Investigation of lead-free BiFeO_3-BaTiO3 piezoelectric ceramics through precise composition control

BiFeO3-BaTiO3 is a promising lead-free piezoelectric ceramic, exhibiting high Curie temperature and superior electrochemical characteristics. In this work, (1-x)BiFeO3-xBaTiO3 (BF-xBT, x=0.26, 0.28, 0.30, 0.32, 0.34, 0.36) ceramics were fabricated using the conventional solid-state reaction method through precise composition control. Multiple characterization techniques, including X-ray powder diffraction (XRD), scanning electron microscope (SEM), and electrical property testing systems, were applied to systematically examine the crystallographic structure, microstructure, as well as the dielectric, ferroelectric and piezoelectric properties of the BF-xBT ceramics. The XRD results confirm that all compositions exhibit a typical perovskite structure, transitioning from a single rhombohedral phase to a rhombohedral-cubic phase mixture as the BT content increases. SEM shows apparent core-shell microstructures in the ceramics. Notably, the results demonstrated that the BF-0.30BT ceramic exhibits the maximum piezoelectric constant (d33) 217pC/N, while the BF-0.34BT ceramic displays the maximum converse piezoelectric constant (d33)323pm/V, which highlights the suitability of BF-BT ceramics for high-performance piezoelectric applications.