Low temperature formation of barium titanate in solid state reaction by mechanical activation of BaCO3 and TiO2

Abstract

In this study, the effects of mechanical activation on BaTiO3 formation from BaCO3 and TiO2 powders were investigated. Differential thermal analysis (DTA), high-temperature x-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) studies were performed following the mechanical activation of the powder mixture to reveal the phase formation and structural changes. In addition, the powder mixtures were sintered at 1350 °C for 3 h. Structural differences between the non-activated and activated samples were observed with scanning electron microscopy (SEM), and their electrical properties were measured to study the effects of mechanical activation. It was observed that mechanical activation increased the chemical reactivity of BaCO3 and TiO2 powders, causing amorphization and structural disorder in their structures. These were confirmed with XRD and FT-IR analysis. The 120-min activation of a mixture of barium carbonate and titania caused a decrease in the formation temperature of the Ba2TiO4 phase from 815 °C to 640 °C, while the formation temperature of the BaTiO3 phase decreased from 1095 °C to 890 °C. It was observed that the dielectric constants of the samples were increased by increasing the mechanical activation time.