Co-firing of PZN-PZT flextensional actuators

Flextensional actuators composed of a piezoelectric PZN-PZT layer and a conducting PZN-PZT/Ag layer were fabricated. Because the newly developed PZN-PZT was sinterable at low temperature (<900degreesC), silver particles could be co-fired with the PZN-PZT. Therefore, an electrically conducting PZN-PZT/Ag layer was fabricated by mixing the silver particles with PZN-PZT powder. When 30-50 wt% Ag particles were mixed with the PZN-PZT, the resulting composites showed a high-electrical conductivity and low-densification mismatch with respect to the PZN-PZT layer. The PZN-PZT/Ag layer had approximately the same resistivity as pure silver, because of the presence of a conducting channel of dispersed silver particles in the PZN-PZT matrix. Two- and three-layered actuators were fabricated with a diameter of 20 mm and a thickness of 0.9 mm using these PZN-PZT and PZN-PZT/Ag composites. When an electric field was applied, the fabricated actuators bent into a convex dome shape, yielding a large axial displacement at the center.