Effect of temperature, time and particle size of Ti precursor on hydrothermal synthesis of barium titanate

Barium titanate (BaTiO3) nanopowder is synthesized using two TiO2 powder precursors with different particle sizes and barium hydroxide via hydrothermal route. Effect of temperature, time and particle size is studied using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques. Crystallite size of barium titanate is observed to decrease with increasing temperature, while morphology of obtained BaTiO3 changed from porous irregular shape at lower reaction temperature (90 deg. C) to compact facetted shape at higher reaction temperature (150 deg. C). TEM observation of low reaction temperature samples (60 deg. C) supports in situ transformation or short range dissolution-precipitation reaction mechanism. The fine grained TiO2 (∼25 nm) precursor reacted faster than coarse grained TiO2 (∼110-125 nm) precursor. Reaction rate may depend on size of TiO2 precursor particles. The phase of obtained BaTiO3 in all samples is found to be cubic