Enhanced piezoelectricity in broad composition range and the temperature dependence research of (Ba1−xCax)(Ti0.95Sn0.05)O3 piezoceramics

BaTiO3-based (Ba1−xCax)(Ti0.95Sn0.05)O3 (x=0-0.07) lead-free piezoceramics were fabricated by a conventional solid state reaction technique. The phase structure and electrical properties of the as-prepared ceramics were researched. The temperature (TO−T) of the orthorhombic-tetragonal phase transition dielectric peak shifts toward lower temperature with increasing Ca content and the Curie temperature (TC) almost does not shift. At room temperature, the polymorphic phase transition (PPT) from the orthorhombic phase to tetragonal phase is jointly identified by the εr-T curves and XRD patterns. The piezoelectricity of the ceramics is enhanced due to the polymorphic phase transition and the best piezoelectricity is obtained at x=0.02 with d33=464 pC/N and kp=43.1%. The piezoelectricity is enhanced in the broad composition range x=0.01-0.06 with d33>400 pC/N and kp>41% which is beneficial for the industrial production. The temperature aging properties of piezoelectric constant d33, planar electromechanical coupling factor kp, the elastic compliance constant S11E and the radial frequency constant Nd are also researched.