High-Pressure Geophysical Properties of Fcc Phase FeH X
High-Pressure Geophysical Properties of Fcc Phase FeH X
复制标题
Fcc相FeH X的高压地球物理性质
DOI：
10.1002/2017gc007168
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Campbell, A. J.
中科院分区：
文献类型：
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作者：
Thompson, E. C.;Davis, A. H.;Bi, W.;Zhao, J.;Alp, E. E.;Zhang, D.;Greenberg, E.;Prakapenka, V. B.;Campbell, A. J.
采用同步辐射X射线衍射仪和核共振非弹性X射线散射仪研究了面心立方(FCC)FeHX在18-68 Gpa压力和1500 K以上温度下的热淬火样品的成分和声速。为了帮助解释非理想(X ≠ 1)化学计量学，将铁的经验状态方程和间隙氢的两条不同的合成压缩曲线结合起来，建立了两个状态方程。使用这些状态方程来匹配地核的密度赤字需要在核幔边界处使用0.8-1.1wt%的氢，在内、外核的界面处需要0.2-0.3wt%的氢。此外，初步参考地球模型(PREM)与我们实验结果的Birch定律外推的比较表明，含∼0.8wt%-1.3wt%氢的铁合金可以再现地球外核的密度和压缩速度(Vp)。
Face centered cubic (fcc) FeHXwas synthesized at pressures of 18–68 GPa and temperatures exceeding 1,500 K. Thermally quenched samples were evaluated using synchrotron X‐ray diffraction (XRD) and nuclear resonant inelastic X‐ray scattering (NRIXS) to determine sample composition and sound velocities to 82 GPa. To aid in the interpretation of nonideal (X ≠ 1) stoichiometries, two equations of state forfccFeHXwere developed, combining an empirical equation of state for iron with two distinct synthetic compression curves for interstitial hydrogen. Matching the density deficit of the Earth's core using these equations of state requires 0.8–1.1 wt % hydrogen at the core‐mantle boundary and 0.2–0.3 wt % hydrogen at the interface of the inner and outer cores. Furthermore, a comparison of Preliminary Reference Earth Model (PREM) to a Birch's law extrapolation of our experimental results suggests that an iron alloy containing ∼0.8–1.3 wt % hydrogen could reproduce both the density and compressional velocity (VP) of the Earth's outer core.