Effect of CuO and MnO2 doping on electrical properties of 0.92(K0.48Na0.54)NbO3–0.08LiNbO3 under low-temperature sintering

Lead-free piezoelectric ceramics 0.92(K0.48Na0.54)NbO3–0.08LiNbO3 have been prepared by low-temperature sintering using excess Na2O additives. The ceramics show a single perovskite phase with tetragonal structure with x ≤ 0.03. It is found that the sintering aids co-doped with CuO and MnO2 are very effective in promoting electrical properties of the ceramics. Our results reveal that the ceramics with 3 mol%CuO and 0.5 mol%MnO2 possess excellent piezoelectric, dielectric and ferroelectric properties at room temperature (d33 = 173 pC/N, kp = 28%, Qm = 207, ɛr = 882, tan δ = 0.011, Tc = 490 °C, Pr = 24.9 μC/cm2, EC = 1.63 kV/mm). These results indicate that the ceramic is a promising candidate material for lead-free piezoelectric ceramics.