Dielectric and piezoelectric properties of MnO2-doped K0.5Na0.5Nb0.92Sb0.08O3 lead-free ceramics

摘要

Lead-free MnO2-doped K0.5Na0.5Nb0.92Sb0.08O3 ceramics have been fabricated by a conventional ceramic technique and their dielectric and piezoelectric properties have been studied. Our results show that a small amount of MnO2 (0.5-1.0 mol%) is enough to improve the densification of the ceramics and decrease the sintering temperature of the ceramics. The co-effects of MnO2 doping and Sb-substitution lead to significant improvements in the ferroelectric and piezoelectric properties. The K0.5Na0.5Nb0.92Sb0.08O3 ceramic with 0.5 mol%MnO2 doping possesses optimum propeties: d (33) = 187 pC/N, k (P) = 47.2%, epsilon (r) = 980, tan delta = 2.71% and T (c) = 287 A degrees C. Due to high tetragonal-orthorhombic phase transition temperature (T (O-T) similar to 150 A degrees C), the K0.5Na0.5Nb0.92Sb0.08O3 ceramic with 0.5 mol%MnO2 doping exhibits a good thermal stability of piezoelectric properties.