The effect of sintering parameters on the microstructure and dielectric properties of bismuth titanate

In the present work, the effect of sintering parameters including sintering temperature, soaking time, and heating rate on densification, microstructure, and dielectrical properties of bismuth titanate (Bi4Ti3O12) ceramics were investigated. Bismuth titanate was synthesized by the solid state method and titanium oxide and bismuth oxide used as raw materials. X-ray diffraction (XRD) indicated, pyrocholore phase of Bi2Ti2O7 as secondary phase was appeared at sintering temperature higher than 1075 °C due to bismuth loss in bismuth titanate. The maximum relative density of 97% with plate-like grains was acquired in optimized sintering condition for samples sintered at 1075°C for 1 h with heating rate of 5 °C/min. The results of the dielectric properties showed that the dielectric constant and the dielectric loss of bismuth titanate ceramic are very sensitive to relative density.  With increase of relative density of samples, the dielectric constant increased linearly and the dielectric loss decreased exponentially. The best dielectric properties with maximum dielectric constant (290) and minimum dielectric loss (0.013) were obtained for samples sintered in optimal sintering conditions.