Fabrication and Characterization of 0.904Bi0.5Na0.5TiO3-0.040Bi0.5K0.5TiO3-0.056BaTiO3 Lead-Free Ceramics Using the Combustion Technique

Abstract

A ternary system lead-free piezoelectric ceramic bismuth sodium titanate-bismuth potassium titanate-barium titanate was studied. (Bi0.472Na0.452K0.02Ba0.056)TiO3 or 0.904Bi0.5Na0.5TiO3-0.04Bi0.5K0.5TiO3-0.056BaTiO3;BNT BKT Bceramics were successfully fabricated using the combustion technique. The effect of sintering temperatures (1050 - 1200 oC) on the phase formation, microstructure and dielectric properties of perovskite BNT BKT BT ceramics were studied. XRD results showed the rhombohedral-tetragonal morphotropic phase boundary (MPB). The SEM results showed that the average grain size (1.03-3.49 ??m) of samples increased with the increase of sintering temperatures. The samples sintered at the optimum temperature of 1175 oC showed the maximum density, shrinkage, dielectric constant at Curie temperature, remanent polarization (Pr), coercive field (Ec) and high piezoelectric constant (d33) were around 5.78 g/cm3, 17.48%, 5890, 9.5 ??C/cm2, 15.1 kV/cm and 156 pC/N, respectively. The dielectric constant was related to the density of the sintered ceramic.

Keywords: microstructure, lead free piezoelectric ceramics, morphotropic phase boundary, BNT-BKT-BT, combustion technique