Phase diagram and electrostrictive properties of Bi₀.₅Na₀.₅TiO₃-BaTiO₃-K₀.₅ Na₀.₅NbO₃ceramics

Abstract

Phase diagram of Bi₀.₅Na₀.₅TiO₃-BaTiO₃–K₀.₅Na₀.₅NbO₃ternary 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-P² 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 m⁴/C², about 1.5 times of the value of traditional Pb-based electrostrictors.