Y2O3-modified Ba(Ti0.96Sn0.04)O3 ceramics with improved piezoelectricity and raised Curie temperature

Ba(Ti0.96Sn0.04)O3–xY2O3 (BTS–Y) lead-free piezoceramics are fabricated by the conventional solid state reaction technique. The influences of Y3+ substitution on the phase structure, dielectric properties and piezoelectricity of BTS–Y piezoceramics are investigated. XRD patterns show the ceramics possess a pure perovskite structure. The orthorhombic–tetragonal (O–T) phase transition dielectric peak shifts toward lower temperature with increasing Y3+ content. The compositions x = 0.15 − 0.25% that are at O–T polymorphic phase transition region possess excellent piezoelectricity and the maximum piezoelectric constant d33 of 454 pC/N is obtained at x = 0.2%. The ceramics’ Curie temperatures (TC) are monotonically increased from 71 °C for x = 0 − 86 °C for x = 0.4% due to Y3+ substitution and the usage temperature range of BTS–Y piezoceramics is broadened. Compared with Ca2+ which also decreases the O–T phase transition temperature (TO–T) but hardly affects the TC of BaTiO3-based ceramics, Y3+ substitution seems to be more beneficial for the practical application of the piezoceramics.