Sinterability of sodium bismuth titanate-based electroceramics at low temperatures

The demand for robust multilayer ceramic capacitors with high-temperature and high-power capabilities is surging. Cost-effective production is a key challenge, often linked to precious metal electrodes like Pt, Pd, and Ag in multilayer ceramic capacitors (MLCCs). To address this, cost-efficient base metal electrodes such as Cu and Ni are sought. Promising lead-free options are Na0.5Bi0.5TiO3 (NBT)-based materials. However, their sintering temperatures exceed Cu's melting point (1085 °C), necessitating sintering aids for compatibility. We investigated several low-temperature sintering aids (Li2O, Na2O, Bi2O3, B2O3, ZnO, and V2O5) to lower the sintering temperature of Na0.5Bi0.5TiO3-BaTiO3-CaZrO3-BiAlO3 solid solutions. Results reveal NBT-based materials' sensitivity to acceptor dopant incorporation from sintering aids, impacting electrical properties. Yet, we successfully reduced the sintering temperature to 975 °C, suitable for Cu co-sintering, with minimal adverse effects on capacitor properties using well-tuned sintering aids.