High piezoelectricity of BaTiO3-CaTiO3-BaSnO3 lead-free ceramics

A series of solid solutions of BaTiO3-x(0.4CaTiO(3)-0.6BaSnO(3)) (abbreviated as BT-x(CT-BS), x = 0.00-0.20 mol) were prepared to search for high performance lead-free piezoelectric ceramics. Through content tailoring, a complex phase transition was confirmed by X-ray diffraction and Raman spectra as well as temperature dependence of the dielectric constant, which occurs from tetragonal(T)orthorhombic( O) coexistence at 0 <= x <= 0.12 to rhombohedral(R)-O-T and R-O/T-cubic(C) multiphase coexistence at x 0.16 and 0.20, respectively. The lower E-C 1.31 kV cm(-1) and higher Pr 9.48 mm cm(-2) as well as high piezoelectric response d33 570 pC N-1 were achieved in BT-x(CT-BS) ceramics at an optimal composition of x = 0.16. The ultrahigh converse piezoelectric coefficient d*(33) = 1444 pm V-1 and strain 0.070% which are the highest values reported so far in lead-free ceramics also were achieved at x 0.16, suggesting that a BT-x(CT-BS) system is a promising lead-free alternative material for electromechanical actuator applications.