| The 0.3Pb(Zn1/3Nb2/3)O3-0.7Pb(Zr0.52Ti0.48)O3 (0.3PZN-0.7PZT-0.2Ce) ternary piezoelectric ceramics doped with 0.2 wt.% CeO2 were prepared by the traditional solid-state reaction process. The effects of sintering temperature (1190~1260 ℃) on their phase structures, microstructural morphologies and electrical properties were studied. XRD and SEM analysis showed that all sintered samples showed pure perovskite phase structure. With the increase of sintering temperature, the phase structure of ceramic samples gradually changes from tripartite phase to tetragonal phase. Sintered at 1230 ℃, both tripartite phase and tetragonal phase coexisted in the prepared samples. When the sintering temperature exceeded 1230 ℃, grains begin to grow significantly until the liquid phase appeared. The study of dielectric temperature spectrum shows that with the increase of sintering temperature, the Curie temperature (TC) of 0.3PZN-0.7PZT-0.2Ce ceramics gradually increases while the dielectric loss factor (tan δ) gradually decreases.The sample sintered at 1230 ℃ achieved the largest dielectric constant (εr) and the lowest temperature coefficient (TKε). The measurements of piezoelectric properties and resonance-antiresonance show that the increase of sintering temperature is conducive to the improvement of the piezoelectric properties (d33) and electromechanical coupling properties (kp), but a too high sintering temperature (1260 ℃) also deteriorates the electrical properties. In general, the sample sintered at 1250 ℃ achieved the best electrical properties including: TC = 293 ℃, d33 = 515 pC/N, kp = 67%, εr = 2493, TKε (120 ℃) = 6.22×10-3/ ℃, tan δ = 0.017. |
