Lead-free piezoelectric ceramics K0.5Na0.5NbO3 modified by doping-BiFeO3

Lead-free piezoelectric ceramics (1-x)(K0.5Na0.5) NbO3-xBiFeO3 [(1-x)KNN-xBF] were prepared by the traditional solid state reaction. The phase composition, microstructure and electrical properties for (1-x)KNN-xBF samples with different BF content (x = 0, 0.175%, 0.5%, 1%, 2%, 3%, in mole) were investigated. The results show that all the (1-x)KNN-xBF ceramics prepared when x≤3% possess the pure perovskite structure. Compared with the pure KNN, the density ρ, piezoelectric constant d33, planar electromechanical coupling coefficient kp and mechanical quality factor Qm of the (1-x)KNN-xBF ceramics increase evidently at 03, d33 = 172 pC/N, kp = 0.45, dielectric loss tan δ = 0.021, relative permittivity Εr = 759 and Qm = 138) can be obtained with the composition of x = 1%, which also exhibits good aging characteristics.