Open AccessPhysical properties of liquid Fe alloys at high pressure and their bearings on the nature of metallic planetary cores
Author(s) -
Sanloup C.,
Guyot F.,
Gillet P.,
Fei Y.
Publication year - 2002
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 - 10.1029/2001jb000808
Subject(s) - silicon , materials science , compressibility , sulfur , diffraction , liquid metal , metal , synchrotron , core (optical fiber) , earth (classical element) , inner core , chemical physics , chemical engineering , metallurgy , thermodynamics , chemistry , composite material , physics , optics , mathematical physics , engineering
Sulfur and silicon are among the expected alloying light elements in planetary liquid iron cores. Structural properties of Fe‐27 wt % S and Fe‐17 wt % Si liquid alloys at high pressure and high temperature (0–5 GPa/1400–2300 K) are measured by synchrotron X‐ray diffraction. Sulfur strongly modifies the local structure of liquid iron whereas silicon has only small structural effects. Fe‐27 wt % S melts are indeed poorly ordered which explains a higher compressibility compared to pure liquid Fe. These results point out the necessity to consider the strong effect of S on liquid Fe properties while modeling planetary interiors. They imply a low S content in the Earth's outer core, leaving Si as a strong candidate, and argue for a present‐day Martian solid core when combined with previous global chemical models.