Enhanced dielectric and electrical properties in CaZrO3-doped X8R BaTiO3-based ceramics sintered at medium temperature

Lead-free X8R BaTiO₃-based ceramics were prepared by conventional solid-state method. The influence of the composition and procedures on the microstructures, lattice parameters and dielectric properties of ceramics materials were systemically studied. XRD results indicate that no secondary phase is formed in the CaZrO₃-doped samples after sintering. The content of Ca²⁺ ions and Zr⁴⁺ ions decrease from grain boundaries to grain interiors referring to EDS results, which indicate that the ions mainly locate in the grain boundaries. The Curie temperatures of all CaZrO₃ doped samples increase due to the increasing tetragonality caused by the addition of CaZrO₃. SEM micrographs reveal that the grain size of CaZrO₃-doped BaTiO₃-based samples are not uniform, ranging from 0.2 to 0.8 µm. Furthermore, samples doped with 1.0 wt % CaZrO₃ exhibit optimal dielectric properties with high temperature stability of capacitance, due to the fine-grain microstructures. Moreover, we obtained a lead-free high performance X8R dielectric ceramic composition sintered at medium temperature (1,135 °C).