Kinetics of Barium Titanate Synthesis

Reaction curves were obtained at various temperatures and concentrations for the formation of BaTiO 3 from particulate titania in Ba(OH) 2 solution. Kinetic analyses were performed by constructing mathematical models which took into account the particle size distribution of the reactant titania for both the topochemically‐rate‐controlled and the diffusion‐rate‐controlled reactions. At [Ba(OH) 2 ] > ca. 0.1 M the rate‐controlling step is the Ba reaction with TiO 2 at the interface. The measured activation energy is 105.5 kJ/mol. The rates are independent of Ba(OH) 2 concentration, indicating that the TiO 2 interface is saturated. At [Ba(OH) 2 ] < ca. 0.1 M the rate‐determining step shifts to diffusion through the product BaTiO 3 layer, the rates are concentration dependent, and the BaTiO 3 particle sizes are inversely proportional to the Ba(OH) 2 concentrations used.