Effect of Sb5+ on the Properties of (K0.5Na0.5)NbO3 Lead-Free Piezoelectric Ceramics.

Antimony modified (Na0.5K0.5)NbO3 lead-free piezoelectric ceramics were prepared by conventional electroceramic process. The role of Sb5+ in (Na0.5K0.5)NbO3 perovskite structure B site was discussed. The degree of crystalline structural symmetry increased with Sb5+ content increasing, changing from orthorhombic to pseudocubic. As a result, the thermal stability of crystalline structure and ferroelectric properties of (Na0.5K0.5)NbO3 ceramics decreased. (Na0.5K0.5)NbO3 ceramics with 3 mol% Sb5+ displayed enhanced piezoelectric properties, the piezoelectric constant d33 was 144 pC/N, planar electromechanical coupling coefficient kp was 49%, mechanical quality factor Qm was 160, and Tc = 344°C, respectively. [ABSTRACT FROM AUTHOR]