Static compression of B2 KCl to 230 GPa and its P-V-T equation of state
Static compression of B2 KCl to 230 GPa and its P-V-T equation of state
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DOI：
10.2138/am-2019-6779
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发表时间：
2019-05
影响因子：
3.1
通讯作者：
Shigehiko Tateno;T. Komabayashi;K. Hirose;N. Hirao;Y. Ohishi
中科院分区：
文献类型：
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作者：
Shigehiko Tateno;T. Komabayashi;K. Hirose;N. Hirao;Y. Ohishi
摘要基于激光加热金刚石压砧室（DAC）中的同步辐射X射线衍射测量，在9-61 GPa/1500-2600 K和室温下对KCl的B2（CsCl型）相进行了压力-体积-温度（P-V-T）测量。基于铂压力标记，对样品室内的非流体静力学应力条件进行了严格评价。在每个压力增量之后通过激光进行热退火，即使在多兆巴压力范围内，偏应力也减小到小于样品压力的1%。采用Mie-Grüneisen-Debye模型对实验数据进行拟合，得到了符合Vinet状态方程的P-V-T数据。KCl的热压力被发现是小的~10 GPa，即使在3000 K在任何给定的体积，这是只有一半的常见的压力标记（即Pt，Au，或MgO）。这种低的热压力验证了在高温下使用KCl压力介质作为压力标记。
Abstract The pressure-volume-temperature (P-V-T) measurements of the B2 (CsCl-type) phase of KCl were performed at 9–61 GPa/1500–2600 K and up to 229 GPa at room temperature, based on synchrotron X‑ray diffraction measurements in a laser-heated diamond-anvil cell (DAC). The nonhydrostatic stress conditions inside the sample chamber were critically evaluated based on the platinum pressure marker. With thermal annealing by laser after each pressure increment, the deviatoric stress was reduced to less than 1% of the sample pressure even at the multi-megabar pressure range. The obtained P-V-T data were fitted to the Vinet equation of state with the Mie-Grüneisen-Debye model for thermal pressure. The thermal pressure of KCl was found to be as small as ~10 GPa even at 3000 K at any given volume, which is only half of that of common pressure markers (i.e. Pt, Au, or MgO). Such a low-thermal pressure validates the use of a KCl pressure medium as a pressure marker at high temperatures.