Effect of rhombohedral-orthorhombic phase transition on structure and electrical properties of KNN-based lead-free piezoceramics

摘要

Lead-free ceramics (1-x)(Na0.7K0.3)(0.92)Li0.08NbO3-xCaZrO(3) (KNNL-xCZ) have been synthesized by the conventional solid-state reaction. X-ray diffraction shows that all ceramics are in pure perovskite phase. The study of their phase transition observed by the temperature-dependent dielectric measurements confirms that the addition of CZ leads to alternation of crystal structure. The KNNL-0.03CZ ceramics exhibit optimum electrical properties and produce large strain response (dS/dE = 193pm/V). The enhanced properties of the KNNL-xCZ are attributed to the effect of rhombohedral-orthorhombic phase transition in the vicinity of room temperature.