ALUMINUM OXIDE LAYER ON ANODE FOIL FOR ALUMINUM ELECTROLYTIC CAPACITOR

A method of producing an oxide layer on a foil for use in a capacitor includes immersing the foil in a first solution; maintaining a target current between the immersed anodic foil and the first solution until a first target voltage is reached to form an oxide layer overlying the foil; maintaining the target current between the immersed foil and the first solution until a second target voltage is reached to reform the oxide layer; removing the foil from the first solution and heating the foil; immersing the heat treated foil in a second solution; maintaining the target current between the immersed foil and the second solution until a third target voltage is reached; and discharging the immersed foil after each of the first, second, and third target voltages are reached.