Phase diagram and electrostrictive properties of Bi0.5Na0.5TiO3-BaTiO3-K0.5Na0.5NbO3 ceramics

Phase diagram of Bi0.5Na0.5TiO3-BaTiO3-K0.5Na0.5NbO3 ternary system has been analyzed and (0.94-x)BNT-0.06BT-xKNN (0.15 <= x <= 0.30) ceramics have been prepared and investigated. Pseudocubic structures were confirmed by x-ray diffractions and its preliminary Rietveld refinements. P-E, S-E, and S-P-2 profiles (where P, E, and S denote polarization, electric field, and strain, respectively) indicate electrostrictive behavior of all ceramics. The compositions with x=0.20 and 0.25 show pure electrostrictive characteristics. The dissipation energy, electrostrictive strain, and electrostrictive coefficient have been determined and compared with other lead-free and lead-containing electrostrictors. The electrostrictive coefficient can reach as high as 0.026 m(4)/C-2, about 1.5 times of the value of traditional Pb-based electrostrictors. (C) 2010 American Institute of Physics. [doi:10.1063/1.3491839]