ETCHING OF ALUMINIUM ELECTROLYTIC CAPACITOR FOIL

摘要

Aluminum electrolytic capacitor foil is etched by first subjecting high-cubicity foil to a chemical etching stage in which the etchant is an acidic aqueous solution containing an acid having anions for anodizing aluminum, hydrochloric acid, transition metal ions, and aluminum ions. Preferably, the anodizing anions are present in a greater concentration than the chloride ions. The foil is then subjected to a second etching step which may be chemical or electrochemical. The process produces a high capacitance foil with high bend strength.