Microstructure and electrical properties of (1-x)K0.5Na0.5NbO3-xBi0.5Na0.5Zr0.85Sn0.15O3 lead-free ceramics

In this work, we simultaneously obtained a large d33 and high TC in a lead-free piezoelectric system of (1-x)K0.5Na0.5NbO3-xBi0.5Na0.5Zr0.85Sn0.15O3 [(1-x)KNN-xBNZS]. This lead-free piezoelectric system was synthesized by conventional solid-state method. We investigated the microstructure and electrical properties of this system. The rhombohedral-tetragonal (R-T) phase coexistence is demonstrated in the ceramics with 0.05 ≤ x ≤ 0.06. Owing to the R-T phase coexistence as well as the enhancement of ferroelectric and dielectric properties, the ceramics with x = 0.05 showed a large d33 of ∼350 pC/N together with a high TC of ∼315 °C, thereby illustrating that it is an effective way to obtain both large d33 and high TC in KNN-based ceramics. It is believed that such a ceramic system with large d33 and high TC is one of the promising candidates for piezoelectric devices.