SYNTHESIS AND CHARACTERIZATION OF SB-SUBSTITUTED (K0.5Na0.5)NbO3 PIEZOELECTRIC CERAMICS
Abstract:Lead-free piezoelectric ceramics (K0.5Na0.5)(Nb1-xSbx)O3+0.5 mol.%MnO2, where x = 0 ÷ 0.10, with single phase structure and rhombohedral symmetry at room temperature were prepared by conventional ceramic technology. The optimal sintering temperatures of compositions were within 1100°-1140°C. MnO2 functions as a sintering aid and effectively improves the densification. The samples reached density from 4.26 g/cm3 for undoped (K0.5Na0.5)NbO3 to 4.40 g/cm3 for Mn/Sb5+ co-doped ceramics. The co-effects of MnO2 doping and Sb5+ substitution lead to significant improvement in dielectric and piezoelectric properties: ε at the Tc increased from 6000 (KNN) to 12400 (x = 0.04), d33 = 92 ÷ 192 pC/N, kp = 0.32 ÷ 0.46, kt = 0.34 ÷ 0.48.
Document Type: Research Article
Affiliations: Institute of Solid State Physics, University of Latvia, Riga, Latvia
Publication date: January 1, 2008