The effects of Sm2O3 doping on properties of PNN-PZT ceramics near morphotropic phase boundary

The present study is an investigation of the effects of Sm2O3 doping on properties near morphotropic phase boundary (MPB) of nickel niobiumternary system lead zirconate titanate (PNN-PZT) ceramics. Pb(Ni1/3Nb2/3)(0.5) (Zr0.3Ti0.7)(0.5)O-3 (0.5PNN-0.5PZT + xSm) piezoelectric ceramics were prepared by a traditional two-step solid-state reaction method. The specimens exhibit the homogeneous perovskite structure without the secondary phase. When x = 0.6 wt% and x = 0.8 wt%, their diffraction peaks are the most obvious, they may have the best P-T MPB composition. The samples exhibit the P-T MPB composition have a good properties, which is in accord with the electric properties variation and the crystalline grain variation well. When x = 0.6 wt%, the ceramics exhibited electric properties: d(33) = 688 pC/N, kp = 0.579, epsilon(r) = 6260, tan delta = 0.0207. It shows that the P-T MPB composition have relationships with the electric properties variation and the crystalline grain variation to some extent.