Densification of MgSiO 3 glass with pressure and temperature
Densification of MgSiO 3 glass with pressure and temperature
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MgSiO 3 玻璃随压力和温度的致密化
DOI：
10.1088/1742-6596/215/1/012085
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
C. Lesher
中科院分区：
文献类型：
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作者：
A. Yamada;S. Gaudio;C. Lesher
用阿基米德法和拉曼光谱分别研究了MgSiO_3玻璃（v-En）在2.0、5.5和8.5GPa压力下1000°C退火后的密度和结构。回收玻璃的密度被发现是一个复杂的函数的压力和温度。在室温下，压缩至8.5 GPa，然后减压，得到密度在1个大气压值的0.6%以内的玻璃。同样，在较高压力下，在2.0 GPa下加热至约500°C的玻璃中，1个大气压的密度完全恢复。在2.0 GPa下在500°C和800°C之间、在5.5 GPa下在200°C和500°C之间以及在8.5 GPa下从室温到300°C观察到恢复密度的急剧增加。在较高的退火温度下，密度的变化更温和。在2.0 GPa下玻璃密度为2.89 g/cm 3，在5.5和8.5 GPa下玻璃密度为2.95 g/cm 3时，出现这种斜率突变。高于~900°C时，v-En在所有压力下结晶。退火玻璃的拉曼光谱显示Si-O-Si弯曲模式向更高波数的渐进移位，并具有恢复的密度。根据这些数据，我们估计随着致密化从2.75 g/cm 3（1-atm，室温）到3.0 g/cm 3，Si-O-Si键角降低约4.5%。
The density and structure of MgSiO3 glass (v-En) recovered from a series of annealing experiments up to 1000°C at 2.0, 5.5 and 8.5 GPa have been investigated using Archimedes' method and Raman spectroscopy, respectively. The densities of recovered glasses are found to be a complex function of pressure and temperature. At room temperature, compression up to 8.5 GPa, followed by decompression, yields a glass with a density within 0.6 % of the 1-atm value. Likewise, the 1-atm density is fully recovered in glass heated up to ~500°C at 2.0 GPa at higher pressures. A sharp increase in recovered density is observed between 500°C and 800°C at 2.0 GPa, 200°C and 500°C at 5.5 GPa and from room-T and 300°C at 8.5 GPa. At higher annealing temperatures the changes in density are more modest. This break in slope occurs for a glass density of 2.89 g/cm3 at 2.0 GPa and 2.95 g/cm3 at 5.5 and 8.5 GPa. Above ~900°C v-En crystallizes at all pressures. Raman spectra for annealed glasses show a progressive shift in the Si-O-Si bending mode to higher wave number with recovered density. From these data we estimate a ~4.5 % decrease in the Si-O-Si bond angle with densification from 2.75 g/cm3 (1-atm, room T) to 3.0 g/cm3.