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

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 °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 °C and does not show clear crystallization temperature in DTA analysis. The XRD peaks of LaAlO3 crystal are observed at 600 °C for all samples prepared by various sol–gel conditions.