Phase Transition and Electrical Properties of Li‐and Ta‐Substituted (Na0.52K0.48)(Nb0.96Sb0.04)O3 Piezoelectric Ceramics

Abstract

Lead‐free (Na0.52K0.48−x)(Nb0.96−xSb0.04)O3–xLiTaO3 ceramics (x=0.0375–0.0575) have been manufactured by a conventional solid‐state method. All compositions form solid solutions with a pure perovskite structure. A morphotropic phase boundary (MPB) between orthorhombic (x≤0.04) and tetragonal (x≥0.045) ferroelectric phases was identified in the composition range of the 0.04<x<0.045. The composition near the MPB (x=0.0425) exhibits the best electrical properties with a dielectric constant of 1644, a piezoelectric constant of 310 pC/N, a planar‐mode electromechanical coupling factor of 0.48, and a Curie temperature of 340°C. The results indicate that the materials studied could be a promising lead‐free piezoelectric candidate for device applications.