Piezoelectric and dielectric properties of 0.05Pb(Al.0.5Nb0.5)O-3-0.95Pb(Zr0.52Ti0.48)O-3 ceramics doped with Nb2O5 and MnO2

Abstract

The solid solution system of 0.05Pb(Al.0.5Nb0.5)O-3-0.95Pb(Zr0.52Ti0.48)O-3 (PAN-PZT) has been studied for the piezoelectric ultrasonic motor with its high T-c. In this article, we doped the Nb2O5 and MnO2 into the 0.05PAN-0.95PZT ceramics as donor and acceptor respectively and reported the doping effect oil the piezoelectric properties. Apparently, Nb2O5 induced the "soft" piezoelectric characteristics. However, as Nb2O5 also affected the sintered density, which is closely related with the piezoelectric properties, it is quite difficult to identify the role of Nb2O5, which might act as the "donor" and/or sintering enhancer. The optimized piezoelectric properties were obtained d(33) = 430 pC/N, k(p) = 59%, Q(m) = 79, and epsilon(T)(3)/epsilon(0) when PAN-PZT + 0.7 wt % Nb2O5 sintered at 1200 degrees C for 1 h. When MnO2 was doped, Mn4+ ions induced the distortion of perovskite Structure and Tc shifted to lower temperature. In addition, d(33) and k(p) decreased and Q(m) dramatically increased with the addition of MnO2. From these results, it was believed that MnO2 mainly acted as acceptor in PAN-PZT ceramics. The optimized piezoelectric properties were obtained d(33) = 340 pC/N, k(p) = 61.6%, Q(m) = 1725, T-c = 392 degrees C, and epsilon(T)(3)/epsilon(0) = 1250, when PAN-PZT + 0.7 wt % Nb2O5 with 0.5 wt % MnO2 ceramics sintered at 1200 degrees C for 1 h.