Phase evolutions and electric properties of BaTiO₃ ceramics by a low-temperature sintering process

BaTiO₃ (BT) nanoparticles were synthesized by a modified polymeric precursor method in a weak acid solution. The synthesized process of BT precursor with increasing calcination temperature was investigated through thermal analysis (DTA/TG), X-ray diffraction, transmission electron microscope and Fourier-transform infrared spectroscopy. Good dispersive and homogeneous cubic BT nanoparticles were calcined at 800 °C, whereas dense BT ceramics were sintered at ~1,160 °C. The present results showed that the dielectric, piezoelectric and ferroelectric properties of BT ceramics were dependent on the ceramics densification and crystallographic structure. The excellent electric properties (P _r = 10.5 μC/cm², d ₃₃ = 217 pC/N, k _p = 0.32 %) were found at a sintering temperature of 1,160 °C, which was due to the coexistence of tetragonal and orthorhombic phase. The depressed electric properties at higher sintering temperature were associated to oxygen vacancies and impurity phases. In addition, phase evolutions of BT nanoparticles and ceramics were all stated in detail.