Barium strontium titanate nano powders were prepared by mixing ethanol solution of tetrabutyl titanate with an aqueous solution of Ba(OH)2•8H2O and Sr(OH)2•8H2O with a certain molar ratio of barium to strontium at 40°C－95°C. The products were characterized by thermogravimetry (TG), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), transmission electron microscope (TEM) and atomic force microscopy (AFM). The results show that the powders prepared with the reactant concentration of 0.8M are spherical in particle shape with the grain size of 50nm－65nm. When the annealing temperature of the powders is higher than 906°C, the hydroxyl groups existed in barium strontium titanate lattice are removed. XRD analysis demonstrate that the as-prepared powders are cubic phase. All the diffraction peaks are shifted towards higher diffraction angles and the lattice parameter a calculated decreases linearly with serial decrease of the molar ratio of barium to strontium.

Perovskite Ba0.7Sr0.3TiO3nanocubes with a hollow structure were prepared by molten hydrated salt method at 180 °C for 15 h, using Ba (OH)2·8H2O, Sr (OH)2·8H2O and anatase-TiO2as raw materials without any additive or template. The phase composition, morphology and microstructure of the products were characterized by XRD, SEM, TEM and HRTEM. The XRD result indicates that the products are phase pure cubic Ba0.7Sr0.3TiO3, with the calculated unit cella=0.3965 nm. The SEM, TEM and HRTEM results show that the products with polycrystalline structure are composed of the hollow nanocubes whose average edge length is about 180 nm, and their morphologies are greatly influenced by reaction temperature and reaction time. In addition, the formation mechanism of the hollow nanocubes also was discussed.