Dielectric, ferroelectric and piezoelectric properties of Bi0.5Na0.5TiO3–(Ba0.7Ca0.3)TiO3 ceramics at morphotropic phase boundary composition

(1−x)Bi0.5Na0.5TiO3–x(Ba0.7Ca0.3)TiO3 (BNT–xBCT, 0≤x≤0.15) solid solutions have been synthesized by a conventional solid state sintering method for obtaining a morphotropic phase boundary (MPB) with good piezoelectric properties. X-ray diffraction patterns reveal that a MPB of rhombohedral and tetragonal phases is formed at compositions 0.09≤x≤0.12. Addition of BCT into BNT greatly lowered coercive field Ec without degrading remanent polarization Pr. The specimen with x=0.09 has the good piezoelectric properties: d33=125pC/N and kp=0.33. A modified Curie–Weiss law was used to fit the dielectric constant of BNT–xBCT ceramics, and a frequency dispersion was observed during the phase transitions from antiferroelectric to paraelectric in specimens with x exceeding 0.06.