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Science 11 January 2002:
Vol. 295. no. 5553, pp. 313 - 315
DOI: 10.1126/science.1066932
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Iron-Silicon Alloy in Earth's Core?
Jung-Fu Lin, Dion L. Heinz, Andrew J. Campbell, James M. Devine, and Guoyin Shen
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Supplementary Material
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Supplemental Figure 1. (A) Representative energy-dispersive x-ray diffraction patterns of Fe7.9wt%Si at 39 GPa upon heating. F, the fluorescence peak of Pb; e, Ge detector escape peak; b1, NaCl in b1 structure; b2, NaCl in b2 structure. NaCl was used as the thermal insulator and the pressure calibrant (1, 2). The sample was in the hcp structure at 39 GPa and 300 K. The hcp phase transformed to the bcc + hcp phases at 1324 K and, upon further heating, to bcc + fcc + hcp phases at 1999 K. (B) Representative angle-dispersive x-ray diffraction patterns of Fe7.9wt%Si at 76 GPa. A monochromatic beam (wavelength = 0.4246 Å) was used as the x-ray source. Re represents the rhenium gasket peak. The sample was in the hcp structure at 76 GPa and 300 K. The hcp phase transformed to the bcc + hcp phases at 1772 K and 1937 K. |
Medium version | Full size version
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Medium version | Full size version
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Supplemental Figure 2. Back-scattered electron image of the quenched LVP sample from 14.1 GPa and 1100 K. The Si contents of the bcc and fcc phases were presumably preserved by turning off the power supply at high pressure. Chemical analyses of the sample indicate that the bcc phase contains 10.3 (±0.1) wt% Si in dark areas and the fcc phase contains 6.7 (±0.1) wt% Si in bright areas. Black areas are the MgO matrix. As shown, no reaction between the sample and the MgO matrix was observed in a SEM. The white bar on the picture is 20 mm.
Medium version | Full size version
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References
1. F. Birch, J. Geophys. Res. 91, 4949 (1986).
2. D. L. Heinz, R. Jeanloz, Phys. Rev. B 30, 6045 (1984).
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Science. ISSN 0036-8075 (print), 1095-9203 (online)
