刚玉（α-Al2O3）在压缩至8 GPa下的熔化：熔化斜率递减

中文摘要 AI 辅助

通过原位电阻率测量，研究了刚玉（α-Al2O3）在压缩至8 GPa条件下的熔化行为。熔化温度从常压下的T0 = 2317 K单调增加至7.7 GPa下的3090 K。将实验数据拟合至Simon-Glatzel方程，得到经验参数a = 5.60 GPa和c = 0.334，从而为整个熔化边界提供了闭合形式的解析描述。最重要的是，熔化斜率dTm/dp从常压下的138 K/GPa持续下降至7.7 GPa下的78 K/GPa，明确证实了熔化曲线具有负曲率（d2Tm/dp2 < 0）。这一现象与液相优先致密化以及随压力升高熔化时体积变化减小相一致。这些发现为刚玉的高压熔化提供了稳健的经验标准，为未来富铝深部地球系统的从头算模拟、热力学数据库和地球物理模型建立了必要的约束条件。

英文摘要

Melting of corundum (α-Al2O3) has been studied under compression up to 8 GPa using in situ electrical resistivity measurements. The melting temperature increases monotonically from T0 = 2317 K at ambient pressure to 3090 K at 7.7 GPa. Fitting the experimental data to the Simon-Glatzel equation yields the empirical parameters a = 5.60 GPa and c = 0.334, providing a closed-form analytical description of the entire melting boundary. Most significantly, the melting slope, dTm/dp, decreases continuously from 138 K/GPa at ambient pressure down to 78 K/GPa at 7.7 GPa, confirming unequivocal negative curvature of the melting curve (d2Tm/dp2 < 0). This phenomenon is consistent with the preferential densification of the liquid phase and the associated reduction in the volume change upon melting as pressure rises. These findings provide a robust empirical standard for the high-pressure melting of corundum, establishing essential constraints for future ab initio simulations, thermodynamic databases, and geophysical models of alumina-rich deep-Earth systems.

发表机构

• LSPM–CNRS, Université Sorbonne Paris Nord（索邦巴黎北大学 LSPM-CNRS）

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