Phase and structural transformations in thin film titanate systems

Abstract

Phase and structural transformations occurring simultaneously with solid state reactions in the multicomponent thin film TiO 2/BaO, TiO 2/BaCO 3, TiO 2/PbO and TiO 2/Bi 2O 3 systems under isothermal annealing were systematically investigated. The general mechanisms and particular features of the nucleation and growth of barium, lead and bismuth titanate phases in these systems were identified. It was found that the phase equilibrium in the thin film TiO 2/BaCO 3 system shifted to a lower temperature range than that for the bulk system. A semiquantitative model was used to analyse the factors causing differences in the solid state reactions in thin film and in bulk titanate systems. The thermodynamics of the phase transformations and the kinetics of formation of nuclei of new phases in fine-grained thin film systems are shown to be appreciably affected by the energy excess at the grain boundaries.