Effect of MnO 2 on the dielectric properties of Nb‐doped BaTiO 3 ‐(Bi 0.5 Na 0.5 )TiO 3 ceramics for X9R MLCC applications

MnO 2 and Nb 2 O 5 co‐doped 0.9BaTiO 3 ‐0.1(Bi 0.5 Na 0.5 )TiO 3 powders with excellent dielectric properties were fabricated using a conventional solid‐state reaction method and sand milling. The doping effects of various amounts of MnO 2 on the dielectric properties were investigated. The results revealed that the dielectric properties greatly depended on the concentration of MnO 2 . All the ceramics met the X9R specification. The dielectric loss decreased with an increasing concentration of MnO 2 . The specimen with an appropriate amount of 0.2 mol% MnO 2 exhibited the most enhanced properties: high insulation resistance (2.49 × 10 13  Ω/cm) and improved degradation properties. Multilayer ceramic capacitor ( MLCC ) chips were prepared by tape casting using a 0.2 mol% Mn‐doped 9010BTBNT‐based ceramic powder. The capacitance of the MLCC chip was approximately 100 nF, and the dielectric loss was approximately 1.75% at room temperature. The high‐temperature accelerated lifetime was over 1000 hours under 250 V (five times the working voltage) and at 230°C, indicating that the MLCC chips possess superior reliability.