Boehmite Derived -Alumina System. 1. Structural Evolution with Temperature, with the Identification and Structural Determination of
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- 作者：Gianluca Paglia ; Craig E. Buckley ; Andrew L. Rohl ; Robert D. Hart ; Kartsen Winter ; Andrew J. Studer ; Brett A. Hunter ; and John V. Hanna
- 刊名：Chemistry of Materials
- 出版年：2004
- 出版时间：January 27, 2004
- 年：2004
- 卷：16
- 期：2
- 页码：220 - 236
- 全文大小：991K
- 年卷期：v.16,no.2(January 27, 2004)
- ISSN：1520-5002
文摘
Variations in the structure of gamma-alumina (
-Al2O3), derived from well-crystallineboehmite, calcined at various temperatures in air were investigated. Consistent distributionof cation coordination, ~69% octahedral and ~31% tetrahedral, was observed for materialcalcined between 500 and 900 
C. Gamma alumina was found to be present between 450and 750 C. Its structure was tetragonally distorted but showed a reduced tetragonaldistortion with increasing temperature. A cubic -Al2O3 phase was never detected. Above750 C, 
-Al2O3 was not observed, but instead a new phase was identified and designatedgamma-prime-alumina ('-Al2O3). Similarly to -Al2O3, '-Al2O3 was determined to be a triplecell of -Al2O3 and was described using the P
m2 space group. The cation ordering in thisstructure is more obvious than that for -Al2O3, with fewer site positions being occupiedwith increasing calcination temperature.
-Al2O3), derived from well-crystallineboehmite, calcined at various temperatures in air were investigated. Consistent distributionof cation coordination, ~69% octahedral and ~31% tetrahedral, was observed for materialcalcined between 500 and 900 C. Gamma alumina was found to be present between 450and 750 C. Its structure was tetragonally distorted but showed a reduced tetragonaldistortion with increasing temperature. A cubic -Al2O3 phase was never detected. Above750 C, -Al2O3 was not observed, but instead a new phase was identified and designatedgamma-prime-alumina ('-Al2O3). Similarly to -Al2O3, '-Al2O3 was determined to be a triplecell of -Al2O3 and was described using the Pm2 space group. The cation ordering in thisstructure is more obvious than that for -Al2O3, with fewer site positions being occupiedwith increasing calcination temperature.