The FeSi phase diagram to 150 GPa
The FeSi phase diagram to 150 GPa
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DOI：
10.1029/2009jb006528
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发表时间：
2010-06
影响因子：
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通讯作者：
Oliver Thomas Lord;M. Walter;D. Dobson;L. Armstrong;S. Clark;A. Kleppe
中科院分区：
文献类型：
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作者：
Oliver Thomas Lord;M. Walter;D. Dobson;L. Armstrong;S. Clark;A. Kleppe
根据功率-温度函数的不连续性，在激光加热的金刚石顶压室(LHDAC)中测定了FeSi的熔化曲线至150 Gpa。在12 GPA下使用织构标准作为熔化代理的多砧板实验交叉检查与我们的LH-DAC结果很好地一致。FeSi在核幔边界的熔点接近4000K，在核-核边界的外推值为4900K。我们还给出了由林德曼熔化定律确定的熔化曲线，这与我们的实验曲线在70 GPa时很好地吻合，然后发散到更高的温度，在ICB处达到6200K。这些温度大大高于以前的LH-DAC测定。在高压下用同步加速器X射线衍射法确定了epsilon-FeSi-&Gt；CsCl-FeSi亚固相线相变的边界，结果证实了相变的负Clapeyron斜率。我们的结论是，如果存在，FeSi很可能在D‘’层内是固体的，而不太可能存在于任何可能的体芯硅含量的内芯中。
The melting curve of FeSi has been determined to 150 GPa in the laser-heated diamond anvil cell (LH-DAC) on the basis of discontinuities in the power versus temperature function. A multianvil experimental cross-check at 12 GPa using textural criteria as a proxy for melting is in good agreement with our LH-DAC results. The melting point of FeSi reaches similar to 4000 K at the core mantle boundary and an extrapolated value of 4900 K at the inner-core boundary (ICB). We also present the melting curve as determined by the Lindemann melting law; this agrees well with our experimental curve to 70 GPa and then diverges to higher temperatures, reaching 6200 K at the ICB. These temperatures are substantially higher than previous LH-DAC determinations. The boundary of the epsilon-FeSi -> CsCl-FeSi subsolidus transition has also been determined by synchrotron-based X-ray diffraction at high pressures, and the results confirm a negative Clapeyron slope for the transition. We conclude that if present, FeSi is likely to be solid within the D '' layer and is unlikely to be present within the inner core for any plausible bulk core silicon content.