Synthesis of Porous Mullite by Vapor Phase Reaction
The porous microstructure with acicular mullites was fabricated using Al(OH) 3, Al 2O 3, and amorphous SiO 2 as starting materials by reaction sintering. Several molar ratios of Al 2O 3/SiO 2 and Al(OH) 32 were selected and AlF 3 of 0, 4, 7, 10wt% was added to each composition to examine the effects of composition and the additives for the mullite formation. Fluorotopaz was produced at a temperature around 900°C under a constant SiF4 atmosphere and it was decomposed to produce the mullite at a relatively low sintering temperature around 1200°C. The acicular mullite was more easily fabricated in the case of the Al(OH) 32 mixture with a larger amount of AlF 3.
S.-G. Kang and T. Kobayashi
B. R. Cho and J. B. Kang, "Synthesis of Porous Mullite by Vapor Phase Reaction", Materials Science Forum, Vols. 449-452, pp. 209-212, 2004