Method for inducing medium-high voltage anode foil to uniformly corrode and form pores by adopting nano pits after anodic oxidation
阅读说明：本技术 一种采用阳极氧化后的纳米凹坑来诱导中高压阳极箔均匀腐蚀发孔的方法 (Method for inducing medium-high voltage anode foil to uniformly corrode and form pores by adopting nano pits after anodic oxidation ) 是由 彭宁 李永钊 徐桂仁 王盼 于 2021-06-15 设计创作，主要内容包括：本发明公开了一种采用阳极氧化后的纳米凹坑来诱导中高压阳极箔均匀腐蚀发孔的方法,涉及了铝电解电容器用中高压阳极铝箔的制造领域。本发明将表面不富集电极电位比铝高的Mn、Fe、Co、Ni、Cu、Zn、Cd、Ga、Ge、In、Sn、Pb元素,纯度为99.99％,经充分退火后其{100}立方织构占有率超过95％的中高压阳极铝箔采用阳极氧化在铝箔表面生成有序多孔氧化铝膜；而后溶解氧化铝膜并暴露出铝箔基体上高度有序分布的纳米凹坑,利用该凹坑来调控铝箔腐蚀发孔时的隧道孔形核位置,可显著提高生成隧道孔的分布均匀性,降低隧道孔并孔,因而可以提高铝箔的比电容。(The invention discloses a method for inducing medium-high voltage anode foil to uniformly corrode and generate holes by adopting nano pits after anodic oxidation, and relates to the field of manufacturing of medium-high voltage anode aluminum foils for aluminum electrolytic capacitors. According to the invention, Mn, Fe, Co, Ni, Cu, Zn, Cd, Ga, Ge, In, Sn and Pb elements with the electrode potential higher than that of aluminum are not enriched on the surface, the purity is 99.99%, and after full annealing, the medium-high voltage anode aluminum foil with the {100} cubic texture occupancy rate of more than 95% is subjected to anodic oxidation to generate an ordered porous alumina film on the surface of the aluminum foil; and then dissolving the aluminum oxide film and exposing the nano pits which are highly and orderly distributed on the aluminum foil substrate, and regulating and controlling the nucleation position of the tunnel holes when the aluminum foil is corroded to generate holes by utilizing the pits, so that the distribution uniformity of the generated tunnel holes can be obviously improved, the number of the tunnel holes is reduced, and the specific capacitance of the aluminum foil can be improved.)
1. A method for inducing medium-high voltage anode foil to uniformly corrode and form pores by using nano pits after anodic oxidation is characterized In that Mn, Fe, Co, Ni, Cu, Zn, Cd, Ga, Ge, In, Sn and Pb elements with the electrode potential higher than that of aluminum are not enriched on the surface, the purity is 99.99%, and after full annealing, the high-purity medium-high voltage aluminum foil with the {100} cubic texture occupancy rate of more than 95% generates an aluminum oxide film with ordered porous distribution on the surface of the aluminum foil by anodic oxidation; and then dissolving the aluminum oxide film and exposing the nano pits which are highly and orderly distributed on the aluminum foil substrate, and regulating and controlling the tunnel hole nucleation position when the aluminum foil corrodes and generates holes by utilizing the pits.
2. The method for inducing the medium-high voltage anode foil to be subjected to uniform corrosion hole forming by adopting the nano pits after the anodic oxidation as claimed In claim 1, wherein the surface of the high-purity medium-high voltage anode foil which is not enriched with Mn, Fe, Co, Ni, Cu, Zn, Cd, Ga, Ge, In, Sn and Pb elements with the electrode potential higher than that of aluminum and the purity of 99.99% is subjected to anodic oxidation for 10-60 seconds In a mixed solution of 2-5 Wt.% tartaric acid or 2-5 Wt.% tartaric acid + 1-10 Wt.% ethylene glycol + 0.1-1 Wt.% phosphoric acid with the {100} cubic texture occupancy rate of over 95% at 5-10 ℃ after full annealing, wherein the anodic oxidation voltage is 200-230V, and an aluminum oxide film with ordered porous distribution is generated on the surface of the aluminum foil.
3. The method for inducing uniform corrosion and hole forming of the medium-high voltage anode foil by using the nano pits after anodic oxidation according to claim 1 or 2, characterized in that the aluminum foil for preparing the ordered porous alumina film is subjected to cathodic polarization in sulfuric acid with a solution of 0.1-5 Wt.% at 30-70 ℃, or is soaked in sodium bicarbonate with a solution of 0.1-5 Wt.% at 60-90 ℃, the porous alumina film on the surface is removed and the highly orderly distributed nano pits on the aluminum foil substrate are exposed, and the pits are utilized to regulate and control the positions of the tunnel hole-shaped cores when the aluminum foil corrodes and hole forming, so as to obtain tunnel holes approximately orderly distributed.
Technical Field
The invention relates to a method for preparing a high-voltage anode aluminum foil material in an aluminum electrolytic capacitor, which can remarkably improve the capability of corroding and holing an anode aluminum foil by a surface oxidation technology, an oxide film removing technology and a hole corroding technology of the anode aluminum foil.
Background
The aluminum electrolytic capacitor is an important electronic component, and is widely applied to electronic instruments and equipment due to the advantages of large capacity, small volume, low cost, light weight and the like. With the rapid development of the electronic industry, especially the popularization of new energy automobiles, the further popularization of mobile phones, and the rapid development in the fields of aerospace military industry, the usage amount of aluminum electrolytic capacitors is continuously expanding, and the medium-high voltage aluminum electrolytic capacitors serving as basic components are required to be developed towards high capacity and miniaturization so as to meet the development requirements of electronic products.
An anode aluminum foil of a medium-high voltage aluminum electrolytic capacitor is generally formed with a large number of tunnel holes on the surface thereof by an electrochemical etching method to enlarge the specific surface area of a high-purity aluminum foil, thereby increasing the specific capacitance, and high capacity and miniaturization of the capacitor are achieved by the method. In order to ensure the winding performance of the anode aluminum foil in the preparation of the aluminum electrolytic capacitor, the corroded aluminum foil must have certain tensile strength and bending performance, so that an aluminum foil layer with certain thickness and without corrosion needs to be arranged in the middle of the corroded aluminum foil. In order to optimize the comprehensive performance of the aluminum foil after corrosion, in the electrolytic corrosion process, the uniformity of the distribution of the tunnel holes on the surface of the anode aluminum foil needs to be improved, and the generation of tunnel merging holes needs to be avoided as much as possible.
The process for corroding and perforating the medium-high voltage anode aluminum foil mainly comprises the following steps: pretreatment before corrosion, perforation treatment and reaming treatment. When the holes are corroded, the shape and distribution mode of the tunnel holes are mainly determined by the surface state of the aluminum foil, and the surface state of the high-purity aluminum foil is mainly determined by the pretreatment step before corrosion. At present, the pretreatment technology for the surface of the aluminum foil at home and abroad mainly comprises heat treatment, acid and alkali treatment, cathode polarization treatment, oxidation treatment, deposited metal treatment and the like. Chinese patent ZL201210391778.0 discloses a method for generating a hydrated oxide film by hydration of a medium-high voltage aluminum foil in pure water, ammonia water and amine aqueous solution at the temperature of 70-100 ℃, and guiding corrosion and hole formation of the aluminum foil through defects of the hydrated oxide film, and the method has the effects of improving distribution uniformity of tunnel holes and improving specific capacitance. However, we have found that the above patent directly adopts the method of hydrated oxygen, and the obtained hydrated oxide film has poor defect distribution uniformity and size uniformity, and is prone to have tunnel holes and holes in local areas when the aluminum foil is corroded to generate holes, which significantly reduces the mechanical properties of the aluminum foil and limits further improvement of the specific capacitance of the aluminum foil. The Chinese patent ZL201910311928.4 discloses a method for pulse deposition of nano tin dots on the surface of an anode aluminum foil, which obtains the nano tin dots which are approximately and orderly distributed and have consistent sizes, and has obvious effects on improving the uniformity of aluminum foil corrosion hole formation and reducing tunnel hole merging. The method is based on the defects that hydration treatment is adopted to generate a hydrated oxide film, and the problems of ordered distribution and larger distance exist when nano tin points are deposited in a pulse mode, and can obtain a better research result on the basis of changing the pretreatment mode to obtain a positive effect.
Disclosure of Invention
The key technology of the invention is to adopt an anodic oxidation technology to obtain nanometer pits with ordered distribution, consistent size and smaller space on the surface of the aluminum foil, as shown in figure 1, a scanning electron microscope morphology graph of the anodic aluminum foil surface passing through the anodic oxidation nanometer pits.
Mn, Fe, Co, Ni, Cu, Zn, Cd, Ga, Ge, In, Sn and Pb elements with electrode potentials higher than that of aluminum are not enriched on the surface, the purity is 99.99%, and after full annealing, the high-purity medium-high voltage aluminum foil with the {100} cubic texture occupancy rate of more than 95% generates an aluminum oxide film with ordered porous distribution on the surface of the aluminum foil by adopting anodic oxidation; and then dissolving the aluminum oxide film and exposing the nano pits which are highly and orderly distributed on the aluminum foil substrate, and regulating and controlling the tunnel hole nucleation position when the aluminum foil corrodes and generates holes by utilizing the pits.
The specific process is as follows: mn, Fe, Co, Ni, Cu, Zn, Cd, Ga, Ge, In, Sn and Pb elements with the electrode potential higher than that of aluminum are not enriched on the surface, the purity is 99.99%, and after full annealing, the {100} cubic texture occupancy rate of the high-purity medium-high voltage aluminum foil with the electrode potential higher than 95% is anodized In a mixed solution of 2-5 Wt.% tartaric acid or 2-5 Wt.% tartaric acid + 1-10 Wt.% ethylene glycol + 0.1-1 Wt.% phosphoric acid at the temperature of 5-10 ℃ for 10-60 seconds, wherein the anodization voltage is 200-230V, and an aluminum oxide film with ordered porous distribution is generated on the surface of the aluminum foil. And then, carrying out cathodic polarization on the aluminum foil with the prepared ordered porous alumina film in sulfuric acid with a solution of 0.1-5 Wt.% at 30-70 ℃, or soaking the aluminum foil in sodium bicarbonate with a solution of 0.1-5 Wt.% at 60-90 ℃, removing the porous alumina film on the surface, exposing nano pits with highly ordered distribution on the aluminum foil substrate, and regulating and controlling the tunnel hole shape core positions when the aluminum foil is subjected to corrosion and hole forming by using the pits to obtain tunnel holes with approximately ordered distribution.
The invention discloses a novel method for adopting anodic oxidation nanometer pits on the surface of an anode aluminum foil, aiming at the defects of a hydrated oxide film generated by hydration treatment and the problems of ordered distribution and larger distance when nanometer tin points are deposited in a pulse mode. Compared with the defects of a hydrated oxide film generated by hydration treatment and nano tin points obtained by pulse deposition, the nano pits obtained by anodic oxidation have highly ordered distribution, more uniform size and small spacing, and can solve the problems of the defects of the hydrated oxide film generated by hydration treatment, ordered distribution and large spacing existing when the nano tin points are deposited by pulse, thereby further improving the specific capacitance of the corroded aluminum foil.
Drawings
Fig. 1 is a nano-pit SEM image of the anode aluminum foil after being anodized.
Fig. 2 is an SEM picture of aluminum foil corrosion perforation induced by ordered pits.
Detailed Description
The invention is further described below by way of examples.
The anode aluminum foil with highly orderly distributed nano pits oxidized on the surface of the anode is adopted for pore-forming corrosion, and the pore-forming solution is 0.6M HCl +7.4M H2SO4+0.8M Al3+The mixed solution is subjected to reaming corrosion at the temperature of 72 ℃, and the reaming solution is 3 Wt.% of HNO3The solution is processed into nitric acid solution at the temperature of 70 ℃, and finally cleaned, dried and finally subjected to 520V formation according to the industry standard.
Comparative example
The lead-containing aluminum foil with the purity of 99.99 percent, the thickness of 120 mu M and the cubic texture occupancy rate of more than 95 percent adopts the traditional mixed acid pretreatment process, and the used pretreatment solution is 1M HCl +7M H2SO4At a temperature of 8And (3) directly soaking the aluminum foil in the pretreatment solution for 120s at 0 ℃, and then performing the perforation corrosion, the reaming corrosion, the post-treatment and the 520V formation treatment.
Example 1
Mn, Fe, Co, Ni, Cu, Zn, Cd, Ga, Ge, In, Sn and Pb elements with the electrode potential higher than that of aluminum are not enriched on the surface, the purity is 99.99%, and after full annealing, the high-purity medium-high voltage aluminum foil with the {100} cubic texture occupancy rate of more than 95% is placed In a tartaric acid solution with the temperature of 5 ℃ and the solubility of 2 Wt.% for anodic oxidation for 10 seconds, wherein the voltage of anodic oxidation is 200V. And then, carrying out cathodic polarization on the aluminum foil with the prepared ordered porous alumina film in sulfuric acid with the solution of 0.1 Wt.% at the temperature of 30 ℃, removing the porous alumina film on the surface and exposing the nano pits with highly ordered distribution on the aluminum foil substrate.
Removing the oxide film after the anodic oxidation, and performing pore-forming corrosion on the aluminum foil with the nano pits on the surface, wherein the pore-forming solution is 0.6M HCl +7.4M H2SO4+0.8M Al3+The temperature of the mixed solution is 75 ℃, and then the hole expanding corrosion, the post-treatment and the 520V formation treatment which are the same as the comparative example are carried out.
Example 2
Mn, Fe, Co, Ni, Cu, Zn, Cd, Ga, Ge, In, Sn and Pb elements with the electrode potential higher than that of aluminum are not enriched on the surface, the purity is 99.99%, and after full annealing, the high-purity medium-high voltage aluminum foil with the {100} cubic texture occupancy rate of more than 95% is placed In a tartaric acid solution with the temperature of 5 ℃ and the solubility of 2 Wt.% for anodic oxidation for 60 seconds, wherein the voltage of anodic oxidation is 200V. And then soaking the aluminum foil with the prepared ordered porous alumina film in sodium bicarbonate with a solution of 0.1 Wt.% at 60 ℃, removing the surface porous alumina film and exposing the nano pits with highly ordered distribution on the aluminum foil substrate.
Removing the oxide film after the anodic oxidation, and performing pore-forming corrosion on the aluminum foil with the nano pits on the surface, wherein the pore-forming solution is 0.6M HCl +7.4M H2SO4+0.8M Al3+The temperature of the mixed solution is 75 ℃, and then the hole expanding corrosion, the post-treatment and the 520V formation treatment which are the same as the comparative example are carried out.
Example 3
Mn, Fe, Co, Ni, Cu, Zn, Cd, Ga, Ge, In, Sn and Pb elements with the electrode potential higher than that of aluminum are not enriched on the surface, the purity is 99.99%, and after full annealing, the high-purity medium-high voltage aluminum foil with the {100} cubic texture occupancy rate of more than 95% is placed In a mixed solution of 2 Wt.% tartaric acid, 5 Wt.% glycol and 0.5 Wt.% phosphoric acid at the temperature of 5 ℃ for anodic oxidation for 30 seconds, wherein the voltage of anodic oxidation is 220V. And then soaking the aluminum foil with the prepared ordered porous alumina film in sodium bicarbonate with a solution of 5 Wt.% at 80 ℃, removing the surface porous alumina film and exposing the nano pits with highly ordered distribution on the aluminum foil substrate.
Removing the oxide film after the anodic oxidation, and performing pore-forming corrosion on the aluminum foil with the nano pits on the surface, wherein the pore-forming solution is 0.6M HCl +7.4M H2SO4+0.8M Al3+The temperature of the mixed solution is 75 ℃, and then the hole expanding corrosion, the post-treatment and the 520V formation treatment which are the same as the comparative example are carried out.
Example 4
Mn, Fe, Co, Ni, Cu, Zn, Cd, Ga, Ge, In, Sn and Pb elements with the electrode potential higher than that of aluminum are not enriched on the surface, the purity is 99.99%, after full annealing, the high-purity medium-high voltage aluminum foil with the {100} cubic texture occupancy rate of more than 95% is placed In a mixed solution of 2 Wt.% tartaric acid, 5 Wt.% glycol and 0.5 Wt.% phosphoric acid at the temperature of 10 ℃ for anodization for 60 seconds, wherein the anodization voltage is 220V. And then, carrying out cathodic polarization on the aluminum foil with the prepared ordered porous alumina film in sulfuric acid with the solution of 5 Wt.% at 60 ℃, removing the porous alumina film on the surface and exposing the nano pits with highly ordered distribution on the aluminum foil substrate.
Removing the oxide film after the anodic oxidation, and performing pore-forming corrosion on the aluminum foil with the nano pits on the surface, wherein the pore-forming solution is 0.6M HCl +7.4M H2SO4+0.8M Al3+The temperature of the mixed solution is 75 ℃, and then the hole expanding corrosion, the post-treatment and the 520V formation treatment which are the same as the comparative example are carried out.
Example 5
Mn, Fe, Co, Ni, Cu, Zn, Cd, Ga, Ge, In, Sn and Pb elements with the electrode potential higher than that of aluminum are not enriched on the surface, the purity is 99.99%, and after full annealing, the high-purity medium-high voltage aluminum foil with the {100} cubic texture occupancy rate of more than 95% is placed In a tartaric acid solution with the temperature of 10 ℃ and the solubility of 5 Wt.% for anodic oxidation for 60 seconds, wherein the voltage of anodic oxidation is 220V. And then, carrying out cathodic polarization on the aluminum foil with the prepared ordered porous alumina film in sulfuric acid with the solution of 5 Wt.% at 70 ℃, removing the porous alumina film on the surface and exposing the nano pits with highly ordered distribution on the aluminum foil substrate.
Removing the oxide film after the anodic oxidation, and performing pore-forming corrosion on the aluminum foil with the nano pits on the surface, wherein the pore-forming solution is 0.6M HCl +7.4M H2SO4+0.8M Al3+The temperature of the mixed solution is 75 ℃, and then the hole expanding corrosion, the post-treatment and the 520V formation treatment which are the same as the comparative example are carried out.
Example 6
Mn, Fe, Co, Ni, Cu, Zn, Cd, Ga, Ge, In, Sn and Pb elements with the electrode potential higher than that of aluminum are not enriched on the surface, the purity is 99.99%, and after full annealing, the high-purity medium-high voltage aluminum foil with the {100} cubic texture occupancy rate of more than 95% is placed In a tartaric acid solution with the temperature of 5 ℃ and the solubility of 5 Wt.% for anodic oxidation for 30 seconds, wherein the voltage of anodic oxidation is 230V. And then soaking the aluminum foil with the prepared ordered porous alumina film in sodium bicarbonate with a solution of 5 Wt.% at 30 ℃, removing the surface porous alumina film and exposing the nano pits with highly ordered distribution on the aluminum foil substrate.
Removing the oxide film after the anodic oxidation, and performing pore-forming corrosion on the aluminum foil with the nano pits on the surface, wherein the pore-forming solution is 0.6M HCl +7.4M H2SO4+0.8M Al3+The temperature of the mixed solution is 75 ℃, and then the hole expanding corrosion, the post-treatment and the 520V formation treatment which are the same as the comparative example are carried out.
Example 7
Mn, Fe, Co, Ni, Cu, Zn, Cd, Ga, Ge, In, Sn and Pb elements with the electrode potential higher than that of aluminum are not enriched on the surface, the purity is 99.99%, and after full annealing, the high-purity medium-high voltage aluminum foil with the {100} cubic texture occupancy rate of more than 95% is placed In a mixed solution of tartaric acid with the concentration of 5Wt percent, ethylene glycol with the concentration of 10Wt percent and phosphoric acid with the concentration of 1Wt percent for anodic oxidation for 30 seconds, wherein the voltage of anodic oxidation is 200V. And then soaking the aluminum foil with the prepared ordered porous alumina film in sodium bicarbonate with a solution of 0.1 Wt.% at 60 ℃, removing the surface porous alumina film and exposing the nano pits with highly ordered distribution on the aluminum foil substrate.
Removing the oxide film after the anodic oxidation, and performing pore-forming corrosion on the aluminum foil with the nano pits on the surface, wherein the pore-forming solution is 0.6M HCl +7.4M H2SO4+0.8M Al3+The temperature of the mixed solution is 75 ℃, and then the hole expanding corrosion, the post-treatment and the 520V formation treatment which are the same as the comparative example are carried out.
Example 8
Mn, Fe, Co, Ni, Cu, Zn, Cd, Ga, Ge, In, Sn and Pb elements with the electrode potential higher than that of aluminum are not enriched on the surface, the purity is 99.99%, after full annealing, the high-purity medium-high voltage aluminum foil with the {100} cubic texture occupancy rate of more than 95% is placed In a mixed solution of 2 Wt.% tartaric acid, 5 Wt.% glycol and 0.5 Wt.% phosphoric acid at the temperature of 5 ℃ for anodization for 60 seconds, wherein the anodization voltage is 230V. And then, carrying out cathodic polarization on the aluminum foil with the prepared ordered porous alumina film in sulfuric acid with the solution of 0.1 Wt.% at 90 ℃, removing the porous alumina film on the surface and exposing the nano pits with highly ordered distribution on the aluminum foil substrate.
Removing the oxide film after the anodic oxidation, and performing pore-forming corrosion on the aluminum foil with the nano pits on the surface, wherein the pore-forming solution is 0.6M HCl +7.4M H2SO4+0.8M Al3+The temperature of the mixed solution is 75 ℃, and then the hole expanding corrosion, the post-treatment and the 520V formation treatment which are the same as the comparative example are carried out.
Table 1 shows the specific capacitance and the bending times of the aluminum foil with nano pits oxidized on the surface by the anode of the present invention after the aluminum foil with nano pits oxidized on the surface by the anode of the present invention is subjected to anodic electrolytic corrosion and formed in the comparative examples and examples, and it can be seen that the specific capacitance of the aluminum foil with nano pits oxidized on the surface by the anode of the present invention is increased by 4% to 9%, and the bending times are increased by about 20%.
TABLE 1 specific capacitance and number of bends of anode aluminum foils of comparative examples and examples
Sample (I)
Specific capacitance (. mu.F/cm)2)
Number of times of bending
Comparative example
0.731
18
Example 1
0.763
22
Example 2
0.775
23
Example 3
0.789
21
Example 4
0.778
22
Example 5
0.781
22
Example 6
0.770
23
Example 7
0.776
22
Example 8
0.798
24