| 摘要 |
PURPOSE:To obtain an extremely high magnification rate for an etching foil, by a method wherein etching is performed with an alternating current in a water solution to which phosphoric acid ion is added, after an etching treatment with a direct current is finished in a water solution of hydrochloric acid. CONSTITUTION:As a first step, in a water solution of comparatively dilute hydrochloric acid of 3-10%, an etching treatment with a direct current whose current density is 0.05-0.25 A/cm<2> is performed. As a second step, in a water solution in which phosphoric acid ion (PO<-3>4) of 0.5-3% is added to the water solution of hydrochloric acid of 3-9%, an aluminum foil is anodized with an alternating current. Thereby, an aluminum foil, whose mechanical strength is large, is obtained with an extremely high magnification. In the case of etching applying DC only, the magnification rate is 15 times. On the contrary, in the case of 220V formation, the etching magnification rate shows an extremely high value, i.e., 19 times.
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