Balanced Development of Piezoelectricity and Curie Temperature in KNN-BC-xBNH Lead-Free Ceramics

Abstract

In this work, (0.996 À x)(K 0.48 Na 0.52)NbO 3-0.004BiCoO 3-xBi 0.5 Na 0.5 HfO 3 (abbreviated as KNN-BC-xBNH) lead-free ceramics were prepared by the conventional solid-state sintering method. The effects of Bi 0.5 Na 0.5 HfO 3 content on the microstructure and piezoelectric properties of ceramic crystals were systematically studied. The results of x-ray diffraction (XRD) and temperature dependence of the dielectric constant showed that with the increase of Bi 0.5-Na 0.5 HfO 3 content, the rhombohedral-orthorhombic (T R-O) and orthorhombic-tetragonal (T O-T) phase-transition temperature gradually moved to the vicinity of room temperature. The KNN-BC-xBNH lead-free ceramics with x = 0.