LAUSR

Abstract A new ceramic system of (1− x )(K 0.40 Na 0.60 )(Nb 0.96 Sb 0.04 )O 3 - x (Bi 0.5 Na 0.5 ) 0.9 Cu 0.1 ZrO 3 were fabricated by the conventional solid-state method, and effects of (Bi 0.5 Na 0.5 ) 0.9 Cu 0.1 ZrO 3 (BNCZ) contents on their phase structure, microstructure and electrical properties were investigated. It was found that the ceramics endured a series of phase structures with the addition of BNCZ, that is, orthorhombic (O) for 0 ≤  x  ≤ 0.02, orthorhombic-tetragonal (O-T) phase coexistence for 0.02  x  ≤ 0.035, and multiphase (R-O-T) coexistence for 0.035  x  ≤ 0.05, as confirmed by their temperature dependence of dielectric constant and X-ray diffraction patterns. Their grain sizes firstly increased and then decreased with increasing BNCZ contents. In addition, the ceramics with x  = 0.04 located at R-O&O-T phase boundaries possessed optimum electrical properties (i.e., d 33 ∼415 pC/N, k p ∼46%, P r ∼16.08 μC/cm 2 , E C ∼8.53 kV/cm, strain∼0.21%, and T C ∼245 °C). More importantly, a good thermal stability of piezoelectricity was also shown in the ceramics with x  = 0.04. We believe that this material system is one of the most promising lead-free piezoelectric candidates for practical applications.