Effect of frequency and current density on A.C. etching of aluminum electrolytic capacitor foil

Abstract

This work studies the effects of current frequency and current density on etching morphology, microstructure and static capacity of the aluminum foils used in electrolytic capacitors. The behavior associated with electrochemical etching during an anodic half cycle was investigated by a potentiostat. The oxide covering of the anode, which protected aluminum from etching, thickened as the frequency increased. Increasing the current density inhibit the passing of chlorine ions through the passive cover. The static capacity increased to 70μF/cm2 with 20 V forming voltage by optimization the etching parameters used herein this work.