Bulk nanohole aluminum with macroscopic size based on the principle of solid solution dealloying and method

Abstract

The application discloses a macro-sized bulk nanometer porous aluminum prepared based on a solid solution dealloying principle and a method thereof, and belongs to the technical field of metal materials. In the application, the homogenous distribution of main component Al and alloy elements Me in the melt at the atomic level is realized in the process of melting and alloying, then the alloy sheet is obtained through casting and rolling fast cooling, and then the alloy sheet is aged, so that the enrichment of solute atoms Me in the alloy sheet with the atomic level homogenous distribution is caused, the whole alloy is still a single-phase aluminum solid solution, then the aluminum single-phase solid solution alloy sheet with Me enrichment is corroded in a sulfuric acid solution, the active alloy element Me in the solid solution is dissolved into the sulfuric acid solution by controlling the corrosion speed, meanwhile, the inert element Al in the alloy is gathered together through diffusion, a hole edge (hole ligament) connected with each other is formed, and the space between the adjacent two hole ligaments becomes a hole, so that a simple, convenient and low-cost preparation method of the bulk nanometer porous Al is provided.

Description

Technical Field

[0001] This invention belongs to the field of metallic materials technology, specifically relating to a method for preparing bulk nanoporous aluminum with macroscopic dimensions based on the solid solution dealloying principle. Background Technology

[0002] Nanoporous metals possess high specific surface area, low density, and high catalytic activity due to their nanoscale ligaments and pore structures, making them widely applicable in catalysis, energy storage, and sensing.

[0003] Existing methods for preparing nanoporous aluminum primarily involve removing active components from alloys using a dealloying process in anhydrous ionic liquids. However, the stringent environmental requirements and high cost of anhydrous ionic liquid systems limit the preparation of nanoporous Al, resulting in high costs and demanding environmental conditions. Therefore, efficiently preparing nanoporous Al under simpler environmental conditions is crucial for advancing nanoporous Al preparation technology.

[0004] Aqueous solutions are inexpensive, readily available, and can be used to prepare various corrosive solutions. Therefore, removing active components from alloys through corrosion in aqueous solutions, followed by the diffusion self-assembly of inert components into porous materials, is a major existing method for preparing nanoporous metal materials. Aluminum, due to its amphoteric properties, can be corroded in acidic solutions, alkaline solutions, and even pure aqueous solutions. Therefore, aluminum is frequently used as the active component in the corrosion preparation of nanoporous metals, removed during the alloy corrosion process to prepare various other nanoporous metal materials. However, preparing porous Al through corrosion in aqueous solutions is difficult. Furthermore, due to its large specific surface area and high activity, nanoporous Al can dissolve rapidly in aqueous solutions, even in pure water. Therefore, even if a submicron-thick porous Al layer can be formed on the alloy surface using corrosion, the surface layer will dissolve due to its high activity as subsequent corrosion progresses into the alloy. This makes it impossible to obtain micron-thick nanoporous Al foils, let alone nanoporous Al bulk materials with thicknesses exceeding millimeters. Therefore, to date, there are few reports on the preparation of nanoporous Al using corrosion-based methods in aqueous solutions, and even fewer reports on the preparation of nanoporous Al bulk materials using corrosion-based methods in aqueous solutions. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing bulk nanoporous aluminum with macroscopic dimensions based on the solid solution dealloying principle, in order to solve the technical problems of complex preparation process and difficult experimental conditions in existing nanoporous aluminum preparation methods.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] This invention discloses a method for preparing bulk nanoporous aluminum with macroscopic dimensions based on the solid solution dealloying principle, comprising the following steps:

[0008] Al ingots and Zn ingots are mixed and smelted to obtain an Al-Zn alloy melt; the Al-Zn alloy melt is then cast and rolled to obtain alloy sheets.

[0009] After aging treatment, the alloy sheet is placed in a corrosion solution for corrosion treatment. After the corrosion treatment is completed, the pretreated alloy is obtained.

[0010] After the pretreated alloy was cleaned and dried in sequence, bulk nanoporous aluminum with macroscopic dimensions was obtained.

[0011] Furthermore, the melting temperature is 680-720℃, and the melting holding time is 30 minutes.

[0012] Furthermore, the Al content in the Al-Zn alloy melt is 17%-28%.

[0013] Furthermore, the speed of the rolls during the casting and rolling process is greater than 300 r / min, and the cooling rate of the Al-Zn alloy melt during the casting and rolling process is greater than 150 °C / s.

[0014] Furthermore, the alloy sheet is an Al-based single-phase solid solution, and the thickness of the alloy sheet is 1.0-1.2 mm.

[0015] Furthermore, the aging treatment is carried out at a temperature of 0-20℃ for a time of 0.5-5h.

[0016] Furthermore, after the alloy sheet undergoes aging treatment, it is polished with 400 and 1000 grit sandpaper to a thickness of 0.5-1.0 mm, and then immersed in a corrosion solution for corrosion treatment.

[0017] Furthermore, the corrosion solution is an aqueous sulfuric acid solution, and the concentration of the aqueous sulfuric acid solution is 0.01-0.1 mol / L.

[0018] Furthermore, the corrosion treatment is carried out at a temperature of -10 to 5°C for a duration of 20 to 30 hours.

[0019] The cleaning process involves sequentially using deionized water and acetone; the drying process is carried out in a vacuum drying oven with a vacuum degree of -0.1 MPa.

[0020] This invention also discloses a bulk nanoporous aluminum with macroscopic dimensions prepared by the above-described method, wherein the specific surface area of ​​the bulk nanoporous aluminum is greater than 22 m². 2 / g.

[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 with macroscopic dimensions based on the principle of solid solution dealloying. Through alloy composition design and heat treatment process control, the main component Al and its alloying element Me are first uniformly distributed at the atomic level in the melt during alloy smelting. Then, through casting and rapid cooling, alloy sheets with uniformly distributed Al and Me are obtained. The cast-rolled alloy sheets are then aged to ensure that only solute atoms Me accumulate in the atomically uniformly distributed alloy sheets, while the alloy sheets as a whole remain a single-phase Al solid solution. Finally, the alloy sheets are etched in sulfuric acid solution, and the etching rate is controlled. This invention enables the active alloying element Me in a solid solution to dissolve in a sulfuric acid solution, while the inert element Al in the alloy diffuses and aggregates together to form interconnected pore ridges (pore ligaments), and the space between two adjacent pore ligaments becomes a pore. The method provided by this invention is obtained by corroding a single-phase Al solid solution in an aqueous solution. The raw materials are readily available, the operation is simple, and the conditions for preparing nanoporous Al are easy to achieve. It is a simple, convenient, and low-cost method for preparing nanoporous Al bulk materials, which has important practical significance for enriching the preparation methods of nanoporous Al, improving the preparation technology of nanoporous Al bulk materials, and promoting the widespread application of nanoporous Al bulk materials.

[0023] This invention also discloses a bulk nanoporous aluminum with macroscopic dimensions prepared by the above-described method. The microstructure of this bulk nanoporous aluminum with macroscopic dimensions consists of nanoscale pores and gaps, exhibiting a uniform and continuous pore structure. The macroscopic dimensions are on the centimeter scale, and it possesses characteristics such as structural integrity, high porosity, large specific surface area, low preparation cost, and short preparation cycle. The nanoporous Al bulk prepared using this method has small pore sizes, approximately 20 nm, and hierarchical pores, meaning that smaller pores exist within the walls of larger pores. Since the pore wall thickness is only tens of nanometers, the nanoporous Al bulk prepared by this method has a high specific surface area, exceeding 22 m². 2 / g.

[0024] Furthermore, the size of the nanopores can be controlled by adjusting the composition of the precursor alloy, the temperature of the etching solution, the concentration of the etching solution, and the etching time, thereby obtaining bulk nanoporous aluminum with a high specific surface area. The method of preparing bulk nanoporous aluminum using this invention has advantages such as low preparation cost, simple experimental conditions, and simple operation process, and is of great significance to the advancement of bulk nanoporous Al preparation technology and the widespread application of nanoporous Al. Attached Figure Description

[0025] Figure 1 The image shows the metallographic microstructure of the alloy sheet after casting and rolling.

[0026] Figure 2 Metallographic microstructure (OM) of the alloy sheet after aging treatment;

[0027] Figure 3 SEM image of bulk nanoporous aluminum with macroscopic dimensions;

[0028] Figure 4 This is a diagram showing the macroscopic shape and dimensions of bulk nanoporous aluminum with macroscopic dimensions. Detailed Implementation

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.”

[0033] 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.

[0034] This invention provides a method for preparing bulk nanoporous aluminum with macroscopic dimensions based on the solid solution dealloying principle, comprising the following steps:

[0035] Step 1: Weigh industrial pure Al ingots and industrial pure Zn ingots to prepare Al-Zn alloys. The Al content in the Al-Zn alloys is 17%-28%.

[0036] Step 2: Melt the weighed industrial pure Al ingots and industrial pure Zn ingots into an alloy in a resistance furnace at a melting temperature of 680-720℃ and a holding time of 30 minutes. Then, directly cast and roll the molten alloy into alloy sheets.

[0037] The speed of the rolls during casting and rolling needs to be greater than 300 r / min to ensure that the cooling rate of the melt during casting and rolling is greater than 150℃ / s; the thickness of the alloy sheet obtained after casting and rolling is 1.0~1.2mm;

[0038] Step 3: Place the alloy sheet obtained in Step 2 in a drying oven for aging treatment: the aging temperature should not exceed 20℃, and the aging time should be 0.5-5h;

[0039] Step 4: Polish the alloy sheet with 400 and 1000 grit sandpaper to remove the oxide film on the surface. The thickness of the alloy sheet after polishing is 0.5-1.0 mm. Place the polished alloy sheet in a corrosion solution for corrosion. The corrosion solution is a 0.01-0.1 mol / L sulfuric acid aqueous solution. The temperature during corrosion is -10 to 5℃, and the reaction time is 20-30 hours.

[0040] Step 5: Wash the sample obtained after etching in Step 4 with deionized water, then with acetone, and then place it in a vacuum drying oven. Evacuate the oven to -0.1 MPa and allow the acetone to evaporate naturally. Remove the sample and store it under vacuum to obtain bulk nanoporous aluminum with macroscopic dimensions and a specific surface area of ​​22 m². 2 / g or more.

[0041] 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.

[0042] 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.

[0043] Example 1

[0044] A method for preparing bulk nanoporous aluminum with macroscopic dimensions based on the solid solution dealloying principle includes the following steps:

[0045] Step 1: Weigh industrial pure Al ingots and industrial pure Zn ingots to prepare Al-Zn alloy. The Al content in the Al-Zn alloy is 17%.

[0046] Step 2: The weighed industrial pure Al ingots and industrial pure Zn ingots are melted into an alloy in a resistance furnace at a melting temperature of 680℃ for 30 minutes to obtain an Al-Zn alloy melt. The Al-Zn alloy melt is then directly cast and rolled into an alloy sheet. The speed of the rolls during casting and rolling is 300 r / min, and the cooling rate of the melt during casting and rolling is 150℃ / s. The thickness of the alloy sheet obtained after casting and rolling is 1 mm.

[0047] Step 3: Place the alloy sheet obtained in Step 2 in a drying oven for aging treatment at a temperature of 20°C for 0.5 hours.

[0048] Step 4: Polish the alloy sheet with 400 and 1000 grit sandpaper to remove the oxide film on the surface. The thickness of the alloy sheet after polishing is 0.5 mm. Place the polished alloy sheet in a corrosion solution for corrosion treatment. The corrosion solution is a 0.01 mol / L sulfuric acid aqueous solution. The temperature of the corrosion treatment is -10℃ and the reaction time of the corrosion treatment is 30 h.

[0049] Step 5: The sample obtained after etching in Step 4 is washed in deionized water, then washed with acetone, and then placed in a vacuum drying oven. The vacuum is then drawn to -0.1 MPa. After the acetone evaporates naturally, the sample is removed and vacuum-preserved, ultimately yielding bulk nanoporous aluminum with macroscopic dimensions and a specific surface area of ​​22 m². 2 / g.

[0050] Example 2

[0051] A method for preparing bulk nanoporous aluminum with macroscopic dimensions based on the solid solution dealloying principle includes the following steps:

[0052] Step 1: Weigh industrial pure Al ingots and industrial pure Zn ingots to prepare Al-Zn alloy. The Al content in the Al-Zn alloy is 28%.

[0053] Step 2: The weighed industrial pure Al ingots and industrial pure Zn ingots are melted into an alloy in a resistance furnace at a melting temperature of 720℃ for 30 minutes to obtain an Al-Zn alloy melt. The Al-Zn alloy melt is then directly cast and rolled into an alloy sheet. The speed of the rolls during casting and rolling is 400 r / min, and the cooling rate of the melt during casting and rolling is 200℃ / s. The thickness of the alloy sheet obtained after casting and rolling is 1.2 mm.

[0054] Step 3: Place the alloy sheet obtained in Step 2 in a drying oven for aging treatment at a temperature of 10℃ for 5 hours.

[0055] Step 4: Polish the alloy sheet with 400 and 1000 grit sandpaper to remove the oxide film on the surface. The thickness of the alloy sheet after polishing is 1.0 mm. Place the polished alloy sheet in a corrosion solution for corrosion treatment. The corrosion solution is a 0.1 mol / L sulfuric acid aqueous solution. The temperature of the corrosion treatment is -5℃ and the reaction time of the corrosion treatment is 20 h.

[0056] Step 5: The sample obtained after etching in Step 4 is washed in deionized water, then washed with acetone, and then placed in a vacuum drying oven. The vacuum is then drawn to -0.1 MPa. After the acetone has naturally evaporated, the sample is removed and vacuum-preserved, ultimately yielding bulk nanoporous aluminum with macroscopic dimensions and a specific surface area of ​​25 m². 2 / g.

[0057] Example 3

[0058] A method for preparing bulk nanoporous aluminum with macroscopic dimensions based on the solid solution dealloying principle includes the following steps:

[0059] Step 1: Weigh industrial pure Al ingots and industrial pure Zn ingots to prepare Al-Zn alloy. The Al content in the Al-Zn alloy is 22%.

[0060] Step 2: The weighed industrial pure Al ingots and industrial pure Zn ingots are melted into an alloy in a resistance furnace at a melting temperature of 700℃ for 30 minutes to obtain an Al-Zn alloy melt. The Al-Zn alloy melt is then directly cast and rolled into an alloy sheet. The speed of the rolls during casting and rolling is 450 r / min, and the cooling rate of the melt during casting and rolling is 230℃ / s. The thickness of the alloy sheet obtained after casting and rolling is 1.1 mm.

[0061] Step 3: Place the alloy sheet obtained in Step 2 in a drying oven for aging treatment. The aging treatment temperature is 0℃ and the time is 3h.

[0062] Step 4: Polish the alloy sheet with 400 and 1000 grit sandpaper to remove the oxide film on the surface. The thickness of the alloy sheet after polishing is 0.8 mm. Place the polished alloy sheet in a corrosion solution for corrosion treatment. The corrosion solution is a 0.05 mol / L sulfuric acid aqueous solution. The temperature during corrosion treatment is 0℃ and the reaction time is 25 h.

[0063] Step 5: The sample obtained after etching in Step 4 is washed in deionized water, then washed with acetone, and then placed in a vacuum drying oven. The vacuum is then drawn to -0.1 MPa. After the acetone has naturally evaporated, the sample is removed and vacuum-preserved, ultimately yielding bulk nanoporous aluminum with macroscopic dimensions and a specific surface area of ​​24 m². 2 / g.

[0064] Example 4

[0065] A method for preparing bulk nanoporous aluminum with macroscopic dimensions based on the solid solution dealloying principle includes the following steps:

[0066] Step 1: Weigh industrial pure Al ingots and industrial pure Zn ingots to prepare Al-Zn alloy, with the Al content in the Al-Zn alloy being 25%;

[0067] Step 2: The weighed industrial pure Al ingots and industrial pure Zn ingots are melted into an alloy in a resistance furnace at a melting temperature of 710℃ for 30 minutes to obtain an Al-Zn alloy melt. The Al-Zn alloy melt is then directly cast and rolled into an alloy sheet. The speed of the rolls during casting and rolling is 350 r / min, and the cooling rate of the melt during casting and rolling is 180℃ / s. The thickness of the alloy sheet obtained after casting and rolling is 1.0 mm.

[0068] Step 3: Place the alloy sheet obtained in Step 2 in a drying oven for aging treatment at a temperature of 5°C for 4 hours.

[0069] Step 4: Polish the alloy sheet with 400 and 1000 grit sandpaper to remove the oxide film on the surface. The thickness of the alloy sheet after polishing is 0.7 mm. Place the polished alloy sheet in a corrosion solution for corrosion treatment. The corrosion solution is a 0.08 mol / L sulfuric acid aqueous solution. The temperature during corrosion treatment is 0℃ and the reaction time is 20 h.

[0070] Step 5: The sample obtained after etching in Step 4 is washed in deionized water, then washed with acetone, and then placed in a vacuum drying oven. The oven is evacuated to -0.1 MPa, and after the acetone has naturally evaporated, the sample is removed and vacuum-preserved. Finally, bulk nanoporous aluminum with macroscopic dimensions is obtained, with a specific surface area of ​​26 m². 2 / g.

[0071] Figure 1 The image shows the metallographic microstructure of the alloy sheet after casting and rolling. As can be seen from the image, the grain boundaries formed by corrosion (thin black lines, indicated by arrows in the image) indicate that the alloy is a single-phase solid solution.

[0072] Figure 2 Metallographic microstructure (OM) of the alloy sheet after aging treatment. As can be seen from the figure, the grain boundaries formed by corrosion (thin black lines, indicated by arrows in the figure) indicate that the alloy is still a single-phase solid solution.

[0073] Figure 3 The image shows a SEM image of a bulk nanoporous aluminum with macroscopic dimensions. As can be seen, the white areas in the image represent the pore walls (pore ligaments, pore edges) of the porous Al, with a thickness of approximately 20 nm. The pore structure exhibits hierarchical pore characteristics (e.g., the area enclosed by the black line is a large pore, and there are smaller pores on the pore wall of the large pore, in the area enclosed by the white line).

[0074] Figure 4 The figure shows the macroscopic shape and size of bulk nanoporous aluminum. As can be seen from the figure, the length and width of the bulk nanoporous Al are in the cm range (this figure is for illustrative purposes only and does not mean that its size is limited to the cm range), and the thickness is in the millimeter range.

[0075] 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 bulk nanoporous aluminum with macroscopic dimensions based on the solid solution dealloying principle, characterized in that, Includes the following steps: Al ingots and Zn ingots are mixed and smelted to obtain an Al-Zn alloy melt; the Al-Zn alloy melt is then cast and rolled to obtain alloy sheets. After aging treatment, the alloy sheet is placed in a corrosion solution for corrosion treatment. After the corrosion treatment is completed, the pretreated alloy is obtained. After the pretreated alloy was cleaned and dried in sequence, bulk nanoporous aluminum with macroscopic dimensions was obtained. The aging treatment is performed at a temperature of 0-20℃ for a time of 0.5-5 hours. The corrosive solution is an aqueous sulfuric acid solution with a concentration of 0.01-0.1 mol / L. The corrosion treatment is performed at a temperature of -10 to 5°C for 20 to 30 hours. The cleaning process involves sequentially washing with deionized water and acetone; the drying process is carried out in a vacuum drying oven with a vacuum degree of -0.1 MPa. The melting temperature is 680-720℃, and the melting holding time is 30 minutes. The speed of the rolls during the casting and rolling process is greater than 300 r / min, and the cooling rate of the Al-Zn alloy melt during the casting and rolling process is greater than 150 °C / s. The bulk nanoporous aluminum has a hierarchical pore structure, meaning that the walls of the macropores also contain micropores, with the pore ligaments measuring approximately 20 nm in size; the macroscopic dimensions of the bulk nanoporous aluminum are on the centimeter scale, and the thickness is on the millimeter scale; the specific surface area of ​​the bulk nanoporous aluminum is greater than 22 m². 2 / g.

2. The method for preparing bulk nanoporous aluminum with macroscopic dimensions based on the solid solution dealloying principle according to claim 1, characterized in that, The Al content in the Al-Zn alloy melt is 17%-28%.

3. The method for preparing bulk nanoporous aluminum with macroscopic dimensions based on the solid solution dealloying principle according to claim 1, characterized in that, The alloy sheet is an Al-based single-phase solid solution, and the thickness of the alloy sheet is 1.0-1.2 mm.

4. The method for preparing bulk nanoporous aluminum with macroscopic dimensions based on the solid solution dealloying principle according to claim 1, characterized in that, After the alloy sheet undergoes aging treatment, it is polished with 400 and 1000 grit sandpaper until the thickness is 0.5-1.0 mm, and then immersed in a corrosion solution for corrosion treatment.

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