Effect of LiBiO₂ on low-temperature sintering of PZT-PZNN ceramics

In this study, the sintering characteristics of 0.69Pb(Zr_0.47Ti_0.53)O₃-0.31Pb[(Zn_0.4Ni_0.6)_1/3Nb_2/3] (PZT-PZNN) ceramics after the addition of LiBiO₂ were studied. This addition lowered the sintering temperature from 1150 to 900 °C. The crystal structure changed from tetragonal to rhombohedral as the additive content increased by 0.7%. The polarization of the sintered specimen was conducted at an electric field of 3 kV/mm. When 0.7 wt% of LiBiO₂ was added and sintered at 900 °C, the piezoelectric constant (d₃₃) was 602 pC/N; moreover, the electromechanical coupling coefficient (k_P), sintered density, and Curie temperature (T_c) at 1 kHz were 66.3%, 7.99 g/cm³, and 252.8 °C, respectively. When 0.7 wt% of LiBiO₂ was added, the PZT-PZNN ceramic showed an increased strain curve of 0.118% at 2 kV/mm. The interdiffusion between the copper (Cu) electrode and ceramic material was not observed in the scanning electron microscopy (SEM) results; thus, the possibility of manufacturing an actuator using a Cu electrode using a novel composition was confirmed. The actuator displacement with the voltage 400 V was 1.2 μm. The thickness of the multi-layered actuator was 1 mm. Through this, the possibility of manufacturing a multi-layered actuator with a Cu electrode was confirmed through the composition of 0.69PZT-0.31PZNN (LiBiO₂ 0.7 wt%).