Synergistic enhancement of dielectric, piezoelectric, and ferroelectric properties in (Ba0.95Ca0.05)(Ti0.92Sn0.08)O3 ceramics via sintering temperature optimization and surface treatment

Piezoelectric ceramics have been widely employed in critical functional components, such as sensors, actuators, and transducers. With growing environmental concerns over lead pollution associated with conventional lead-based piezoelectric materials, considerable research efforts have been directed toward developing high-performance lead-free alternatives. Addressing the challenge of enhancing piezoelectric response in these eco-friendly materials has emerged as a crucial research focus. In this work, we synthesize (Ba_0.95Ca_0.05)(Ti_0.92Sn_0.08)O₃ (BCST) ceramics through a conventional solid-state reaction method. Systematic investigation of grain morphology, phase composition, dielectric, piezoelectric, and ferroelectric characteristics revealed 1440 °C as the optimal sintering temperature. The 1440 °C-sintered ceramics demonstrate superior dielectric and ferroelectric properties with a relative permittivity of ε_r = 20,472 and remanent polarization P_r = 10.73 µC/cm². Electrostrictive analysis and direct piezoelectric measurements confirm that this optimized sample achieves a maximum piezoelectric coefficient of d₃₃ = 469 pC/N. Subsequent post-annealing treatments in N₂ atmosphere significantly modified the functional properties of materials. The 700 °C-annealed ceramic exhibits a remarkable property enhancement, achieving ε_r = 27,589, d₃₃ = 519 pC/N, and P_r = 13.39 µC/cm² − representing 35 %, 11 %, and 25 % improvements respectively over non-annealed counterparts. This work establishes a dual optimization strategy combining sintering control and defect engineering to significantly boost the dielectric, piezoelectric, and ferroelectric properties of lead-free ceramics, thereby advancing their potential for practical electromechanical applications.