Preparation and characterization of barium iron niobate (BaFe0.5Nb0.5O3) ceramics

Barium iron niobate (BaFe0.5Nb0.5O3: BFN) is a relaxor ferroelectric material that has a diffuse phase transition (DPT) with a broad maximum in the temperature dependence of the dielectric constant. This ceramic is useful for high voltage capacitors and other applications. In this research, ceramic powder of BFN was synthesized by the solid state reaction technique and calcined at 800–1200 °C for 4 h with 5 °C/min heating and cooling rate. The phase identification of calcined powders was performed using X-ray diffraction technique (XRD). The XRD patterns show that pure cubic BFN powder could be obtained at 1200 °C. The powder was then pressed into disc shape which was subsequently sintered at 1250–1400 °C for 4 h with 5 °C/min heating and cooling rate. Densities of the sintered discs were determined by Archimedes principle. The microstructure of the ceramics was examined by the scanning electron microscopy (SEM). The temperature dependence of dielectric constant was presented.