Study on Phase Structure and Electrical Properties of La-Doped (K0.5Na0.5)0.94Li0.06NbO3 Ceramics

Lead-free piezoceramics (K0.5Na0.5)0.94-3xLi0.06LaxNbO3 were synthesized by the conventional solid-state reaction process. The effect of La-doping on the phase structure and electrical properties of (K0.5Na0.5)0.94Li0.06NbO3 ceramics was investigated. X-ray diffraction analysis showed that the crystal structure of the ceramics changed from coexistence of orthorhombic and tetragonal phases to pseudo-cubic phase with the increase of La-doping level, and the change of phase structure seriously weakened the dielectric, ferroelectric and piezoelectric properties of the ceramics. In addition, it was found that the La-doping improved the density of the ceramics and the ceramics became dense. Meanwhile, the ceramics with La-doping displayed a relative lower loss tangent (tanδ) from room temperature to approximately 350°C.