Melting and thermal expansion in the Fe-FeO system at high pressure
- Maryland
Melting in the Fe-FeO system was investigated at pressures up to 93 GPa using synchrotron X-ray diffraction (XRD) and a laser heated diamond anvil cell (DAC). The criteria for melting were the disappearance of reflections associated with one of the end-member phases upon raising the temperature above the eutectic and the reappearance of those reflections on dropping the temperature below the eutectic. The Fe-FeO system is a simple eutectic at 50 GPa and remains eutectic to at least 93 GPa. The eutectic temperature was bound at several pressure points between 19 and 93 GPa, and in some cases the liquidus temperature was also determined. The eutectic temperature rises rapidly with pressure closely following the melting curve of pure Fe. A detailed phase diagram at 50 GPa is presented; the eutectic temperature is 2500 {+-} 150 K and the eutectic composition is bound between 7.6 {+-} 1.0 and 9.5 {+-} 1.0 wt.% O. The coefficient of thermal expansion of FeO is a strong function of volume and decreases with pressure according to a simple power law.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- OSTI ID:
- 1018543
- Journal Information:
- Earth and Planetary Science Letters, Vol. 265, Issue 2008; ISSN 0012-821X
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- ENGLISH
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