Stoichiometric control in Bi₄Ti₃O₁₂ synthesis by novel hybrid solid state reaction

The synthesis of bismuth titanate Bi₄Ti₃O₁₂ (BiT) is performed via a novel solid state reaction. The reaction is designed to control the stoichiometric content of the highly volatile element, i.e. Bi. The chemical route consists in trapping bismuth oxide colloids in a stabilized titanium based sol gel solution. The resulting colloidal-solution hybrid ink can be processed via various ceramic processes. After gelation of TiO₂ in the sol-gel component the mixture reacts at high temperature (850 °C) to yield the BiT phase. The obtained material is c-axis oriented, and its lattice parameters, shrinkage and density matches the pure Bi₄Ti₃O₁₂ phase. The sintered material exhibits enhanced higher dielectric constant (2 3 2) than usually reported for this phase.