Structure and Properties of 0.996(KNN-LS)-0.004BF Lead-free Piezoelectric Ceramics Sintered for Various Time

Abstract

0.996(0.95Na0.5K0.5NbO3-0.05LiSbO3)-0.004 FeBiO3 (0.996(KNN-LS)-0.004BF) lead-free piezoelectric ceramics were synthesized by the conventional solid-state sintering at 1060°C, and the piezoelectric and electromechanical properties were characterized as a function of sintering time. It was found that the sintering time has not changed their tetragonal phase structure, but has significant influence on the crystalline and properties. When the sintering time increase from 2 hours to 4 hours, the better crystallization and larger grain has been observed, but the increase for grain size would be insignificant when the sintering time is longer than 4 hours. The properties in the piezoelectric constant d33, planar coupling coefficient kp, dielectric constant er, dielectric loss tgδ and mechanical quality factor Qm all have been remarkably improved when the sintering time increase to 4 hours, but the tgδ and Qm would be deteriorated when the sintering time is over 4 hours.