Effect of sintering temperature on the electrical properties of pristine BF-35BT piezoelectric ceramics

In this study, 0.65Bi_1.05FeO₃–0.35BaTiO₃ (BF-35BT) lead-free piezoelectric ceramics were prepared using a conventional solid-state method to determine the effects of sintering temperature on their microstructures and electrical properties. The average grain size increased with sintering temperature, but not significantly, and the relative density of the ceramics increased and then decreased at high sintering temperatures due to the volatilization of Bi₂O₃. At the optimal sintering temperature (1030 °C), BF-35BT ceramics showed minimum coercive field (E_c) with enhanced remanent polarization (P_r) and consequently resulted in a high converse piezoelectric coefficient (d^* ₃₃) value of 305 pm/V. The results indicate that the optimum sintering temperature, maximum relative density, and appropriate grain size, which are significantly related to the domain size and configuration, as well as the minimum concentration of associated charged defects, are critical factors that influence the piezoelectric performance of BF-35BT ceramics.