Synthesis, sintering, and characterization of BNT perovskite powders prepared by the solution combustion method

Pure Bi0.5Na0.5TiO3 powders have been successfully synthesized by a single-step solution combustion technology using urea as fuel and metal (Bi and Na) nitrates as reactants. The phase structure and morphology of the as-prepared product were examined by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Effects of reaction parameters including fuel to oxidizers ratio and ignition temperature on the phase formation and morphology evolution were investigated. XRD shows that a single perovskite BNT phase is formed at the ignition temperature of 600 °C with fuel to oxidizers ratio of 2.0. Well-dispersed powders with the average particle size of 200 nm are obtained after milling for 24 h. BNT ceramics can be well densified at 1140 °C for 2 h with average grain size about 2 μm and show evidence of relaxor ferroelectric behaviors with diffuse phase transition and frequency dispersion.