Degradation of Multilayer Ceramic Capacitors with Nickel Electrodes

The mechanism of degradation, or IR drop, of BaTiO₃-based Ni-electrode chip capacitors has been studied, with special attention to the microstructure. Degradation occurred mainly at the center of the capacitors. Longer-life capacitors were obtained under conditions of low oxygen partial pressure, 10^?12 atm, during sintering, and had larger grain sizes and smaller quantities of grain boundary phase. The existence of oxygen vacancies in the grain boundary phase was confirmed by cathode luminescence measurement. Double layers along the surfaces of the Ni electrodes were also related to the life of the capacitors.