Preparation of mullite fibers from aluminum isopropoxide aluminum nitrate tetraethylorthosilicate solutions by sol-gel method

Mullite fibers were synthesized from an aqueous solution of aluminum isopropoxide, aluminum nitrate and tetraethylorthosilicate by the sol-gel method. Gels obtained from spinnable sols seem to have the homogeneity in the mixing scale of the Al-Si components, leading to a sharp 980 degrees C exothermic peak in the DTA curve and a mullitization temperature of 1000 degrees C. Whereas in the case of gels obtained from non-spinnable sols, a small 980 degrees C exothermic peak was detected, and the mullitization temperature was as high as 1200 degrees C, probably due to the heterogeneity in the mixing scale of the Al-Si components. (C) 1998 Elsevier Science B.V. All rights reserved.