| The Pb1-xLax(ZryTi1-y)1-x/4O3 (x = 0.07, 0.565≤y≤0.58)(PLZT)piezoelectric ceramics doped by Nb2O5 and the PZT piezoelectric ceramics samples doped by Sb2O3 were prepared by conventional solid solution method. The X-ray diffraction (XRD) and the scanning electronic microscope (SEM) were applied to analyze phases and microstructure, respectively. The effects of the composition and the sintering temperature on the dielectric and piezoelectric properties and temperature stability of the system were also discussed. Also, the polarization temperature of the ceramics, the sintering temperature of the pole and the intensity of the electric field were confirmed by research. The study on the properties of the PLZT system doped by Nb on Zr/Ti ratio indicated that the MPB of the tetragonal and rhombohedral phase lay in a broad composition region. The optimum properties were obtained with Zr/Ti=57.5/42.5 at calcination temperature of 1060℃and sintering temperature of 1240℃. The main parameters:ε33T /ε0=3100, tanδ=1.96%, d33=550pC/N, Kp =66%, TC=210℃. The dielectric and pielectric property increased with the Nb5+ raplacing the (ZrTi)4+, the Curie temperature declined so much. This piezoceramics have a good temperature and coefficient stability, the temperature and electromechanical coupling coefficient of resonant frequency shifted least and obtained a minimum value (TKfr=2.1×10-4/℃, TKKp=4.6×10-4/℃). The results of this study play an importrent part in the manufacture.In addition, the dielectric and piezoelectric properties of the PZT system doped by Sb2O3 close to the morphotropic phase boundary (MPB) were investigated systematically as a function of the mass of Sb2O3 doping and the Zr/Ti ratio. When calcination temperature is 900℃and sintering temperature is 1250℃, the optimum properties ofε33T /ε0(2100), tanδ(1.96%), d33 (450pC/N), Kp(66.8%), Tc(300℃) were obtained with Sb2O3=1.9wt%,Zr/Ti=53/47. The TC of the ceramic went up, which increased the working temperature area of the piezoceramics.
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