In situ topochemically converted 2D BaTiO3 polycrystals with multifarious zone axes

BaTiO3 polycrystals with platelike morphology are prepared on the basis of an in situ topochemical conversion mechanism from a layered titanate H4x/3Ti2-x/3x/3O4 center dot nH(2)O (HTO) single crystal as the precursor and different barium compounds. BaTiO3 polycrystals present single-crystal-like electron diffraction points, indicating mesocrystals. The different BaTiO3 mesocrystals present non-uniform zone axes; however, the [100] zone axis of 60% is dominant owing to the intermediate mesocrystalline TiO2 polymorphs derived from the HTO precursors with the allied TiO6 octahedral layers. First-principles density functional theory calculations were performed for the verification of the most easily generated BaTiO3(100) surface compared to the other surfaces. BaTiO3 mesocrystals with high purity and multifarious zone axes can be formed using the HTO crystals as a precursor. Furthermore, [100]-textured BaTiO3 ceramics with high density, enhanced degree of orientation, and high piezoelectric constant are fabricated via templated grain growth, using the BaTiO3 mesocrystals as templates. Textured BaTiO3 ceramics with excellent physical properties are developed mainly by the growth of oriented template BaTiO3 mesocrystals with the [100] zone axis at the expense of matrix grains, which are BaTiO3 mesocrystals with the non-[100] zone axis. This novel strategy can control the desired orientation of textured materials with high piezoelectric properties.