Study On The Materials And Applications In Filters Of Sodium Potassium Niobate-based Lead-free Piezoelectric Ceramics

In this paper, (Na0.5K0.5)NbO3 based (abbreviated as KNN) ceramics were prepared by conventional solid-state reaction method. The phase composition, microstructure, piezoelectric, dielectric and ferroelectric properties were investigated. With the (1?x)Li0.04Na0.52K0.44Nb0.86Ta0.10Sb0.04O3-xBiFeO3(LF4-BF) lead-free material, the single and multi-section ladder middle frequency passband filters were developed.Firstly, 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, 0.00175, 0.005, 0.01, 0.02, 0.03, in mole) were investigated. The results show that all the (1?x)KNN-xBF ceramics prepared when x≤0.03 possess the pure perovskite structure. Compared with the pure KNN, the densityρ, piezoelectric constant d33, planar electromechanical coupling coefficient kp and mechanical quality factor Qm of the (1?x)KNN-xBF ceramics increase evidently at 010KHz, the loss insertion≤7dB and the out-band attenuation >37dB) were obtained.