Piezoelectric grain-size effects of BaTiO₃ ceramics under different sintering atmospheres

Two groups of barium titanate (BaTiO₃) ceramics with high piezoelectric coefficient (d ₃₃) have been successfully fabricated by the conventional solid-state reaction technique under different sintering atmospheres. The influences of sintering atmosphere on piezoelectric grain-size effects were systematically investigated. It was found that d ₃₃ first increases then decreases with the increase of grain size (g) for both two groups of ceramics. However, the d ₃₃ value reaches the maxima (501pC/N) at g = 1.13 µm for the samples sintered under the air sintering atmosphere (BaTiO₃–Air). The samples sintered under the oxygen atmosphere (BaTiO₃–O₂) exhibit a large d ₃₃ (>450pC/N) plateau at g from 0.98 to 7.30 µm. The experimental results indicated that the piezoelectric grain-size effects of BaTiO₃ ceramics were strongly affected by the sintering atmosphere. Related mechanisms may be attributed to the variations of the domain configuration under different sintering atmospheres.