钨酸锆制备与高压下的相变研究

Preparation and Pressure-Induced Cubic-to-Orthorhombic Phase Transition in ZrW_2O_8

采用固相烧结法制备了纯度较高的钨酸锆(ZrW2O8)粉体,并利用金刚石对顶压砧(DAC)对其进行了原位高压同步辐射X射线衍射研究。结果表明:在常温下,压力0.27GPa附近,晶体的对称性降低,并发生α-ZrW2O8向γ-ZrW2O8晶体结构相变;压力3.81GPa附近,γ-ZrW2O8完全转变为非晶相。通过拟合得到α-ZrW2O8的体弹模量B=(40.0±3.8)GPa,γ-ZrW2O8的体弹模量B=(37.0±3.0)GPa。

Negative thermal expansion(NTE)ZrW2O8 powders were prepared by solid-state reaction with ZrO2 and WO3 powders.In situ high-pressure X-ray diffraction measurements for powder ZrW2O8 were performed by using a diamond anvil cell(DAC)with synchrotron radiation facility.The result shows that powder ZrW2O8 is cubic phase with a little WO3.At about 0.27 GPa and room temperature,theα-ZrW2O8 phase transforms into a quenchable orthorhombic structure called theγphase.Upon further compression,theγphase becomes amorphous at the pressure of 3.81 GPa.The obtained bulk modulus ofα-ZrW2O8andγ-ZrW2O8are(40.0±3.8)GPa and(37.0±3.0)GPa.