A method for suppressing nano-scale hydrogen-water magnetic suspension bubbles in preparing finished foil

Abstract

The invention belongs to the technical field of aluminum electrolytic capacitors, and particularly relates to a method for inhibiting nano-scale hydrogen-water magnetic suspension bubbles in preparing finished foils. When performing a pore corrosion step, nano-scale barium ferrite magnetic powder and an organic defoamer are added and ultrasonically uniformly prepared into an aqueous solution BFE, which is added into a tank liquid. The organic defoamer is driven by magnetic powder and uses water as a carrier to inhibit the generation of nano-scale hydrogen-water magnetic suspension bubbles. By inhibiting the generation of nano-scale hydrogen-water bubbles, the probability of branch hole formation is reduced, and the capacity and strength of the finished foil are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum electrolytic capacitors, and in particular relates to a method for suppressing nano-scale hydrogen-water magnetic suspension bubbles in preparing finished foil. Background Art

[0002] Foil is an important raw material. In the prior art, the electromechanical corrosion process of high-voltage aluminum foil generally includes pre-treatment, primary pore formation corrosion, secondary pore expansion corrosion, post-treatment and other steps. For the HCl-H2SO4 system, by adding a magnetic field outside the corrosion tank and controlling the eddy current effect in the tank liquid, the Cl on the double electric layer interface during the pore formation process of the aluminum foil can be significantly improved. - With SO4 2- At the same time, the external coupling magnetic field can inhibit the excessive growth of the aluminum oxide layer and improve the Cl - The adsorption capacity in the etch tunnel increases effective corrosion and greatly improves the uniformity of the residual core.

[0003] However, this technology has the following problems: the magnetic eddy current effect will cause a large number of nano-scale hydrogen-water magnetic suspension bubbles to be generated in the slot, and prevent them from escaping quickly, blocking them at the bottom of the etched hole, affecting further pore formation, thus causing branch holes in the tunnel, affecting the capacity and strength of the finished foil. Therefore, this technology still needs to be improved. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a method for suppressing nano-scale hydrogen-water magnetic suspension bubbles in preparing finished foil.

[0005] The object of the present invention is achieved through the following technical scheme: a method for suppressing nano-scale hydrogen-water magnetic suspension bubbles in preparing a finished foil, the method is as follows:

[0006] Step S1: soak the original foil in a 0.2% - 4% sodium hydroxide solution at 70 - 80°C for 1-2 minutes for pretreatment, and then wash it with pure water;

[0007] Step S2: Place the original foil obtained in step S1 in a pore-forming solution, with an N pole at the top and an S pole at the bottom, and a constant magnetic field strength of 0.02T-0.12T; and a current range of 0.20 A / cm -2 -0.25 A / cm -2 Constant current, perform 3-5 times of pore etching treatment at a time interval of 40-60 seconds, and then wash with pure water;

[0008] Step S3: Place the pore-forming foil obtained in step S2 in a pore-enlarging solution and heat it at a current range of 0.16 A / cm -2 -0.18A / cm -2Constant current, 7-9 times of hole enlargement and corrosion treatment at intervals of 20-30s, and then washed with pure water;

[0009] Step S4: treating the expanded foil obtained in step S3 in a HCl solution, washing it with pure water, and then treating it in a HNO3 solution, and washing it with pure water;

[0010] Step S5: placing the expanded hole foil obtained in step S4 in an oven for heat treatment, and then cooling it to room temperature;

[0011] Step S6: subjecting the expanded foil obtained in step S5 to chemical treatment, washing and drying to obtain a finished foil;

[0012] Wherein, in step S2, barium ferrite magnetic powder is added to the pore-forming liquid to drive an organic defoaming agent BFE in the form of water as a carrier, wherein the organic defoaming agent is an organic ether or an organic silicon.

[0013] Preferably, the preparation method of the aqueous solution BFE is as follows: 1-1.5 g / L of 50-100 nm barium ferrite magnetic powder, 2-5 g / L of polyoxypropylene ether and water are ultrasonically mixed at room temperature to obtain the aqueous solution BFE.

[0014] Preferably, the thickness of the original foil in step S1 is 125-135 μm.

[0015] Preferably, the pore-forming liquid in step S2 is 3%-5% HCl, 30%-50% H2SO4, 0.5%-3% Al, and 0.02%-0.05% aqueous BFE.

[0016] Preferably, the intensity in step S2 is 0.06T, at 0.20 A / cm -2 The pore corrosion treatment was performed 5 times at a constant current density of 60 s.

[0017] Preferably, the pore expansion liquid in step S3 is 3%-8% HNO3, 0.07%-0.14% H3PO4, and 0.02%-0.05% corrosion inhibitor.

[0018] Preferably, the corrosion inhibitor is polyethylene glycol.

[0019] Preferably, in step S3, the -2 The constant current density was 28 s, and the hole expansion corrosion treatment was performed 9 times at a time interval of 28 s.

[0020] Preferably, the specific steps of step S4 are as follows: the expanded foil obtained in step S3 is placed in a 55-65°C, 2.5%-5% HCl solution for 40-60s, rinsed with pure water, and then placed in a 55-65°C, 2.5%-5% HNO3 solution for 40-60s, and rinsed with pure water.

[0021] Preferably, the oven temperature in step S5 is 60-180°C.

[0022] The invention has the following beneficial effects: in the pore-forming liquid, the present invention adds nano-scale barium ferrite magnetic powder and organic defoamer to prepare aqueous solution BFE after ultrasonic homogenization, adds the aqueous solution to the tank liquid, drives the organic defoamer with water as a carrier by magnetic powder, and under the action of the magnetic field, the barium ferrite magnetic powder will carry polyoxypropylene ether, and gather on the corrosion tunnel hole through the double electric layer, and the polyoxypropylene ether penetrates into the tunnel hole to decompose the double electric layer on the surface of the nano-scale hydrogen-water magnetic suspension bubble, so that the internal and external liquids flow rapidly, thereby causing the bubble to burst, and by inhibiting the generation of nano-scale hydrogen-water bubbles, the probability of branch hole formation is reduced, and the capacity and strength of the finished foil are improved, and the problem that the magnetic eddy current effect in the prior art will cause a large number of nano-scale hydrogen-water magnetic suspension bubbles to be generated in the tank, which will be blocked at the bottom of the etched hole, affecting further pore formation, thereby causing branch holes to be generated in the tunnel, affecting the capacity and strength of the finished foil; at the same time, the Cl - The adsorption amount in the etch tunnel increases effective corrosion and greatly improves the uniformity of the residual core. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 : Polarization curve test diagram of adding aqueous solution BFE and not adding aqueous solution BFE;

[0024] Figure 2 : Microscopic image of residual core etch pits when no water-soluble BFE is added to sample 1;

[0025] Figure 3 : Microscopic image of residual core pitting when aqueous solution BFE is added to sample 2;

[0026] Figure 4 : Microscopic image of residual core pitting when aqueous solution BFE is added to sample 3;

[0027] Figure 5 : Microscopic image of residual core etch pits when aqueous solution of BFE is added to sample 4. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the embodiments, but they are not intended to limit the present invention.

[0029] A method for suppressing nano-scale hydrogen-water magnetic suspension bubbles in preparing a finished foil, the method being as follows:

[0030] Step S1: soak the selected 125-135 μm original foil in a 0.2% - 4% sodium hydroxide solution at 70 - 80°C for 1-2 minutes for pretreatment, and then wash with pure water;

[0031] Step S2: The original foil obtained in step S1 is placed in a pore-forming solution containing 3%-5% HCl, 30%-50% H2SO4, 0.5%-3% Al, and 0.02%-0.05% aqueous BFE, with the N pole at the top and the S pole at the bottom, and a constant magnetic field strength of 0.02T-0.12T; the current range is 0.20 A / cm -2 -0.25 A / cm -2 Constant current, perform 3-5 times of pore etching treatment at a time interval of 40-60 seconds, and then wash with pure water;

[0032] Step S3: Place the pore-forming foil obtained in step S2 in a pore-enlarging solution containing 3%-8% HNO3, 0.07%-0.14% H3PO4, and 0.02%-0.05% corrosion inhibitor at a current range of 0.16A / cm -2 -0.18A / cm -2 Constant current, 7-9 times of hole enlargement and corrosion treatment at intervals of 20-30s, and then washed with pure water;

[0033] Step S4: the expanded hole foil obtained in step S3 is placed in a 55-65° C., 2.5%-5% HCl solution for 40-60 seconds for post-treatment, washed with pure water, and then placed in a 55-65° C., 2.5%-5% HNO3 solution for 40-60 seconds for post-treatment, and washed with pure water;

[0034] Step S5: placing the expanded hole foil obtained in step S4 in an oven at 60-180° C. for heat treatment, and then cooling to room temperature;

[0035] Step S6: subjecting the expanded foil obtained in step S5 to chemical treatment, washing and drying to obtain a finished foil;

[0036] Wherein, in step S2, barium ferrite magnetic powder is added to the pore-forming liquid to drive an organic defoaming agent in the form of an aqueous solution BFE with water as a carrier, wherein the organic defoaming agent is an organic ether or an organic silicon;

[0037] The preparation method of the aqueous solution BFE is as follows: 1-1.5 g / L of 50-100 nm barium ferrite magnetic powder, 2-5 g / L of polyoxypropylene ether and water are ultrasonically mixed at room temperature to obtain the aqueous solution BFE.

[0038] Example 1

[0039] A 130 μm original foil was used, and an aqueous solution of BFE: 1 g / L 100 nm barium ferrite magnetic powder and 2 g / L polyoxypropylene ether were ultrasonically mixed at room temperature for 20 minutes.

[0040] S1: After pretreatment, the selected 130 μm original foil was immersed in 0.22% sodium hydroxide solution at 70°C for 1.5 min, and then washed with pure water;

[0041] S2: The original foil obtained in S1 was placed in a pore-forming solution containing 3.2% HCl, 50% H2SO4, 1.3% Al, and 0.02% aqueous BFE solution, with N pole at the top and S pole at the bottom, and a constant magnetic field strength of 0.06T; the current was 0.20 A / cm -2 After 5 times of pore etching treatment at a constant current density and a time interval of 60 s, it was washed with pure water;

[0042] S3: The pore-forming foil obtained in S2 was placed in a pore-enlarging solution containing 7.1% HNO3, 0.08% H3PO4, and 0.025% polyethylene glycol at a current range of 0.16 A / cm -2 The constant current density was used to perform 9 times of hole enlargement corrosion treatment at a time interval of 28 s, and then the treatment was washed with pure water;

[0043] S4: The expanded foil obtained in S3 was placed in a 55°C, 2.5% HCl solution for 40 seconds for post-treatment, rinsed with pure water, and then placed in a 55°C, 5% HNO3 solution for 60 seconds for post-treatment, and rinsed with pure water;

[0044] S5: placing the expanded hole foil obtained in S4 in an oven at 100° C. for heat treatment, and then cooling to room temperature;

[0045] S6: The expanded foil obtained in S5 is subjected to chemical treatment, and a finished foil is obtained after washing and drying.

[0046] like Figure 1 As shown in the figure, the self-corrosion potential of the samples with 0.02% aqueous solution BFE and 0.05% aqueous solution BFE is significantly shifted to the left compared with that without adding aqueous solution BFE, indicating that the nanoscale hydrogen-water magnetic suspension bubbles blocked in the pores are suppressed by aqueous solution BFE, and the pores adsorb more Cl under the external magnetic field. - , more susceptible to corrosion.

[0047] Experimental data:

[0048]

[0049] like Figure 2 As shown in the figure, the aqueous solution BFE is added to make the residual core etched holes have obvious branch holes, and the residual core is uneven; Figure 3-5As shown in the figure, after adding 0.02% aqueous solution of BFE, the residual core was significantly improved, becoming more uniform and more tidy, and the strength and capacity were enhanced.

[0050] The above shows and describes the basic principles, main features and advantages of the present invention. However, the above is only a specific embodiment of the present invention, and the technical features of the present invention are not limited thereto. Any other implementation methods derived by any technician in the field without departing from the technical solution of the present invention should be included in the patent scope of the present invention.

Claims

1. A method for suppressing nano-scale hydrogen-water magnetic suspension bubbles in preparing finished foil, characterized in that: The method is as follows: Step S1: soak the original foil in a 0.2% - 4% sodium hydroxide solution at 70 - 80°C for 1-2 minutes for pretreatment, and then wash it with pure water; Step S2: Place the original foil obtained in step S1 in a pore-forming liquid, with an N pole at the top and an S pole at the bottom, and a constant magnetic field strength of 0.02T-0.12T; and a current range of 0.20 A / cm -2 -0.25 A / cm -2 Constant current, perform 3-5 times of pore etching treatment at a time interval of 40-60 seconds, and then wash with pure water; Step S3: Place the pore-forming foil obtained in step S2 in a pore-enlarging solution and heat it at a current range of 0.16 A / cm -2 -0.18A / cm -2 Constant current, 7-9 times of hole enlargement and corrosion treatment at intervals of 20-30s, and then washed with pure water; Step S4: treating the expanded foil obtained in step S3 in a HCl solution, washing it with pure water, and then treating it in a HNO3 solution, and washing it with pure water; Step S5: placing the expanded hole foil obtained in step S4 in an oven for heat treatment, and then cooling it to room temperature; Step S6: subjecting the expanded foil obtained in step S5 to chemical treatment, washing and drying to obtain a finished foil; Wherein, in step S2, barium ferrite magnetic powder is added to the pore-forming liquid to drive an organic defoaming agent BFE in the form of water as a carrier, wherein the organic defoaming agent is an organic ether or an organic silicon.

2. The method for preparing nano-scale hydrogen-water magnetic suspension bubbles by suppressing the pore formation by applying an external magnetic field according to claim 1, characterized in that: The preparation method of the aqueous solution BFE is as follows: 1-1.5 g / L of 50-100 nm barium ferrite magnetic powder, 2-5 g / L of polyoxypropylene ether and water are ultrasonically mixed at room temperature to obtain the aqueous solution BFE.

3. The method for preparing nano-scale hydrogen-water magnetic suspension bubbles by suppressing the pore formation by applying an external magnetic field according to claim 1, characterized in that: The thickness of the original foil in step S1 is 125-135 μm.

4. The method for preparing nano-scale hydrogen-water magnetic suspension bubbles by suppressing the pore formation by applying an external magnetic field according to claim 1, characterized in that: The pore-forming liquid in step S2 is 3%-5% HCl, 30%-50% H2SO4, 0.5%-3% Al, and 0.02%-0.05% aqueous BFE.

5. The method for preparing nano-scale hydrogen water magnetic suspension bubbles by suppressing external magnetic field pore formation technology for finished foil according to claim 1, characterized in that: The intensity in step S2 is 0.06T, and the -2 The pore corrosion treatment was performed five times at a constant current density of 60 s.

6. The method for preparing nano-scale hydrogen-water magnetic suspension bubbles by suppressing the pore formation by applying an external magnetic field according to claim 1, characterized in that: The pore-enlarging liquid in step S3 is 3%-8% HNO3, 0.07%-0.14% H3PO4, and 0.02%-0.05% corrosion inhibitor.

7. The method for preparing nano-scale hydrogen-water magnetic suspension bubbles by suppressing the pore formation by applying an external magnetic field according to claim 6, characterized in that: The corrosion inhibitor is polyethylene glycol.

8. The method for preparing nano-scale hydrogen-water magnetic suspension bubbles by suppressing pore formation by applying an external magnetic field according to claim 1, characterized in that: In step S3, the temperature is 0.16A / cm -2 The constant current density was 28 s and the hole enlargement corrosion treatment was performed 9 times at a time interval of 28 s.

9. The method for preparing nano-scale hydrogen-water magnetic suspension bubbles by suppressing the pore formation by applying an external magnetic field according to claim 1, characterized in that: The details of step S4 are as follows: the expanded foil obtained in step S3 is placed in a 55-65° C., 2.5%-5% HCl solution for 40-60 seconds, washed with pure water, and then placed in a 55-65° C., 2.5%-5% HNO3 solution for 40-60 seconds, and washed with pure water.

10. The method for preparing nano-scale hydrogen-water magnetic suspension bubbles by suppressing pore formation by applying an external magnetic field for preparing finished foil according to claim 1, characterized in that: The oven temperature in step S5 is 60-180°C.

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