Dielectric properties of BaTiO3 and Ba0.95Ca0.05TiO3 sintered in a reducing atmosphere

The dielectric materials utilized in high-performance barium titanate-based base-metal electrode multilayer ceramic capacitors (BME MLCCs) must satisfy stringent criteria such as high dielectric constant, low dielectric loss, high insulation resistivity, and reliability. In this investigation, the effects of raw materials, BaTiO3 (BT), and Ba0.95Ca0.05TiO3 (BCT) on densification, microstructure, and dielectric behavior were explored by introducing acceptor and rare earth elements. The findings revealed that BCT could attain densification at a lower sintering temperature of 1275 °C than BT. Moreover, BCT samples displayed relatively smaller grain sizes, resulting in a greater number of grain boundaries, which in turn increased the insulation resistivity. BCT had a lower oxygen vacancy concentration, thus resulting in lower leakage currents at high temperatures than BT. Substituting BCT for BT resulted in higher activation energies for conductivity in the core, shell, and grain boundary. This investigation demonstrates that BCT can enhance the dielectric properties, insulation resistance, and reliability of the BME MLCCs.