Method for etching holes by corroding aluminum foil

Abstract

The invention discloses a method for etching holes by eroding an aluminum foil, which comprises the steps of pretreatment, first level corrosion, second level corrosion, post treatment and drying. The first level corrosion comprises the following steps of: putting the aluminum foil after the pretreatment into mixed solution of hydrochloric acid and sulfuric acid, wherein the mixed solution contains 0.5 to 1.0 N / L of aluminum, the temperature of the mixed solution is between 65 and 90 DEG C and the total acidity of the mixed solution is 5.0 to 8.0 N / L; and applying 45 to 80 seconds of direct current of which the current density changes along with the time to perform electrolytic corrosion for etching the holes in mainly three modes that: one, the current density changes from high to low along with the time; two, the current density changes from low to high and then to low again; and three, the current density changes form low to high. The hole etching mode that the current density changes from high to low along with the time improves the specific volume by 7 to 12 percent compared with the existing hole etching method with constant current density under the premise of not reducing the mechanical strength of the aluminum foil.

Description

technical field [0001] The invention relates to a method for corroding an anode aluminum foil of an aluminum electrolytic capacitor, in particular to a corrosion porosity method in which the performance of the corroded foil changes due to changes in current density with time during the first-stage porosity corrosion in the electrolytic corrosion process of the aluminum foil. Background technique [0002] Anode aluminum foil for electrolytic capacitors, increasing its electrostatic capacity per unit area (specific capacitance) plays a decisive role in reducing the size of the capacitor. The general process of aluminum foil corrosion method is: pre-treatment, primary corrosion, secondary or multi-stage corrosion, post-treatment, and drying. The purpose of primary corrosion is to create pores, that is, to generate a large number of evenly distributed initial pores with a certain depth on the surface of the aluminum foil, in order to obtain the maximum specific surface area afte...

AI Technical Summary

Problems solved by technology

In order to achieve the purpose of first-level corrosion pores, people have been constantly exploring the method of corrosion pores, especially a large number of experiments on the formulation of the corrosion solution and its method control, and achieved good results. Corrosion research mainly uses constant current density to corrode pores in the corrosive solution. There is still room for further improvement in the density and uniformity of the initial pores. At present, no pores that use current density that changes with time have been seen. method reporting

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