Evolution of structure and properties of BiFeO₃-(Ba_0.85Ca_0.15)(Ti_0.9H f_0.1)O₃ high Curie temperature lead-free piezoelectric ceramics

BiFeO3-based ceramics is the high-temperature piezoelectric material with great potential applications. In this paper, the evolution of structure and properties of BiFeO3-(Ba0.85Ca0.15)(Ti0.9Hf0.1)O-3 (BFO-BCTH) ceramics was investigated. XRD analysis showed that rhombohedral R3c phase and pseudocubic (PC) phase coexisted in all samples, and the content of PC phase increased with the increase of BCTH content. Two dielectric anomalies were observed for all BFO-BCTH samples. Among them, the dielectric relaxation at 300-500 & DEG;C exhibited a significant frequency dispersion. Besides, a frequency-independent dielectric anomaly was detected for all samples, accompanied with thermal hysteresis, indicating the primary ferroelectric phase transition, and the peak temperature slightly decreased with increasing BCTH content. The leakage current density significantly decreased with increasing doping BCTH content, and the ferroelectric and piezoelectric properties were enhanced for x = 0.25-0.27 samples. The magnetic properties of the moderately doped ceramics were significantly improved, but the magnetic dilution due to the increase in doping content led to a decrease in magnetization intensity instead.