Piezoelectric Ceramics for Use in Multilayer Actuators and Energy Harvesters

Microstructural and piezoelectric properties of 0.72Pb(Zr1-xTix)-0.28Pb(Zn0.4Ni0.6)(1/3)Nb2/3O3 (PZ(1-x)T(x)-PZNN) ceramics with 0.50 x0.55 were investigated for evaluating the possibility of their use in multilayer actuators and energy harvesters, which demand a large piezoelectric strain constant (d(33)) and a small dielectric constant (epsilon(T)(33)/epsilon(o)). The PZ(0.47)T(0.53)-PZNN ceramic with a morphotropic phase boundary (MPB) composition showed large d(33) and epsilon(T)(33)/epsilon(o) values, making it unsuitable for use in multilayer actuators and energy harvesters. However, the PZ(0.48)T(0.52)-PZNN ceramic with a rhombohedral structure showed a small epsilon(T)(33)/epsilon(o) value of 1605, yet maintained a large d(33) of 550 pC/N. Thermal stimulation did not have any significant effect on the piezoelectric properties of this specimen, except for a slight increase in the epsilon(T)(33)/epsilon(o) value upon heating the specimen at 150 degrees C for 4h. In an effort to reduce the sintering temperature, CuO was used as an additive for the ceramic. As a result, the CuO-added PZ(0.48)T(0.52)-PZNN ceramic was well sintered at 900 degrees C. In particular, the 1.0mol% CuO-added PZ(0.48)T(0.52)-PZNN ceramic exhibited a large d(33) value of 554 pC/N and a small epsilon(T)(33)/epsilon(o) value of 1620, making it highly suitable for use in multilayer actuators and energy harvesters.