Structural study for hydrolytic condensed amorphous(Y,Zr)O_x.

水解缩合非晶态(Y,Zr)O_x的结构研究。

基本信息

批准号：
03805058
负责人：
WASEDA Yoshio
金额：
$ 1.09万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

The sol-gel technique using metal alkoxides and other metal organic compounds as master materials has been developed for making various advanced materials and ZrO_2 is known to be included in this category. Thermal decomposition of amorphous-ZrO_2(a-ZrO_2) obtained by this sol-gel method produces a metastable tetragonal-ZrO_2(t-ZrO_2) in addition to monoclinic-ZrO_2(m-ZrO_2). In order to clarify this crystallization behavior, we analyzed the structure of a- ZrO_2 systematically. Two kinds of a-ZrO_2 were prepared by the hydrolytic condensation of Zr(OC_4H_9)_4 and the aqueous solution of ZrOCl_2+8H_2O. The anomalous X-ray scattering technique has been applied to obtain the environmental radial distribution function around a zirconium. Zirconium is quantitatively confirmed to be coordinated by six oxygens at a distance of 0.214nm and this Zr-octahedron is surrounded by other four octahedra at a distance of 0.341nm. This typical local ordering is suggested to be similar to that in the structure of m-ZrO_2 rather than that of t-ZrO_2. The structure of REE(Y or Er) substituted a-ZrO_2 have been analyzed in similar way. The typical local structure was not changed by the addition of REE elements to the a-ZrO_2, although cubic-ZrO_2 is produced by the crystallization of REE substituted a-ZrO_2. Therefore, it is rather suggested that the crystallization behavior is independent of the structural feature of a-ZrO_2 in this system. The research by using X-ray small-angle diffraction is strongly required for discussing the structural inhomogeneity in a-ZrO_2, which is one of the characteristic natures of the materials produced by sol-gel technique.

使用金属烷氧化物和其他金属有机化合物作为主材料的Sol-GEL技术已开发出用于制造各种高级材料，并且已知Zro_2已包含在此类别中。除了单斜胶-ZRO_2（M-ZRO_2）之外，该Sol-Gel方法获得的无定形-ZRO_2（A-ZRO_2）的热分解可产生亚稳态的四方ZRO_2（T-ZRO_2）。为了阐明这种结晶行为，我们系统地分析了A-Zro_2的结构。通过ZR（OC_4H_9）_4的水解冷凝和Zrocl_2+8H_2O的水溶液来制备两种A-ZRO_2。已经应用了异常的X射线散射技术来获得锆周围的环境径向分布函数。锆被定量确认是由六个氧气以0.214nm的距离协调的，并且该Zr-Octahedron在0.341nm的距离上被其他四个八面体包围。建议这种典型的本地排序与M-Zro_2的结构相似，而不是T-Zro_2的结构。 REE（Y或ER）取代A-ZRO_2的结构已以相似的方式进行分析。尽管Cubic-Zro_2是通过REE替换为A-Zro_2的A-Zro_2产生的，但在A-Zro_2中添加REE元素并未改变典型的局部结构。因此，相反，结晶行为与该系统中A-Zro_2的结构特征无关。对于讨论A-Zro_2中的结构不均匀性，使用X射线小角度衍射是强烈需要的，这是Sol-Gel Technique产生的材料的特征性质之一。