PIEZOELECTRIC PROPERTIES OF NB2O5 DOPED AND MNO2-NB2O5 CO-DOPED PB(ZR0.53TI0.47)O-3 CERAMICS

The effects of Nb2O5 addition and MnO2-Nb2O5 co-addition on the piezoe lectric properties of Pb(Zr0.53Ti0.47)O-3 (PZT) ceramics are investiga ted. When Nb2O5 is added to PZT, the planar coupling factor (K-P) sign ificantly increases but the mechanical quality factor (Q(M)) as well a s the electrical quality factor (Q(E)) decreases. When MnO2 and Nb2O5 are co-doped, Q(M) increases remarkably while K-P rarely changes. This increase in Q(M) is ascribed to the domain pinning by Mn as is the ca se of previously reported MnO2-doped PZT, and the negligible change in K-P is ascribed to the barely changed tetragonality. Even though MnO2 -Nb2O5 co-doped PZT shows a smaller induced strain than that of Nb2O5- doped PZT, excellent temperature stability is obtained. It is shown th at MnO2-Nb2O5 co-doped PZT may be a very suitable material for high-po wer piezoelectric actuators because of its high K-P, Q(M) and Q(E), it s low dielectric constant and its excellent temperature stability.