TWO-STAGE ELECTROCHEMICAL ETCHING OF HIGH PRESSURE ALUMINUM ANODE FOIL

摘要

Aluminum electrolytic capacitor anode foil of a high cubic texture is etched using a two step process by treating the foil in an electrolyte bath containing 3% hydrochloric acid and 1% aluminum as aluminum chloride under the influence of a direct current of high current density and at a temperature of 75° C., and in a second step treating said etched foil in a similar bath with a much lower current density and at a temperature of 80° to 82.5° C. The foil thus etched has a significantly higher capacitance resulting from a greater density of tunnels, and a fairly linear tunnel structure.