Piezoelectric Properties and Temperature Dependences of Resonant Frequency of WO3-MnO2-Modified Ceramics of Pb(Zr-Ti)O3

Abstract

Pb(Zr-Ti)O₃ ceramics modified with WO₃ show low mechanical quality factor and low coercive field, but ones modified with combination of WO₃ and MnO₂ show high mechanical quality factor, high coercive field and stable aging characteristics. Temperature dependence of the resonant frequency is investigated in the wide range of Zr/Ti ratio in the WO₃-MnO₂-modified ceramics of Pb(Zr-Ti)O₃. There are four compositions which are stable in the resonant frequency. In two compositions in the rhombohedral phase, variation in frequency can not be minimized to zero because of an anomaly in the frequency-temperature curve owing to “F E ₁-F E ₂ transition”. One of the rests near the morphotropic phase boundary is slightly shifted to Zr-rich side by heat treatment after the removal of the poling electric field. The last one in the heat treatment after the removal of the poling electric field. The last one in the tetragonal phase has most stable temperature characteristics of the resonant frequency.