| 摘要 |
PURPOSE:To prevent the deposition of Cu on Al foil contg. Cu during AC electrolytic etching in an aq. soln. contg. Cl<-> and to obtain an electrolytic capacitor of stable quality, by using an electrolytic soln. contg. an additive forming complex ions with Cu as the aq. soln. CONSTITUTION:When Al foil contg. Cu is subjected to AC electrolytic etching, an electrolytic soln. contg. an additive forming complex ions with Cu is used. The additive may be one or more among PCl5, a cyanogen compd. and a compd. having a carboxyl group and the concn. may be 0.1-25g/l. During the AC electrolytic etching, the deposition of Cu is inhibited and an electrolytic capacitor of stable quality can be produced. Accordingly, Al of 99.98% purity used in the field of low voltage capacitors at the present time can be replaced by Al of lower purity such as 99.94%. KCN may be used as the cyanogen compd. and glycine as the compd. having a COOH group.
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