Abstract: The effect of alumina sol on the α phase transformation in γ-alumina powder has been studied. In comparison with α-alumina seeds, the alumina sol can also act as seeds. Moreover, because of the small particle size and perfect dispersibility of the alumina sol, the α phase transformation temperature is decreased and, meanwhile, the microstructure of the produced powders is modified. So ultrafined powders with a particle size less than 100 nm were produced with good dispersibility. The α phase transformation of the alumina precursors with alumina sol doping was studied on the base of the TEM photographs of the produced powders.

Key words: Ultrafined, Alumina, Sol, Seeding, α phase transformation