Synthesis and Characterization of Sol-Gel Alumina Fiber by Seeding α-Alumina Through Extended Ball Milling

Alumina fibers were prepared by sol-gel process using alpha-Al2O3 seeded boehmite sol. The starting material used for the preparation of boehmite sol was aluminium-tri-isopropoxide. Extended ball milling of boehmite sol using alumina grinding media was carried out to incorporate nucleating seeds of alpha-Al2O3 to boehmite sol. Differential thermal analysis showed that the phase transition to alpha-Al2O3 takes place at a much lower temperature by seeding alpha-Al2O3. The presence of alpha-Al2O3 seeds decreases the sintering temperature and a relatively dense microstructure with very fine grain size is formed at 1300 degrees C. The fibers sintered at 1300 degrees C have the highest tensile strength.