Preparation and Characterization of Large Surface Area BaO·6Al2O3

Abstract

Barium hexaaluminate, BaO·6Al₂O₃, exhibited excellent heat resistance in maintaining a large surface area. Preparation from hydrolysis of metal alkoxides was a superior process in deriving the large surface area of BaO·6Al₂O₃, to that from mixtures of BaCO₃⁄γ-Al₂O₃. Direct formation of BaO·6Al₂O₃ phase at low temperature plays the key role in retaining the fine particle size. The amount of water added for hydrolysis and the aging period of hydrolyzed precursors strongly influenced the surface area of alkoxide-derived BaO·6Al₂O₃. These effects of the preparation conditions originated from the difference in microstructure and chemical structure of the hydrolyzed precursors. Monodispersed fine precursor particles with high oxide content generated large surface area BaO·6Al₂O₃.