Rhombohedral-Tetragonal Phase Coexistence and Piezoelectric Properties of (NaK)(NbSb)O_3-LiTaO_3-BaZrO_3 Lead-Free Ceramics

摘要

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-tetrag-onal (R-T) ferroelectric phase boundary connecting orthorhom-bic 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.