Synthesis and Piezoelectric Properties of KNbO3 Ceramics by Molten-Salt Synthetic Method

Potassium niobate (KNbO3) single-crystalline nanocubes have been successfully synthesized through a large-scale and facile molten-salt synthetic method. High-density KNbO3 ceramics can be obtained by the conventional sintering of the synthesized KNbO3 single-crystalline nanocubes without the addition of sintering additive. The crystal structure, microstructure, and dielectric and piezoelectric properties of these ceramics were characterized. The KNbO3 ceramics show a comparatively saturated polarization-electric field (P-E) hysteresis loop. The remnant polarization P-r and coercive field E-c are 23 mu C/cm(2) and 8 kV/cm, respectively. The KNbO3 ceramics also show enhanced piezoelectric properties in terms of the planar electromechanical coupling factor k(p), the piezoelectric constant d(33), and the mechanical quality factor Q(m), which are 0.34, 105 pC/N, and 216, respectively. (c) 2009 The Japan Society of Applied Physics