Formation method for sintered aluminum foil

Abstract

The present disclosure provides a formation method for sintered aluminum foil, comprising: placing the sintered aluminum foil into a solution containing a blocking agent for boiling treatment, wherein the blocking agent is used to form a passivation film on the surface of the sintered aluminum foil; and performing formation treatment on the sintered aluminum foil. The present disclosure can avoid the blockage of the pore channel of the sintered aluminum foil, thereby improving the capacity of the sintered aluminum foil after formation treatment and improving the performance of the sintered aluminum foil.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of electrode foil, and particularly relates to a formation method for sintered aluminum foil. BACKGROUND

[0002] The sintered aluminum foil is an electrode foil prepared by a sintering process of aluminum powder accumulation, which can significantly improve the capacity of an anode foil for aluminum electrolytic capacitor. The formation treatment is an indispensable key process step in the preparation process of the electrode foil. However, the traditional formation treatment technology is easy to have adverse effects on the capacity and other performances of the sintered aluminum foil. SUMMARY

[0003] The present disclosure provides a formation method for sintered aluminum foil.

[0004] The present disclosure provides a formation method for sintered aluminum foil, which comprises: placing the sintered aluminum foil into a solution containing a blocking agent for boiling treatment, wherein the blocking agent is used to form a passivation film on the surface of the sintered aluminum foil; and performing formation treatment on the sintered aluminum foil.

[0005] In some embodiments, before the formation treatment on the sintered aluminum foil, the method further comprises: performing first heat treatment on the sintered aluminum foil after the boiling treatment.

[0006] In some embodiments, the formation treatment on the sintered aluminum foil comprises: performing formation treatment on the sintered aluminum foil after the first heat treatment by using a formation liquid containing phosphoric acid.

[0007] In some embodiments, the blocking agent comprises one or more of nitrate, borate, alginate, silicate and chromate, and the mass concentration of the blocking agent is 0.1% to 10%.

[0008] In some embodiments, the boiling treatment is performed at a temperature of 80°C to 98°C for 1min to 20min.

[0009] In some embodiments, the first heat treatment is performed at a temperature of 300°C to 550°C for 1min to 5min.

[0010] In some embodiments, the formation liquid contains boric acid, phosphoric acid, ammonium pentaborate and citric acid, the mass concentration of the boric acid is 1% to 10%, the mass concentration of the phosphoric acid is 0.01% to 0.1%, the mass concentration of the ammonium pentaborate is 0.5% to 5%, and the mass concentration of the citric acid is 0.1% to 3%.

[0011] In some embodiments, the first heat-treated sintered aluminum foil is subjected to formation treatment, including: subjecting the first heat-treated sintered aluminum foil to multi-stage segmented formation treatment, wherein the temperature of the formation treatment is 70-90°C, and the voltage of the formation treatment is gradually increased in the range of 400-700V.

[0012] In some embodiments, before the sintered aluminum foil is placed in a solution containing a blocking agent for water boiling treatment, the sintered aluminum foil is further subjected to acid treatment or alkali treatment.

[0013] In some embodiments, the sintered aluminum foil is subjected to acid treatment or alkali treatment, including: subjecting the sintered aluminum foil to acid treatment using one or more of H2O2, H2SO4 and HNO3; or subjecting the sintered aluminum foil to alkali treatment using one or both of NaOH and ammonia; wherein the mass concentration of the solution used for acid treatment or alkali treatment of the sintered aluminum foil is 0.1%-10%, the temperature is 20-60°C, and the time is 10s-10min.

[0014] In some embodiments, after the sintered aluminum foil is subjected to formation treatment, the sintered aluminum foil after formation treatment is sequentially subjected to passivation treatment, second heat treatment, repair formation, post-treatment and drying.

[0015] When the sintered aluminum foil is subjected to formation treatment in the present disclosure, a pre-formation step is added, the sintered aluminum foil is placed in a solution containing a blocking agent for water boiling treatment, so that the blocking agent reacts with the aluminum powder of the sintered aluminum foil to form a passivation film on the surface of the sintered aluminum foil, which can inhibit the degree of contact between water and aluminum powder, and can avoid excessive generation of hydrated oxide film, thereby avoiding blockage of the pore channels of the sintered aluminum foil, which is conducive to improving the capacity of the sintered aluminum foil after formation treatment and enhancing the performance of the sintered aluminum foil. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A flowchart of a formation method for sintered aluminum foil according to an embodiment of the present disclosure is shown.

[0017] Figure 2 A pore size distribution comparison diagram of aluminum foil according to an embodiment of the present disclosure and a comparative example is shown. DETAILED DESCRIPTION

[0018] To enable persons skilled in the art to better understand the technical solutions of the present disclosure, the technical solutions of the present disclosure will be described in detail below with reference to the drawings.

[0019] In the following, example embodiments will be described more fully with reference to the accompanying drawings, in which, however, these example embodiments can be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0020] In the case of no conflict, each embodiment of the disclosure and each feature in the embodiment can be combined with each other.

[0021] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0022] The terms used herein are only used to describe specific embodiments and are not intended to limit the disclosure. As used herein, the singular forms "a" and "the" are also intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that when the terms "comprise" and / or "consist of" are used in the specification, the specified features, integers, steps, operations, elements, and / or components are present, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0023] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0024] The conventional formation process includes a high-pressure formation process, which is suitable for a tunnel pore structure of etched aluminum foil, and the tunnel pore diameter of the etched aluminum foil is about 1-2 microns. The sintered aluminum foil formed by the accumulation of aluminum powder has a gap between the aluminum powder and the aluminum powder below 1 micron, for example, a few hundred nanometers. If the high-pressure formation process is used to perform formation treatment on the sintered aluminum foil, the pores of the sintered aluminum foil are easily blocked by the excessive oxide film grown, thereby affecting the capacity of the final product foil. The smaller pores also make the time for the formation solution to enter the sintered aluminum foil longer during the formation treatment process, resulting in difficulty in boosting the voltage, the need for more stages of formation, and poor treatment effect of phosphoric acid and ammonium dihydrogen phosphate, which leads to poor water resistance of the sintered aluminum foil.

[0025] Embodiments of the disclosure provide a formation method for sintered aluminum foil, as shown in Figure 1 The formation method comprises:

[0026] S1, placing the sintered aluminum foil into a solution containing a blocking agent for boiling treatment, wherein the blocking agent is used to form a passivation film on the surface of the sintered aluminum foil.

[0027] S2, performing formation treatment on the sintered aluminum foil.

[0028] In the embodiments of the present disclosure, when the sintered aluminum foil is subjected to formation treatment, a pre-formation step is added, the sintered aluminum foil is subjected to boiling treatment in a solution containing a blocking agent, the blocking agent reacts with aluminum powder of the sintered aluminum foil, a passivation film is formed on the surface of the sintered aluminum foil, the contact degree of water and aluminum powder can be inhibited, and the excessive generation of a hydrated oxide film can be avoided, thereby avoiding the blockage of the pore channel of the sintered aluminum foil.

[0029] In some embodiments, before the sintered aluminum foil is subjected to formation treatment, the formation method further comprises: subjecting the sintered aluminum foil after boiling treatment to first heat treatment. In some embodiments, by adding the step of first heat treatment between boiling treatment and formation treatment, the transition of the hydrated oxide film to the crystalline oxide film is promoted in advance, the volume ratio of the hydrated oxide film is reduced, the pore channel blockage is further avoided, and the difficulty of voltage increase in the formation treatment can be reduced.

[0030] In some embodiments, the blocking agent comprises one or more of nitrate, borate, alginate, silicate and chromate, and the mass concentration of the blocking agent is 0.1% to 10%. In some embodiments, considering the cleaning difficulty, one or more of nitrate, borate and alginate is preferably used. In some embodiments, the salt of these substances can include ammonium salt. In some embodiments, the mass concentration of the blocking agent can be 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or any suitable value therebetween. If the concentration of the blocking agent is too low, its effect of inhibiting the generation of the hydrated oxide film is relatively limited, and if the concentration of the blocking agent is too high, the hydrated oxide film cannot be formed, and the voltage increase in the subsequent formation process will be difficult due to the lack of the hydrated oxide film.

[0031] In some embodiments, the boiling treatment temperature is 80°C to 98°C, and the boiling treatment time is 1 min to 20 min. In some embodiments, the boiling treatment temperature is 80°C, 85°C, 90°C, 95°C, 98°C or any suitable value therebetween. If the boiling treatment temperature is too low, the hydrated film will be formed too little, the power consumption of the subsequent formation will be large, and the time will be long; if the boiling treatment temperature is too high, the hydrated film will block the pores, and the capacity will decrease. In some embodiments, the boiling treatment time is 1 min, 5 min, 10 min, 15 min, 20 min or any suitable value therebetween. If the time is too long, the hydrated film will block the pores, and the capacity will decrease; if the time is too short, the hydrated film will be formed too little, the power consumption of the subsequent formation will be large, and the time will be long.

[0032] In some embodiments, the first heat treatment has a temperature of 300°C to 550°C and a time of 1 min to 5 min. In some embodiments, the first heat treatment is performed in a muffle furnace. In some embodiments, the first heat treatment has a temperature of 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, or any suitable value therebetween. If the temperature of the first heat treatment is too low, the speed of the transition of the hydrated oxide film to the crystalline oxide film is too slow, reducing the efficiency of the heat treatment; if the temperature of the first heat treatment is too high, it can cause undesirable changes or excessive growth of the surface oxide layer of the aluminum foil, and can even cause softening or deformation of the aluminum foil itself. In some embodiments, the first heat treatment has a time of 1 min, 2 min, 3 min, 4 min, 5 min, or any suitable value therebetween. If the time of the first heat treatment is too short, the degree of the transition of the hydrated oxide film to the crystalline oxide film can be insufficient; if the time of the first heat treatment is too long, it can cause unnecessary coarsening of the grains or other negative effects, such as accelerated oxidation, etc.

[0033] In some embodiments, the chemical conversion method further comprises: before the water boiling treatment, performing an acid treatment or an alkali treatment on the sintered aluminum foil. By means of acid or alkali treatment before the chemical conversion of the aluminum foil, the oxide film on the surface of the sintered aluminum foil and part of the small particle aluminum powder are dissolved away, so as to increase the porosity of the aluminum powder. Generally, in a conventional etched aluminum foil, the pores are tunnel-shaped, and the chemical conversion oxide film is difficult to block the pores. In the aluminum foil to be chemically converted according to the present disclosure, the pores are the porosity formed by the accumulation of spherical aluminum powder, which is smaller than that of a general etched aluminum foil. In addition to the conventional effect of removing the self-borne oxide film, the acid treatment or alkali treatment used in the present disclosure also has the effect of dissolving away the small particle aluminum powder. The porosity around the small particle aluminum powder is smaller, and after chemical conversion, it will be completely blocked, thus not contributing to the capacity. Therefore, by removing this part of the aluminum powder in advance through acid treatment or alkali treatment, the porosity is expanded, and the effect of improving the capacity can be achieved.

[0034] In some embodiments, the acid treatment includes treatment with one or more of H2O2, H2SO4, and HNO3. In some embodiments, the base treatment includes treatment with one or both of NaOH and ammonia. In some embodiments, the acid treatment or base treatment employs a solution having a mass concentration of 0.1% to 10%, for example, 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any suitable value therebetween. If the concentration is too low, the effect of removing small-particle aluminum powder is relatively limited; if the concentration is too high, it can cause a large amount of aluminum powder to dissolve, reducing the capacity of the aluminum foil. In some embodiments, the acid treatment or base treatment has a temperature of 20°C to 60°C, for example, 20°C, 30°C, 40°C, 50°C, 60°C, or any suitable value therebetween. If the temperature is too low, the efficiency of removing small-particle aluminum powder is reduced; if the temperature is too high, it can cause excessive corrosion, even damaging the aluminum foil substrate, causing the material to thin or pitting to occur. In some embodiments, the acid treatment or base treatment has a time of 10 s to 10 min, for example, 10 s, 1 min, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, or any suitable value therebetween. If the time is too short, the surface cannot be thoroughly cleaned and small-particle aluminum powder cannot be removed, while if the time is too long, it can cause excessive erosion, also damaging the quality of the aluminum foil.

[0035] In some embodiments, the sintered aluminum foil is subjected to formation treatment, including formation treatment of the first heat-treated sintered aluminum foil with a formation solution containing phosphoric acid.

[0036] In the embodiments of the present disclosure, the addition of phosphoric acid, for example, very dilute phosphoric acid, to the formation solution can form aluminum phosphate on the surface of the sintered aluminum foil, thereby enhancing the water boiling resistance of the sintered aluminum foil after formation treatment.

[0037] In some embodiments, the formation solution used in the formation treatment includes 1% to 10% boric acid, 0.01% to 0.1% phosphoric acid, 0.5% to 5% ammonium pentaborate, and 0.1% to 3% citric acid by mass concentration. The addition of very dilute phosphoric acid to the formation solution can generate aluminum phosphate on the surface of the aluminum foil, enhancing the final water boiling resistance of the sintered aluminum foil after formation. In some embodiments, the concentration of phosphoric acid in the formation solution is 0.01%, 0.05%, 0.1%, or any suitable value therebetween. If the concentration of phosphoric acid is too high, the oxide film formed during the formation process can be corroded, so very dilute phosphoric acid is used to pre- generate a small amount of aluminum phosphate at different depths of the oxide film during the formation process, thereby better improving the final water boiling resistance.

[0038] In some embodiments, the chemical conversion treatment includes a multi-stage segmented chemical conversion treatment, the temperature of the chemical conversion treatment is 70-90°C, the voltage of the chemical conversion treatment is 400-700V, and the voltage is increased step by step. In some embodiments, the chemical conversion treatment adopts a four-to-seven-stage (for example, six-stage) chemical conversion treatment, but the present disclosure is not limited thereto.

[0039] In some embodiments, the chemical conversion method further includes sequentially performing a passivation treatment, a second heat treatment, a repair chemical conversion, a post-treatment, and drying on the sintered aluminum foil after the chemical conversion treatment. In some embodiments, the passivation treatment uses a phosphoric acid solution with a mass concentration of 3-10%, the temperature of the passivation treatment is 50-75°C, and the time of the passivation treatment is 1-20 min. In some embodiments, the temperature of the second heat treatment is 300-550°C, and the time of the second heat treatment is 1-5 min. In some embodiments, the repair chemical conversion uses boric acid with a mass concentration of 1-10%, and the temperature of the repair chemical conversion is 70-90°C. In some embodiments, the post-treatment uses ammonium dihydrogen phosphate with a mass concentration of 1-5%, the temperature of the post-treatment is 50-75°C, and the time of the post-treatment is 1-10 min. In some embodiments, the temperature of the drying is 150-300°C, and the time of the drying is 1-3 min.

[0040] The present disclosure will be better understood with reference to the specific embodiments described below.

[0041] Embodiment 1

[0042] 1. The treated sintered aluminum foil is placed in a 1% ammonium alginate solution and boiled in water at 90°C for 10 min, and then placed in a 500°C muffle furnace for 2 min;

[0043] 2. The sintered aluminum foil after high-temperature treatment is placed in a chemical conversion solution at a temperature of 80°C, and six-stage chemical conversion is performed, with the chemical conversion voltage increasing step by step (400V, 425V, 450V, 475V, 500V, and 520V, respectively), the boric acid content increasing step by step (1%, 3%, 5%, 7%, 9%, and 10%, respectively), the ammonium pentaborate content decreasing step by step (5%, 4%, 3%, 2%, 1%, and 0.5%, respectively), the phosphoric acid being added in the first three stages and decreasing step by step (0.1%, 0.05%, and 0.01%, respectively), and the citric acid acting to adjust the pH to about 5;

[0044] 3. The sintered aluminum foil after formation is placed in a phosphoric acid solution with a concentration of 5% at a temperature of 60°C for passivation treatment for 12 min, then heat treated at 450°C for 2 min, and then placed in a boric acid solution with a concentration of 8% at a temperature of 80°C for repair formation, and finally soaked in a 3% ammonium dihydrogen phosphate solution at 50°C for 5 min, and then placed in an oven at 200°C for drying for 2 min.

[0045] Example 2

[0046] 1. The sintered aluminum foil is treated in a nitric acid solution with a concentration of 0.5% at 30°C for 2 min;

[0047] 2. The treated sintered aluminum foil is placed in an ammonium alginate solution with a concentration of 1% at 90°C for boiling for 10 min, and then placed in a muffle furnace at 500°C for 2 min;

[0048] 3. The sintered aluminum foil after high-temperature treatment is placed in a formation solution at a temperature of 80°C for six-stage formation, with the formation voltage gradually increasing (400V, 425V, 450V, 475V, 500V and 520V, respectively), the boric acid content gradually increasing (1%, 3%, 5%, 7%, 9% and 10%, respectively), the ammonium pentaborate content gradually decreasing (5%, 4%, 3%, 2%, 1% and 0.5%, respectively), the phosphoric acid being added in the first three stages and gradually decreasing (0.1%, 0.05% and 0.01%, respectively), and the citric acid being used to adjust the pH to about 5;

[0049] 4. The sintered aluminum foil after formation is placed in a phosphoric acid solution with a concentration of 5% at a temperature of 60°C for passivation treatment for 12 min, then heat treated at 450°C for 2 min, and then placed in a boric acid solution with a concentration of 8% at a temperature of 80°C for repair formation, and finally soaked in a 3% ammonium dihydrogen phosphate solution at 50°C for 5 min, and then placed in an oven at 200°C for drying for 2 min.

[0050] Example 3

[0051] 1. The sintered aluminum foil is treated in a nitric acid solution with a concentration of 0.1% at 20°C for 10 min;

[0052] 2. The treated sintered aluminum foil is placed in an ammonium alginate solution with a concentration of 0.1% at 80°C for boiling for 20 min, and then placed in a muffle furnace at 550°C for 1 min;

[0053] 3. The sintered aluminum foil after high temperature treatment is placed in a temperature of 70℃ forming solution, and six-stage forming is carried out, the forming voltage is gradually increased (400V, 425V, 450V, 475V, 500V and 520V respectively), the boric acid content is gradually increased (1%, 3%, 5%, 7%, 9% and 10% respectively), the ammonium pentaborate content is gradually reduced (5%, 4%, 3%, 2%, 1% and 0.5% respectively), the phosphoric acid is added in the first three stages and gradually reduced (0.1%, 0.05% and 0.01% respectively), the citric acid is used to adjust the pH, and the pH is adjusted to about 5;

[0054] 4. The sintered aluminum foil after forming is placed in a temperature of 50℃, a concentration of 3% phosphoric acid solution for passivation treatment, the treatment time is 20min, then heat treated at 300℃ for 5min, then placed in a temperature of 70℃, a concentration of 10% boric acid solution for repair forming, finally immersed in a 1% ammonium dihydrogen phosphate solution at 75℃ for 1min, and then placed in a 150℃ oven for drying for 3min.

[0055] Example 4

[0056] 1. The sintered aluminum foil is treated in a 10% nitric acid solution at 60℃ for 10s;

[0057] 2. The treated sintered aluminum foil is placed in a 10% ammonium alginate solution and boiled in water at 98℃ for 10min, and then placed in a 300℃ muffle furnace for 5min;

[0058] 3. The sintered aluminum foil after high temperature treatment is placed in a temperature of 90℃ forming solution, and six-stage forming is carried out, the forming voltage is gradually increased (400V, 425V, 450V, 475V, 500V and 520V respectively), the boric acid content is gradually increased (1%, 3%, 5%, 7%, 9% and 10% respectively), the ammonium pentaborate content is gradually reduced (5%, 4%, 3%, 2%, 1% and 0.5% respectively), the phosphoric acid is added in the first three stages and gradually reduced (0.1%, 0.05% and 0.01% respectively), the citric acid is used to adjust the pH, and the pH is adjusted to about 5;

[0059] 4. The sintered aluminum foil after forming is placed in a temperature of 75℃, a concentration of 10% phosphoric acid solution for passivation treatment, the treatment time is 1min, then heat treated at 550℃ for 1min, then placed in a temperature of 90℃, a concentration of 1% boric acid solution for repair forming, finally immersed in a 5% ammonium dihydrogen phosphate solution at 60℃ for 9min, and then placed in a 300℃ oven for drying for 1min.

[0060] Comparative Example 1

[0061] 1. The treated sintered aluminum foil is placed in pure water at 90°C for 10 minutes;

[0062] 2. The sintered aluminum foil after high temperature treatment is placed in a formation solution at a temperature of 80°C for six-stage formation, with the formation voltage gradually increasing (400V, 425V, 450V, 475V, 500V and 520V respectively) and the boric acid content gradually increasing (1%, 3%, 5%, 7%, 9% and 10% respectively), the ammonium pentaborate content gradually decreasing (5%, 4%, 3%, 2%, 1% and 0.5% respectively), and the citric acid acting to adjust the pH to about 5;

[0063] 3. The sintered aluminum foil after formation is placed in a phosphoric acid solution at a temperature of 60°C and a concentration of 5% for passivation treatment for 12 minutes, then heat treated at 450°C for 2 minutes, placed in a boric acid solution at a temperature of 80°C and a concentration of 8% for repair formation, and finally immersed in a 3% ammonium dihydrogen phosphate solution at 50°C for 5 minutes, and then placed in an oven at 200°C for drying for 2 minutes.

[0064] The performance parameters of the aluminum foils obtained in Examples 1-4 and Comparative Example 1 were tested using conventional industry standard test methods, as shown in Table 1.

[0065] Table 1

[0066]

[0067] As can be seen from Table 1, the voltage resistance of Examples 1-4 is increased compared to Comparative Example 1, the specific capacity is increased, the voltage increase time is reduced, and the 1h water boiling voltage increase time is reduced. See Figure 2 FIG. 2 shows the pore size distribution of the aluminum foils of Example 2 and Comparative Example 1, where the horizontal axis is the pore size and the vertical axis is the proportion of pores of the corresponding pore size. By improving the steps of the examples, the porosity is increased and the capacity decay caused by pore blockage is reduced.

[0068] Table 2 shows the parameter test results of Example 2 and Examples 5-7, where the difference between Examples 5-7 and Example 2 is only the type of blocking agent used. Example 5 uses ammonium nitrate as the blocking agent, Example 6 uses ammonium borate as the blocking agent, and Example 7 uses a 1:1 mixture of ammonium nitrate and ammonium borate as the blocking agent.

[0069] Table 2

[0070]

[0071] Table 3 shows the parameter test results of Example 2 and Examples 8-15, where the difference between Examples 8-15 and Example 2 is only the concentration of the blocking agent used.

[0072] Table 3

[0073]

[0074] If the concentration of the blocking agent is too low, its effect of inhibiting the generation of the hydrated oxide film is relatively limited, and if the concentration of the blocking agent is too high, it will lead to the hydrated oxide film being unable to form, and it will be difficult to raise the voltage in the subsequent formation process due to the lack of the hydrated oxide film.

[0075] Table 4 shows the parameter test results of Example 2 and Examples 16-19 and Comparative Example 2, wherein Examples 16-18 differ from Example 2 only in that the type of acid or base used in the first step of acid-base treatment is different, Example 16 uses sulfuric acid, Example 17 uses ammonia, and Example 18 uses NaOH. Example 19 differs from Example 2 in that the formation solution does not contain phosphoric acid, and the other conditions are the same as Example 2. Comparative Example 2 differs from Example 2 in that the formation treatment is directly performed after the water boiling, and no first heat treatment is performed.

[0076] Table 4

[0077]

[0078] As can be seen from Table 4, when the formation solution does not contain extremely dilute phosphoric acid, the performance of the aluminum foil decreases; when no first heat treatment is performed, the performance of the aluminum foil decreases.

[0079] Example embodiments have been disclosed herein and, although the use of specific terms is expressly used herein, they are intended in a generic sense only and are not intended to limit the scope of the present disclosure. In some instances, it will be apparent to those skilled in the art that features, components, and / or elements described with a specific embodiment can be utilized singularly or in combination with other embodiments unless otherwise specifically noted. Therefore, it will be understood by those skilled in the art that various changes in form and details can be made without departing from the scope of the present disclosure as set forth in the appended claims.

Claims

1. A formation method for sintered aluminum foil, characterized by, The method comprises the following steps: putting the sintered aluminum foil into a solution containing a blocking agent for water boiling treatment, wherein the blocking agent is used to form a passivation film on the surface of the sintered aluminum foil, and the blocking agent comprises one or more of nitrate, borate, alginate and chromate; carrying out formation treatment on the sintered aluminum foil.

2. The formation method according to claim 1, characterized by, Before the formation treatment on the sintered aluminum foil, the method further comprises: carrying out first heat treatment on the sintered aluminum foil after the water boiling treatment.

3. The formation method according to claim 2, characterized by, The formation treatment on the sintered aluminum foil comprises: carrying out formation treatment on the sintered aluminum foil after the first heat treatment by using a formation solution containing phosphoric acid.

4. The formation method according to any one of claims 1 to 3, characterized by, The mass concentration of the blocking agent is 0.1% to 10%.

5. The formation method according to any one of claims 1 to 3, characterized by, The temperature of the water boiling treatment is 80°C to 98°C, and the time of the water boiling treatment is 1min to 20min.

6. The formation method according to claim 2 or 3, characterized by, The temperature of the first heat treatment is 300°C to 550°C, and the time of the first heat treatment is 1min to 5min.

7. The formation method according to claim 3, characterized by, The formation solution contains boric acid, phosphoric acid, ammonium pentaborate and citric acid, the mass concentration of the boric acid is 1% to 10%, the mass concentration of the phosphoric acid is 0.01% to 0.1%, the mass concentration of the ammonium pentaborate is 0.5% to 5%, and the mass concentration of the citric acid is 0.1% to 3%.

8. The formation method according to claim 7, characterized by, The formation treatment on the sintered aluminum foil after the first heat treatment comprises: carrying out multi-stage segmented formation treatment on the sintered aluminum foil after the first heat treatment, wherein the temperature of the formation treatment is 70°C to 90°C, and the voltage of the formation treatment is increased step by step in the range of 400V to 700V.

9. The formation method according to any one of claims 1 to 3, characterized by, Before the sintered aluminum foil is put into the solution containing the blocking agent for the water boiling treatment, the method further comprises: carrying out acid treatment or alkali treatment on the sintered aluminum foil.

10. The formation method according to claim 7, characterized by, The acid treatment or alkali treatment on the sintered aluminum foil comprises: carrying out acid treatment on the sintered aluminum foil by using one or more of H2O2, H2SO4 and HNO3; or carrying out alkali treatment on the sintered aluminum foil by using one or both of NaOH and ammonia water; wherein the mass concentration of the solution used for the acid treatment or alkali treatment on the sintered aluminum foil is 0.1% to 10%, the temperature is 20°C to 60°C, and the time is 10s to 10min.

11. The formation method according to any one of claims 1 to 3, characterized by, After the formation treatment on the sintered aluminum foil, the method further comprises: carrying out passivation treatment, second heat treatment, repair formation, post-treatment and drying on the sintered aluminum foil after the formation treatment in sequence.

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