Preparation of γ-Al₂O₃ film by high temperature transformation of nanosized γ-AlOOH precursors

Mesoporous boehmite (γ-AlOOH) and gamma-alumina (γ-Al₂O₃) self-supported films were prepared by high temperature transformation of γ-AlOOH precursor fibers. A polymer, sodium polyacrylate, was used as a size/morphology controlling agent yielding to a stable colloidal suspension of boehmite ribbon-like fibers after a 168 h hydrothermal treatment at 160 °C. The slow evaporation of the solvent leads to γ-AlOOH film without any cracks and pinholes. The γ-Al₂O₃ film, obtained after calcination of the γ-AlOOH film, exhibit a high thermal stability up to 1000 °C and two distinct kinds of mesopores with average diameters of 20–30 Å and 50 Å. Structural and textural properties of these films confer them interesting properties for filtration processes.