Influence of feedstock concentration on tetragonality and particle size of hydrothermally synthesized barium titanate powders

Barium titanate (BaTiO3) powders were synthesized through hydrothermal process with Ba(OH)2·8H2O and TiO2. By increasing the feedstock concentration (FC) from 0.25 to 1.50 M, BaTiO3 powders maintain a stable average particle size (~180 nm and ~6.4441 m2/g) with an increasing tetragonality (c/a: 1.0065-1.0075). Johnson-Mehl-Avrami and standard reaction rate equations were adopted to analyze the kinetic process of BaTiO3 formation. The reaction is governed by first-order and phase-boundary-controlled mechanism for 0.25 M and 1.50 M, respectively. Lower extent of reaction is believed to lead to the better tetragonality for BaTiO3 powders fabricated with higher FC. On the other hand, the relative stable particle size is correlated with the unvaried nucleation frequency and grain growth rate with various FC. This work can provide a guideline to manipulate the properties of BaTiO3 powders used in electronic industry.