Method of forming an aluminum oxide layer on anode foil for aluminum electrolytic capacitor

A method of producing an oxide layer on an anodic foil for use in a capacitor, the method comprising:

• immersing an anodic 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 anodic foil;
• discharging the immersed anodic foil after the first target voltage is reached;
• maintaining the target current between the immersed anodic foil and the first solution until a second target voltage is reached to reform the oxide layer a first time;
• discharging the immersed anodic foil after the second target voltage is reached;
• removing the anodic foil from the first solution and heating the anodic foil at a temperature sufficient to induce defects in the reformed oxide layer;
• immersing the heat treated anodic foil in a second solution;
• maintaining the target current between the immersed anodic foil and the second solution until a third target voltage is reached to reform the oxide layer a second time;
• and
• discharging the immersed anodic foil after the third target voltage is reached.