Open AccessCompression of Fe 88.1 Ni 9.1 S 2.8 alloy up to the pressure of Earth's inner core
Author(s) -
Sakai Takeshi,
Ohtani Eiji,
Kamada Seiji,
Terasaki Hidenori,
Hirao Naohisa
Publication year - 2012
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2011jb008745
Subject(s) - inner core , alloy , materials science , equation of state , outer core , earth (classical element) , compression (physics) , nickel , analytical chemistry (journal) , core (optical fiber) , hexagonal crystal system , thermodynamics , metallurgy , crystallography , composite material , chemistry , physics , mathematical physics , chromatography
Fe 88.1 Ni 9.1 S 2.8 alloy was compressed up to 335 GPa, corresponding to the pressure at the Earth's inner core, and the hexagonal close‐packed structure was found to be stable. The axial (c/a) ratio gradually decreased with increasing pressure. A linear fit as a function of pressure gave c/a = 1.605(2)–6.1(9) × 10 −5 P for P in GPa. The compression curve of Fe 88.1 Ni 9.1 S 2.8 alloy was expressed by the third‐order Birch‐Murnaghan equation of state, giving K 0 = 167.0 ± 15.0 GPa, K 0 ′ = 4.46 ± 0.14, and V 0 = 22.93 ± 0.29 Å 3 . Our results indicate that the hcp Fe‐5 wt % Ni‐5.7 wt % S alloy can account for the density of the inner core at 328.9 GPa, assuming a linear relationship exists between the density and the nickel and sulfur content.