Heat-resistant ceramics based on LAS-system non-metallic mineral and its thermal shock resistance

초록

Li2O-Al2O3-SiO2 (LAS) system-based ceramics have been prepared with petalite and kaolin and their thermal shock resistances investigated. Feed slurries in five combinations of petalite and kaolin composition between 40% and 60% were first prepared with 5, 15 and 35 mu m fractions of petalite and slip casted into moulds. Then the casts were subjected to 2-stage sintering: in the first stage, at 850 degrees C for 2 h and in the second stage, at 1200, 1250 and 1300 degrees C for 2 h. Heating rate was 3 degrees C per minute. The characteristics of sintering, microstructure, X-ray diffraction pattern and water absorption rate of the LAS ceramics produced were studied. Their thermal shock resistances were also measured by a directly flame contact method. Petallite was transformed into beta-eucryptite and beta-spodumene at temperatures higher than 1200 degrees C. The LAS ceramics were found to have the highest thermal shock resistance at 1250 degrees C. Even at the reduced addition of 45% petalite, the more the particle size of petalite increase, the better is thermal shock resistance of the LAS system ceramics. (C)2010 The Ceramic Society Of Japan. All rights reserved

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