Influence of zirconium addition on final properties of K0.5Na0.5NbO3-based ceramics

Abstract

Microstructure, electrical and dielectric properties of K1/2Na1/2NbO3 (KNN) modified with ZrO2 were investigated. Powders were obtained by a conventional solid-state method. In this way, samples doped with 0.2 mol% of ZrO2 were sintered at 1125 ºC for 2 h. Through XRD spectra, the perovskyte structure was seen, in addition to small peaks corresponding to secondary phases. It was also observed that zirconium changed the microstructure and grain size of KNN ceramics drastically. The addition of up to 1.0 mol% of Zr+4 produced a softening effect in the ferroelectric properties of the material, and increased the density. Conversely, samples prepared with higher contents than 1.0 mol% reduced piezoelectric and dielectric properties.