Enhanced Reliability and Microstructure Control in Dy/Y Co-Doped BaTiO3 Ceramics

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.