Abstract: Aiming at the urgent demand of the new generation of sonic logging tools for their core components, piezoelectric ceramics, which have high Curie temperature, high voltage electrical coefficient and high stability, 0.06BiYbO₃-0.94Pb(Zr_0.48Ti_0.52)O₃(BY-PZT) ternary piezoceramics with addition of different oxide additives were prepared by traditional solid-state reaction method. The effects of oxide additives on the phase structures and electrical properties of the BY-PZT ternary piezoceramics were investigated. XRD and SEM analysis show that all samples are pure tetragonal perovskite structure. When doped with Cr₂O₃, the average grain size of the samples has a maximum value. Dielectric temperature spectrum and resonance spectrum analysis illustrated that doping of four kinds of oxide improved the temperature stability of dielectric properties respectively. The lanthanum-doped sample got the lowest temperature coefficient of dielectric constant (Tk_ε). The mechanical quality factor (Q_m) has a maximum value when MnO₂ are doped; but the samples doped with CeO₂ have the best thermal depolarization resistance. The analysis of high temperature complex impedance (Cole-Cole) shows that Cr₂O₃ doping significantly improve the high temperature resistivity of the ceramic. It is found that the electrical conduction behavior of the ceramics at high temperature is dominated by the grain-boundary response. The lanthanum-doped sample has both high Curie temperature (T_C=397 ℃) and high piezoelectric constant (d₃₃=290 pC/N), and after annealed at 300 ℃ for 4 h,the d₃₃ value of the sample still retains above 270 pC/N,which provides great promising for application in the high-temperature piezoelectric devices with an extreme operating temperature of 300 ℃.

Key words: BY-PZT, piezoceramics, oxide doping, temperature stability, piezoelectric property, thermal depoling, dielectric property