Preparation of Barium Titanate and Related Materials by the Alkoxide-Hydroxide Route

Formation of perovskites MTiO3 (M = Ba, Sr) at low temperature (< 100°C) by heterogeneous reactions of M(OH)2 aqueous solutions with hydrolysis products of Ti(OBu)4 is discussed. Reaction products are characterized by means of chemical and X-ray analysis, and electron microscopy. Reaction rate is enhanced by hydroxide concentration and reaction temperature, and increases drastically when Sr(OH)2 is used instead of Ba(OH)2. Particles shape and size of the perovskites formed is independent of morphology of Ti(OBu)4 hydrolysis product. The main factor of perovskites morphology regulation lies in the rate of M(OH)2 absorption. Lowering the absorption rate allows us to prepare uniform perovskite powders which can be readily sintered to ceramic bodies with high dielectric permittivity.