New potassium-sodium niobate material system: a giant-d<subscript>33</subscript> and high-T<subscript>C</subscript> lead-free piezoelectric.

In this work, we elucidate the influence of Bi0.5Li0.5ZrO3 (BLZ) content on the phase structure, microstructure, and electrical properties of (1 - x)K0.40Na0.60Nb0.965Sb0.035O3-xBi0.5Li0.5ZrO3 lead-free ceramics. We simultaneously achieved a giant d33 and a high TC in this material system. The coexistence of rhombohedral and tetragonal phases is responsible for such a large d33 in the ceramics with BLZ contents (x) ranging from 0.025 to 0.035. Doping with BLZ not only induces the formation of the phase boundary, but also maintains a high TC. The ceramic with x = 0.03 shows an enhanced piezoelectric behaviour (d33 ~ 400 pC N-1 and kp ~ 0.47) together with a high TC of 292 °C. A good temperature stability for ferroelectricity and piezoelectricity is also observed in these ceramics. This study is the first time that such a good comprehensive performance has been obtained in potassium-sodium niobate materials. We believe that this type of material system possessing giant-d33 and high-TC is a promising candidate for use in high-temperature piezoelectric devices. [ABSTRACT FROM AUTHOR]