Intermediate phases formation during the synthesis of Bi4Ti3O12 by solid state reaction

In this work, the formation of Bi4Ti3O12 by solid state reaction from Bi2O3 and TiO2 starting powders has been studied. The Bi4Ti3O12 formation occurs through an intermediate Bi12TiO20 sillenite phase formed at temperatures sligthly over 300 °C. This sillenite phase is stable up to ∼750 °C, but in the presence of TiO2 reacts to form Bi4Ti3O12 at temperatures >500 °C. Raman spectroscopy has been used to evidence the amorphization of TiO2, demonstrating that the Bi4Ti3O12 formation occurs through the reaction of sillenite Bi12TiO20 and TiO2.