Application of an Ion‐Packing Model Based on Defect Clusters to Zirconia Solid Solutions: I, Modeling and Local Structure of Solid Solutions
作者:
Masatomo Yashima,
Nobuo Ishizawa,
Masahiro Yoshimura,
期刊:
Journal of the American Ceramic Society
(WILEY Available online 1992)
卷期:
Volume 75,
issue 6
页码: 1541-1549
ISSN:0002-7820
年代: 1992
DOI:10.1111/j.1151-2916.1992.tb04222.x
出版商: Blackwell Publishing Ltd
关键词: zirconia;defects;solid solutions;modeling;spectroscopy
数据来源: WILEY
摘要:
Oxygen vacancies can be introduced into zirconia solid solution ZrO2–MOu(u= 1 and 1.5) to maintain electroneutrality. Recently, the local structures around Zr4+and M2u+ions in ZrO2–MOusolid solutions have been studied through EXAFS spectroscopy, diffuse scattering analysis, and single‐crystal structure analysis. The present study constructs an ion‐packing model for zirconia solid solutions based on some defect cluster models. The decrease of cell volume with the occurrence of vacancies is assumed to be expressed by decreasing the coordination number (CN) of cations around the vacancy. The distribution of CNs in a solid solution was calculated from a certain defect cluster model. The average interatomic distances, the average CN, and the short‐range order parameters were calculated using this distribution of CNs. The local structures calculated from the model were compared with experimental data in the systems ZrO2–MO1.5(M = Y, Gd, Yb, and Ca). In the ZrO2–YO1.5system, ther(s–O) interatomic distance, where s represents Zr4+or Y3+and O represents O2−, decreased with Y content and therefore vacancy content. The probability of finding Y3+around a vacancy increases with increasing yttria content from a comparison of the calculated results with the ones from recent EXAFS studies. The present model can qualitatively explain compositional and size dependences of the dopant on various
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