Effect of sol-gel modifications on formation and morphology of nanocrystalline lanthanum aluminate

Abstract

LaAlO3 powders are prepared by sol-gel method. The effect of preparation conditions on morphological properties and crystal formations are investigated. iso-Propanol/tert-butanol and ethyl acetoacetate/ethylene glycol monomethylether are used solvents and complexing agents, respectively. Samples are dried with conventional and freeze-drying methods and calcined between 600 and 1000 degrees C. TGA, DTA, XRD, SEM and TEM methods are used for characterization. It is observed that freeze-dried sample prepared with tert-butanol has the lowest LaAlO3 formation temperature and uniform rhombohedral crystals. But conventionally dried sample, prepared with iso-propanol has smallest agglomerates at 1000 degrees C and does not show clear crystallization temperature in DTA analysis. The XRD peaks of LaAlO3 crystal are observed at 600 degrees C for all samples prepared by various sol-gel conditions. (C) 2006 Elsevier Ltd. All rights reserved.