Optimum conditions for fabrication high-density KNN-LS-BF ceramics by combustion method

Abstract

The 0.996(0.95K0.5Na0.5NbO3-0.05LiSbO 3)-0.004BiFeO3 (KNN-LS-BF) ceramics were prepared by the combustion method using glycine as a fuel. The raw materials were mixed and calcined at various calcination temperatures (650-750°C) with different dwell time (0.5-3 h). Then, the calcined powders were pressed and sintered at various temperatures (1000-1100°C) with 0.5-4 h dwell time. The highest % perovskite orthorhombic phase was found in powder calcined at 700°C for 1 h. For the sintered pellets, the orthorhombic structure was found in ceramic sintered at 1075°C for 2 h using heating and cooling rate of 10°C/min. The SEM photographs showed square or rectangular morphology. The average grain size increased with the increasing of soak time. The highest densisty (4.47 g/cm3), maximum dielectric constant (εr = 6180) and lowest dielectric loss (tanδ = 0.1) at Tc were obtained in the sample sintered at 1075°C for 3 h. The densest sample showed the P r = 14.3 μC/cm3 and Ec = 20.68 kV/cm at 40 kV/cm. © 2013 Copyright Taylor and Francis Group, LLC.