Combustion technique synthesis of lead-free piezoelectric bismuth sodium titanate-bismuth potassium titanate-barium titanate ceramics

Fabrication of lead-free piezoelectric ceramic bismuth sodium titanate-bismuth potassium titanate-barium titanate, focusing on the morphotropic phase boundary (MPB) between the rhombohedral and tetragonal phases was studied. a[0.935(Bi0.5Na0.5)TiO3-0.065BaTiO(3)]-(1-a)[0.8(Bi0.5Na0.5)TiO3-0.2(Bi0.5K0.5)TiO3]; BNBK ceramics with 0 a 1 were successfully fabricated using the combustion technique. All BNBK samples were sintered at 1150 degrees C for 2h. The effect of a changing on the phase formation, microstructure, dielectric properties and piezoelectric properties of perovskite BNBK ceramics were investigated. XRD results of BNBK ceramics with 0 a 1 showed the rhombohedral-tetragonal morphotropic phase boundary (MPB). The SEM results showed the average grain size is between 1.18 and 2.56 mu m. The effect of the a content had no influence on the tendency of grain sizes. The maximum density, shrinkage, dielectric constant at Curie temperature (E-r), remanent polarization (P-r), coercive field (E-c) and piezoelectric constant (d(33)) were found from BNBK ceramic with a = 1, which is around 5.76g/cm(3), 18.43%, 6503, 15.4C/cm(2), 20.1kV/cm and 289 pC/N, respectively.