Phase structure, piezoelectric properties, and stability of new K0.48Na0.52NbO3-Bi0.5Ag0.5ZrO3 lead-free ceramics

In this work, (1 - x)(K0.48Na0.52)NbO3-x(Bi0.5Ag0.5)ZrO3 [(1 - x)KNN-xBAZ] lead-free piezoceramics was prepared by the conventional solid-state method, and a new phase boundary consisting of three phases [e.g., rhombohedral, orthorhombic, and tetragonal (R-O-T) phases] has been constructed by adding both (Bi0.5Ag0.5)(2+) and Zr4+. The ceramic with x = 0.05 possesses an R-O-T phase coexistence. A large d (33) of similar to 347 pC/N and a high T (C) of similar to 318 A degrees C have been shown in the ceramic with x = 0.05. In addition, such a ceramic also possesses enhanced thermal and temperature stability of piezoelectricity and ferroelectricity. Both the phase boundary and the grain size play a critical role in large piezoelectricity and good stability. We think that this material belongs to be one of the promising candidates for the high-temperature piezoelectric devices.