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US 4,395,305 AGranted
Chemical etching of aluminum capacitor foil
AssigneeSprague Electric Company
InventorAlfred Whitman
Life of this patent
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Abstract
Aluminum capacitor foil is chemically etched to produce a fine etch structure by passing the foil through an etch bath containing sodium chloride and at least an equal amount of sulfuric acid, preferably 11 to about 22 wt %. Etching is carried out at 90.degree. to 105.degree. C.
Claims6
A process for the chemical etching of aluminum capacitor foil to produce a fine tunnel etch structure comprising passing said foil through an aqueous etchant bath containing sodium chloride and sulfuric acid, the weight percentage of said sulfuric acid being at least equal to the weight percentage of said sodium chloride.
Dependencies are inferred from the claim text.