Enhanced Reliability and Microstructure Control in Dy/Y Co‐Doped BaTiO ₃ Ceramics

ABSTRACT A series of fine‐grained Dy/Y co‐doped BaTiO 3 ‐based ceramics were prepared by sintering in a reducing atmosphere to evaluate their potential as dielectric materials for base–metal–electrode multilayer ceramic capacitors (BME‐MLCCs). X‐ray diffraction, scanning electron microscope, transmission electron microscope, and energy‐dispersive spectrometer analyses confirmed the formation of a core–shell structure with grain sizes of ∼200 nm, as well as localized interfacial stress at grain boundaries. Among all compositions, the Y5 sample (moderate Y doping, 1.5 mol%) exhibited a high dielectric constant of 2968, maintained excellent temperature stability within the EIA X7P specification (temperature coefficient of capacitance, TCC ≤ ±10%, temperature range from –55°C to 125°C), and suppressed abnormal grain growth. Reliability tests showed that this composition exhibited the longest lifetime and the highest breakdown field. Impedance spectroscopy and COMSOL simulations further substantiated the role of Y 3 + in suppressing vacancy migration and dispersing local electric fields. This study provides a theoretical reference for miniaturized, high‐reliability BME‐MLCCs.