Effects of temperature and composition on the bulk modulus of (Mg,Fe)O
Effects of temperature and composition on the bulk modulus of (Mg,Fe)O
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DOI：
10.2138/am-1999-0308
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发表时间：
1999-03
影响因子：
3.1
通讯作者：
Y. Fei
中科院分区：
文献类型：
--
作者：
Y. Fei
摘要利用同步辐射X射线衍射技术和外部加热的高温金刚石压砧装置，获得了MgO在300和1100 K下的等温静态压缩数据，该装置能够在1100 K以下获得大于125 GPa的压力。在300 K的实验进行了流体静力和非流体静力条件下。非流体静力环境中的偏应力对晶格参数的测量结果有显著影响。与MgO在300 K下的静态压缩数据拟合，在非流体静力学和流体静力学条件下的体积模量分别为185（7）GPa和160（2）GPa。偏应力随温度的升高而减小，当NaCl用作压力介质时，在900 K以上的温度下实现了近静水条件。MgO的体积模量在1100 K时为135（3）GPa，其温度导数为20.030（3）GPa/K。将这些结果与以前在MgO-FeO系统中的研究结果进行比较，表明（Mg，Fe）O的体积模量随着FeO含量的增加而减小，从MgO的160 GPa减小到FeO的146 GPa。
Abstract Isothermal static compression data for MgO at 300 and 1100 K were obtained by combining synchrotron X-ray diffraction techniques with an externally heated high-temperature diamond-anvil cell that is capable of achieving pressures greater than 125 GPa at temperatures up to 1100 K. The experiments at 300 K were conducted under both hydrostatic and nonhydrostatic conditions. The deviatoric stress in non-hydrostatic environment significantly effects the measured lattice parameters. Fits to the static compression data of MgO at 300 K yield a bulk modulus of 185(7) GPa and 160(2) GPa under nonhydrostatic and hydrostatic conditions, respectively. The deviatoric stress decreases with increasing temperature, and a nearly hydrostatic condition was achieved at temperatures above 900 K when NaCl was used as a pressure-medium. The bulk modulus of MgO was determined to be 135(3) GPa at a temperature of 1100 K, yielding its temperature derivative of 20.030(3) GPa/K. Comparing these results with previous studies in the system MgO-FeO, shows that the bulk modulus of (Mg,Fe)O decreases with increasing FeO content, from 160 GPa for MgO to 146 GPa for FeO.