A method for preparing high-voltage corrosion foil by using non-electric hole expansion

Abstract

The present invention discloses a method for preparing high-voltage corrosion foil by utilizing non-electric hole expansion, which belongs to the technical field of aluminum electrolytic capacitors. The method comprises: pre-treatment, pore formation treatment, intermediate treatment, primary hole expansion treatment, secondary hole expansion treatment, and post-treatment; a two-stage non-electric hole expansion method is adopted, in the first stage of hole expansion, polyethylene glycol laurate can reduce the erosion of the aluminum foil surface, and by adjusting the amount of polyethylene glycol laurate added, the effective growth of the aluminum foil holes inside is guaranteed; in the second stage of hole expansion, by adjusting the amount of glycolic acid added, the erosion of the aluminum foil surface is reduced, and the excessive growth of the aluminum foil holes inside is slowed down. The two-stage non-electric hole expansion improves the uniformity of the corrosion foil holes during the hole expansion process and increases the specific capacity of the non-electric hole expansion. The hole growth of the medium and high voltage corrosion foil prepared by the present invention is orderly and controllable, and the 520V capacity of the high voltage corrosion foil is 0.900-0.920μF / cm 2 .

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum electrolytic capacitors, and particularly relates to a method for preparing high-voltage corrosion foil by utilizing non-electrical hole expansion. Background Art

[0002] Aluminum electrolytic capacitors feature small size, high capacity, low price, stable operation, and long life. They are widely used in the communications, computing, and consumer electronics sectors. With the continuous advancement of new energy vehicles, photovoltaic power generation, communications equipment, and smartphone technology, aluminum electrolytic capacitors are required to be smaller, thinner, and lighter. The key to achieving high capacity in aluminum electrolytic capacitors lies in increasing the capacitance of the anode foil.

[0003] Currently, the mainstream process for producing medium- and high-voltage high-specific-capacity corrosion foils is the electrochemical expansion process. The advantage of electrochemical expansion is that the corrosion foils produced have a high specific capacity, but there are two disadvantages:

[0004] 1. Nitric acid is often used in the hole expansion stage. Nitric acid decomposes during the reaction to produce nitrogen oxide waste gas and nitric acid waste liquid during the production process. Enterprises need to invest higher environmental protection treatment costs to achieve standard emissions.

[0005] 2. The hole expansion stage consumes a lot of electricity, which increases the production cost of the enterprise.

[0006] CN115240984A discloses a method for cleaning and etching anode foil for high-voltage aluminum electrolytic capacitors, using hydrochloric acid and polyethylene glycol additives for electrochemical etching and hole expansion. Although this invention does not use nitric acid in the hole expansion stage, it does use electrochemical etching, which consumes a lot of electricity in the hole expansion stage. CN110289171A discloses a method for manufacturing phosphorus-free, hole-expanding aluminum electrolytic capacitor electrode foil, using a mixed solution of nitric acid, polyethanol ion active agent, and oxalic acid or oxalate for three-stage chemical etching. This invention uses nitric acid in the hole expansion stage, and the specific capacitance value at 520V is 0.78-0.81μF / cm 2 , the specific capacitance value of the etched foil 520V can be further improved.

[0007] Therefore, it is of great significance to develop an electroless pore expansion process that does not use nitric acid. Summary of the Invention

[0008] In order to solve the problems existing in the above-mentioned prior art, the object of the present invention is to provide a method for preparing high-voltage corrosion foil by using non-electrical hole expansion.

[0009] Another object of the present invention is to provide a high voltage etching foil.

[0010] Another object of the present invention is to provide an aluminum electrolytic capacitor.

[0011] In order to achieve the above object, the present invention provides the following technical solutions:

[0012] A method for preparing a high-voltage corrosion foil by using non-electrical hole expansion comprises the following steps:

[0013] S1. Pretreatment: Pre-treat the aluminum foil in hydrochloric acid;

[0014] S2. Pore treatment: The aluminum foil treated in step S1 is electrolyzed in a mixed solution of 25-35 wt% sulfuric acid and 2-8 wt% hydrochloric acid. The porosity treatment temperature is 65-75 ° C, the porosity treatment time is 80-120 s, and the current density is 0.1-0.8 A / cm 2 ;

[0015] S3 treatment: the aluminum foil after step S2 treatment in 0.5 ~ 1.5wt% hydrochloric acid treatment, the treatment temperature is 30 ~ 40 ℃, the treatment time is 60 ~ 120s;

[0016] S4. Primary pore expansion treatment: The aluminum foil treated in step S3 was subjected to a non-electric pore expansion in a mixed solution of 5 to 10 wt% hydrochloric acid and polyethylene glycol laurate, wherein the content of polyethylene glycol laurate was 0.1 to 1 g / L, the non-electric pore expansion temperature was 70 to 85 ° C, and the non-electric pore expansion time was 600 to 800 s;

[0017] S5. Secondary pore expansion treatment: The aluminum foil treated in step S4 is subjected to secondary non-electric pore expansion in a mixed solution of 1 to 5 wt% hydrochloric acid and glycolic acid, the glycolic acid content is 0.5 to 2 g / L, the non-electric pore expansion temperature is 70 to 80 ° C, and the non-electric pore expansion time is 600 to 800 s;

[0018] S6. Post-processing: Post-process the aluminum foil after the treatment in step S5.

[0019] The present invention adopts a two-stage non-electric pore expansion technology that does not use nitric acid, replaces the existing nitric acid electrochemical pore expansion with hydrochloric acid non-electric pore expansion, and adds different corrosion inhibitors to the etching solution of the two stages of non-electric pore expansion respectively. By controlling the amount of corrosion inhibitor added, the growth of the pores in the corrosion foil is effectively controlled. The first stage of pore expansion uses a large molecular organic corrosion inhibitor, polyethylene glycol laurate, which is dispersed on the surface of the aluminum foil and cannot enter the small pores of the aluminum foil, thereby inhibiting the corrosion of the aluminum foil surface and not affecting the growth of the internal pores of the aluminum foil. The second stage of pore expansion uses a small molecular organic corrosion inhibitor, glycolic acid. After the small molecular organic corrosion inhibitor enters the interior of the aluminum foil pores, the growth of the internal pores of the aluminum foil can be effectively controlled, and the pore merging caused by the collapse of the pore walls of adjacent pores can be reduced. The method adopted by the present invention greatly reduces the amount of nitric acid used in the non-electric pore expansion technology, reduces the cost of environmental protection treatment, reduces the power consumption in the pore expansion stage, and the two-stage non-electric pore expansion improves the uniformity of the pores in the corrosion foil, increases the number of pores in the corrosion foil, and thus increases the specific capacity of the corrosion foil.

[0020] The present invention provides an intermediate treatment between the pore forming treatment step and the pore enlargement treatment step, i.e., treating the corroded foil with hydrochloric acid, the purpose of which is to remove sulfate impurities attached to the surface of the aluminum foil after the pore forming (sulfate impurities form a passivation film on the corroded foil, which is not conducive to pore enlargement) and metal impurities such as copper and iron (metal impurities easily accelerate the reaction between the aluminum foil and the corrosive solution, resulting in comprehensive corrosion of the aluminum foil, which is not conducive to the longitudinal expansion of the hole inside), thereby ensuring that the subsequent pore enlargement proceeds smoothly.

[0021] Specifically, the content of polyethylene glycol laurate in step S4 can be 0.1 g / L, 0.2 g / L, 0.5Ag / L, 1.0 g / L or an interval range formed by any of the above values.

[0022] Preferably, the content of polyethylene glycol laurate in step S4 is 0.5-1 g / L.

[0023] Specifically, the content of glycolic acid in step S5 can be 0.5 g / L, 1.0 g / L, 1.5 g / L, 2.0 g / L or an interval range formed by any of the above values.

[0024] Preferably, the content of glycolic acid in step S5 is 0.5-1.5 g / L.

[0025] Specifically, the current density in step S2 can be 0.3A / cm 2 , 0.4A / cm 2 , 0.5A / cm 2 , 0.6A / cm 2 , 0.7A / cm 2 , 0.8A / cm 2 , or the range formed by any of the above values.

[0026] Preferably, the current density in step S2 is 0.3-0.8 A / cm 2 .

[0027] Specifically, the content of hydrochloric acid in step S3 can be 0.5 wt%, 0.8 wt%, 1.2 wt%, 1.5 wt% or any range formed by the above values.

[0028] Preferably, the content of hydrochloric acid in step S3 is 1-1.5 wt%.

[0029] Specifically, the content of hydrochloric acid in step S1 is 5-10 wt %, the pretreatment temperature is 75-85° C., and the pretreatment time is 100-150 s.

[0030] More specifically, the content of hydrochloric acid in step S1 can be 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt% or an interval range formed by any of the above values.

[0031] More specifically, the pre-treatment temperature in step S1 can be 75° C., 77° C., 80° C., 85° C., or any range formed by the above values.

[0032] Specifically, the post-processing includes washing the aluminum foil treated in step S5 with nitric acid and pure water in sequence, and drying it.

[0033] The present invention also protects the high-voltage etching foil prepared by the above method for preparing the high-voltage etching foil by utilizing non-electrical hole expansion.

[0034] Specifically, the capacity of the high voltage corrosion foil 520V is 0.900-0.920 μF / cm 2 .

[0035] The present invention also protects an aluminum electrolytic capacitor comprising the high-voltage corrosion foil.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention adopts a two-stage non-electric pore expansion method that does not use nitric acid, and adds polyethylene glycol laurate and glycolic acid to the mixed solution of the two-stage non-electric pore expansion, respectively. In the first stage of pore expansion, polyethylene glycol laurate can reduce the corrosion of the aluminum foil surface. By adjusting the amount of polyethylene glycol laurate added, the effective growth of the aluminum foil holes inside is guaranteed; in the second stage of pore expansion, by adjusting the amount of glycolic acid added, the aluminum foil surface corrosion is reduced and the excessive growth of the aluminum foil holes inside is slowed down. The two-stage non-electric pore expansion improves the uniformity of the pores in the etched foil during the pore expansion process and increases the specific volume of the non-electric pore expansion. In addition, the present invention adds a hydrochloric acid treatment before the pore expansion process to remove impurity ions attached to the aluminum foil surface, thereby improving the controllable operation of the distribution and number of pores in the etched foil.

[0038] The pore growth of the medium and high voltage corrosion foil prepared by the present invention is orderly and controllable, and the 520V capacity is 0.900~0.920μF / cm 2 . BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a surface SEM image of the high-voltage corrosion foil prepared in Example 1 taken at a magnification of 1000 times after the surface was polished to 10 μm.

[0040] Figure 2 This is a cross-sectional SEM image of the high-voltage corrosion foil sample prepared in Example 1, taken at a magnification of 600 times after being heated to 520V.

[0041] Figure 3 This is a surface SEM image of the high-voltage corrosion foil prepared in Comparative Example 2, taken at a magnification of 1000 times after the surface was polished to 10 μm.

[0042] Figure 4 This is a cross-sectional SEM image of the high-voltage corrosion foil sample prepared in Comparative Example 2, taken at a magnification of 600 times after being heated to 520V. DETAILED DESCRIPTION

[0043] The present invention is further described below with reference to the examples. These examples are intended to illustrate the present invention only and are not intended to limit the scope of the present invention. Experimental methods in the following examples where specific conditions are not specified are generally performed in accordance with conventional conditions in the art or the conditions recommended by the manufacturer; the raw materials and reagents used, unless otherwise specified, are all commercially available from conventional markets. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention fall within the scope of protection claimed in the present invention.

[0044] Example 1

[0045] This embodiment provides a method for preparing a high-voltage etching foil by using electroless hole expansion, comprising the following steps:

[0046] S1. Pretreatment: Soak aluminum foil in 10 wt% hydrochloric acid solution at 75°C for 100 s.

[0047] S2. Pore treatment: The foil treated in step S1 was placed in a mixed solution of 35wt% sulfuric acid and 5wt% hydrochloric acid for DC electrolysis. The porosity treatment temperature was 70°C and the current density was 0.60A / cm 2 , the pore treatment time is 100s;

[0048] S3 treatment: The foil after step S2 was immersed in a 0.5wt% hydrochloric acid solution, the immersion temperature was 40 ℃, and the immersion time was 120s;

[0049] S4. Primary pore expansion treatment: The foil treated in step S3 was placed in a 10% hydrochloric acid solution containing 0.1 g / L polyethylene glycol laurate for non-electrical pore expansion; the non-electrical pore expansion temperature was 75 ° C, and the non-electrical pore expansion time was 800 s;

[0050] S5. Secondary pore expansion treatment: The foil treated in step S4 was placed in a 5 wt % hydrochloric acid solution containing 0.5 g / L glycolic acid for non-electrical pore expansion; the non-electrical pore expansion temperature was 70 ° C, and the non-electrical pore expansion time was 800 s;

[0051] S6. Post-processing: The foil processed in step S5 is washed in nitric acid solution, washed with pure water, and dried to obtain a medium- and high-voltage corrosion foil.

[0052] Example 2

[0053] This embodiment provides a method for preparing a high-voltage etching foil by using electroless hole expansion, comprising the following steps:

[0054] S1. Pretreatment: Soak aluminum foil in 5 wt% hydrochloric acid solution at 85°C for 150 s.

[0055] S2. Pore treatment: The foil after step S1 was placed in a mixed solution of 25wt% sulfuric acid and 8wt% hydrochloric acid for DC electrolysis. The porosity treatment temperature was 75°C and the current density was 0.80A / cm 2 , the pore treatment time is 80s;

[0056] S3 treatment: the foil after step S2 was immersed in a 1wt% hydrochloric acid solution, the immersion temperature was 30 ℃, the immersion time was 60s;

[0057] S4 primary pore expansion treatment: The foil after step S3 was placed in a 5wt% hydrochloric acid solution containing 1g / L polyethylene glycol laurate for non-electrical pore expansion; the non-electrical pore expansion temperature was 85 ° C, and the non-electrical pore expansion time was 600s;

[0058] S5. Secondary pore expansion treatment: The foil treated in step S4 was placed in a 1 wt % hydrochloric acid solution containing 0.5 g / L glycolic acid for non-electrical pore expansion; the non-electrical pore expansion temperature was 80 ° C, and the non-electrical pore expansion time was 600 s;

[0059] S6. Post-processing: The foil processed in step S5 is washed in nitric acid solution, washed with pure water, and dried to obtain a medium- and high-voltage corrosion foil.

[0060] Example 3

[0061] This embodiment provides a method for preparing a high-voltage etching foil by using electroless hole expansion, comprising the following steps:

[0062] S1. Pretreatment: Soak aluminum foil in 8 wt% hydrochloric acid solution at 80°C for 120 s.

[0063] S2. Pore treatment: The foil treated in step S1 was placed in a mixed solution of 30wt% sulfuric acid and 2wt% hydrochloric acid for DC electrolysis. The porosity treatment temperature was 75°C and the current density was 0.30A / cm 2 , the pore treatment time is 120s;

[0064] S3 treatment: the foil after step S2 was immersed in a 1.5wt% hydrochloric acid solution, the immersion temperature was 35 ℃, the immersion time was 90s;

[0065] S4 primary pore expansion treatment: The foil after step S3 was placed in an 8% hydrochloric acid solution containing 0.5 g / L polyethylene glycol laurate for non-electrical pore expansion; the non-electrical pore expansion temperature was 80 ° C, and the non-electrical pore expansion time was 700s;

[0066] S5. Secondary pore expansion treatment: The foil treated in step S4 was placed in a 3 wt % hydrochloric acid solution containing 1 g / L glycolic acid for non-electrical pore expansion; the non-electrical pore expansion temperature was 75 ° C, and the non-electrical pore expansion time was 600 s;

[0067] S6. Post-processing: The foil processed in step S5 is washed in nitric acid solution, washed with pure water, and dried to obtain a medium- and high-voltage corrosion foil.

[0068] Example 4

[0069] This embodiment provides a method for preparing a high-voltage corrosion foil by using electroless hole expansion. The steps are basically the same as those in Example 1, except that in step S4, the content of polyethylene glycol laurate in the mixed solution is 0.8 g / L.

[0070] Example 5

[0071] This embodiment provides a method for preparing a high-voltage etching foil by electroless hole expansion. The steps are basically the same as those in Example 2, except that in step S5, the glycolic acid content in the mixed solution is 1.5 g / L.

[0072] Example 6

[0073] This embodiment provides a method for preparing a high-voltage corrosion foil by using non-electric expansion. The steps are basically the same as those in Example 3, except that: in step S3, the concentration of the hydrochloric acid solution in the treatment is 1.0wt%, the immersion temperature is 40°C, and the treatment time is 110s.

[0074] Example 7

[0075] This embodiment provides a method for preparing a high-voltage corrosion foil by using non-electric expansion. The steps are basically the same as those in Example 1, except that: in step S4, the temperature of the non-electric expansion is 85°C, and the time of the non-electric expansion is 650s.

[0076] Example 8

[0077] This embodiment provides a method for preparing a high-voltage corrosion foil by using non-electric expansion. The steps are basically the same as those in Example 2, except that: in step S5, the temperature of the non-electric expansion is 75°C, and the time of the non-electric expansion is 650s.

[0078] Comparative Example 1

[0079] This comparative example provides a method for preparing a high-voltage corrosion foil by electrochemical hole expansion, comprising the following steps:

[0080] S1. Pretreatment: Soak aluminum foil in 1.5 wt% hydrochloric acid at 65°C for 200 seconds.

[0081] S2. Pore treatment: The foil treated in step S1 was placed in a mixed solution of 35wt% sulfuric acid and 5wt% hydrochloric acid for DC electrolysis. The porosity treatment temperature was 70°C and the current density was 0.60A / cm 2 The pore treatment time is 100s.

[0082] S3. Intermediate treatment: soak the foil treated in step S2 in a 1 wt % hydrochloric acid solution at a temperature of 30° C. for 60 seconds.

[0083] S4. Hole expansion treatment: After the foil was cleaned with tap water, a DC constant current was applied to expand the hole in a 10 wt% nitric acid solution at a temperature of 70°C and a current density of 0.15 A / cm 2 , the expansion time is 600s.

[0084] S5. Post-processing: The foil after electrochemical expansion in S4 is chemically cleaned with a nitric acid solution, washed with pure water, and then dried to obtain a high-voltage corrosion foil.

[0085] Comparative Example 2

[0086] This comparative example provides a method for preparing a high-voltage corrosion foil by using non-electric hole expansion. The steps are basically the same as those in Example 1, except that: there is no treatment in step S3, and the first-level hole expansion treatment is directly performed after the hole forming treatment.

[0087] Comparative Example 3

[0088] This comparative example provides a method for preparing a high-voltage etching foil by using non-electrolytic hole expansion. The steps are basically the same as those in Example 1, except that the treatment temperature in step S3 is 45°C.

[0089] Comparative Example 4

[0090] This comparative example provides a method for preparing a high-voltage corrosion foil by using electroless hole expansion. The steps are basically the same as those in Example 2, except that: in step S4, the content of polyethylene glycol laurate is 0.05 g / L.

[0091] Comparative Example 5

[0092] This comparative example provides a method for preparing a high-voltage corrosion foil by using electroless hole expansion. The steps are basically the same as those in Example 2, except that: in step S4, the content of polyethylene glycol laurate is 1.5 g / L.

[0093] Comparative Example 6

[0094] This comparative example provides a method for preparing a high-voltage corrosion foil by using electroless hole expansion. The steps are basically the same as those in Example 2, except that: in step S5, the glycolic acid content is 0.25 g / L.

[0095] Comparative Example 7

[0096] This comparative example provides a method for preparing a high-voltage corrosion foil by using electroless hole expansion. The steps are basically the same as those in Example 2, except that: in step S5, the glycolic acid content is 2.5 g / L.

[0097] Comparative Example 8

[0098] This comparative example provides a method for preparing a high-voltage corrosion foil by using electroless hole expansion. The steps are basically the same as those in Example 2, except that: in step S4, the content of lauric acid polyethylene glycol is 0 g / L, and in step S5, the content of glycolic acid is 0 g / L.

[0099] Performance Testing

[0100] The prepared corrosion foil was subjected to 520V chemical conversion according to the "Electronic Industry Standard of the People's Republic of China SJ / T1140-2012: Electrode Foil for Aluminum Electrolytic Capacitors" to obtain aluminum foil products, and the performance of the aluminum foil products was tested. The specific results are shown in Table 1

[0101] Table 1

[0102] Serial number Bending strength (back) <![CDATA[520V capacitance (μF / cm 2 )]]> Example 1 70 0.920 Example 2 72 0.916 Example 3 76 0.912 Example 4 77 0.905 Example 5 78 0.902 Example 6 76 0.908 Example 7 73 0.911 Example 8 71 0.917 Comparative Example 1 72 0.880 Comparative Example 2 95 0.801 Comparative Example 3 85 0.851 Comparative Example 4 81 0.875 Comparative Example 5 86 0.845 Comparative Example 6 83 0.862 Comparative Example 7 85 0.850 Comparative Example 8 110 0.735

[0103] From the data of Examples 1 to 8, it can be seen that the bending strength of the high-voltage corrosion foil prepared by the present invention is 70 to 78 times, which meets the requirements of product use. The capacitance under the 520V specific capacitance test is 0.900 to 0.920 μF / cm 2 .

[0104] It can be seen from Example 1 and Comparative Example 1 that the specific volume of the etched foil prepared by the non-electrolytic pore expansion method of the present invention is higher than the specific volume of the etched foil prepared by electrochemical pore expansion.

[0105] As shown in Example 1, Comparative Examples 2, and 3, when the method of the present invention does not utilize the intermediate treatment step to treat the aluminum foil, the capacity of the resulting high-voltage etched foil is significantly reduced. The intermediate treatment temperature also has a certain impact on the capacity of the high-voltage etched foil. When the treatment temperature is 45°C, the capacity of the high-voltage etched foil prepared is lower than that of the high-voltage etched foil prepared at 30°C in Example 1.

[0106] It can be seen from Example 2, Comparative Example 4, Comparative Example 5, Comparative Example 6, and Comparative Example 7 that when the amount of the two corrosion inhibitors polyethylene glycol laurate and glycolic acid used in the method described in the present invention is too much or insufficient, the capacity of the high-voltage corrosion foil prepared is significantly reduced. When the amount of polyethylene glycol laurate is too low, the surface of the aluminum foil is severely corroded, resulting in a low specific volume; when the amount of polyethylene glycol laurate is too high, the amount of polyethylene glycol laurate attached to the surface of the aluminum foil is large, making it difficult for the aluminum ions produced by the pore expansion reaction inside the aluminum foil pores to be transported to the outside of the pores, hindering the continued expansion of the pores, resulting in a low specific volume. When the glycolic acid content is too low, the amount of glycolic acid entering the aluminum foil pores is too small, causing the internal pore expansion speed of the aluminum foil to be too fast, thereby causing adjacent pores to merge and resulting in a low specific volume; when the glycolic acid content is too high, the amount of glycolic acid entering the aluminum foil pores is too much, seriously hindering the internal pore expansion reaction and resulting in a low specific volume.

[0107] As can be seen from Example 2 and Comparative 8, when neither polyethylene glycol laurate nor glycolic acid corrosion inhibitors are used during the electroless pore expansion process, the specific volume of the corroded foil decreases significantly. This is because when the pore expansion solution lacks a corrosion inhibitor, surface erosion of the aluminum foil and disordered internal pore expansion proceed simultaneously, resulting in severe pore consolidation in the corroded foil and a low specific volume.

[0108] Figure 1This is a surface SEM image of the high-voltage corrosion foil prepared in Example 1 taken at a magnification of 1000 times after the surface was polished to 10 μm. Figure 2 This is a cross-sectional SEM image of the high-voltage corrosion foil sample prepared in Example 1, taken at 600 times magnification after being heated to 520V. Figure 1 It can be seen that the number of holes in the corrosion foil obtained in Example 1 is greater and the distribution is more uniform. Figure 2 It can be seen that the longitudinal growth depth of the holes in the etched foil obtained in Example 1 is relatively long.

[0109] Figure 3 This is a surface SEM image of the high-voltage corrosion foil prepared in Comparative Example 2, taken at a magnification of 1000 times after the surface was polished to 10 μm. Figure 4 This is a cross-sectional SEM image of the high-voltage corrosion foil sample prepared in Comparative Example 2, taken at 600 times magnification after being heated to 520V. Figure 3 It can be seen that the number of holes in the etched foil obtained in Example 2 is relatively small and unevenly distributed. Figure 4 It can be seen that the longitudinal growth depth of the holes in the etched foil obtained in Example 2 is shorter.

[0110] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing high-voltage corrosion foil by using non-electric expansion, characterized in that: The following steps are involved: S1. Pretreatment: Pre-treat the aluminum foil in hydrochloric acid; S2. Pore treatment: The aluminum foil treated in step S1 is electrolyzed in a mixed solution of 25-35 wt% sulfuric acid and 2-8 wt% hydrochloric acid. The porosity treatment temperature is 65-75 ° C, the porosity treatment time is 80-120 s, and the current density is 0.1-0.8 A / cm 2 ; S3 treatment: the aluminum foil after step S2 treatment in 0.5 ~ 1.5wt% hydrochloric acid treatment, the treatment temperature is 30 ~ 40 ℃, the treatment time is 60 ~ 120s; S4. Primary pore expansion treatment: The aluminum foil treated in step S3 was subjected to a non-electric pore expansion in a mixed solution of 5 to 10 wt% hydrochloric acid and polyethylene glycol laurate, wherein the content of polyethylene glycol laurate was 0.1 to 1 g / L, the non-electric pore expansion temperature was 70 to 85 ° C, and the non-electric pore expansion time was 600 to 800 s; S5. Secondary pore expansion treatment: The aluminum foil treated in step S4 is subjected to secondary non-electric pore expansion in a mixed solution of 1 to 5 wt% hydrochloric acid and glycolic acid, the glycolic acid content is 0.5 to 2 g / L, the non-electric pore expansion temperature is 70 to 80 ° C, and the non-electric pore expansion time is 600 to 800 s; S6. Post-processing: Post-process the aluminum foil after the treatment in step S5.

2. The method according to claim 1, characterized in that The content of polyethylene glycol laurate in step S4 is 0.5-1 g / L.

3. The method according to claim 1, characterized in that The content of glycolic acid in step S5 is 0.5-1.5 g / L.

4. The method according to claim 1, characterized in that The current density in step S2 is 0.3-0.8 A / cm 2 .

5. The method according to claim 1, characterized in that: The content of hydrochloric acid in step S3 is 1-1.5 wt%.

6. The method according to claim 1, characterized in that The content of hydrochloric acid in step S1 is 5-10 wt %, the pretreatment temperature is 75-85° C., and the pretreatment time is 100-150 s.

7. The method according to claim 1, characterized in that: The post-processing includes washing the aluminum foil treated in step S5 with nitric acid and pure water in sequence, and drying it.

8. A high voltage etched foil produced by the method for producing a high voltage etched foil by using non-electrical hole expansion as claimed in any one of claims 1 to 7.

9. The high voltage corrosion foil according to claim 8, characterized in that: The capacity of the high voltage corrosion foil 520V is 0.900~0.920μF / cm 2 .

10. An aluminum electrolytic capacitor, characterized in that: The invention comprises the high-voltage corrosion foil according to claim 8 or 9.

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