Sonochemical activation in aqueous medium for solid-state synthesis of BaTiO

Highlights • Enhanced solid-state synthesis of BaTiO3 by sonochemical activation in aqueous medium. • Investigations of physical and chemical effects of sonochemical activation. • Model proposal for the role of aqueous medium in solid-state synthesis. • Verification of the competitiveness of the resulting BaTiO3 powders and ceramics.
BaTiO3-based oxide compounds are important ceramic materials for multilayer ceramic capacitors. In this paper, we report a sonochemical activation process of BaCO3 and TiO2 in an aqueous medium for the synthesis of BaTiO3 powders through a solid-state process. Owing to the physical and chemical effects of the ultrasonication in aqueous medium on the raw materials, BaTiO3 powders could be successfully synthesized at relatively low temperatures through a solid-state reaction, which was significantly enhanced as compared to the case in ethanol medium. Detailed investigations on the resulting BaTiO3 powders and ceramics were performed, and a model to understand the role of aqueous medium on the enhancement of the solid-state reaction was proposed in terms of Ba2+ ion leaching and zeta potential of TiO2, which are strongly affected by the pH of the aqueous medium. Our results are not only helpful for cost-effective synthesis of BaTiO3 through the highly reliable solid-state reaction process, but they also provide an understanding of the role of aqueous medium for the sonochemical process using raw materials with partial solubility in water.