MnO2 was added to 0.75Pb(Zr0.47Ti0.53)O3–0.25Pb(Zn1/3Nb2/3)O3 (0.75PZT–0.25PZN) ceramics in order to make a high‐power piezoelectric material. The Mn4+ ion produced a defect dipole consisting of an Mn4+ ion and an oxygen vacancy that transformed the 0.75PZT–0.25PZN ceramics into hard materials. The Qm value significantly increased with the addition of MnO2 and reached a value of 1680 for the 1.5 mol% MnO2‐added 0.75PZT–0.25PZN ceramic. Moreover, this specimen exhibited a high kp of 0.53 with a ɛ3T/ɛ0 of 1518. Additionally, the 1.5 mol% MnO2‐added 0.75PZT–0.25PZN ceramics sintered at 900°C for 4 h also exhibited high piezoelectric properties of Qm=1115, kp=0.50, and ɛ3T/ɛ0=1537.

0.65Pb(Zr 1Àx Ti x )O 3 -0.35Pb(Ni 0.33 Nb 0.67 )O 3 (0.65PZTx-0.35 PNN) ceramics exhibited a morphotropic phase boundary at approximately x 5 0.58-0.59. The 0.65PZT58-0.35PNN ceramics sintered at 12001C exhibited the high piezoelectric properties of d 33 5 605pC/N, k p 5 0.61, and e 3 T /e 0 5 3600. The sintering temperature of the PZT58-PNN ceramics decreased from 1200 to 8501C with the addition of a small amount of CuO. The CuO reacted with the PbO and formed a liquid phase during sintering, which assisted in the densification of the specimens. Most of the Cu 21 ions existed in the CuO second phase, thereby preventing any possible hardening effect due to the Cu 21 ions. The Curie temperature of the 0.65PZT58-0.35PNN ceramic was approximately 2001C and was not altered by the addition of CuO. The d 33 , k p , and e 3 T /e 0 values of the 0.65PZT58-0.35PNN ceramics were considerably increased with the addition of CuO and similar results were also observed for the 0.65PZT59-0.35PNN ceramics. In particular, 1.0 mol% CuO-added 0.65PZT58-0.35PNN ceramics sintered at 9001C exhibited the high piezoelectric properties of d 33 5 620 pC/N, k p 5 0.64, and e 3 T /e 0 5 3750. Moreover, the reaction between the Ag electrode and the Cu-added 0.65PZT58-0.35PNN ceramic sintered at 9001C was negligible.

No abstract

No abstract