Fe88.1Ni9.1S2.8 alloy was compressed up to 335GPa, 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) × 10-5P for P in GPa. The compression curve of Fe88.1Ni9.1S2.8 alloy was expressed by the third-order Birch-Murnaghan equation of state, giving K 0 = 167.0 15.0GPa, K0 = 4.46±0.14, and V 0 = 22.93±0.29 Å3. 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 328.9GPa, assuming a linear relationship exists between the density and the nickel and sulfur content.
ASJC Scopus subject areas
- Geochemistry and Petrology
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science