A nanoporous aluminum bulk and its preparation method

Abstract

This invention discloses a nanoporous aluminum bulk and its preparation method, belonging to the technical field of macroscopic large-size nanoporous metal material bulk preparation. The method for preparing the nanoporous aluminum bulk involves first preparing a precursor alloy by blending alloys, followed by solution treatment and anodizing. By controlling the composition of the precursor alloy, reaction temperature, electrolyte acid ratio, and current, the depth of the porous layer and the size and distribution of the nanopores are adjusted, resulting in a macroscopic large-size bulk nanoporous aluminum with a high specific surface area, composed of nanoscale pores and pores, and a porous layer thickness of up to 2 mm. The nanoporous aluminum bulk prepared using this invention features a large specific surface area, unrestricted length and width dimensions of the porous Al with a thickness up to 2 mm, and a bending strength up to 5 MPa. Furthermore, the preparation method is characterized by simple and easy-to-prepare electrolytes, readily available experimental conditions, and simple operation.

Description

Technical Field

[0001] This invention relates to the field of macroscopic large-size nanoporous metal material bulk preparation technology, specifically to a nanoporous aluminum bulk and its preparation method. Background Technology

[0002] Nanoporous metals, due to their nanoscale pore structure, possess characteristics such as large specific surface area, high catalytic activity, and good conductivity, and have wide applications in catalysis, sensing, energy storage, electrode materials, and many other fields.

[0003] Common methods for preparing nanoporous metals are mostly suitable for chemically stable noble metals, but not for chemically reactive and inexpensive metals, thus greatly limiting the research and application of nanoporous metals. Aluminum, as a lightweight metal, is highly reactive and abundant. However, it is difficult to prepare nanoporous aluminum using common methods (such as template methods). Studies have shown that porous aluminum with nanostructures has great application potential in areas such as surface plasmon resonance enhancement, catalysis, and electrode materials. However, due to the high reactivity of aluminum itself and its nanostructure, it can react with water and be consumed, making its preparation very difficult and resulting in few reports. Therefore, the preparation of bulk nanoporous aluminum with high macroscopic and large specific surface area and uniform structure has become a research focus in recent years.

[0004] Due to aluminum's high reactivity, reacting in acidic, alkaline, and even aqueous solutions, conventional dealloying methods in aqueous solutions have consistently failed to produce macroscopically large-sized nanoporous aluminum. Meanwhile, given the wide range of applications for macroscopically large-sized nanoporous Al, researchers have made tireless efforts to successfully prepare it. However, a breakthrough was finally achieved in 2018 by Yang Wei et al. using a chemical ion exchange method with ionic liquids, resulting in a related invention patent (Yang Wei et al., application number 201810288276.2, publication number CN). Patent 110343898A, entitled "A Nanoporous Aluminum and Its Preparation Method," proposes using pure metals or alloys as precursor materials and ionic liquids as the medium. Under an inert atmosphere, the precursor alloy is immersed in an ionic liquid composed of organic cations and aluminum-containing anions (such as aluminum halides), ensuring the temperature is below the decomposition temperature of the ionic liquid. A displacement reaction removes metal elements more reactive than aluminum from the precursor material, yielding nanoporous aluminum. However, this method for preparing large-scale nanoporous Al suffers from drawbacks such as slow reaction time, long production cycle, not being carried out at room temperature, complex operation, and stringent preparation conditions. To date, no research reports have been published on how to prepare nanoporous Al, or even large-scale nanoporous Al, in conventional aqueous solutions.

[0005] Anodizing aluminum alloy sheets can form a porous oxide film on the surface (this film is a pure oxide, containing no Al, i.e., not a porous Al layer). Even so, limited by the anodizing mechanism, the thickness of this oxide layer is generally 2-15 micrometers, with a maximum of 40 micrometers, far from meeting the requirements for large-scale macroscopic applications (i.e., current aluminum alloy anodizing technology cannot obtain a porous oxide layer with a thickness of 0.5 millimeters). Furthermore, the product of anodizing aluminum alloy sheets is generally a solid aluminum alloy sheet covered with a porous oxide layer no thicker than 40 micrometers. In other words, even though existing aluminum alloy anodizing technology can prepare a porous oxide layer on the surface of an aluminum alloy substrate, this porous layer is not porous Al with a porous structure; that is, current anodizing cannot be used to prepare large-scale, nanoporous Al. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the present invention aims to provide a nanoporous aluminum bulk material and its preparation method, so as to solve the technical problems of the prior art in preparing nanoporous aluminum, such as harsh conditions, complex operation, and inability to be used for macroscopic large-size preparation.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] This invention discloses a method for preparing nanoporous aluminum bulk materials, comprising the following steps:

[0009] S1: The prepared precursor alloy is rolled into an alloy sheet; then the alloy sheet is subjected to solution treatment and cooled to obtain an alloy profile;

[0010] S2: After the alloy profile is anodized in a mixed aqueous solution, it is then cleaned and dried to obtain a nanoporous aluminum.

[0011] Further, in S1, the method for preparing the precursor alloy includes the following steps:

[0012] Industrial pure aluminum and pure iron are mixed to obtain a mixed raw material. The mixed raw material is then heated and smelted to obtain a precursor alloy. The industrial pure aluminum accounts for 15%-35% of the mass percentage of the mixed raw material. The heating and smelting temperature is 800-1000℃. The thickness of the alloy sheet is 0.5-2mm.

[0013] Furthermore, in S1, the solution treatment temperature is 800–1000°C, and the time is 3–6 hours; the cooling method is water cooling.

[0014] Furthermore, in S2, before the alloy profile undergoes anodizing, it is successively ground and polished using sandpaper of 500 mesh, 1000 mesh, 1500 mesh, and 2000 mesh.

[0015] Further, in S2, the process parameters for the anodic oxidation reaction are as follows: the alloy profile is connected to the anode, the cathode is connected to the metal reaction tank, the reaction time is 30–120 min, the temperature of the electrolyte solution is 0–20 °C, a constant current power supply is used, and the current density is 0.2–0.5 A / cm². 2 .

[0016] Further, the electrolyte solution is a mixed aqueous solution consisting of 0.5–2 mol / L sulfuric acid or 10–40 ml / L ethylene glycol; or a mixed aqueous solution consisting of 0.1–1.0 mol / L oxalic acid, 0.4–2 mol / L sulfuric acid, and 10–40 ml / L ethylene glycol.

[0017] Furthermore, in S2, the cleaning is performed by alternating between deionized water and alcohol; the drying is performed in a vacuum drying oven, where a vacuum is drawn to -0.1 MPa until the alcohol after cleaning evaporates naturally.

[0018] The present invention also discloses a nanoporous aluminum bulk material obtained by the above preparation method.

[0019] Furthermore, the microstructure of the nanoporous aluminum block consists of nanoscale pores and pores; the thickness of the pores is about 20 nm; and the pore size is 200 nm to 1000 nm.

[0020] Furthermore, the specific surface area of ​​the nanoporous aluminum bulk material is 21.56–49.93 m². 2 / g, with a maximum bending strength of 5MPa; the external dimensions of the nanoporous aluminum block are in the centimeter range.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This invention discloses a method for preparing bulk nanoporous aluminum. First, a precursor alloy is prepared by blending alloys, followed by solution treatment and anodizing. By controlling the composition of the precursor alloy, reaction temperature, electrolyte acid ratio, and current, the depth of the porous layer and the size and distribution of nanopores are adjusted, resulting in macroscopically large-sized bulk nanoporous aluminum with a porous layer thickness of up to 2 mm, composed of nanoscale pores and pores, and possessing a high specific surface area. The preparation method disclosed in this invention enables the preparation of macroscopically large-sized bulk nanoporous Al under anodizing conditions in aqueous solution. The bulk nanoporous aluminum prepared using this method has a simple and easy-to-prepare electrolyte, readily available experimental conditions, and a simple operating process.

[0023] This invention also discloses a nanoporous aluminum bulk material prepared using the above method. The microstructure of the prepared bulk nanoporous aluminum bulk material consists of nanoscale pores and gaps, with a uniform and continuous pore structure. The overall size is macroscopic, exceeding the centimeter level. The bulk nanoporous aluminum has a complete structure and a specific surface area of ​​21.56–49.93 m². 2 / g, which has the characteristics of complete structure, high porosity, large specific surface area and short preparation cycle. Attached Figure Description

[0024] Figure 1 This is a SEM image of the nanoporous aluminum block prepared in Example 1 of the present invention;

[0025] Figure 2 The image shows the XRD pattern of the nanoporous aluminum block prepared in Example 1 of this invention.

[0026] Figure 3 The bending strength of the nanoporous aluminum block prepared in Example 1 of this invention was obtained by a three-point bending experiment. Detailed Implementation

[0027] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0028] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0029] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0030] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0031] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0032] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0033] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0034] Example 1

[0035] A method for preparing a nanoporous aluminum bulk material includes the following steps:

[0036] S1: Based on the assumption that industrial pure aluminum accounts for 35% of the total raw material mass, weigh out 35g of industrial pure aluminum blocks and 65g of industrial pure iron blocks, mix them together to obtain a mixed raw material, and heat and melt the mixed raw material. During the heating and melting process, first heat the resistance furnace to 800℃, put the weighed industrial pure aluminum blocks into the crucible, and after they melt, add industrial pure iron blocks to the melt. The heating and melting temperature is 800℃, and the temperature is held for 30 minutes to obtain the precursor alloy. Pour out the precursor alloy and roll it into an alloy sheet with a thickness of 0.5mm.

[0037] The alloy sheet obtained in the above steps is placed in a box furnace for solution treatment at a solution temperature of 800℃ for 6 hours. The alloy sheet after solution treatment is then subjected to water quenching to obtain alloy profiles.

[0038] S2: The alloy profiles obtained in the above steps are successively polished with 500-grit, 1000-grit, 1500-grit, and 2000-grit sandpaper until they are 0.4 mm thick. After polishing, the samples are cleaned with alcohol and allowed to air dry. Then, they are connected to an anodizing system for anodizing. During the anodizing reaction, an alloy profile with a length of 1 cm and a width of 1 cm is connected to the anode, and the cathode is connected to the metal reaction tank. The reaction time is 120 minutes, the electrolyte solution temperature is 0℃, and a constant current power supply with a current density of 0.2 A / cm² is used. 2 The electrolyte solution used was a mixed acid solution with sulfuric acid concentration of 0.4 mol / L, oxalic acid concentration of 0.1 mol / L, and ethylene glycol concentration of 10 ml / L. After the anodizing reaction was completed, the alloy profile after the reaction was placed in deionized water for cleaning, then cleaned with alcohol, and then placed in a vacuum drying oven and evacuated to -0.1 MPa. After the alcohol evaporated naturally, a nanoporous aluminum block was obtained. The sample was taken out and vacuum stored.

[0039] The microstructure and phase composition diagrams of the bulk nanoporous aluminum block obtained in this embodiment are shown below. Figure 1 (Microstructure diagram) and Figure 2 (XRD pattern of phase composition) Figure 1 It can be seen that the entire sample is a porous material composed of interconnected nanoscale pores and edges. The microstructure is composed of nanoscale pores and edges and pores (where the thickness of the pores or pore walls is about 20 nanometers and the pore diameter is 20 nanometers to 1000 nanometers). The structure is uniform and continuous and distributed throughout the entire block. Its overall size is above the macroscopic centimeter level. Figure 2 It can be seen that the sample obtained in this example is aluminum, and the bulk nanoporous Al obtained after anodizing is porous Al with a dense Al2O3 film covering the pore wall surface. The bulk nanoporous aluminum material prepared in this example has a specific surface area of ​​49.93 m². 2 / g.

[0040] Example 2

[0041] A method for preparing a nanoporous aluminum bulk material includes the following steps:

[0042] S1: According to the principle that industrial pure aluminum accounts for 15% of the total raw material mass, weigh out 15g of industrial pure aluminum block and 85g of industrial pure iron block and mix them to obtain a mixed raw material. Heat the mixed raw material to melt it. When heating and melting, first heat the resistance furnace to 1000℃, put the weighed industrial pure aluminum block in the crucible, and after it melts, add the industrial pure iron block to the melt. Heat and melt it at 1000℃ and hold for 30 minutes to obtain the precursor alloy. Pour out the precursor alloy and roll it into an alloy sheet with a thickness of 2mm.

[0043] The alloy sheet obtained in the above steps is placed in a box furnace for solution treatment at a solution temperature of 1000℃ for 3 hours. The alloy sheet after solution treatment is then subjected to water quenching to obtain alloy profiles.

[0044] S2: The alloy profiles obtained in the above steps are successively polished with 500-grit, 1000-grit, 1500-grit, and 2000-grit sandpaper until they reach a thickness of 0.6 mm. After polishing, the samples are cleaned with alcohol and allowed to air dry. Then, they are connected to an anodizing system for anodizing. During the anodizing reaction, an alloy profile with a length of 1 cm and a width of 1 cm is connected to the anode, and the cathode is connected to the metal reaction tank. The reaction time is 120 minutes, the electrolyte solution temperature is 20℃, and a constant current power supply with a current density of 0.5 A / cm² is used. 2 The electrolyte is a mixed acid solution with sulfuric acid concentration of 2 mol / L, oxalic acid concentration of 1.0 mol / L and ethylene glycol concentration of 40 ml / L. After the anodizing reaction is completed, the alloy profile after the reaction is placed in deionized water for cleaning, then cleaned with alcohol, and then placed in a vacuum drying oven and evacuated to -0.1 MPa. After the alcohol evaporates naturally, a nanoporous aluminum block is obtained. The sample is taken out and vacuum stored.

[0045] The bulk nanoporous aluminum material prepared in this embodiment has a specific surface area of ​​41.41 m². 2 / g.

[0046] Example 3

[0047] A method for preparing a nanoporous aluminum bulk material includes the following steps:

[0048] S1: Assuming that industrial pure aluminum accounts for 20% of the total raw material mass, weigh out 20g of industrial pure aluminum block and 80g of industrial pure iron block and mix them to obtain a mixed raw material. Heat the mixed raw material to melt it. When heating and melting, first heat the resistance furnace to 900℃, put the weighed industrial pure aluminum block in the crucible, and after it melts, add the industrial pure iron block to the melt. Heat and melt it at 900℃ and hold for 30 minutes to obtain the precursor alloy. Pour out the precursor alloy and roll it into an alloy sheet with a thickness of 1mm.

[0049] The alloy sheet obtained in the above steps is placed in a box furnace for solution treatment at a solution temperature of 900℃ for 4 hours. The alloy sheet after solution treatment is then water-quenched to obtain the alloy profile.

[0050] S2: The alloy profiles obtained in the above steps are successively polished with 500-grit, 1000-grit, 1500-grit, and 2000-grit sandpaper until they are 0.4 mm thick. After polishing, the samples are cleaned with alcohol and allowed to air dry. Then, they are connected to an anodizing system for anodizing. During the anodizing reaction, an alloy profile with a length of 1 cm and a width of 1 cm is connected to the anode, and the cathode is connected to the metal reaction tank. The reaction time is 80 minutes, the electrolyte solution temperature is 10℃, and a constant current power supply with a current density of 0.4 A / cm² is used. 2 The electrolyte is a mixed acid solution with sulfuric acid concentration of 1 mol / L, oxalic acid concentration of 0.5 mol / L, and ethylene glycol concentration of 20 ml / L. After the anodizing reaction is completed, the alloy profile after the reaction is placed in deionized water for cleaning, then cleaned with alcohol, and then placed in a vacuum drying oven and evacuated to -0.1 MPa. After the alcohol evaporates naturally, a nanoporous aluminum block is obtained. The sample is taken out and vacuum stored.

[0051] The bulk nanoporous aluminum material prepared in this embodiment has a specific surface area of ​​28.38 m². 2 / g.

[0052] Example 4

[0053] A method for preparing a nanoporous aluminum bulk material includes the following steps:

[0054] S1: According to the principle that industrial pure aluminum accounts for 30% of the total raw material mass, weigh out 30g of industrial pure aluminum block and 70g of industrial pure iron block and mix them to obtain a mixed raw material. Heat the mixed raw material to melt it. When heating and melting, first heat the resistance furnace to 850℃, put the weighed industrial pure aluminum block in the crucible, and after it melts, add the industrial pure iron block to the melt. Heat and melt it at 850℃ and hold for 30 minutes to obtain the precursor alloy. Pour out the precursor alloy and roll it into an alloy sheet with a thickness of 1mm.

[0055] The alloy sheet obtained in the above steps is placed in a box furnace for solution treatment at a solution temperature of 850℃ for 5 hours. The alloy sheet after solution treatment is then water-quenched to obtain the alloy profile.

[0056] S2: The alloy profiles obtained in the above steps are successively polished with 500-grit, 1000-grit, 1500-grit, and 2000-grit sandpaper until they reach a thickness of 0.8 mm. After polishing, the samples are cleaned with alcohol and allowed to air dry. Then, they are connected to an anodizing system for anodizing. During the anodizing reaction, an alloy profile with a length of 1 cm and a width of 1 cm is connected to the anode, and the cathode is connected to the metal reaction tank. The reaction time is 120 minutes, the electrolyte solution temperature is 5℃, and a constant current power supply with a current density of 0.4 A / cm² is used. 2The electrolyte is a mixed acid solution with sulfuric acid concentration of 1.5 mol / L, oxalic acid concentration of 0.6 mol / L and ethylene glycol concentration of 20 ml / L. After the anodizing reaction is completed, the alloy profile after the reaction is placed in deionized water for cleaning, then cleaned with alcohol, and then placed in a vacuum drying oven and evacuated to -0.1 MPa. After the alcohol evaporates naturally, a nanoporous aluminum block is obtained. The sample is taken out and vacuum stored.

[0057] The bulk nanoporous aluminum material prepared in this embodiment has a specific surface area of ​​21.56 m². 2 / g.

[0058] Example 5

[0059] A method for preparing a nanoporous aluminum bulk material includes the following steps:

[0060] S1: Based on the assumption that industrial pure aluminum accounts for 25% of the total raw material mass, weigh out 25g of industrial pure aluminum block and 75g of industrial pure iron block, mix them together to obtain a mixed raw material, heat and melt the mixed raw material. When heating and melting, first heat the resistance furnace to 950℃, put the weighed industrial pure aluminum block into the crucible, and after it melts, add the industrial pure iron block to the melt. Heat and melt at 950℃ for 30 minutes to obtain the precursor alloy; pour out the precursor alloy and roll it into an alloy sheet with a thickness of 1.5mm.

[0061] The alloy sheet obtained in the above steps is placed in a box furnace for solution treatment at a solution temperature of 1000℃ for 5 hours. The alloy sheet after solution treatment is then subjected to water quenching to obtain alloy profiles.

[0062] S2: The alloy profiles obtained in the above steps are successively polished with 500-grit, 1000-grit, 1500-grit, and 2000-grit sandpaper until they are 0.2 mm thick. After polishing, the samples are cleaned with alcohol and allowed to air dry. Then, they are connected to an anodizing system for anodizing. During the anodizing reaction, an alloy profile with a length of 1 cm and a width of 1 cm is connected to the anode, and the cathode is connected to the metal reaction tank. The reaction time is 90 minutes, the electrolyte solution temperature is 15℃, and a constant current power supply with a current density of 0.4 A / cm² is used. 2 The electrolyte is a mixed acid solution with sulfuric acid concentration of 0.8 mol / L, oxalic acid concentration of 1.2 mol / L and ethylene glycol concentration of 20 ml / L. After the anodizing reaction is completed, the alloy profile after the reaction is placed in deionized water for cleaning, then cleaned with alcohol, and then placed in a vacuum drying oven and evacuated to -0.1 MPa. After the alcohol evaporates naturally, a nanoporous aluminum block is obtained. The sample is taken out and vacuum stored.

[0063] The bulk nanoporous aluminum material prepared in this embodiment has a specific surface area of ​​30.42 m².2 / g.

[0064] Example 6

[0065] A method for preparing a nanoporous aluminum bulk material includes the following steps:

[0066] S1: According to the principle that industrial pure aluminum accounts for 15% of the total raw material mass, weigh out 15g of industrial pure aluminum block and 85g of industrial pure iron block and mix them to obtain a mixed raw material. Heat the mixed raw material to melt it. When heating and melting, first heat the resistance furnace to 900℃, put the weighed industrial pure aluminum block in the crucible, and after it melts, add the industrial pure iron block to the melt. Heat and melt it at 900℃ and hold for 30 minutes to obtain the precursor alloy. Pour out the precursor alloy and roll it into an alloy sheet with a thickness of 1mm.

[0067] The alloy sheet obtained in the above steps is placed in a box furnace for solution treatment at a solution temperature of 950℃ for 4 hours. The alloy sheet after solution treatment is then water-quenched to obtain the alloy profile.

[0068] S2: The alloy profiles obtained in the above steps are successively polished with 500-grit, 1000-grit, 1500-grit, and 2000-grit sandpaper until they reach a thickness of 1.0 mm. After polishing, the samples are cleaned with alcohol and allowed to air dry. Then, they are connected to an anodizing system for anodizing. During the anodizing reaction, an alloy profile with a length of 1 cm and a width of 1 cm is connected to the anode, and the cathode is connected to the metal reaction tank. The reaction time is 120 minutes, the electrolyte solution temperature is 0℃, and a constant current power supply with a current density of 0.4 A / cm² is used. 2 The electrolyte is a mixed acid solution of sulfuric acid with a concentration of 0.5 mol / L and ethylene glycol with a concentration of 10 ml / L. After the anodizing reaction is completed, the alloy profile after the reaction is placed in deionized water for cleaning, then cleaned with alcohol, and then placed in a vacuum drying oven and evacuated to -0.1 MPa. After the alcohol evaporates naturally, a nanoporous aluminum block is obtained. The sample is taken out and stored in a vacuum.

[0069] The bulk nanoporous aluminum material prepared in this embodiment has a specific surface area of ​​26.34 m². 2 / g.

[0070] Example 7

[0071] A method for preparing a nanoporous aluminum bulk material includes the following steps:

[0072] S1: According to the principle that industrial pure aluminum accounts for 35% of the total raw material mass, weigh out 37g of industrial pure aluminum block and 65g of industrial pure iron block and mix them to obtain a mixed raw material. Heat the mixed raw material to melt it. When heating and melting, first heat the resistance furnace to 800℃, put the weighed industrial pure aluminum block in the crucible, and after it melts, add the industrial pure iron block to the melt. Heat and melt it at 800℃ and hold for 30 minutes to obtain the precursor alloy. Pour out the precursor alloy and roll it into an alloy sheet with a thickness of 2mm.

[0073] The alloy sheet obtained in the above steps is placed in a box furnace for solution treatment at a solution temperature of 1000℃ for 6 hours. The alloy sheet after solution treatment is then subjected to water quenching to obtain alloy profiles.

[0074] S2: The alloy profiles obtained in the above steps are successively polished with 500-grit, 1000-grit, 1500-grit, and 2000-grit sandpaper until they are 0.4 mm thick. After polishing, the samples are cleaned with alcohol and allowed to air dry. Then, they are connected to an anodizing system for anodizing. During the anodizing reaction, an alloy profile 1 cm long and 1 cm wide is connected to the anode, and the cathode is connected to the metal reaction tank. The reaction time is 30 minutes, the electrolyte solution temperature is 0℃, and a constant current power supply with a current density of 0.4 A / cm² is used. 2 The electrolyte is a mixed acid solution with a sulfuric acid concentration of 2 mol / L and an ethylene glycol concentration of 40 ml / L. After the anodizing reaction is completed, the alloy profile after the reaction is placed in deionized water for cleaning, then cleaned with alcohol, and then placed in a vacuum drying oven and evacuated to -0.1 MPa. After the alcohol evaporates naturally, a nanoporous aluminum block is obtained. The sample is taken out and vacuum stored.

[0075] The bulk nanoporous aluminum material prepared in this embodiment has a specific surface area of ​​45.51 m². 2 / g.

[0076] The nanoporous aluminum bulk material prepared in the above embodiments was subjected to a bending resistance test, such as... Figure 3 As shown, its flexural strength can reach 5MPa.

[0077] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing a nanoporous aluminum bulk material, characterized in that, The following steps are involved: S1: The prepared precursor alloy is rolled into an alloy sheet; then the alloy sheet is subjected to solution treatment and cooled to obtain an alloy profile; S2: After the alloy profile is anodized in a mixed aqueous solution, it is then washed and dried to obtain a nanoporous aluminum. The process parameters for the anodic oxidation reaction are as follows: the alloy profile is connected to the anode, the cathode is connected to the metal reaction tank, the reaction time is 30~120 min, the electrolyte solution temperature is 0~20℃, a constant current power supply is used, and the current density is 0.2~0.5 A / cm². 2 ; The electrolyte solution is a mixed aqueous solution consisting of 0.5-2 mol / L sulfuric acid and 10-40 ml / L ethylene glycol, or the electrolyte solution is a mixed aqueous solution consisting of 0.1-1.0 mol / L oxalic acid, 0.4-2 mol / L sulfuric acid and 10-40 ml / L ethylene glycol.

2. The method for preparing a nanoporous aluminum bulk body according to claim 1, characterized in that, In S1, the method for preparing the precursor alloy includes the following steps: Industrial pure aluminum and pure iron are mixed to obtain a mixed raw material. The mixed raw material is then heated and smelted to obtain a precursor alloy. The industrial pure aluminum accounts for 15%-35% of the mass of the mixed raw material. The heating and smelting temperature is 800-1000℃. The thickness of the alloy sheet is 0.5-2mm.

3. The method for preparing a nanoporous aluminum bulk body according to claim 1, characterized in that, In S1, the solution treatment temperature is 800~1000℃ and the time is 3~6h; the cooling method is water cooling.

4. The method for preparing a nanoporous aluminum bulk body according to claim 1, characterized in that, In S2, before the alloy profile undergoes anodizing, it is successively ground and polished using sandpaper of 500 mesh, 1000 mesh, 1500 mesh, and 2000 mesh.

5. The method for preparing a nanoporous aluminum bulk body according to claim 1, characterized in that, In S2, the cleaning is performed by alternating between deionized water and alcohol; the drying is performed in a vacuum drying oven, where a vacuum of -0.1 MPa is applied until the alcohol evaporates naturally after cleaning.

6. A nanoporous aluminum bulk material, characterized in that, It was prepared using the method for preparing a nanoporous aluminum bulk material according to any one of claims 1 to 5.

7. The nanoporous aluminum bulk body according to claim 6, characterized in that, The microstructure of the nanoporous aluminum block consists of nanoscale pores and pores; the thickness of the pores is 20 nm; and the pore size is 200 nm to 1000 nm.

8. A nanoporous aluminum bulk body according to claim 6, characterized in that, The specific surface area of ​​the nanoporous aluminum block is 21.56~49.93m². 2 / g, with a maximum bending strength of 5MPa; the external dimensions of the nanoporous aluminum block are in the centimeter range.

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