientific research from the Ministry of Education, Culture, Science, Sport, and Technology of the Japanese Government to E.O. (nos. 18104009 and 22000002 ). The work was conducted as a part of the Global COE program, Global Research and Education Center for the Earth and Planetary Dynamics at Tohoku University.
PY - 2011/10/1
Y1 - 2011/10/1
N2 - The pressure-volume equations of state of iron-nickel-silicon alloy Fe0.83Ni0.09Si0.08 (Fe-9.8wt.% Ni-4.0wt.% Si) and iron-silicon alloy Fe0.93Si0.07 (Fe-3.4wt.% Si) have been investigated up to 374GPa and 252GPa, respectively. The present compression data covered pressures of the Earth's core. We confirmed that both Fe0.83Ni0.09Si0.08 and Fe0.93Si0.07 alloys remain in the hexagonal close packed structure at all pressures studied.We obtained the density of these alloys at the pressure of the inner core boundary (ICB), 330GPa at 300K by fitting the compression data to the third order Birch-Murnaghan equation of state. Using these density values combined with the previous data for hcp-Fe, hcp-Fe0.8Ni0.2, and hcp-Fe0.84Si0.16 alloys and comparing with the density of the PREM inner core, we estimated the Ni and Si contents of the inner core. The Si content of the inner core estimated here is slightly greater than that estimated previously based on the sound velocity measurement of the hcp-Fe-Ni-Si alloy at high pressure.
AB - The pressure-volume equations of state of iron-nickel-silicon alloy Fe0.83Ni0.09Si0.08 (Fe-9.8wt.% Ni-4.0wt.% Si) and iron-silicon alloy Fe0.93Si0.07 (Fe-3.4wt.% Si) have been investigated up to 374GPa and 252GPa, respectively. The present compression data covered pressures of the Earth's core. We confirmed that both Fe0.83Ni0.09Si0.08 and Fe0.93Si0.07 alloys remain in the hexagonal close packed structure at all pressures studied.We obtained the density of these alloys at the pressure of the inner core boundary (ICB), 330GPa at 300K by fitting the compression data to the third order Birch-Murnaghan equation of state. Using these density values combined with the previous data for hcp-Fe, hcp-Fe0.8Ni0.2, and hcp-Fe0.84Si0.16 alloys and comparing with the density of the PREM inner core, we estimated the Ni and Si contents of the inner core. The Si content of the inner core estimated here is slightly greater than that estimated previously based on the sound velocity measurement of the hcp-Fe-Ni-Si alloy at high pressure.
KW - Compression
KW - Hcp structure
KW - Inner core
KW - Iron-nickel-silicon alloy
KW - Iron-silicon alloy
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U2 - 10.1016/j.epsl.2011.06.034
DO - 10.1016/j.epsl.2011.06.034
M3 - Article
AN - SCOPUS:80054067438
SN - 0012-821X
VL - 310
SP - 113
EP - 118
JO - Earth and Planetary Sciences Letters
JF - Earth and Planetary Sciences Letters
IS - 1-2
ER -