Effect of Solution Concentration on Low-Temperature Synthesis of BCZT Powders by Sol–gel-Hydrothermal Method

Lead-free Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) powders were successfully synthesized by sol–gel-hydrothermal method. The effect of NaOH concentration on microstructure and phase composition of BCZT powders was studied. The results of XRD, SEM, TEM, FTIR, and EDS showed that the synthesis temperature of BCZT powders could be decreased to a low temperature of 180 °C, which was about 1150 °C lower when compared with solid-state reaction and 800 °C lower when compared with sol–gel methods respectively. The NaOH concentration exerted a great effect on the structure of BCZT powders, as well as the average particle size. When the NaOH concentration was 8 M, BCZT powders had a cubic phase perovskite structure with a homogeneous composition, and the average particle size was about 60 nm. The BCZT ceramics followed by sintering had dense structure and excellent electrical properties (2Pr = 24.62 μC/cm2, 2Ec = 3.24 kV/cm, d33 = 488 pC/N). The significant properties could be attributed to the high activity of powders synthesized by sol–gel-hydrothermal method. The present study may provide a new method for low-temperature synthesis of lead-free piezoelectric powders with fine phase, microscopic morphology, and high activity.