Preparation of Alumina by Sol-Gel Process, Its Structures and Properties

Alumina monolithic gel has been prepared by ammonia method from anhydrous aluminium chloride and n-butanol using formamide as the solvent. The gel has been made by hydrochloric acid catalysis and using large quantity of water for hydrolysis (molar ratio of water to aluminium-n-butoxide, R > 99). Transparent alumina xerogel of size 37.5 x 20 x 5 mm approximately has been prepared. The alumina gel has been dried and sintered at 400 degrees C, 1000 degrees C and 1200 degrees C respectively and the powders formed thereby have been examined by XRD, FTIR spectroscopy, SEM and particle size analysis. These studies have confirmed the formation of a-alumina at 1200 degrees C having particle size as low as 0.2 mu m or less along with agglomerates. The density of the powder has increased gradually, where as its particle size has decreased, with the increase of the sintering temperature.