Phase transitions and dielectric, ferroelectric and piezoelectric properties of Bi0.5(Na0.82K0.18)0.5TiO3-doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 cera

This paper reports an investigation of (Ba_0.85Ca_0.15)(Zr_0.1Ti_0.9)O₃ (50BCZT) piezoelectric ceramics doped with Bi_0.5(Na_0.82K_0.18)_0.5TiO₃ (18BNKT). For compositions between 1-5 wt% 18BNKT, a perovskite phase was observed in the sintered ceramics, with d₃₃ values of approximately 370 pC/N measured at room temperature, which is about 80 % of that of pure 50BCZT. Also, the doped materials exhibit a remanent polarization of 2-5 μC/cm² at temperatures above the Curie temperature (> 90 °C) of the pure 50BCZT composition. This research shows a promising route to improve the working temperature range whilst maintain good piezoelectric properties of the 50BCZT ceramics.