Polyethyleneimine surfactant effect on the formation of nano-sized BaTiO3 powder via a solid state reaction

Barium titanate powder is widely used in multilayer ceramic capacitors (MLCC) because of its’ superior ferroelectric and dielectric properties. Presently, barium titanate powder is mass-produced using a conventional solid state reaction. However, the conflicting literature reports clearly show that the solid state reaction mechanism is not well understood. Synthesizing nano-sized barium titanate powders with less agglomeration using a solid state reaction method at a low calcination temperature has become a hot research topic. This study examines the effect of polyethyleneimine (PEI) surfactant addition on BaTiO3 formation in a solid sate reaction. XRD, DTA and TEM are used in this investigation. The results indicate that PEI addition can promote BaCO3 and TiO2 mixing homogeneity, which enhances the interfacial reaction between BaCO3 and TiO2. BaTiO3 formation can be obtained through the interfacial reaction between BaCO3 and TiO2 at the intimate contact between the reactants and Ti+4 ion diffusion along the surfaces or grain boundaries of BaTiO3 powders, thereby obtaining a single phase BaTiO3 powder when calcining at low temperatures for a long period.

► PEI addition can promote BaCO3 and TiO2 mixing homogeneity, which enhances the interfacial reaction between BaCO3 and TiO2.
► BaTiO3 formation is obtained through the interfacial reaction between small-sized BaCO3 and TiO2 at the intimate contacts between the reactants and the diffusion of Ti4+ ions along the surfaces or grain boundaries of BaTiO3 nanoparticles, thereby obtaining a single phase BaTiO3 powder by calcining at low temperatures for a long period.