Study on the hydrothermal synthesis of barium titanate nano-powders and calcination parameters

Barium titanate nano-powders were synthesized by hydrothermal synthesis of Ba(OH)(2)center dot 8H(2)O and Ti(OH)(4) as precursors. The size and distribution of BaTiO3 crystallites could be adjusted and controlled by varying heat treatment conditions and hydrothermal medium. Smaller crystallite size and narrow distribution of BaTiO3 nano-powders were obtained by reacting at 180 A degrees C and crystalized in a mixed solvents of water and ethanol (V-water:V-ethanol = 2:1), which was characterized by BET, PSD, SEM and XRD. The specific surface area and equivalent diameter (d(BET)) of synthesized BaTiO3 powders were 19.43 m(2) g(-1), 51 nm respectively, D-10 = 48 nm, D-50 = 86.5 nm, D-90 = 147 nm. Only after calcined at 950 A degrees C, would the powders of BaTiO3 in the form of metastable cubic phase fully complete tetragonal phase transition, during which the agglomeration and abnormal grain growth could be avoided by adding some nano cabon black.