| 摘要 |
PURPOSE:To obtain stable characteristics in a severe circumstances, by forming a dielectric oxide film on the surface of an anode substrate, and then anodizing the anode body in a high concentration phosphoric acid solution whose concentration is higher than or equal to 65 wt.% at a temperature higher than that of film formation. CONSTITUTION:At the time of forming a dielectric oxide film, anodizing is performed by applying a usual electrolyte, i.e., 0.005-20% phosphoric acid concentration at 40-90 deg.C. After that, a second anodizing is performed wherein phosphoric acid solution of 65% or more is used which is extremely high concentration as compared with prior art, and the temperature of electrolyte is higher than that of usual electrolyte. Thereby, in severe circumstances of extremely high temperature and high humidity such as 58 deg.C, 90%, a solid electrolyte capacitor of resin clad type can be realized, whose leak current characteristics are extremely stable and dielectric strength is remarkably improved.
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