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 $S-P2$ 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 $0.026m4/C2$⁠, about 1.5 times of the value of traditional Pb-based electrostrictors.