Effect of sintering temperature on the dielectric, impedance and piezoelectric properties of Ba0.85Ca0.15Ti0.90Sn0.09Zr0.01O3 ceramics

Ba0.85Ca0.15Ti0.90Sn0.09Zr0.01O3 ceramics were prepared by the conventional solid-state route. The effect of different sintering temperatures (1250 °C, 1350 °C, and 1450 °C) on the structural, dielectric, piezoelectric, and microstructure of the samples was investigated. The ceramics exhibited a tetragonal structure with a space group of P4mm and demonstrated a stable crystal structure despite the different sintering temperatures. The ceramic samples obtained similar Curie temperature, Tc approximately ~ 60 °C. Among all, the sample sintered at 1450 °C showed an improved pellet’s relative density with the highest dielectric constant, εr value at Tc of 6615. The sintering effect gives ~ 53% increment on dielectric constant at Tc due to the enhancement of the pellet density from 80.35% (sintered at 1250 °C) up to 91.21% (sintered at 1450 °C). Meanwhile, the sample sintered at 1250 °C obtained the highest piezoelectric constant, d33 value, due to the small grain size of 5.186 µm, which might lead to more 90° domain wall motion. The equivalent circuit analysis shows that the electrical microstructures of the samples were influenced by their ceramic microstructures. The sample sintered at 1450 °C exhibits an excellent fit using two sets of the parallel resistor, R and capacitor, C; R1–C1 (grain) and R2–C2 (grain boundary) elements. However, samples sintered at 1350 °C and 1250 °C required a constant phase element (CPE) to fit the R2–C2 element.