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SOLID IONIC PROPERTIES OF METASTABLE ZrO_2-CeO_2-CeO_<1.5> SOLID SOLUTIONS

亚稳态ZrO_2-CeO_2-CeO_<1.5>固体溶液的固体离子性质

基本信息

批准号：
09555225
负责人：
MATSUO Shinya
金额：
$ 8.13万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09555225/
关键词：
metastable phase cerid zirconia noble compounds electric conductivity solid ionic electron conduction fluorite-related structure 電気伝導性

项目摘要

In the metal-oxygen system, reduction and successive oxidation of a single phase make possible to prepare various metastable phases ; the oxidation proceeds remaining the cation distribution in the precursor of reduced phase. This principle was applied to ZrO_2 - CeO_2 system, the local atom displacements and solid ionics properties of the noble metastable phases obtained were characterizedThe precursors were prepared by reducing the t'-(Ge_<0.5>Zr_<0.5>O_2) phase at T_<de>=873K-1573K.When the precursor with T_<de>=1573K was oxidized at 873 K, a noble metastable kappa-CeZiO_4 phas was obtained in which Ce and Zr are in an ordered arrangement. The oxidation of the precursor with 1173K produced another noble metastable t'_<meta>, -(Ce_<0.5>Z_<0.5>O_2) phase in which Ce and Zr are in an disordered arrangement similar to t'-(Ce_<0.5>, Zr_<0.5>O_2). The distance between Ce-O-Ce ions decreased in the order of t'* t'_<meta> * kappa.In spite of the same composition : CeZrO_4, the electrical conductivity of the metastable t'_<meta> and kappa phases were found to be fairly larger than that of t'. The results couled be interpreted in terms of the Ce-O-Ce distance, cation distribution, and oxygen displacement. The present results imply that the electrical properties could be controlled by the preparation of metastable phase as well as doping of impurities.

在金属-氧体系中，单个相的还原和连续氧化使制备各种亚稳相成为可能；氧化继续进行，在还原相前驱体中保留阳离子分布。将此原理应用于ZrO_2 - CeO_2体系，表征了所得到的稀有亚稳相的局部原子位移和固体离子性质。在T_<de>=873K-1573K处还原t'-(Ge_<0.5>Zr_<0.5>O_2)相制备了前驱体。当T_<de>=1573K的前驱体在873 K下氧化时，得到Ce和Zr有序排列的优亚稳kappa-CeZiO_4相。前驱体与1173K氧化产生另一种稀有亚稳相t′_<meta>, -(Ce_<0.5>Z_<0.5>O_2)，其中Ce和Zr呈类似于t′-(Ce_<0.5>, Zr_<0.5>O_2)的无序排列。Ce-O-Ce离子之间的距离以t'* t'_<meta> * kappa的顺序递减。在相同的CeZrO_4组成下，亚稳相t′_<meta>和kappa的电导率明显大于t′。结果可以用Ce-O-Ce距离、阳离子分布和氧位移来解释。目前的结果表明，可以通过制备亚稳相和掺杂杂质来控制电学性能。