Shaping of a RBAO-Membrane Support

Ceramic membranes are mostly multilayer materials based on the coating of a porous substrate. The importance of this support material is frequently neglected. Nevertheless, it is often the reason why no pin-hole free top layers can be produced. By adapting the existing reaction bonded Al2O3 (RBAO) m...

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Bibliographic Details
Published in:Key engineering materials 1997-04, Vol.132-136, p.1691-1694
Main Authors: Cooymans, J.F.C., Leysen, Roger, Luyten, Jan
Format: Article
Language:English
Subjects:
Applied sciences
Building materials. Ceramics. Glasses
Ceramic industries
Chemical industry and chemicals
Exact sciences and technology
Miscellaneous
Technical ceramics
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Summary:Ceramic membranes are mostly multilayer materials based on the coating of a porous substrate. The importance of this support material is frequently neglected. Nevertheless, it is often the reason why no pin-hole free top layers can be produced. By adapting the existing reaction bonded Al2O3 (RBAO) manufacturing route for dense materials, porous RBAO discs, tubes and hollow fibres could be processed. Pore volume and pore size are controlled by the forming and heat treatment parameters to maximise the gas flux through the support, and in such a way that the substrate can be coated directly with a mesoporous gamma-Al2O3 layer. The obtained porous RBAO substrates are three times stronger than the more conventional Al2O3 ones with comparable porosity. Special attention is given to the mechanism of neck forming to explain the surprising mechanical strength. It is thought that the presence of smaller grains surrounding the larger original Al2O3 grains may explain the high strength. 8 refs.
ISSN:1013-9826
1662-9795
1662-9795
DOI:10.4028/www.scientific.net/KEM.132-136.1691