Equation of state of iron-silicon alloys to megabar pressure
Equation of state of iron-silicon alloys to megabar pressure
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DOI：
10.1007/s00269-004-0387-x
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发表时间：
2004-07-01
影响因子：
1.4
通讯作者：
Kikegawa, T
中科院分区：
文献类型：
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作者：
Hirao, N;Ohtani, E;Kikegawa, T
用金刚石压砧技术研究了Fe-8.7wt%Si和Fe-17.8wt%Si铁硅合金在196和124 GPa压力下的稳定性和压力-体积状态方程。在室温下用单色同步辐射和成像板（IP）测量了铁硅合金的角色散X射线衍射。bcc-Fe-8.7wt%Si合金在16 ~ 36 GPa压力下转变为hcp结构。具有六方密排（hcp）结构的Fe-8.7wt% Si高压相在196 GPa以下保持稳定，在124 GPa以下未观察到bcc-Fe-17.8wt% Si的相变。将压力-体积数据拟合至具有零压力参数的三阶Birch-Murnaghan状态方程（BM EOS）：对于hcp-Fe-8.7wt%Si，V-0=22.2（8）埃（3），K-0=198（9）GPa，和K-0 ′ = 4.7（3），和V-0=179.41（45）埃（3），对于Fe-17.8wt%Si，K-0=207（15）GPa和K-0 '= 5.1（6）。hcp-Fe-8.7wt%Si的密度和体声速表明内核可以包含3- 5wt%Si。
The stability and pressure-volume equation of state of iron-silicon alloys, Fe-8.7 wt% Si and Fe-17.8 wt% Si, have been investigated using diamond-anvil cell techniques up to 196 and 124 GPa, respectively. Angular-dispersive X-ray diffractions of iron-silicon alloys were measured at room temperature using monochromatic synchrotron radiation and an imaging plate (IP). A bcc-Fe-8.7 wt% Si transformed to hcp structure at around 16similar to36 GPa. The high-pressure phase of Fe-8.7 wt% Si with hexagonal close-packed (hcp) structure was found to be stable up to 196 GPa and no phase transition of bcc-Fe-17.8 wt% Si was observed up to 124 GPa. The pressure-volume data were fitted to a third-order Birch-Murnaghan equation of state (BM EOS) with zero-pressure parameters: V-0=22.2(8) Angstrom(3), K-0=198(9) GPa, and K-0'=4.7(3) for hcp-Fe-8.7 wt% Si and V-0=179.41(45) Angstrom(3), K-0=207(15) GPa and K-0'=5.1(6) for Fe-17.8 wt% Si. The density and bulk sound velocity of hcp-Fe-8.7 wt% Si indicate that the inner core could contain 3-5 wt% Si.