Effects of the Reaction Temperature and Ba/Ti Precursor Ratio/Concentration on the Crystallite Size of Barium Titanate in Hydrothermal Synthesis

Nanocrystalline BaTiO 3 has been prepared by hydrothermal synthesis from titanium isopropoxide and barium hydroxide octahydrate. Reaction conditions including synthesis temperature and Ba/Ti precursor ratio/concentration have been explored with the aim of producing small crystallites of phase-pure BaTiO 3 with low concentration of defects. The synthesis temperature has been found to have a profound effect on the crystallite size of the BaTiO 3 samples, with a lower synthesis temperature producing crystallites of a smaller size. Also, the crystallite size and morphology of BaTiO 3 are affected by the Ba/Ti precursor ratio. The BaTiO 3 sample synthesised using a Ba/Ti precursor ratio of 2:1 at a reaction temperature of 120 °C exhibited homogeneous crystallites of the smallest size of 107 nm, as concluded from the analysis of XRD and SEM results. In addition, the Ba:Ti ratio of 2:1 was also found to produce smaller concentration of defects, as obtained from the quantitative analysis of WDS data.