Effects of the solution flow rate on the growth of aluminum etch tunnels

Abstract Increasing the specific surface area of the anode foil of aluminum electrolytic capacitors is a research direction to improve the performance of capacitors. Industrial mass‐produced anode foil increases the specific surface area by electrochemical etching of the aluminum foil. However, the tunnels created by corrosion stop growing midway through this process. In this study, the effect of the solution flow rate on tunnel growth is investigated, and the growth of tunnels is analyzed using a new method of preparing oblique sections. Neater tunnels can be grown by increasing the solution flow rate to facilitate active tunnels.