Nickel diffusion in base-metal-electrode MLCCs

Nickel is frequently used as an internal electrode in the advanced base-metal-electrode (BME) multilayer ceramic capacitors (MLCCs). The diffusion of nickel element into the non-reducing perovskite dielectric layers plays an important role in the final quality of MLCCs. In this paper, the diffusion of nickel element from internal electrode to the dielectric ceramic layer was investigated by AES and EPMA experiments. It was shown that during sintering, nickel atoms migrate towards the dielectric layer and an interdiffusion region of hundreds of nanometers in thickness is generated near the internal electrode. The difference in dielectric characteristics between MLCC and disk specimens can be attributed to the existence of the interdiffusion region.