Ultrahigh-pressure etched foil and etching method thereof

Abstract

The invention belongs to the technical field of electrode materials for capacitors, and particularly provides ultrahigh-pressure etched foil and an etching method thereof. The etching method comprisesthe following steps: pretreatment, first-stage direct current (DC) pitting etching, second-stage DC pitting etching, first middle treatment, third-stage DC reaming etching, fourth-stage DC reaming etching, second middle treatment and after-treatment, wherein three-section combined attenuation current waveforms are adopted during the first-stage DC pitting etching and the second-stage DC pitting etching. The etched foil obtained by the etching process can be applicable to ultrahigh pressure requirements of 850 V or above, and has large pit diameters, good pit consistency and higher electrostatic capacity and bending strength.

Description

technical field [0001] The invention belongs to the technical field of electrode materials for capacitors, and in particular relates to an ultrahigh-voltage corrosion foil and a corrosion method thereof. Background technique [0002] The conventional manufacturing process of medium and high pressure corroded foil mainly includes pretreatment, porosity corrosion, hole expansion corrosion, post-treatment and other processes. The porosity is carried out in the sulfuric acid-hydrochloric acid mixture to form high-density, uniform and fine tunnel holes. Hole expansion is generally carried out in nitric acid solution, and the diameter of the small tunnel hole is enlarged to a degree greater than the thickness of the oxide film formed by high pressure to obtain a high specific volume. Corrosion determines the density of the tunnel hole, the uniformity of the distribution of the hole and the size of the hole. depth etc. However, the conventional medium and high pressure etching pr...

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Problems solved by technology

Based on this, the corrosion process provided by the present invention adopts one-stage and two-stage two-stage porosity treatment, and a special three-stage combined attenuation DC power-on method is adopted during the one-stage and two-stage two-stage porosity. , the large current attenuation in the first stage promotes the formation of pits on the surface of the aluminum foil in a short period of time to ensure the density of the pores on the surface of the aluminum foil. In the second stage, power supply provides energy for the continuous growth of the pores while attenuating the current and does not generate new pores. The third Stage small current attenuation provides the energy required for the growth of the generated pores, ensures that the pores grow to a sufficient length, and avoids the generation of new pits and insufficient growth of the pores during the application of the current in the later stage. It is effective through hierarchical powering Improve the arrangement of the hole position, the special electrochemical waveform corrosion current density changes from large to small, try to make the pores occur at the same time, and at the same time make most of the pores grow in a uniform length, that is, increase the capacity of the corrosion foil and increase the strength of the corrosion foil , thereby solving the problem of poor uniformity of corroded foil pores and different channel lengths, and completing the present invention

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