Preparation of mullite fiber

Transparent mullite fibers have been prepared using aluminum carboxylates (ACs) and tetraethyl orthosilicate (TEOS) as starting materials, The ACs are derived from the catalyzed dissolution of elemental aluminum in a mixture of formic acid and acetic acid. The solubility of aluminum in the acids is influenced by the concentrations of the acids, mater, and additives and the preparation temperature. A 1:4:3:24 molar ratio of aluminum, formic acid, acetic acid, and mater dissolves the aluminum completely to give a colorless, clear solution suitable for fiber synthesis. The mixture of the ACs and TEOS, in the presence of ethyl alcohol as a mutual solvent at 50 degrees-60 degrees C, is concentrated to give a spinnable dope, from which mullite precursor fibers can be drawn, Heat treatment of the precursor at 1250 degrees C yields crystallized and transparent mullite fibers.