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

Abstract

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.

Keywords:

• Al₂O₃
• Fibers
• Grain size
• Mechanical properties
• Microstructure
• SEM
• Sintering
• Sol–gel processes
• Strength
• Thermal analysis
• X-ray diffraction

ACKNOWLEDGMENT

The authors are thankful to the Ministry of Human Resources and Development, Government of India for financial support to this work.