Effects of LiBiO2addition on the microstructure and piezoelectric properties of CuO-doped PNN-PZT ceramics

CuO-doped 0.35Pb(Ni1/3Nb2/3)O3–0.65Pb(Zr0.41Ti0.59)O3 (PNN–PZT) piezoelectric ceramics with the addition of LiBiO2 were fabricated by the conventional solid-state reaction, and the dependence of microstructure, dielectric properties, and piezoelectric properties on the amount of LiBiO2 addition and the sintering temperature was systematically investigated. The CuO and LiBiO2 additions significantly reduced the sintering temperature of PNN–PZT from 1230 to 1000 °C, while the average grain size slowly grew, but still within the range of 2–3 µm, and the ceramics maintained high piezoelectric properties. When the sample with 0.1 wt.% CuO and 1.0 wt.% LiBiO2 additive was sintered at 1000 °C, the high piezoelectric constant d33 of 538 pC/N, the electromechanical coupling factor Kp of 0.62, the relative dielectric constant /ϵ0 of 3381, the quality factor Qm of 61 and the low loss tan δ of 0.016 were obtained.