CHEMICAL CONVERSION COATING OF TANTALUM OR NIOBIUM AND METHOD OF FORMING THE SAME AS WELL AS ELECTROLYTIC CAPACITOR USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a high-performance electrolytic capacitor which makes stable operation even if it is used for a long term under severe conditions. SOLUTION: An intermediate composition region having an intermediate composition of a metal composition and oxide composition in a chemical conversion coating of a valve metal is formed at a thickness above 40 nm so as to suppress the movement of the oxygen atoms in the chemical conversion coating. The chemical conversion coating can be obtained by subjecting a substrate metal containing nitrogen in the valve metal to anodic oxidation treatment.