Composite pulse waveform pore generation technology for high-thickness aluminium foil anode foil

Abstract

The present invention relates to the technical field of anode foil pulse pore generation and specifically relates to a composite pulse waveform pore generation technology for a high-thickness aluminium foil anode foil. In the composite pulse waveform pore generation technology for a high-thickness aluminium foil anode foil of the present invention, a low-frequency pulse is used in the initial stage of pore generation, a high-frequency pulse is used in the middle and later stages of tunnel pore growth, and low-frequency pulsing is performed one more time after alternating between the low-frequency pulse and the high-frequency pulse several times, thereby optimizing the structure and properties of an anodic oxide film, refining pores, improving the density and uniformity of the pores, and significantly improving the specific capacitance and mechanical properties of a finished etched foil.

Description

High-thickness aluminum foil anode foil composite pulse waveform pore-forming technology TECHNICAL FIELD

[0001] The present application relates to the technical field of anode foil pulse pore-forming technology, in particular to high-thickness aluminum foil anode foil composite pulse waveform pore-forming technology. BACKGROUND

[0002] In the modern electronic industry, high-purity aluminum foil anode foil as an important component of electrolytic capacitors, the optimization of its manufacturing process is crucial to improve the performance of the capacitor. At present, many front-end enterprises mostly produce using a single pulse waveform for pore-forming. Compared with traditional direct current pore-forming anode foil, this pore-forming method has obvious improvement in capacity. However, during the pulse waveform pore-forming process, there is a large instantaneous current at the top, and some pore-forming waveforms cause current enrichment on both sides of the electrode, resulting in a decrease in residual core uniformity and an increase in residual core penetration, thereby affecting the capacity and mechanical strength. Moreover, high-thickness aluminum foil anode foil is particularly affected.

[0003] Patent technology document CN104505260A discloses a method for preparing middle-high voltage etching foil by superimposed pulse direct current. The invention generates holes by the method of superimposed pulse direct current through primary pore-forming, which has a simple process flow, improves the specific capacitance and mechanical properties of the etching foil, and solves the limitation that the pore-forming process in the traditional etching process cannot be powered off. However, the distribution uniformity of the holes on the surface of the aluminum foil obtained by the invention is still lacking, resulting in inconsistent specific surface area and affecting the performance of the aluminum foil.

[0004] Composite pulse (pulse waveform superimposed pulse waveform) pore-forming technology reduces the instantaneous current at the top due to the superposition of pulse waveforms, which causes the current to flow continuously without instantaneous current generation. At the same time, by reasonably designing the parameters of the pulse current, the composite pulse can fully utilize the electromigration effect to optimize the current distribution and enrichment, prevent excessive corrosion caused by local current enrichment, and make the distribution of holes more uniform and the specific surface area higher. However, the frequency of the pulse also affects the shape and distribution of the pore-forming of the anode foil. SUMMARY

[0005] In view of the above, the purpose of the present application is to provide high-thickness aluminum foil anode foil composite pulse waveform pore-forming technology, which is a pulse pore-forming technology for high-thickness aluminum foil anode foil, so that the high-thickness aluminum foil anode foil after pulse treatment has excellent specific capacity and mechanical properties.

[0006] To achieve the above purpose, the present application provides high-thickness aluminum foil anode foil composite pulse waveform pore-forming technology, which comprises the following steps:

[0007] S1: placing the light foil in a phosphoric acid solution, and then taking it out for water washing;

[0008] S2: the aluminum foil obtained in S1 is subjected to a pore forming treatment;

[0009] S3: the aluminum foil obtained in S2 is subjected to a pore expanding treatment;

[0010] S4: the aluminum foil obtained in S3 is first washed in a dilute hydrochloric acid solution, then washed in a dilute nitric acid solution, and finally washed with pure water and dried;

[0011] S5: the aluminum foil obtained in S4 is subjected to a chemical conversion treatment to obtain a finished etching foil;

[0012] The pore forming treatment in step S2 is a composite pulse superimposed pore forming treatment of the aluminum foil obtained in S1 in a mixed bath solution of 0.5-1 mol / L hydrochloric acid, 3.2-3.8 mol / L sulfuric acid and 0.01-0.05 mol / L phosphoric acid at a temperature of 60-73℃, and the specific process is as follows:

[0013] firstly at 1.7-1.9 A / cm 2 for 0.5-2 s, superimposed pulse, frequency 500-700 Hz, duty cycle 30%-37%, superimposed size ±0.03-0.05 A / cm 2 ; then at 1.2-1.7 A / cm 2 for 1.5-3 s, superimposed pulse, frequency 700-800 Hz, duty cycle 45%-50%, superimposed size ±0.03-0.05 A / cm 2 ; again at 0.5-1.2 A / cm 2 for 1.5-3 s, superimposed pulse, frequency 700-800 Hz, duty cycle 45%-50%, superimposed size ±0.03-0.05 A / cm 2 ; then at 0.3-0.5 A / cm 2 for 2-5 s, superimposed pulse, frequency 800-900 Hz, duty cycle 45%-50%, superimposed size ±0.02-0.03 A / cm 2 ; finally at 0.15-0.3 A / cm 2 for 10-15 s, superimposed pulse, frequency 1000-1500 Hz, duty cycle 45%-50%, superimposed size ±0.01-0.015 A / cm 2 ; after the above pore forming step is repeated for 3-5 times, at 1.7-1.9 A / cm 2 for 0.5-2 s, superimposed pulse, frequency 500-700 Hz, duty cycle 30%-37%, superimposed size ±0.03-0.05 A / cm 2 .

[0014] Preferably, the concentration of the phosphoric acid solution in step S1 is 1.5-3 mol / L, the temperature is 65-70℃, and the time is 30-120 s.

[0015] Preferably, the light foil in step S1 is a thick light foil of 140-150 μm.

[0016] Preferably, the hole expansion treatment in step S3 is a hole expansion treatment of the aluminum foil obtained in S2 in a mixed tank solution of 1.1-1.5 mol / L nitric acid, 0.05-0.1 mol / L phosphoric acid, and 0.02-0.08 g / L sodium polystyrene sulfonate.

[0017] Preferably, the hole expansion treatment has a temperature of 60-80℃, a constant current density of 0.12-17 A / cm 2 , and a duration of 13-16 min.

[0018] Preferably, the concentration of the dilute hydrochloric acid solution in step S4 is 0.03-0.1 mol / L, and the concentration of the dilute nitric acid solution is 0.1-0.2 mol / L.

[0019] Preferably, the temperature for washing in the dilute hydrochloric acid solution in step S4 is 60-65℃, and the washing time is 1-3 min.

[0020] Preferably, the temperature for washing in the dilute nitric acid solution in step S4 is 65-70℃, and the washing time is 1-3 min.

[0021] Preferably, the pure water rinsing time in step S4 is 8-15 min.

[0022] Preferably, the temperature for drying in step S4 is 180-270℃.

[0023] Preferably, the process of the chemical conversion in step S5 is as follows: the obtained aluminum foil is put into pure water at 90-95°C for boiling for 7-15 min, then put into a mixed solution of adipic acid (0.05wt%-0.2wt%), ammonium adipate (0.1wt%-0.3wt%), boric acid (0.1wt%-0.15wt%) and maleic acid (0.01wt%-0.1wt%) at 90-95°C for primary chemical conversion for 7-10 min, the chemical conversion voltage is 160-170V, then put into a mixed solution of citric acid (0.04wt%-0.06wt%), ammonium citrate (0.01wt%-0.07wt%) and boric acid (0.1wt%-0.3wt%) at 85-90°C for secondary chemical conversion for 7-10 min, the chemical conversion voltage is 290-300V, then put into a mixed solution of citric acid (0.02wt%-0.04wt%), ammonium citrate (0.03wt%-0.08wt%) and boric acid (0.4wt%-1wt%) at 85-90°C for tertiary chemical conversion for 7-10 min, the chemical conversion voltage is 440-450V, then put into a mixed solution of citric acid (0.01wt%-0.03wt%), ammonium citrate (0.04wt%-0.06wt%), boric acid (0.4wt%-1wt%) and azelaic acid (0.003wt%-0.005wt%) at 85-90°C for quaternary chemical conversion for 15-20 min, the chemical conversion voltage is 550-560V; then put into ammonia water (70wt%-80wt%) at 60-80°C for boiling for 5-10 min, then put into a mixed solution of citric acid (0.01wt%-0.03wt%), ammonium citrate (0.04wt%-0.06wt%), boric acid (0.4wt%-1wt%) and azelaic acid (0.003wt%-0.005wt%) at 85-90°C for post-secondary chemical conversion for 15-20 min, the chemical conversion voltage is 550-560V, then put into ammonia water (70wt%-80wt%) at 60-80°C for boiling for 5-10 min, after washing with water, heat treatment at 450-500°C for 5-7 min, then put into a mixed solution of citric acid (0.002wt%-0.01wt%), ammonium citrate (0.002wt%-0.01wt%) and boric acid (0.1wt%-0.5wt%) at 85-90°C for post-secondary chemical conversion for 12-15 min, the chemical conversion voltage is 550-560V, then put into phosphoric acid (7wt%-10wt%) at 85-90°C for boiling for 5-7 min, after washing with water, heat treatment at 450-500°C for 5-7 min, then put into a mixed solution of citric acid (0.002wt%-0.01wt%), ammonium citrate (0.002wt%-0.01wt%) and boric acid (0.1wt%-0.The mixture (5wt%) is subjected to a three-stage formation process at 85-90℃ for 12-15 minutes, with a formation voltage of 550-560V. Then, it is placed in ammonium dihydrogen phosphate (7wt%-10wt%) and boiled in water at 85-90℃ for 5-7 minutes. Finally, it is dried in an oven at 100-150℃. Beneficial effects

[0024] The high-thickness aluminum foil anode foil composite pulse waveform perforation technology of the present invention, compared with the traditional perforation process, results in a high-thickness etched foil with significant improvements in both electrostatic capacitance and mechanical properties.

[0025] The high-thickness aluminum foil anode foil composite pulse waveform aperture generation technology of the present invention, by using low-frequency pulse superposition in the initial stage of aperture generation and high-frequency pulse superposition in the middle and later stages of tunnel hole growth, significantly improves the density and uniformity of the holes on the aluminum foil surface, thereby further improving the electrostatic capacity and mechanical strength of the etched foil. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in this invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0027] Figure 1 is a microscopic characterization diagram of the residual core layer of the sample obtained in Example 2 of the present invention;

[0028] Figure 2 is a microscopic characterization diagram of the surface layer of the sample obtained in Example 2 of the present invention;

[0029] Figure 3 is a microscopic characterization diagram of the residual core layer of the sample obtained in Comparative Example 4 of the present invention.

[0030] Figure 4 is a microscopic characterization diagram of the surface layer of the sample obtained in Comparative Example 4 of the present invention.

[0031] Figure 5 is a schematic diagram of the composite pulse superposition waveform during pulse blasting in Embodiment 2 of the present invention;

[0032] Figure 6 is a partially enlarged view of the composite pulse superposition waveform during pulse blasting in Embodiment 2 of the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0034] The thickness of the thick light foil used in the inventive examples and the comparative examples is 145 μm; the formation process used in the inventive examples and the comparative examples is as follows: the obtained aluminum foil is put into 93℃ pure water and boiled for 10 min, then put into a mixed solution of adipic acid (0.1 wt%), ammonium adipate (0.2 wt%), boric acid (0.1 wt%) and maleic acid (0.05 wt%) at 93℃ for primary formation for 8 min, the formation voltage is 165 V, then put into a mixed solution of citric acid (0.05 wt%), ammonium citrate (0.04 wt%) and boric acid (0.2 wt%) at 87℃ for secondary formation for 8 min, the formation voltage is 295 V, then put into a mixed solution of citric acid (0.03 wt%), ammonium citrate (0.05 wt%) and boric acid (0.7 wt%) at 87℃ for tertiary formation for 7 min, the formation voltage is 447 V, then put into a mixed solution of citric acid (0.02 wt%), ammonium citrate (0.05 wt%), boric acid (0.7 wt%) and azelaic acid (0.004 wt%) at 87℃ for quaternary formation for 17 min, the formation voltage is 555 V; then put into ammonia water (75 wt%) at 60-80℃ and boiled for 8 min, then put into a mixed solution of citric acid (0.02 wt%), ammonium citrate (0.05 wt%), boric acid (0.5 wt%) and azelaic acid (0.004 wt%) at 87℃ for post-secondary formation for 17 min, the formation voltage is 557 V, then put into ammonia water (75 wt%) at 70℃ and boiled for 7 min, after washing with water, heat treatment at 480℃ for 6 min, then put into a mixed solution of citric acid (0.008 wt%), ammonium citrate (0.007 wt%) and boric acid (0.4 wt%) at 87℃ for post-tertiary formation for 13 min, the formation voltage is 555 V, then put into phosphoric acid (8 wt%) at 88℃ and boiled for 6 min, after washing with water, heat treatment at 480℃ for 6 min, then put into a mixed solution of citric acid (0.006 wt%), ammonium citrate (0.008 wt%) and boric acid (0.3 wt%) at 88℃ for post-quaternary formation for 14 min, the formation voltage is 555 V, then put into ammonium dihydrogen phosphate (8 wt%) at 88℃ and boiled for 6 min, and finally dried in an oven at 130℃;

[0035] The parameters of the rest of the formation process can be the same, which will not be repeated here.

[0036] Example 1: A high-thickness aluminum foil anode foil composite pulse waveform pore-forming technology, the specific process is as follows:

[0037] (1) Put the 145 μm thick light foil into a 65℃, 1.5 mol / L phosphoric acid solution, take it out after 120 s, and wash it with pure water;

[0038] (2) The aluminum foil obtained in (1) is placed in a mixed tank solution of 0.5 mol / L hydrochloric acid, 3.2 mol / L sulfuric acid and 0.01 mol / L phosphoric acid, and is subjected to pulse hole formation at a temperature of 60°C. First, 1.7 A / cm 2 for 0.5 s, superimposed pulse, frequency 500 Hz, duty cycle 30%, superimposed size ± 0.03 A / cm 2 ; then 1.2 A / cm 2 for 1.5 s, superimposed pulse, frequency 700 Hz, duty cycle 45%, superimposed size ± 0.03 A / cm 2 ; again 0.5 A / cm 2 for 1.5 s, superimposed pulse, frequency 700 Hz, duty cycle 45%, superimposed size ± 0.03 A / cm 2 ; then 0.3 A / cm 2 for 2 s, superimposed pulse, frequency 800 Hz, duty cycle 45%, superimposed size ± 0.02 A / cm 2 ; finally 0.15 A / cm 2 for 10 s, superimposed pulse, frequency 1000 Hz, duty cycle 45%, superimposed size ± 0.01 A / cm 2 ; after the above hole formation step is repeated 3 times, 1.7 A / cm 2 for 0.5 s, superimposed pulse, frequency 500 Hz, duty cycle 30%, superimposed size ± 0.03 A / cm 2 ;

[0039] (3) The aluminum foil obtained in (2) is placed in a mixed tank solution of 1.1 mol / L nitric acid, 0.05 mol / L phosphoric acid and 0.02 g / L sodium polystyrene sulfonate, and is subjected to hole expansion. The hole expansion temperature is 60°C, the constant current density is 0.12 A / cm 2 , and the duration is 13 min;

[0040] (4) The aluminum foil obtained in (3) is placed in a 0.03 mol / L dilute hydrochloric acid solution, washed at 60°C for 1 min, then placed in a 0.1 mol / L dilute nitric acid solution, washed at 65°C for 1 min, then washed with pure water for 8 min, and dried at 180°C;

[0041] (5) The aluminum foil obtained in (4) is subjected to chemical treatment to obtain a finished etching foil.

[0042] Example 2: A high-thickness aluminum foil anode foil composite pulse waveform hole formation technology, the specific process is as follows:

[0043] (1) Place a 145 μm thick light foil in a 68°C, 2.5 mol / L phosphoric acid solution, and take it out after 60 s, and wash it thoroughly with pure water;

[0044] (2) The aluminum foil obtained in (1) is placed in a mixed tank solution of 0.8 mol / L hydrochloric acid, 3.5 mol / L sulfuric acid and 0.03 mol / L phosphoric acid, and is subjected to pulse hole formation at a temperature of 65°C. First, 1.8 A / cm 2 is applied for 1.5 s, superimposed pulses with a frequency of 600 Hz, a duty cycle of 34%, and a superimposed size of ±0.04 A / cm 2 ; then 1.4 A / cm 2 is applied for 2.5 s, superimposed pulses with a frequency of 750 Hz, a duty cycle of 48%, and a superimposed size of ±0.04 A / cm 2 ; then 0.8 A / cm 2 is applied for 2 s, superimposed pulses with a frequency of 750 Hz, a duty cycle of 48%, and a superimposed size of ±0.04 A / cm 2 ; then 0.4 A / cm 2 is applied for 4 s, superimposed pulses with a frequency of 850 Hz, a duty cycle of 48%, and a superimposed size of ±0.03 A / cm 2 ; finally, 0.25 A / cm 2 is applied for 13 s, superimposed pulses with a frequency of 1300 Hz, a duty cycle of 48%, and a superimposed size of ±0.015 A / cm 2 ; after the above hole formation step is repeated 4 times, 1.8 A / cm 2 is applied for 1.5 s, superimposed pulses with a frequency of 600 Hz, a duty cycle of 33%, and a superimposed size of ±0.04 A / cm 2 ;

[0045] (3) The aluminum foil obtained in (2) is placed in a mixed tank solution of 1.3 mol / L nitric acid, 0.1 mol / L phosphoric acid and 0.05 g / L sodium polystyrene sulfonate, and is subjected to hole expansion. The hole expansion temperature is 70°C, the constant current density is 10 A / cm 2 , and the duration is 15 min;

[0046] (4) The aluminum foil obtained in (3) is placed in a 0.07 mol / L dilute hydrochloric acid solution, washed at 63°C for 2 min, then placed in a 0.2 mol / L dilute nitric acid solution, washed at 68°C for 2 min, then washed with pure water for 12 min, and dried at 220°C;

[0047] (5) The aluminum foil obtained in (4) is subjected to chemical treatment to obtain a finished etching foil.

[0048] Example 3: A high-thickness aluminum foil anode foil composite pulse waveform hole formation technology, the specific process is as follows:

[0049] (1) A 145 μm thick light foil is placed in a 70°C, 3 mol / L phosphoric acid solution, and washed with pure water after 30 s;

[0050] (2) The aluminum foil obtained in (1) is placed in a mixed tank solution of 1 mol / L hydrochloric acid, 3.8 mol / L sulfuric acid and 0.05 mol / L phosphoric acid, and is subjected to pulse hole formation at a temperature of 73°C. First, 1.9 A / cm 2 for 2 s, superimposed pulse, frequency 700 Hz, duty cycle 37%, superimposed size ±0.05 A / cm 2 ; then 1.7 A / cm 2 for 3 s, superimposed pulse, frequency 800 Hz, duty cycle 50%, superimposed size ±0.05 A / cm 2 ; again 1.2 A / cm 2 for 3 s, superimposed pulse, frequency 800 Hz, duty cycle 50%, superimposed size ±0.05 A / cm 2 ; then 0.5 A / cm 2 for 5 s, superimposed pulse, frequency 900 Hz, duty cycle 50%, superimposed size ±0.03 A / cm 2 ; finally 0.3 A / cm 2 for 15 s, superimposed pulse, frequency 1500 Hz, duty cycle 50%, superimposed size ±0.015 A / cm 2 ; after the above hole formation step is repeated 5 times, 1.9 A / cm 2 for 2 s, superimposed pulse, frequency 700 Hz, duty cycle 37%, superimposed size ±0.05 A / cm 2 ;

[0051] (3) The aluminum foil obtained in (2) is placed in a mixed tank solution of 1.5 mol / L nitric acid, 0.1 mol / L phosphoric acid and 0.08 g / L sodium polystyrene sulfonate, and is subjected to hole expansion. The hole expansion temperature is 80°C, the constant current density is 17 A / cm 2 , and the duration is 16 min;

[0052] (4) The aluminum foil obtained in (3) is placed in a 0.1 mol / L dilute hydrochloric acid solution, washed at 65°C for 3 min, then placed in a 0.2 mol / L dilute nitric acid solution, washed at 70°C for 3 min, then washed with pure water for 15 min, and dried at 270°C;

[0053] (5) The aluminum foil obtained in (4) is subjected to chemical treatment to obtain a finished etching foil.

[0054] Comparative Example 1: A high-thickness aluminum foil anode foil pulse hole formation technology, which is different from Example 2 in that the last low-frequency treatment is not performed. The specific process is as follows:

[0055] (1) Put the 145 μm thick light foil into 2.5 mol / L phosphoric acid solution at 68°C, and take it out after 60 s, and wash it with pure water;

[0056] (2) Put the aluminum foil obtained in (1) into a mixed tank solution of 0.8 mol / L hydrochloric acid, 3.5 mol / L sulfuric acid and 0.03 mol / L phosphoric acid, and perform pulse pore forming at a temperature of 65°C. First, 1.8 A / cm 2 is maintained for 1.5 s, the superimposed pulse has a frequency of 600 Hz, a duty cycle of 34%, and a superimposed size of ±0.04 A / cm 2 ; then 1.4 A / cm 2 is maintained for 2.5 s, the superimposed pulse has a frequency of 750 Hz, a duty cycle of 48%, and a superimposed size of ±0.04 A / cm 2 ; then 0.8 A / cm 2 is maintained for 2 s, the superimposed pulse has a frequency of 750 Hz, a duty cycle of 48%, and a superimposed size of ±0.04 A / cm 2 ; then 0.4 A / cm 2 is maintained for 4 s, the superimposed pulse has a frequency of 850 Hz, a duty cycle of 48%, and a superimposed size of ±0.03 A / cm 2 ; finally, 0.25 A / cm 2 is maintained for 13 s, the superimposed pulse has a frequency of 1300 Hz, a duty cycle of 48%, and a superimposed size of ±0.015 A / cm 2 , and the above pore forming step is repeated 4 times;

[0057] (3) Put the aluminum foil obtained in (2) into a mixed tank solution of 1.3 mol / L nitric acid, 0.1 mol / L phosphoric acid and 0.05 g / L sodium polystyrene sulfonate, and perform pore expansion at a temperature of 70°C and a constant current density of 10 A / cm 2 for 15 min;

[0058] (4) Put the aluminum foil obtained in (3) into a 0.07 mol / L dilute hydrochloric acid solution, wash it at 63°C for 2 min, then put it into a 0.2 mol / L dilute nitric acid solution, wash it at 68°C for 2 min, then wash it with pure water for 12 min, and dry it at 220°C;

[0059] (5) Perform formation treatment on the aluminum foil obtained in (4) to obtain a finished etching foil.

[0060] Comparative Example 2: A high-thickness aluminum foil anode foil pulse pore forming technology, which is different from Example 2 in that the pulse pore forming treatment is first performed at a high frequency, and then performed at a low frequency. The specific process is as follows:

[0061] (1) Put the 145 μm thick light foil into 2.5 mol / L phosphoric acid solution at 68°C, and take it out after 60 s, and wash it with pure water;

[0062] (2) Put the aluminum foil obtained in (1) into a mixed tank solution of 0.8 mol / L hydrochloric acid, 3.5 mol / L sulfuric acid and 0.03 mol / L phosphoric acid, and perform pulse pore forming at a temperature of 65°C. First, 0.25 A / cm 2 is applied for 13 s, superimposed pulse, frequency 1300 Hz, duty cycle 48%, superimposed size ±0.015 A / cm 2 ; then 0.4 A / cm 2 is applied for 4 s, superimposed pulse, frequency 850 Hz, duty cycle 48%, superimposed size ±0.03 A / cm 2 ; then 0.8 A / cm 2 is applied for 2 s, superimposed pulse, frequency 750 Hz, duty cycle 48%, superimposed size ±0.04 A / cm 2 ; then 1.4 A / cm 2 is applied for 2.5 s, superimposed pulse, frequency 750 Hz, duty cycle 48%, superimposed size ±0.04 A / cm 2 ; finally, 1.8 A / cm 2 is applied for 1.5 s, superimposed pulse, frequency 600 Hz, duty cycle 34%, superimposed size ±0.04 A / cm 2 ; the above pore forming step is repeated 4 times, then 1.8 A / cm 2 is applied for 1.5 s, superimposed pulse, frequency 600 Hz, duty cycle 33%, superimposed size ±0.04 A / cm 2 ;

[0063] (3) Put the aluminum foil obtained in (2) into a mixed tank solution of 1.3 mol / L nitric acid, 0.1 mol / L phosphoric acid and 0.05 g / L sodium polystyrene sulfonate, and perform pore expansion at a temperature of 70°C and a constant current density of 10 A / cm 2 for 15 min;

[0064] (4) Put the aluminum foil obtained in (3) into 0.07 mol / L dilute hydrochloric acid solution at 63°C for 2 min, then into 0.2 mol / L dilute nitric acid solution at 68°C for 2 min, then wash it with pure water for 12 min, and dry it at 220°C;

[0065] (5) Perform formation treatment on the aluminum foil obtained in (4) to obtain finished etching foil.

[0066] Comparative Example 3: A high-thickness aluminum foil anode foil pulse pore forming technology, which is different from Example 2 in that the mixed treatment is different, and the specific process is as follows:

[0067] (1) Put the 145 μm thick light aluminum foil into 2.5 mol / L phosphoric acid solution at 68°C, and take it out after 60 s, and wash it with pure water;

[0068] (2) Put the aluminum foil obtained in (1) into a mixed tank solution of 0.8 mol / L hydrochloric acid, 3.5 mol / L sulfuric acid and 0.03 mol / L phosphoric acid, and perform pulse pore forming at a temperature of 65°C. First, 0.4 A / cm 2 is maintained for 4 s, the superimposed pulse has a frequency of 850 Hz, a duty cycle of 48%, and a superimposed size of ±0.03 A / cm 2 ; then 0.8 A / cm 2 is maintained for 2 s, the superimposed pulse has a frequency of 750 Hz, a duty cycle of 48%, and a superimposed size of ±0.04 A / cm 2 ; then 1.8 A / cm 2 is maintained for 1.5 s, the superimposed pulse has a frequency of 600 Hz, a duty cycle of 34%, and a superimposed size of ±0.04 A / cm 2 ; then 1.4 A / cm 2 is maintained for 2.5 s, the superimposed pulse has a frequency of 750 Hz, a duty cycle of 48%, and a superimposed size of ±0.04 A / cm 2 ; finally, 0.25 A / cm 2 is maintained for 13 s, the superimposed pulse has a frequency of 1300 Hz, a duty cycle of 48%, and a superimposed size of ±0.015 A / cm 2 ; after the above pore forming step is repeated 4 times, 1.8 A / cm 2 is maintained for 1.5 s, the superimposed pulse has a frequency of 600 Hz, a duty cycle of 33%, and a superimposed size of ±0.04 A / cm 2 ;

[0069] (3) Put the aluminum foil obtained in (2) into a mixed tank solution of 1.3 mol / L nitric acid, 0.1 mol / L phosphoric acid and 0.05 g / L sodium polystyrene sulfonate, and perform pore expansion at a temperature of 70°C and a constant current density of 10 A / cm 2 for 15 min;

[0070] (4) Put the aluminum foil obtained in (3) into a 0.07 mol / L dilute hydrochloric acid solution, wash it at 63°C for 2 min, then put it into a 0.2 mol / L dilute nitric acid solution, wash it at 68°C for 2 min, then wash it with pure water for 12 min, and dry it at 220°C;

[0071] (5) Perform formation treatment on the aluminum foil obtained in (4) to obtain a finished etching foil.

[0072] Comparative Example 4: A high-thickness aluminum foil anode foil pulse hole forming technique, the specific process is as follows:

[0073] (1) Place 145 μm thick light foil in a 68°C, 2.5 mol / L phosphoric acid solution, and after 60 s, wash with pure water;

[0074] (2) Place the aluminum foil obtained in (1) in a mixed tank solution of 0.8 mol / L hydrochloric acid, 3.5 mol / L sulfuric acid and 0.03 mol / L phosphoric acid, and perform pulse hole forming at a temperature of 65°C. First, at 1.8 A / cm 2 for 1.5 s, then at 1.4 A / cm 2 for 2.5 s, then at 0.8 A / cm 2 for 2 s, then at 0.4 A / cm 2 for 4 s, and finally at 0.25 A / cm 2 for 13 s. The above hole forming step is repeated 4 times;

[0075] (3) Place the aluminum foil obtained in (2) in a mixed tank solution of 1.3 mol / L nitric acid, 0.1 mol / L phosphoric acid and 0.05 g / L sodium polystyrene sulfonate, and perform hole expansion at a temperature of 70°C and a constant current density of 10 A / cm 2 for 15 min;

[0076] (4) Place the aluminum foil obtained in (3) in a 0.07 mol / L dilute hydrochloric acid solution, and clean at 63°C for 2 min, then place it in a 0.2 mol / L dilute nitric acid solution, and clean at 68°C for 2 min, then wash with pure water for 12 min, and dry at 220°C;

[0077] (5) Perform formation treatment on the aluminum foil obtained in (4) to obtain a finished etching foil.

[0078] Performance Test

[0079] Bending strength: The samples obtained in the examples and comparative examples were tested using an MIT bending strength tester, and the test results are shown in Table 1.

[0080] Electrostatic capacity: The samples obtained in the examples and comparative examples were tested using an LCR digital automatic bridge, and the test results are shown in Table 1.

[0081] Table 1 Performance test results

[0082]

[0083] Data analysis: from Table 1, Examples 1-3, it can be seen that the high-thickness aluminum foil anode foil composite pulse waveform pore-forming technology of the application ultimately obtains an etched foil sample with excellent electrostatic capacity and mechanical properties.

[0084] From Table 1, Example 2 and Comparative Example 1, it can be seen that by alternating low-frequency pulses and high-frequency pulses 3-5 times during the pulse pore-forming process and then performing a low-frequency pulse at the end, the electrostatic capacity and mechanical strength of the sample are further improved, which is likely to be because the last low-frequency pulse further expands the pores, improves the connectivity and depth of the pores, thereby further improving the specific capacity, and further optimizes the structure of the pores, so that the mechanical properties are also improved.

[0085] From Table 1, Example 2 and Comparative Examples 2 and 3, it can be seen that by alternating low-frequency pulse superposition at the initial stage of pore-forming and high-frequency pulse superposition at the middle and later stages of tunnel pore growth during the pulse pore-forming process, the electrostatic capacity and mechanical strength of the sample are further improved, which is mainly because the use of low-frequency pulses at the initial stage of pore-forming can form larger initial pores with uniform distribution; the use of high-frequency pulses at the middle and later stages of tunnel pore growth can refine the pores and improve the density and uniformity of the pores. Compared with other pulse treatment methods, this low-high pulse treatment method can significantly improve the specific capacity and mechanical properties of the product.

[0086] From Table 1, Example 2 and Comparative Example 4, it can be seen that compared with the conventional pore-forming process, the high-thickness etched foil ultimately obtained by the application has a significant improvement in both electrostatic capacity and mechanical properties.

[0087] Those skilled in the art will understand that the above discussion of any of the embodiments is merely exemplary and is not intended to suggest that the scope of the application is limited to these examples; under the concept of the application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the application as described above. In order to be brief, they are not provided in detail.

Claims

1. High thickness aluminum foil anode foil composite pulse waveform emitting technology, characterized in that, The method comprises the following steps: S1: placing the light foil in a phosphoric acid solution, and then taking out and washing with water; S2: performing pore forming treatment on the aluminum foil obtained in S1; S3: performing hole expanding treatment on the aluminum foil obtained in S2; S4: placing the aluminum foil obtained in S3 in a dilute hydrochloric acid solution for washing, then placing the aluminum foil in a dilute nitric acid solution for washing, and finally washing with pure water and drying; S5: performing chemical conversion treatment on the aluminum foil obtained in S4 to obtain a finished product corrosion foil; The pore forming treatment in step S2 is to place the aluminum foil obtained in S1 in a mixed tank solution of 0.5-1 mol / L hydrochloric acid, 3.2-3.8 mol / L sulfuric acid and 0.01-0.05 mol / L phosphoric acid, and perform complex pulse pore forming treatment at a temperature of 60-73 ℃, and the specific process is as follows: first 1.7-1.9 A / cm 2 for 0.5-2 s, superimposed pulses, frequency 500-700 Hz, duty cycle 30-37%, superimposed size ±0.03-0.05 A / cm 2 ; then 1.2-1.7 A / cm 2 for 1.5-3 s, superimposed pulses, frequency 700-800 Hz, duty cycle 45-50%, superimposed size ±0.03-0.05 A / cm 2 ; again 0.5-1.2 A / cm 2 for 1.5-3 s, superimposed pulses, frequency 700-800 Hz, duty cycle 45-50%, superimposed size ±0.03-0.05 A / cm 2 ; then 0.3-0.5 A / cm 2 for 2-5 s, superimposed pulses, frequency 800-900 Hz, duty cycle 45-50%, superimposed size ±0.02-0.03 A / cm 2 ; finally 0.15-0.3 A / cm 2 for 10-15 s, superimposed pulses, frequency 1000-1500 Hz, duty cycle 45-50%, superimposed size ±0.01-0.015 A / cm 2 ; after 3-5 repetitions of the above hole formation steps, again 1.7-1.9 A / cm 2 for 0.5-2 s, superimposed pulses, frequency 500-700 Hz, duty cycle 30-37%, superimposed size ±0.03-0.05 A / cm 2 .

2. The high thickness aluminum foil anode foil composite pulsed waveform pore technology according to claim 1, characterized in that, The concentration of the phosphoric acid solution in step S1 is 1.5-3 mol / L, the temperature is 65-70 ℃, and the time is 30-120 s.

3. The high thickness aluminum foil anode foil composite pulsed waveform pore technology according to claim 1, characterized in that, The hole expanding treatment in step S3 is to place the aluminum foil obtained in S2 in a mixed tank solution of 1.1-1.5 mol / L nitric acid, 0.05-0.1 mol / L phosphoric acid and 0.02-0.08 g / L sodium polystyrene sulfonate for hole expanding treatment.

4. The high thickness aluminum foil anode foil composite pulsed waveform pore technology according to claim 3, characterized in that, The temperature of the reaming treatment is 60-80℃, the constant current density is 0.12-17 A / cm 2 , and the duration is 13-16 min.

5. The high thickness aluminum foil anode foil composite pulsed waveform pore technology according to claim 1, characterized in that, The concentration of the dilute hydrochloric acid solution in step S4 is 0.03-0.1 mol / L, and the concentration of the dilute nitric acid solution is 0.1-0.2 mol / L.

6. The high thickness aluminum foil anode foil composite pulsed waveform pore technology according to claim 1, characterized in that, The pure water washing time in step S4 is 8-15 min.

7. The high thickness aluminum foil anode foil composite pulsed waveform pore technology according to claim 1, characterized in that, The drying temperature in step S4 is 180-270 ℃.

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