The effects of firing temperatures and barium content on phase formation, microstructure and dielectric properties of lead barium titanate ceramics prepared via the combustion technique

This work concentrated on the phase formation, microstructure and dielectric properties of (Pb1-xBax)TiO3; PBT ceramics with 0.2 ≤ x ≤ 0.8 prepared by the combustion technique under various calcination (600-1200 °C) and sintering temperatures (1125-1275 °C) for 2 h. It was found that the PBT powders indexed in a tetragonal structure. The impurity phases of lead oxide (PbO), lead dioxide (PbO2), titanium dioxide (TiO2) and barium carbonate (BaCO3) were detected in the powders calcinated below 1000 °C, 1050 °C, 1100 °C and 1150 °C for x = 0.2, 0.4, 0.6 and 0.8, respectively. The XRD results corresponded to the DTA-TGA investigations. The sintered pellets showed pure perovskite in all samples. The lattice parameter a tended to decrease, while the lattice parameter c tended to increase with increased firing temperatures. The tetragonality, the average particles size, and the average grain size increased when the firing temperatures increased. The dielectric constant was depended on the sintering temperature. The Curie temperature decreased when x increased. The combustion fuel (urea) performed an important role for reducing soak time and improved the density and dielectric properties.