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 α-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 α-Al2O3 to boehmite sol. Differential thermal analysis showed that the phase transition to α-Al2O3 takes place at a much lower temperature by seeding α -Al2O3. The presence of α-Al2O3 seeds decreases the sintering temperature and a relatively dense microstructure with very fine grain size is formed at 1300°C. The fibers sintered at 1300°C have the highest tensile strength.