Etching Hole Kinetics of Anode Foils for Aluminum Electrolytic Capacitors Prepared at High Speed

The variation trends of the density, the size and the length of the tunnel pits in the anode aluminum foil after each etching stage were studied under the fast corrosion process system condition. The results showed that the generation behavior of pits was mainly occurred during the short stage with high current density, meanwhile the growth of tunnels was the fastest at the stage with decaying density of current.With the increase of the number of etching cycles, the pore density and pore length increased rapidly from the first cycle to the middle of the second cycle, and changed gently from the middle of the second cycle to the fifth cycle. The fast speed etching process could effectively isolate the growth of the hole and the growth of the hole length, which not only improved the etching efficiency, but also enhanced the controllability of specific capacitance and the uniformity of the hole.