STRUCTURE OF KAOLINITE-ALUMINA BASED FOAM CERAMICS FOR HIGH TEMPERATURE APPLICATIONS

Lightweight refractory materials were developed by applying aerated concrete technology. Kaolinite-based suspensions were agitated with Al powders or Al pastes. Under the release of hydrogen gas, foams were formed at pH values from 7 to 9, stabilised, dried and fired at temperatures up to 1600 C. Lo...

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Bibliographic Details
Published in:Journal of the European Ceramic Society 2007-01, Vol.27 (2-3), p.1435-1441
Main Authors: Juettner, T, Moertel, H, Svinka, V, Svinka, R
Format: Article
Language:English
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Summary:Lightweight refractory materials were developed by applying aerated concrete technology. Kaolinite-based suspensions were agitated with Al powders or Al pastes. Under the release of hydrogen gas, foams were formed at pH values from 7 to 9, stabilised, dried and fired at temperatures up to 1600 C. Loading fractions of alumina up to 80 vol% were investigated. The porosity varied with the amount of the metal precursor Al. A macroporosity of 0.2-1 mm was formed which was characterised by image analysis and X-ray tomography. The working temperature of the produced refractory materials depended on the prefiring temperature, the filler character and content and the macroscopic structure. Silica-free pure porous mullite or mullite-corundum ceramics were obtained. Thermal analysis showed that the porous refractories meet the ASTM requirements for application temperatures up to 1550 C. 17 refs.
ISSN:0955-2219