Low-temperature co-fired PZNN-PZT multilayer piezoelectric ceramics with excellent electrical and bending properties

A 0.65Pb(Zr0.47Ti0.53)O3–0.35[Pb(Zn0.1Ni0.9)1/3Nb2/3]O3 (PZNN-PZT) piezoceramic with sintering aids of Li2CO3, Bi2O3, CuO and Sm2O3 was prepared via a traditional solid reaction to achieve a high-performance multilayer actuator. The microstructure and electrical properties of ceramic bulks were systematically explored. The piezoceramics sintered at various temperatures show multi-phase co-existence. The sintering aids are much beneficial for grain growth and microstructure densification. The piezoceramic sintered at 960 oC possesses relatively desirable electrical properties, including d33 ∼ 550 pC/N, kp ∼ 0.7 εr ∼ 2200, tan δ ∼ 0.021, Qm ∼71, Tc ∼240.5 °C, Pr ∼24.44 μC/cm2 and Ec ∼823.7 V/cm. Furthermore, we employed the tape casting and low-temperature co-fire methods to fabricate a PZT-PZNN/Ag-Pd multilayer piezoceramic of 7 × 7 × 36 mm3 in dimension with a single ceramic film of about 80 μm in thickness. The Ag-Pd electrode is effectively bonded with the ceramic layer, especially chemical binding induced by oxygen diffusion at some partial areas, which plays a crucial role in high binding strength (∼9.2 MPa). The multilayer piezoceramic exhibits outstanding actuating characteristics of high Smax ∼ 55.53 μm @ 150V, and low H ∼ 19.8% @ 150V together with outstanding stiffness of 70.87 N/μm @ 150V.