Effects of processing parameter on energy storage density and ferroelectric properties of lead-free bismuth sodium titanate-strontium bismuth titanate ceramics

Abstract

In order to clarify the optimal sintering conditions, the effects of processing parameter on phase evolution, physical, microstructure, dielectric, ferroelectric, and energy storage density properties of bismuth sodium titanate-strontium bismuth titanate ceramics (or BNT-SBT) were investigated. The studied ceramics were fabricated via a conventional mixed oxide method and sintered at temperatures ranging from 1100–1175 °C under normal atmosphere for 3 h dwell time with a heating/cooling rate of 5 °C/min. The XRD data revealed that the coexisting rhombohedral and tetragonal phases were observed in all of the ceramics. With increasing sintering temperature, the cubic-rich phase was dominated; and the average grain size tended to increase. For the ceramics sintered at 1150 °C, the good density (5.74 g/cm3), dielectric ("max = 3510, tan δ = 0.0501, TF-R = 73.80 °C, Tm = 273 °C), and ferroelectric (Pr = 3.05 µC/cm2, Ec = 7.69 kV/cm) were obtained. In addition, the obtimum sintering temperature of 1150 °C was also found to improve the energy storage density properties (W = 0.94 J/cm3, η = 89.93% at 125 °C, and E = Emax).