Determination of the phase boundary between the B1 and B2 phases in NaCl by in situ x-ray diffraction
Determination of the phase boundary between the B1 and B2 phases in NaCl by in situ x-ray diffraction
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DOI：
10.1103/physrevb.68.134109
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发表时间：
2003-10
影响因子：
3.7
通讯作者：
N. Nishiyama;T. Katsura;K. Funakoshi;A. Kubo;T. Kubo;Y. Tange;Yuichiro Sueda;S. Yokoshi
中科院分区：
文献类型：
--
作者：
N. Nishiyama;T. Katsura;K. Funakoshi;A. Kubo;T. Kubo;Y. Tange;Yuichiro Sueda;S. Yokoshi
在NaCl中的$B1$和$B2$相之间的平衡相边界，确定在1150和2000 K之间的温度下，通过原位X射线衍射，使用Kawai型装置在SPring-8，兵库，日本的光束线。压力机在数据采集过程中振荡，以减少晶粒生长对NaCl在高温下的衍射图案的影响，该衍射图案是通过具有固定角度的能量色散方法获得的。在1150和1600 K之间的温度下，独立地观察到向前$（B1$到$B2）$和向后$（B2$到$B1）$转变;发生这些转变的$P\ensuremath{-}T$条件落在一条直线上，表明在这个温度范围内向前和向后转变之间没有动力学效应。平衡相边界由线性方程P$ $（\marthm {in}\marthm {}\marthm {GPa}）=30.6（2）\char21{}0.0053（2）$ $T$（K）表示。在20.1 GPa和2100 K下观察到液态NaCl，这与使用激光加热金刚石砧座单元的先前研究中获得的熔化曲线一致。根据我们的实验结果，$B1，$$B2，$与液体NaCl之间的三相点将位于$19.7\ifmmode\pm\else\textpm\fi{}0.5\mathrm{GPa}$和$2050\ifmmode\pm\else\textpm\fi{}50\mathrm{K}。$
The equilibrium phase boundary between the $B1$ and $B2$ phases in NaCl was determined at temperatures between 1150 and 2000 K by in situ x-ray diffraction, using a Kawai-type apparatus in a beam line of SPring-8, Hyogo, Japan. The press was oscillated during data acquisition in order to reduce the effect of grain growth on the diffraction pattern of NaCl at high temperature, obtained by the energy-dispersive method with a fixed angle. Forward $(B1$ to $B2)$ and backward $(B2$ to $B1)$ transitions were observed independently at temperatures between 1150 and 1600 K; the $P\ensuremath{-}T$ conditions where these transitions occur fall on a straight line, indicating that there is no kinetic effect between the forward and the backward transitions over this temperature range. The equilibrium phase boundary is represented by the linear equation $P$ $(\mathrm{in}\mathrm{}\mathrm{GPa})=30.6(2)\char21{}0.0053(2)$ $T$ (in K). Liquid NaCl was observed at 20.1 GPa and 2100 K, consistent with the melting curve obtained in a previous study using a laser- heated diamond anvil cell. According to our experimental results, the triple point between $B1,$ $B2,$ and liquid NaCl would be located at $19.7\ifmmode\pm\else\textpm\fi{}0.5\mathrm{GPa}$ and $2050\ifmmode\pm\else\textpm\fi{}50\mathrm{K}.$