Nb/Y co-doped 85BaTiO3-15Na0.5Bi0.5TiO3 with CaZrO3 modification for X9R dielectric ceramics

In this study, a compositional optimization strategy was formulated within the 85BaTiO 3 -15Na 0.5 Bi 0.5 TiO 3 (85BT-15NBT) system to attain X9R-type stability while maintaining a comparatively high dielectric response. Nb/Y co-doping was introduced to adjust the phase structure and dielectric behavior of the parent 85BT-15NBT. Rietveld refinement revealed a structural evolution from a tetragonal P 4 mm symmetry to pseudocubic Pm 3 ˉ m symmetry. X9R requirement, with a room-temperature permittivity of 1496 and a dielectric loss of 1.82%, was achieved. CaZrO 3 modification increased the relative permittivity to 1679 along with a dielectric loss of 1.50% without compromising the temperature stability. High-temperature impedance and Arrhenius analyses revealed improved high-temperature insulation and CZ-induced changes in the local defect and chemical environment. These findings illustrate that compositional optimization is effective for designing lead-free X9R dielectric ceramics for high-temperature MLCC applications.