High-Pressure Phase Transition and Constant-Temperature Compression of Caiclum Titanate Ore
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摘要: 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=(2107)GPa，此数据是根据Birch-Murnaghan状态方程求得的体模量。Abstract: 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 (2107)GPa by using Birch-Murnaghan equation.
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Key words:
- calcium titanate /
- Phase transition /
- volume ratio /
- lattice distortion /
- cell parameter
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Liu L G. Earth Planetary Science Letters, 1976, 31: 200; Liu L G. Geophys Res Lett, 1974, 1(6): 277. Yagi T, Bell P M, Mao H G. Carnegie Inst. of Washingion Yearbook, 1979, 78: 614. Jeanloz R, Thompson A B. Rev Geophys Space Phys, 1983, 21: 51. Mao H K, Bell P M, Yagi Y. Iron-Magnesium Fractionation Model for the Earth, in High Pressure Research in Geophysics. Edited by S Akimoto and M H Manghnani, 1982: 319. Ito E, Takahashi E, Matsui Y. Earth Planet Science Lett, 1984, 67: 238. Glazer A M. Acta Crystal B, 1972, 28: 3384. Magaw H D. Crystal Structure: A Working Approach, Saunders Philadelphia, 1973. Yagi T, Mao H G, Bell P M. Phys Chem Minerals, 1978, 3: 97. Kay H F, Bailey P C. Acta Cryst, 1957, 10: 219. Naylor B F, Cook O A. J Am Chem Soc, 1946, 68: 1003. Licbermann R C, Jones L E A, Ringwood A E. Phys Earth and Planet Int, 1977, 14: 165. Sasaki S, Prewitt C T, Bass J D. Orthorhombic Perovskite CaTiO, and CaTiO, Crystal Structure and Space Group, a Preprint Submitted to Acta Crystal C,1985. Bassett W A, Takahashi T, Stook P. Rev Sci Instrum, 1967, 38: 37. Ming L C, Manghnani M H. J Appl Phys, 1978, 49(1): 28. O'Keeffe M, Hyde B G, Bovin J O. Phys Chem Minerals, 1979, 4: 299. Sasaki S, Prewitt C T, Liebermann R C. Am Mineral, 1983, 68: 1189. Beattie A G, Samara G A. J Appl Phys, 1971, 12(6): 2376. Bass J D. Phys Earth Planet Interiors, 1984, 36: 145. Johnson L R. Bull Seismol Soc Amer, 1969, 59: 973. Butler R, Anderson D l. Phys Earih Planet Interiors, 1978, 17: 147. Cleary J R, Anderson R S. Seismology and the Internal Structure of the Earth, in: The Earth, Its Origin Sttucture and Evolution. Edited by M W McEihinny. London: Acad Press, 1979: 137. -
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