Li2O excess (Na0.51K0.47Li0.02)(Nb0.8Ta0.2)O3 lead free piezoelectric ceramics

1 mol% Li2O excess (Na0.51K0.47Li0.02)(Nb0.8Ta0.2)O3 ceramics were prepared by the conventional mixed oxide method and sintered from 950 to 1200 °C. Also, Li2O was employed as a sintering aid for high densification and low temperature sintering process. X-ray diffraction results of 1 mol% Li2O excess (Na0.51K0.47Li0.02)(Nb0.8Ta0.2)O3 lead free piezoelectric ceramics indicated that the specimens were well crystallized and have tetragonal structure. The specimens which sintered at 1050 °C showed the highest piezoelectric properties compared with others. The measured piezoelectric constant and electromechanical coupling coefficient were 231 pC/N and 38.9%, respectively. Curie temperature of (Na0.51K0.47Li0.02)(Nb0.8Ta0.2)O3 ceramics was 344.32, 344.4 and 344.5 °C at 1, 10 and 100 kHz, respectively.