Sound velocity measurements of hcp Fe-Si alloy at high pressure and high temperature by inelastic X-ray scattering

Takanori Sakairi, Tatsuya Sakamaki, Eiji Otani, Hiroshi Fukui, Seiji Kamada, Satoshi Tsutsui, Hiroshi Uchiyama, Alfred Q.R. Baron

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

The sound velocity of hcp Fe0.89Si0.11 (Fe-6wt% Si) alloy was measured at pressures from 45 to 84 GPa and temperatures of 300 and 1800 K using inelastic X-ray scattering (IXS) from laser-heated samples in diamond-anvil cells (DACs). The compressional velocity (νP) and density (ρ) of the Fe-Si alloy are observed to follow a linear relationship at a given temperature. For hcp Fe0.89Si0.11 alloy we found νP = 1.030 (±0.008) × ρ - 1.45 (±0.08) + [3.8 × 10-5(T - 300)×(ρ - 15.37)], including non-negligible temperature dependence. The present results of sound velocity and density of hcp Fe0.89Si0.11 alloy indicates that 3~6 wt% of silicon in the inner core with additional amount of Ni can explain the compressional velocity (νP) and density (ρ) of the "preliminary Earth reference model" (PREM), assuming a temperature of 5500 K and that silicon is the only light element in the inner core.

Original languageEnglish
Pages (from-to)85-90
Number of pages6
JournalAmerican Mineralogist
Volume103
Issue number1
DOIs
Publication statusPublished - 2018 Jan 26

Keywords

  • Birch's law
  • Fe-Si alloy
  • High pressure
  • High temperature
  • Inelastic X-ray scattering
  • Inner core
  • Silicon
  • Sound velocity

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

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