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 degrees C, 1350 degrees C, and 1450 degrees 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, T-c, approximately similar to 60 degrees C. Among all, the sample sintered at 1450 degrees C showed an improved pellet's relative density with the highest dielectric constant, epsilon(r) value at T-c, of 6615. The sintering effect gives similar to 53% increment on dielectric constant at T-c due to the enhancement of the pellet density from 80.35% (sintered at 1250 degrees C) up to 91.21% (sintered at 1450 degrees C). Meanwhile, the sample sintered at 1250 degrees C obtained the highest piezoelectric constant, d 33 value, due to the small grain size of 5.186 mu m, which might lead to more 90 degrees 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 degrees C exhibits an excellent fit using two sets of the parallel resistor, R and capacitor, C; R-1-C-1 (grain) and R-2-C-2 (grain boundary) elements. However, samples sintered at 1350 degrees C and 1250 degrees C required a constant phase element (CPE) to fit the R-2-C-2 element.