不同温度下U_3O_8结构的XRD研究

XRD STUDY OF U_3O_8 STRUCTURE AT DIFFERENT TEMPERATURE

摘要: 在大气环境及25～850℃条件下,用X射线衍射(XRD)法研究了八氧化三铀(U3O8)的结构变化情况。在实验温度范围内发现,U3O8存在两种相结构,相变温度约为300℃。低于300℃时,U3O8为底心正交结构(Amm2),在300℃附近转变为对称性更高的简单六方结构(P 62m)。在两种相结构稳定的温度范围内,U3O8的点阵参数随温度的增加呈现出规律性变化。

Abstract: The structure change of triuranium octaoxide (U3O8) is studied by Xray diffraction in ambient atmosphere at temperature from 25 ℃ to 850 ℃.There are two kinds of phases of U3O8 in the temperature range are studied,and the transformation temperature is about 300 ℃.The lower temperature phase is orthorhombic with space group Amm2,and it changes to another phase with better symmetry around 300 ℃.Another phase,the higher temperature phase,is hexagonal with space group P62m,which is stable from 300 ℃ to 800 ℃.The lattice parameters of XRD peaks of U3O8 are also investigated at different temperature.It is found that they change with the temperature under rules.