Effect of BCZT on the Properties of KNLNTS Lead-free Piezo-Ceramics

(1-x)(K(0.49)Na0.51)(0.98)Li-0.02(Nb0.77Ta0.18Sb0.05)O3-x(Ba0.85Ca0.15)(Ti(0.9)Z(r0.1))O-3 [(1-x) KNLNTS-xBCZT, x = 0 similar to 0.02] lead-free piezoelectric ceramics were prepared by the solid state reaction method. The effect of BCZT doping amount on the electrical properties were investigated. Results indicate that dielectric constants of the ceramics are decreased effectively, grain sizes are reduced and the density increases with the increasing of BCZT doping amount. The crystal structure of the ceramics changes from orthorhombic phase to tetragonal phase, and the coexistence of orthorhombic-tetragonal phases are observed when x = 0.008 similar to 0.01. The optimized piezoelectric properties can be obtained for the ceramics with x=0.01 as follows: the piezoelectric constant d(33) = 345 pC/N, planar electromechanical coupling coefficient k(p) = 44.7%, mechanical quality factor Q(m)= 63, dielectric loss tan delta = 0.026 and very high dielectric constant epsilon(T)(33) /epsilon(0)=2248.