Preparation and Piezoelectric Properties of (Na0.52-xK0.48)Nb0.95-xTa0.05O3-xLiSbO3 Ceramics

(Na0.52-xK0.48)Nb0.95-xTa0.05O3-xLiSbO3 (NKNT-xLS) lead-free piezoelectric ceramics have been prepared by the conventional mixed oxide method. The effect of the substitution of Sb5+, Li+ for Nb5+ and Na+ respectively on the microstructure and electrical properties of NKNT-xLS ceramics were investigated. Morphotropic phase boundary is formed in the range of 0.03 <= x < 0.05 at room temperature, leading to a significant enhancement of the piezoelectric properties. When x = 0.045, the ceramics possess optimum properties: piezoelectric constant d(33) = 250 pC/N, planar electromechanical coupling factors k(p) = 43.6%, remanent polarization P-r = 33.8 mu C/cm(2), coercive field E-c = 12.7 kV/cm. These results show that the NKNT-xLS ceramics may be regarded as a promising lead-free piezoelectric material.