Preparation of alumina films from a new sol-gel route

A new sol-gel route was applied to prepare alumina films by using AlCl₃·6H₂O as starting material and acetylacetone (AcAc) as additive. Our research results show that AcAc and aluminum form a complex compound in the sol, which makes the sol very stable. Meanwhile, the complex structure prevents the decomposition going on quickly during the sintering process and the obtained films are free of cracks. The as-prepared films were amorphous. When the sintering temperature reached up to 600°C, γ-Al₂O₃ began to form and was transformed to α-Al₂O₃ at temperatures over 1200°C.