钙钛矿（GaTiO3）高压相变及等温压缩

 高温高压条件下对钙钛矿（Perovstsite）多晶进行了研究，在金刚石压砧设备上压力条件最高达38 GPa，YAG莱塞加热温度近1 000 ℃以上，用红宝石荧光校压系统进行压力标定。实验结果表明静水压条件X射线就位测量，GaTiO₃(Ⅰ)由斜方晶系在10 GPa时直接向六方GaTiO₃(Ⅱ)结构相变，体积变化为1.6％；1 000 ℃加热及其非静水压条件下GaTiO₃(Ⅰ)由斜方晶系首先转变为四方晶系GaTiO₃(Ⅲ)转变压力为8.5 GPa，体积变化为0％，继续增加压力导15 GPa，GaTiO₃(Ⅲ)向GaTiO₃(Ⅱ')转化成六方晶系，体积变化亦为1.6％。三种高压相，在压力降到一个大气压时都会消失，所以是逆转化的非淬火相。等温压缩在标准静水压条件下进行，压力应小于10.4 GPa，K₀'=5.6时，K₀=(210±7)GPa，此数据是根据Birch-Murnaghan状态方程求得的体模量。

High-Pressure Phase Transition and Constant-Temperature Compression of Caiclum Titanate Ore

By using a diamond anvil cell with ruby fluorescence pressure calibration system and aYAG laser, polyerystalline GaTiO₃ (perovskite) was investigated under static pressure up to 38 GPa and temperature up to 1 000 ℃. In situ X-ray diffration data reveals that at room temperature, orthorhombic GaTiO₃(Ⅰ) transforms into hexagonal GaTiO₃(Ⅱ) at 10 GPa with a volume change of 1.6%; at 1 000 ℃ and non-hydrostatic environment, orthorhombic GaTiO₃(Ⅰ) transforms into tetragonal GaTiO₃(Ⅲ) at 8.5 GPa and then into hexagonal GaTiO₃(Ⅱ') at 15 GPa with volume changes of 0% and 1.6% respectively. All these three high pressure polymorphs occured in the study are nonquenchable. The isothermal compression of orthorhombic GaTiO₃ was performed under standard hydrostatic environment with pressures not greater than 10.4 GPa. By assuming K₀'=5.6, which was obtained on SrTiO₃ perovskite ultrasonically, the value of bulk modulus K₀ was calculated to be (210±7)GPa by using Birch-Murnaghan equation.