Rhombohedral–Tetragonal Phase Coexistence and Piezoelectric Properties of (NaK)(NbSb)O ₃ –LiTaO ₃ –BaZrO ₃ Lead‐Free Ceramics

Abstract

The phase transitional behavior and composition‐dependent piezoelectric properties of (NaK)(NbSb)O 3 –LiTaO 3 –BaZrO 3 (NKNS–LT–BZ) pseudo‐ternary system were investigated. A composition–temperature phase diagram was generalized within a certain range of BZ content in which a rhombohedral–tetragonal ( R – T ) ferroelectric phase boundary connecting orthorhombic and cubic phase zones is formed near room temperature between two trifurcate points. Piezoelectric and electromechanical properties of NKNS–LT–BZ ceramics exhibit optimum values of d 33 =365 pC/N and k p =45% in the vicinity of the R – T phase coexistence zone. The dielectric and ferroelectric properties and the phase transition of NKNS–LT–BZ ceramics were discussed from a crystallographic point of view.