斜锆石(ZrO_2)高温高压相变的Raman光谱研究

Investigation of Phase Transitions of ZrO_2 under High-Pressure and High-Temperature Conditions by Raman Spectroscopy

以Ar作压力介质,在0～23 GPa压力范围内,利用金刚石压腔装置（DAC）和激光加温技术,采用显微拉曼光谱进行原位测试,对处于准静水压力条件下的斜锆石开展高温高压相变研究。研究结果表明：室温下斜锆石ZrO2于3.4 GPa时开始发生相变,到10.4 GPa时其明显转变成一个空间群为Pbca的斜方相。此新相随着压力升高,直到15.3 GPa,仍稳定存在。通过研究,首次获得了Pbca相的拉曼谱图。随后在15.3 GPa压力下进行了激光加温后淬火,结果发现,加热前的Pbca相又转变成了空间群为Pnam的PbCl2结构类型的高压相,该相直到实验最高压力23 GPa仍稳定存在。

Using argon as a pressure medium,the phase transitions of monoclinic-structured ZrO2 under high-pressure and high-temperature have been investigated by means of in-situ Raman spectra method and a laser-heated diamond anvil cell（DAC）.At room temperature,the baddeleyite-type ZrO2 begins to transform to a new phase at 3.4 GPa,Raman bands from the new phase become prominent at 10.4 GPa,and this new high-pressure structure retains up to 15.3 GPa,the highest pressure before heated.The new phase has been identified as Pbca phase.Raman spectrum of Pbca phase is presented for the first time based on our experiments.At pressure of 15.3 GPa the Pbca phase was heated by YAG laser to about 1 000～1 500 ℃,and then it transforms to a PbCl2 phase.This phase is stable up to 23 GPa,the highest pressure in this study.