缺陷萤石型(Sm0.6Y0.4)2Zr2O7陶瓷中的短程有序化现象

Short-Range Order Phenomena in Defect Fluorite-Type (Sm0.6Y0.4)2Zr2O7 Ceramic

摘要:

采用X射线衍射、高分辨透射电镜、选区电子衍射以及拉曼光谱等技术手段研究了(Sm0.6Y0.4)2Zr2O7陶瓷的晶体结构。X射线衍射表明，(Sm0.6Y0.4)2Zr2O7 陶瓷为单一立方相缺陷型萤石结构。然而高分辨电镜和选区电子衍射观察结果显示，在电子衍射花样中除了缺陷型萤石相点阵的衍射外，还发现有对应于烧绿石相的弱散射斑点。这表明在无序的缺陷型萤石相点阵中存在短程有序化现象。拉曼光谱结果进一步证实了在微米或纳米尺度范围内存在短程有序化现象

Abstract:

The crystal structure of (Sm0.6Y0.4)2Zr2O7 ceramic has been investigated by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) coupled with selected area electron diffraction (SAED) and Raman spectroscopy. XRD result shows that (Sm0.6Y0.4)2Zr2O7 ceramic exhibits a single defect fluorite-type structure. However, HRTEM and SAED observation reveals that additional weak diffuse reflections belonging to the pyrochlore-type structure appear in the electron diffraction patterns expect for the characteristic reflections of the defect fluorite-type lattice, which suggests short-range ordering in the bulk defect fluorite lattice. Raman spectroscopy also confirms the short-range order phenomenon at the micro- or nano-scaled regions