| 摘要 |
PURPOSE:To increase the etching magnification rate, by a method wherein an aluminum foil is subjected to an alternating current etching with a specific small current density for about 1/3 or less period of the total etching hour, and subjected to the etching with a large current density for the remaining period by increasing gradually the current intensity. CONSTITUTION:An aluminum foil is subjected to an etching for about 1/3 or less period of the total etching hour, by an alternating current with a small current density such as 0.05-0.30 A/cm<2>. The current intensity is gradually increased, and the etching is progressed with a large current intensity of 0.5-1.5 A/cm<2> for the remaining period. According to this etching method, the current intensity is changed, so that the uneveness of an etching surface is fine as compared with the case of constant current intensity etching. Therefore, the mechanical strength of the etching foil does not decrease.
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