The effect of firing conditions on phase formation, microstructure and dielectric properties of BNKTNb-LSb ceramics prepared via the combustion technique

The fabrication of 0.99[Bi-0.5(Na0.82K0.18)(0.5)Ti0.995Nb0.005O3]-0.01LiSbO(3) ceramics (BNKTNb-LSb) prepared by the combustion technique was studied. A single perovskite phase of BNKTNb-LSb powder was observed by the powders calcined at 700 degrees C for 2 h, which was lower than the solid-state reaction technique similar to 150 degrees C. The BNKTNb-LSb ceramics showed the coexistence of a rhombohedral and tetragonal phase at a low sintering temperature. Then, the phase formation changed from a tetragonal to a pseudocubic phase when sintered at higher temperatures. The grain morphology of the BNKTNb-LSb ceramics exhibited a rather square shape and the average grain size of the ceramics was increased with increased sintering temperatures. The density, linear shrinkage, epsilon(r) and epsilon(max) of the BNKTNb-LSb ceramics tended to increase with increasing sintering temperatures up to 1125 degrees C and then decreased. At 1125 degrees C, the highest density, shrinkage, epsilon(r) and epsilon(max) were about 5.82 g/cm(3), 18.7%, 1625 and 4465, respectively. The dielectric behavior corresponded with the XRD, density and the microstructure results.