• Journal of the Korean Ceramic Society
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• v.33 no.6
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• pp.679-685
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• 1996

• Journal of the Korean Ceramic Society
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• v.28 no.7
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• pp.503-508
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• 1991

High pure and fine mullite powders were synthesized from Al-secbutoxide[Al(OC4H9)3] and TEOS[Si(OC2H5)4] (SiO2/Al2O3=2/3 mole). Sol-Gel process by partial hydrolysis technique, as it were, first, TEOS was partially hydrolysized and then mixed with Al-secbutoxide for complete hydrolysis was used. The mullite precursor was synthesized within 30 hrs, which was reduced about a half of synthetic time in comparison with the other's study. Al-Si spinel was formed at 980℃ and mullite crystal was formed at 1200℃. Mullite powders synthesized in this study was spherical type like those of the other studies and particle sizes were very fine. Also mullite powders calcined at 1,600℃ had a stoichiometric composition (3Al2O3·2SiO2) and lattice constants were coincided with known theoretical values.

• Korean Journal of Materials Research
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• v.16 no.12
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• pp.719-724
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• 2006

Ultrafine mullite powder was prepared from aluminium-secbutoxide and tetraethyl orthosilicate(TEOS) in the molar $Al_2O_3/SiO_2$=3/2. Sol-gel method by partial hydrolysis technique, as it were, first, TEOS was partially hydrolysized and then mixed with Al-secbutoxide for complete hydrolysis was used. X-ray diffraction, infrared spectroscopy and transmission electron microscopy, etc. confirmed that the mullite powder prepared by this method is in the stoichiometric $Al_2O_3/SiO_2$ ratio. Al-Si spinel was formed at $980^{\circ}C$ and ultrafine mullite powder with about 20 nm particle size was obtained above $1,200^{\circ}C$. Also mullite powders calcined at $1,600^{\circ}C$ had a stoichiometric composition, $3Al_2O_3{\cdot}2SiO_2$ and the lattice constants of the mullite powders calcined above $1,200^{\circ}C$ were almost coincided with theoretical values.