Nanostructured alumina from freeze-dried precursors

Nanocrystalline alumina has been obtained on the 100 g scale by thermal decomposition of precursors resulting from the freeze-drying of aqueous solutions of different aluminum-containing products, namely aluminum acetate and aluminum l-lactate. Samples prepared at different temperatures (from 873 to 1573 K in steps of 100 K) were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and surface area measurements. In the acetate case, the transformation sequence involves the formation of θ-Al2O3 as an intermediate phase between γ-Al2O3 and α-Al2O3, whereas this θ phase is not observed in the lactate case. TEM and SEM i…

Nanotecnologia a l'aula