方石英
无定形固体
亚稳态
柯石英
金刚石顶砧
石英
辉锑矿
材料科学
大气温度范围
衍射
无定形二氧化硅
环境压力
同步加速器
分析化学(期刊)
矿物学
热力学
结晶学
化学工程
化学
复合材料
光学
地质学
物理
有机化学
工程类
古生物学
榴辉岩
构造学
俯冲
作者
WS Xiao,李延春,Jing Liu,YC Li,Jing Liu,KN Weng,HS Xie
出处
期刊:Chinese Physics C
[IOP Publishing]
日期:2005-01-02
卷期号:29: 116-119
被引量:1
摘要
Aimed at the transformation methods and mechanism of amorphous silica on the conditions of high pressure and high temperature, we used the Changbaishan diatomite, which had been heating treated at 700 degrees C, as the sample of amorphous silica, to carried out the in situ high pressure and high temperature synchrotron X-ray diffraction determinations (EDXD method) in the range of pressure of 0-4GPa and temperature of 1000-1300K by the diamond anvil cell apparatus and double-sided laser heating technique. The experimental results indicate that amorphous silica transform to alpha-quartz, but not beta-quartz and cristobalite in the range of pressure of 0.8-2.4GPa and temperature of 1000-1300K. The crystalline temperature of amorphous silica under high pressure is much lower than that of ambient condition. The results means that the pressure is favored to low the activation energy of amorphous transform to crystalline phases, and would change the metastable phase transformation mechanism, leading to the different crystalline phases. In the range of pressure of 3-4GPa and temperature at 1300K, both amorphous silica and quartz transform to coesite.
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