Effects of Cr2O3 doping on the electrical properties and the temperature stabilities of PZT binary piezoelectric ceramics

The ceramics with Pb_1.04Zr_0.52Ti_0.48O₃ + z wt.% Cr₂O₃ were prepared using the traditional technique. The effects of Cr₂O₃ doping on the phase structure, the microstructure, and the electrical properties of ceramics were investigated. Meanwhile, the temperature stabilities of the resonant frequency (f_r) were studied. The results showed that the Δf_r/f_r,25°C decreased with the addition of 0.2 wt.% −0.8 wt.% Cr₂O₃ as compared with the undoped samples. The minimum value (−0(−0.182%) of Δf_r/f_r,25°C was obtained for z = 0.6 wt.% Cr₂O₃ samples that sintered at 1260°C. The values of ?^T₃₃/?₀ = 1650, tanΔ = 0.006, d₃₃ = 328 pC/N, K_p = 0.63, Q_m = 2300 were obtained when Cr₂O₃ was 0.6 wt.%, which exhibited more excellent piezoelectric properties than other compositions such as those with z = 0.2 wt.%, 0.4 wt.%, and 0.8 wt.%, but had a similar value as compared with the undoped samples. When the Cr₂O₃ additive increased, the Curie temperature moved toward low temperature and the changes of resonant frequency changed from positive to negative with increasing temperature.