Disclosure of Invention
The invention aims to provide an electrochemical corrosion process for producing medium-high voltage anode foils. The electrochemical corrosion process for producing the medium-high voltage anode foil is simple in process and easy to control in process, can effectively ensure stable foil surface quality of the prepared medium-high voltage anode foil, and has the performance of high specific volume and high strength (high bending times).
In order to solve the technical problems, the technical scheme provided by the invention is as follows:
an electrochemical corrosion process for the production of medium and high voltage anode foils comprising the steps of:
A. pretreatment:
putting the aluminum foil into a mixed solution of sodium hydroxide and potassium hydroxide at the temperature of 35-45 ℃, soaking for 40-60 s, and then washing for 2-5 times by using deionized water; the molar concentrations of the sodium hydroxide and the potassium hydroxide in the mixed solution of the sodium hydroxide and the potassium hydroxide are 0.06-0.08 mol/L and 0.02-0.03 mol/L respectively;
compared with the traditional pretreatment by acid, the pretreatment process steps have the advantages of higher treatment speed, higher efficiency, lower temperature during treatment, energy consumption saving, good treatment effect, capability of effectively ensuring the stable quality of the foil surface of the prepared medium-high voltage anode foil, and high specific volume and high strength (high bending times). In addition, compared with the single alkali such as sodium hydroxide or potassium hydroxide, the processing speed is higher, and the foil surface quality stability and high strength (high bending times) of the prepared medium-high voltage anode foil can be improved.
B. And (3) punching:
placing the pretreated aluminum foil into a mixed solution containing 10-15% by mass of hydrochloric acid and 35-45% by mass of sulfuric acid at the temperature of 65-75 ℃, controlling the corrosion current density to be 250-400 mA/cm2, and performing perforation corrosion for 100-120 s;
compared with the traditional perforation process steps, the pretreatment process steps better aim at the process system of the invention, optimize the process conditions, enable the process to be more easily and accurately controlled, ensure the foil surface quality of the prepared middle-high voltage anode foil to be stable, and have the performance of high specific volume and high strength (high bending times).
C. Reaming:
washing the aluminum foil subjected to hole forming with deionized water, putting the aluminum foil into a nitric acid solution with the temperature of 80-90 ℃ and the mass percent of 11-15%, controlling the hole expanding current to be 50-150 mA/cm2, and expanding the hole for 9-12 min;
compared with the traditional reaming process steps, the pretreatment process steps better aim at the process system of the invention, optimize the process conditions, enable the process to be more easily and accurately controlled, ensure the foil surface quality of the prepared medium-high voltage anode foil to be stable, and have the performance of high specific volume and high strength (high bending times).
D. And (3) post-treatment:
cleaning the aluminum foil after hole expansion by using deionized water, and soaking the aluminum foil in a nitric acid solution with the temperature of 70-80 ℃ and the mass percent of 3-5% for 2-3 min;
E. and (3) drying:
and (3) cleaning the post-treated aluminum foil with deionized water, putting the aluminum foil into drying equipment, controlling the temperature to be 70-90 ℃, and drying for 2-5 hours to obtain the medium-high voltage anode foil.
The electrochemical corrosion process for producing the medium-high voltage anode foil is simple in process and easy to control in process, can effectively ensure stable foil surface quality of the prepared medium-high voltage anode foil, and has the performance of high specific volume and high strength (high bending times).
Preferably, in the step A, the aluminum foil is an aluminum foil for an electrolytic capacitor anode with the aluminum content of more than or equal to 99.99% and the thickness of 120 um.
Preferably, in the step B, the mixed solution containing 10 to 15 mass% of hydrochloric acid and 35 to 45 mass% of sulfuric acid further contains 0.35 to 0.45 mass% of zinc nitrite.
In the pretreatment process steps, 0.35-0.45% of zinc nitrite is added as a corrosion inhibitor, so that the corrosion inhibitor is better adapted (matched) with the process system, the foil surface quality stability and the strength (bending times are high) of the prepared medium-high voltage anode foil can be improved, and the specific volume is also improved to a certain extent.
Preferably, in the step B, the mixed solution containing 10 to 15 mass% of hydrochloric acid and 35 to 45 mass% of sulfuric acid further contains 0.5 to 0.7 mass% of isopropyl alcohol.
In the pretreatment process steps, 0.5-0.7% of isopropanol is added as an additive, so that the process system is better adapted (matched), the specific volume and the foil surface quality stability of the prepared medium-high voltage anode foil are improved, and the strength (high bending times) is also improved to a certain extent.
Preferably, in the step C, the 11-15% by mass nitric acid solution further contains 0.65-0.85% by mass zinc nitrite.
In the pretreatment process steps, 0.65-0.85% of zinc nitrite is added as a corrosion inhibitor, so that the corrosion inhibitor is better adapted (matched) with the process system, the foil surface quality stability and the strength (bending times are high) of the prepared medium-high voltage anode foil can be improved, and the specific volume is also improved to a certain extent.
Preferably, in the step C, the nitric acid solution with the mass percentage of 11-15% further contains 0.15-0.25% of toluenesulfonic acid.
In the pretreatment process steps, 0.15-0.25% of toluenesulfonic acid is added as an additive, so that the process system is better adapted (matched), the specific volume and the foil surface quality stability of the prepared medium-high voltage anode foil are improved, and the strength (high bending frequency) is also improved to a certain extent.
Preferably, in step a, the pretreatment: putting the aluminum foil into a mixed solution of sodium hydroxide and potassium hydroxide at the temperature of 40 ℃, soaking for 55s, and then washing for 3 times by using deionized water; the molar concentrations of the sodium hydroxide and the potassium hydroxide in the mixed solution of the sodium hydroxide and the potassium hydroxide are 0.07mol/L and 0.024mol/L respectively;
preferably, in step B, the pore: placing the pretreated aluminum foil into a mixed solution containing 12.5 mass percent of hydrochloric acid and 42 mass percent of sulfuric acid at the temperature of 68 ℃, controlling the corrosion current density to be 280mA/cm2, and performing perforation corrosion for 110 s; the mixed solution containing 12.5 percent by mass of hydrochloric acid and 42 percent by mass of sulfuric acid also contains 0.41 percent by mass of zinc nitrite; the mixed solution containing 12.5% by mass of hydrochloric acid and 42% by mass of sulfuric acid also contains 0.65% by mass of isopropanol.
Preferably, in step C, reaming: washing the aluminum foil subjected to hole forming with deionized water, putting into a nitric acid solution with the temperature of 82 ℃ and the mass percent of 13%, controlling the hole-expanding current to be 75mA/cm2, and expanding the hole for 11 min; the nitric acid solution with the mass percentage of 13 percent also contains zinc nitrite with the mass percentage of 0.75 percent; the nitric acid solution with the mass percent of 13% also contains 0.18% of toluenesulfonic acid with the mass percent.
Preferably, in step E, the drying device is an oven.
Compared with the prior art, the invention has the following advantages and beneficial effects:
the electrochemical corrosion process for producing the medium-high voltage anode foil is simple in process and easy to control in process, can effectively ensure stable foil surface quality of the prepared medium-high voltage anode foil, and has the performance of high specific volume and high strength (high bending times).
Detailed Description
In order that those skilled in the art will better understand the technical solutions of the present invention, the following description of the preferred embodiments of the present invention is provided in connection with specific examples, which should not be construed as limiting the present patent.
The test methods or test methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials, unless otherwise indicated, are conventionally obtained commercially or prepared by conventional methods.
Example 1:
an electrochemical corrosion process for the production of medium and high voltage anode foils comprising the steps of:
A. pretreatment:
putting the aluminum foil into a mixed solution of sodium hydroxide and potassium hydroxide at the temperature of 35-45 ℃, soaking for 40-60 s, and then washing for 2-5 times by using deionized water; the molar concentrations of the sodium hydroxide and the potassium hydroxide in the mixed solution of the sodium hydroxide and the potassium hydroxide are 0.06-0.08 mol/L and 0.02-0.03 mol/L respectively;
B. and (3) punching:
placing the pretreated aluminum foil into a mixed solution containing 10-15% by mass of hydrochloric acid and 35-45% by mass of sulfuric acid at the temperature of 65-75 ℃, controlling the corrosion current density to be 250-400 mA/cm2, and performing perforation corrosion for 100-120 s;
C. reaming:
washing the aluminum foil subjected to hole forming with deionized water, putting the aluminum foil into a nitric acid solution with the temperature of 80-90 ℃ and the mass percent of 11-15%, controlling the hole expanding current to be 50-150 mA/cm2, and expanding the hole for 9-12 min;
D. and (3) post-treatment:
cleaning the aluminum foil after hole expansion by using deionized water, and soaking the aluminum foil in a nitric acid solution with the temperature of 70-80 ℃ and the mass percent of 3-5% for 2-3 min;
E. and (3) drying:
and (3) cleaning the post-treated aluminum foil with deionized water, putting the aluminum foil into drying equipment, controlling the temperature to be 70-90 ℃, and drying for 2-5 hours to obtain the medium-high voltage anode foil.
Example 2:
an electrochemical corrosion process for the production of medium and high voltage anode foils comprising the steps of:
A. pretreatment:
putting the aluminum foil into a mixed solution of sodium hydroxide and potassium hydroxide at the temperature of 35 ℃, soaking for 60s, and then washing for 2 times by using deionized water; the molar concentrations of the sodium hydroxide and the potassium hydroxide in the mixed solution of the sodium hydroxide and the potassium hydroxide are 0.08mol/L and 0.02mol/L respectively;
B. and (3) punching:
placing the pretreated aluminum foil into a mixed solution containing 15% by mass of hydrochloric acid and 35% by mass of sulfuric acid at the temperature of 65 ℃, controlling the corrosion current density to be 400mA/cm2, and performing perforation corrosion for 120 s;
C. reaming:
washing the aluminum foil subjected to hole forming with deionized water, putting into a nitric acid solution with the temperature of 80 ℃ and the mass percent of 15%, controlling the hole-expanding current to be 150mA/cm2, and expanding the hole for 12 min;
D. and (3) post-treatment:
cleaning the aluminum foil after hole expansion with deionized water, and soaking in a nitric acid solution with the temperature of 70 ℃ and the mass percent of 5% for 3 min;
E. and (3) drying:
and (3) cleaning the post-treated aluminum foil with deionized water, putting the aluminum foil into drying equipment, controlling the temperature to be 70 ℃, and drying for 5 hours to obtain the medium-high voltage anode foil.
In this embodiment, in the step a, the aluminum foil is an aluminum foil for an electrolytic capacitor anode with an aluminum content of not less than 99.99% and a thickness of 120 um.
In this embodiment, in step B, the mixed solution containing 15% by mass of hydrochloric acid and 35% by mass of sulfuric acid further contains 0.35% by mass of zinc nitrite.
In this embodiment, in the step B, the mixed solution containing 15% by mass of hydrochloric acid and 35% by mass of sulfuric acid further contains 0.5% by mass of isopropyl alcohol.
In this embodiment, in step C, the nitric acid solution with a mass percentage of 15% further contains zinc nitrite with a mass percentage of 0.65%.
In this embodiment, in step C, the nitric acid solution with a mass percentage of 15% further contains 0.15% by mass of toluenesulfonic acid.
In this embodiment, in step E, the drying device is an oven.
Through tests, the 520Vt specific volume of the medium-high voltage anode foil prepared by the electrochemical corrosion process for producing the medium-high voltage anode foil is 0.62uF/cm2, the strength (bending times are 134 times), the foil surface quality is stable, and the high-voltage anode foil has the performance of both high specific volume and high strength (bending times are high).
Example 3:
an electrochemical corrosion process for the production of medium and high voltage anode foils comprising the steps of:
A. pretreatment:
putting the aluminum foil into a mixed solution of sodium hydroxide and potassium hydroxide at the temperature of 45 ℃, soaking for 40s, and then washing for 5 times by using deionized water; the molar concentrations of the sodium hydroxide and the potassium hydroxide in the mixed solution of the sodium hydroxide and the potassium hydroxide are 0.06mol/L and 0.03mol/L respectively;
B. and (3) punching:
placing the pretreated aluminum foil into a mixed solution containing 10 mass percent of hydrochloric acid and 45 mass percent of sulfuric acid at the temperature of 75 ℃, controlling the corrosion current density to be 250mA/cm2, and carrying out perforation corrosion for 100 s;
C. reaming:
washing the aluminum foil subjected to hole forming with deionized water, putting into a nitric acid solution with the temperature of 90 ℃ and the mass percent of 11%, controlling the hole-expanding current to be 50mA/cm2, and expanding the hole for 9 min;
D. and (3) post-treatment:
cleaning the aluminum foil after hole expansion with deionized water, and soaking in a nitric acid solution with the temperature of 80 ℃ and the mass percent of 3% for 2 min;
E. and (3) drying:
and (3) cleaning the post-treated aluminum foil with deionized water, putting the aluminum foil into drying equipment, controlling the temperature to be 90 ℃, and drying for 2h to obtain the medium-high voltage anode foil.
In this embodiment, in the step a, the aluminum foil is an aluminum foil for an electrolytic capacitor anode with an aluminum content of not less than 99.99% and a thickness of 120 um.
In this embodiment, in step B, the mixed solution containing 10% by mass of hydrochloric acid and 45% by mass of sulfuric acid further contains 0.45% by mass of zinc nitrite.
In this embodiment, in the step B, the mixed solution containing 10% by mass of hydrochloric acid and 45% by mass of sulfuric acid further contains 0.7% by mass of isopropyl alcohol.
In this embodiment, in step C, the 11% by mass nitric acid solution further contains 0.85% by mass zinc nitrite.
In this embodiment, in step C, the 11% by mass nitric acid solution further contains 0.25% by mass toluenesulfonic acid.
In this embodiment, in step E, the drying device is an oven.
Through tests, the 520Vt specific volume of the medium-high voltage anode foil prepared by the electrochemical corrosion process for producing the medium-high voltage anode foil is 0.65uF/cm2, the strength (bending times of 136 times) is high, the foil surface quality is stable, and the high-voltage anode foil has the performance of both high specific volume and high strength (bending times of high).
Example 4:
an electrochemical corrosion process for the production of medium and high voltage anode foils comprising the steps of:
A. pre-treating;
B. hair holes;
C. reaming;
D. and (3) post-treatment:
cleaning the aluminum foil after hole expansion with deionized water, and soaking in a nitric acid solution with the temperature of 75 ℃ and the mass percent of 4.5% for 2.5 min;
E. and (3) drying:
and (3) cleaning the post-treated aluminum foil with deionized water, putting the aluminum foil into drying equipment, controlling the temperature to be 80 ℃, and drying for 3 hours to obtain the medium-high voltage anode foil.
In this embodiment, in the step a, the aluminum foil is an aluminum foil for an electrolytic capacitor anode with an aluminum content of not less than 99.99% and a thickness of 120 um.
In this embodiment, in step a, the pretreatment: putting the aluminum foil into a mixed solution of sodium hydroxide and potassium hydroxide at the temperature of 40 ℃, soaking for 55s, and then washing for 3 times by using deionized water; the molar concentrations of the sodium hydroxide and the potassium hydroxide in the mixed solution of the sodium hydroxide and the potassium hydroxide are 0.07mol/L and 0.024mol/L respectively;
in this embodiment, in step B, the perforation: placing the pretreated aluminum foil into a mixed solution containing 12.5 mass percent of hydrochloric acid and 42 mass percent of sulfuric acid at the temperature of 68 ℃, controlling the corrosion current density to be 280mA/cm2, and performing perforation corrosion for 110 s; the mixed solution containing 12.5 percent by mass of hydrochloric acid and 42 percent by mass of sulfuric acid also contains 0.41 percent by mass of zinc nitrite; the mixed solution containing 12.5% by mass of hydrochloric acid and 42% by mass of sulfuric acid also contains 0.65% by mass of isopropanol.
In this embodiment, in step C, hole expansion: washing the aluminum foil subjected to hole forming with deionized water, putting into a nitric acid solution with the temperature of 82 ℃ and the mass percent of 13%, controlling the hole-expanding current to be 75mA/cm2, and expanding the hole for 11 min; the nitric acid solution with the mass percentage of 13 percent also contains zinc nitrite with the mass percentage of 0.75 percent; the nitric acid solution with the mass percent of 13% also contains 0.18% of toluenesulfonic acid with the mass percent.
In this embodiment, in step E, the drying device is an oven.
Through tests, the 520Vt specific volume of the medium-high voltage anode foil prepared by the electrochemical corrosion process for producing the medium-high voltage anode foil is 0.68uF/cm2, the strength (bending times are 145 times), the foil surface quality is stable, and the high-voltage anode foil has the performance of both high specific volume and high strength (bending times are high).
The above is only a preferred embodiment of the present invention, and it should be noted that the above preferred embodiment should not be considered as limiting the present invention, and the protection scope of the present invention should be subject to the scope defined by the claims. It will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the spirit and scope of the invention, and these modifications and adaptations should be considered within the scope of the invention.