Effect of sintering atmosphere on the pore-structure stability of cerium-doped nanostructured alumina

Pore-structure stability of pure and Ce-doped alumina in air and argon atmospheres was studied using DTA, TGA, N 2 ads./des. and XRD with a view to understand the importance of the ionic size of the dopant cation on the pore-structure stability of alumina. The ionic size effect was studied by heat t...

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Bibliographic Details
Published in:Materials research bulletin 1994-05, Vol.29 (5), p.551-558
Main Authors: Kumar, Krishnankutty-Nair P., Tranto, Janne, Nair, Balagopal N., Kumar, Jalajakumari, Høj, Jacob W., Engell, John E.
Format: Article
Language:English
Subjects:
360201 - Ceramics, Cermets, & Refractories- Preparation & Fabrication
360204 - Ceramics, Cermets, & Refractories- Physical Properties
ADSORPTION
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CATALYSTS
CERIUM
CHALCOGENIDES
CHEMICAL ANALYSIS
Chemistry
COHERENT SCATTERING
Colloidal state and disperse state
DESORPTION
DIFFERENTIAL THERMAL ANALYSIS
DIFFRACTION
ELEMENTS
Exact sciences and technology
FABRICATION
General and physical chemistry
GRAVIMETRIC ANALYSIS
MATERIALS SCIENCE
METALS
MICROSTRUCTURE
NITROGEN
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PORE STRUCTURE
Porous materials
QUANTITATIVE CHEMICAL ANALYSIS
RARE EARTHS
SCATTERING
SEPARATION PROCESSES
SINTERING
SORPTION
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
VALENCE
X-RAY DIFFRACTION
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Summary:Pore-structure stability of pure and Ce-doped alumina in air and argon atmospheres was studied using DTA, TGA, N 2 ads./des. and XRD with a view to understand the importance of the ionic size of the dopant cation on the pore-structure stability of alumina. The ionic size effect was studied by heat treating the Ce-alumina system in both oxidizing and reducing atmospheres to have Ce 4+ (87 pm) and Ce 3+ (106 pm) respectively. No compound formation between Ce and alumina was observed. In the case of pure alumina there is a drastic reduction in porosity during the transformation to α-alumina. Ce-doped alumina has a higher DSC transformation temperature corresponding to the α-alumina transformation compared to pure alumina. Ce-doped alumina showed higher pore-structure stability compared with pure alumina and the stability was relatively higher in reducing atmosphere (higher Ce 3+ Ce 4+ ratio, higher effective ionic size) compared with oxidizing conditions (lower Ce 3+ Ce 4+ ratio, lower effective ionic size).
ISSN:0025-5408
1873-4227
DOI:10.1016/0025-5408(94)90045-0