(1-x)(K_0.475Na_0.475Li_0.05)(Nb _0.975Sb_0.025)O₃-xBiFeO₃ lead-free piezoelectric ceramics with CuO sintering aid

(1-x) (K_0.475Na_0.475Li_0.05)(Nb _0.975Sb_0.025)O₃-xmolBiFeO₃ (x=0, 0.002, 0.004, 0.006, 0.008) doped with 0.8mol%CuO lead-free piezoelectric ceramics were prepared by the solid state reaction technique. X-ray diffraction patterns suggested that all the ceramics presented perovskite structure. The compositional dependence of the phase structure and the electrical properties of the ceramics were studied. The ceramic (x=0.002) near room temperature exhibited excellent electrical properties (piezoelectric constant d ₃₃=172pC/N, planar electromechanical coupling factor k _p=0.43, and dielectric constant ε₃₃ ^T/ε₀=418). A relatively high mechanical quality factor (Q_m=200) was also obtained in this particular composition. All these results revealed that this system might become a promising candidate for lead-free piezoelectric materials.