Reliability of multilayer ceramic capacitors with nickel electrodes

The reliability of multilayer ceramic capacitors (MLCCs) with Ni internal electrodes has been studied from the viewpoint of partial oxygen pressure (P-O2) during firing. It is shown that the load-life time of the insulation resistance (IR) was prolonged by firing under low P-O2, annealing after firing, and the addition of dopants. It is also shown that the generation of oxygen vacancies led to the degradation of IR. Annealing treatment for the oxidation of the dielectric body accelerates the dielectric aging of MLCCs. It is found that the appropriate control of the P-O2 during firing can improve the reliability of MLCCs with Ni electrodes to a level as high as that of MLCCs with precious metal electrodes. Thus, we have developed an MLCC with Ni electrodes that features high reliability and a large capacitance of 10 mu F for the Y5V characteristic and 4.7 mu F for the X7R characteristic, both in the case of the C3216 (3.2 mm x 1.6 mm x 1.4 mm) form.