Low Temperature One Step Synthesis of Barium Titanate: Particle Formation Mechanism and Large-scale Synthesis

摘要

The formation of BaTiO_3 nanoparticles via the reaction of BaCl_2, TiCl_4 and NaOH in aqueous solution has been systematically studied. The formation of BaTiO_3 from the ionic precursors has been elucidated to be a very rapid process, occurring at temperature higher than 60℃. Furthermore, the particle size could be controlled by the proper selection of the synthesis conditions (e.g. reactant concentration of 0.5-1.0 mol·L~(-1), temperature of 80-95℃ and pH ≥ 13). Atwo-step precipitation mechanism was proposed. The first stage of the synthesis involved the formation of amorphous Ti-rich gel phase. The second stage of the synthesis was the reaction between the amorphous phase and the solution-based Ba~(2+) ions, which led to the crystallization of BaTiO_3. Based on the particle formation mechanism, a novel method, high gravity reactive precipitation, was proposed and used to mass production of BaTiO_3 of average particle size of about 60 nm and with narrow particle size distribution. Because it could break up the amorphous Ti-rich gel into small pieces, intensify mass transfer, promote the reaction rate of amorphous Ti-rich gel with Ba~(2+) ions.