Antibacterial aluminum alloy and preparation method thereof

Abstract

The present invention relates to the technical field of metal surface treatment, and in particular to an antibacterial aluminum alloy and a preparation method thereof. The antibacterial aluminum alloy is prepared by the following steps: the cleaned aluminum alloy is sequentially subjected to an organic acid heat treatment, a methyl amide compound and an organic polar solvent mixture heat treatment, and a sulfur-containing silane coupling agent microwave treatment. The antibacterial aluminum alloy prepared by the present invention prepares a nano-antibacterial layer on the surface by a chemical etching method. The nano-antibacterial layer is composed of a protruding nano-column structure, and the nano-column structure has a suitable gap, height and top size, so that it can effectively adsorb bacteria while piercing the bacterial cell membrane or cell wall, thereby effectively killing Gram-negative bacteria and Gram-positive bacteria. Since the nano-antibacterial layer of the present invention does not have additional antibacterial components added, there is no need to worry about the antibacterial components falling off due to long-term light aging of the aluminum alloy, nor is there any need to worry about the emergence of drug-resistant bacteria, thereby reducing the antibacterial effect.

Description

Technical Field

[0001] The present invention relates to the technical field of metal surface treatment, and in particular to an antibacterial aluminum alloy and a preparation method thereof. Background Art

[0002] While the aluminum oxide film on aluminum alloy surfaces effectively protects the aluminum alloy substrate from further oxidative corrosion, it cannot resist the attachment and growth of microorganisms. Microbial attachment to the aluminum alloy surface can contaminate the alloy and cause pitting corrosion, thereby degrading its performance and compromising its application. Therefore, antimicrobial functionalization of aluminum alloys or their surfaces is of paramount importance. Manned space flight programs utilize extensive amounts of aluminum alloys, including many cabin panels made of rust-resistant aluminum alloys. Due to the astronauts' activities within manned spacecraft cabins, the presence of microorganisms is unavoidable. Once bacteria grow on surfaces in the enclosed cabin environment, they are difficult to remove. The presence of large numbers of microorganisms poses significant risks to both the safety of the spacecraft itself and the health of the astronauts. Therefore, antimicrobial functionalization of aluminum alloys, which are widely used in manned space flight programs, is urgent. Conventional coating methods for surface modification of aluminum alloys are not suitable for the microgravity environment of space. If the coating peels off and floats within the cabin, it poses a greater risk. Therefore, new and stable methods for antimicrobial treatment of aluminum alloy surfaces are urgently needed.

[0003] Antimicrobial functionalization of aluminum alloy surfaces does not alter the microstructure and elemental composition of the aluminum alloy itself; instead, it simply modifies the surface. Compared to preparing alloy-type antimicrobial aluminum alloys, surface modification of aluminum alloys offers the greatest advantage of direct modification of pre-formed aluminum alloys, coupled with a simple process. Currently, it is the most widely used method for antimicrobial functionalization of aluminum alloys. As an inorganic metal material, the most common surface modification method is to apply an antimicrobial coating to the surface. Dogan et al. used an ion exchange method to prepare Ag and Zn-loaded zeolites. They then incorporated the antimicrobial zeolites into vinyl acetate lacquer and applied the coating to aluminum foil to produce a 6-10 mm thick antimicrobial coating that exhibited good antimicrobial activity against Escherichia coli. Zhang et al. used a sol-gel method to mix TiO2 with butyl titanate to prepare a sol. They then deposited a dense TiO2 antimicrobial film on the aluminum alloy surface, demonstrating moderate antimicrobial activity. Currently, the most commonly used method for antimicrobial coating of aluminum alloy surfaces is simple and convenient, but the coating can age and fall off, leading to poor long-term antimicrobial efficacy. In addition, anodizing of aluminum alloy surfaces is a very mature surface treatment process for aluminum alloys. It can produce a dense oxide film, and the uniform and regular nanopores on the surface become an excellent location for the deposition of functional ions. Many aluminum alloy surface functionalizations are achieved through a two-step process, first anodizing the surface, and then depositing a layer of effective active ingredients. Antibacterial functionalization of aluminum alloy surfaces can also be achieved through this two-step process. Tomioka et al. used anodizing to form AAO on the surface of an aluminum alloy, and then filled the pores of the AAO surface with silver thiosulfate complexes to prepare aluminum alloy products with better antibacterial properties. This method of preparing antibacterial aluminum alloys has a very wide range of choices for antibacterial ingredients, but it is not suitable for irregularly shaped aluminum alloy components. In addition, anodizing can obtain a very regular nanopore structure, but such a regular pore structure is not required for particle deposition, so the anodizing method is too complicated and energy-consuming.

[0004] The antibacterial properties of surface biomimetic nanostructures were first discovered in 2007 by American researcher Kenneth. He studied the unique nanostructures on shark skin and constructed this nanopattern on a polydimethylsiloxane elastomer. He found that this surface structure effectively inhibited the growth and formation of Staphylococcus aureus films. Australian researchers also discovered this phenomenon by studying the nanostructures on the wings of cicadas and dragonflies. These surfaces are covered with a layer of regularly arranged nanoprotrusions with a high aspect ratio. Their antibacterial properties are independent of the substrate or surface chemicals, relying entirely on the physical and mechanical effects of the surface structure. This eliminates the need for antimicrobial agents, which can also potentially harm the environment and operators with heavy metal ions and toxic agents, making them more environmentally friendly. This structure can kill bacteria or inhibit their growth and reproduction over a long period of time through a spontaneous effect. Bacterial cells are typically 500 to 1000 nm in size, while the spacing between nanopillar arrays is approximately 170 nm. Therefore, when bacterial cells come into contact with the nanopillar array, the cells cannot be in the gap, and because the height of the nanopillars is about 200nm, it is an order of magnitude higher than the cell membrane which is less than 10nm thick. This makes it impossible for bacterial cells to contact the substrate over a large area by slightly deforming the cell membrane when approaching and contacting the nanopillar array. They lie on the substrate and can only be held in the air by the nanopillar array. However, the study found that bacterial cells have a characteristic that they will try their best to make the cell membrane contact with the maximum surface area of ​​the attachable object. In order to contact the nanopillars or substrate over a larger area, the cell membrane begins to deform irregularly. When the deformation limit is reached, the cell membrane will rupture. Once the cell membrane of a single-celled organism is damaged, the cell will die quickly. The whole process looks like a suicidal process of the bacterial cell, so that this nanoprotrusion array structure can achieve a bactericidal effect. At the same time, this also explains why Gram-positive bacteria with strong cell wall stiffness show resistance to this structure. Therefore, the mechanical properties of bacterial cells, especially the stiffness of the cell wall, are the key factors that determine the resistance of cells to micro-nano structures. The sterilization of micro-nano structures is actually the deformation and rupture of the bacterial cell membrane or cell wall attached to the array by the nanocolumn array, causing the bacteria to die, thereby achieving the purpose of sterilization.

[0005] Based on the above situation, the present invention proposes an antibacterial aluminum alloy and a preparation method thereof. Summary of the Invention

[0006] The purpose of the present invention is to provide an antibacterial aluminum alloy and a preparation method thereof.

[0007] To achieve the above object, the present invention provides an antibacterial aluminum alloy, which is prepared by the following steps:

[0008] (1) The aluminum alloy was ultrasonically cleaned with anhydrous ethanol and deionized water at 20-25°C for 10-15 minutes at an ultrasonic power of 100-150 Hz. After cleaning, the aluminum alloy was taken out and naturally dried for later use;

[0009] (2) completely immersing the aluminum alloy treated in step (1) in an organic acid solution having a concentration of 0.005 to 0.01 mol / L for 10 to 15 minutes, then heating the solution to 90 to 95° C. at a rate of 2 to 3° C. per minute, maintaining the solution at 90 to 95° C. for 25 to 30 minutes, and then naturally cooling the solution to room temperature to obtain an aluminum alloy treated with an organic acid;

[0010] (3) uniformly mixing a methyl-containing amide compound and an organic polar solvent at a volume ratio of 1:1.5-2, then heating to 85-90° C., completely immersing the aluminum alloy treated with the organic acid in step (2) in the aqueous solution of the methyl-containing amide compound and heat-treating for 10-24 hours, taking out, washing with anhydrous ethanol 2-3 times, and drying to obtain an aluminum alloy having a nanocolumn structure on the surface;

[0011] (4) A sulfur-containing silane coupling agent was mixed and hydrolyzed with deionized water at a mass-liquid ratio of 1 g:15 ml to obtain a silane aqueous solution. The aluminum alloy having a nanocolumn structure on its surface was completely immersed in the silane aqueous solution and subjected to microwave treatment for 1 to 3 times at a power of 400 to 600 W for 10 to 15 min. The aluminum alloy was taken out and washed with anhydrous ethanol for 2 to 3 times and dried to obtain an aluminum alloy having an ultra-long nanocolumn structure.

[0012] Preferably, the organic acid comprises one or a combination of two or more of phytic acid, tannic acid, gallic acid, fumaric acid, and tartaric acid. In one embodiment, the organic acid is fumaric acid.

[0013] Preferably, the methyl-containing amide compound includes one of N,N-dimethylacrylamide, N-isopropylacrylamide, N,N-dimethylformamide, and N-dimethylformamide. In one embodiment, the methyl-containing amide compound is N,N-dimethylacrylamide.

[0014] Preferably, the organic polar solvent comprises one of dimethyl sulfoxide, pyridine, tetramethylethylenediamine, and isopropyl alcohol. In one embodiment, the organic polar solvent is dimethyl sulfoxide.

[0015] Preferably, the sulfur-containing silane coupling agent includes one of 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane and 3-thiocyanatopropyltriethoxysilane.

[0016] Preferably, the sulfur-containing silane coupling agent is a thiocyanate-containing silane coupling agent. In one embodiment, the thiocyanate-containing silane coupling agent is 3-thiocyanatepropyltriethoxysilane, CAS No. 34708-08-2.

[0017] Preferably, a surfactant is further added in step (3), and the volume ratio of the surfactant added to the methyl-containing amide compound is 1:0.01-0.02.

[0018] Preferably, the surfactant is an anionic surfactant, a nonionic surfactant, or a zwitterionic surfactant. In one embodiment, the surfactant is Tween-80.

[0019] Preferably, the aluminum alloy is a 7 series aluminum alloy.

[0020] Preferably, the antibacterial aluminum alloy is prepared by the following steps:

[0021] (1) The aluminum alloy was ultrasonically cleaned with anhydrous ethanol and deionized water at 20-25°C for 10-15 minutes at an ultrasonic power of 100-150 Hz. After cleaning, the aluminum alloy was taken out and naturally dried for later use;

[0022] (2) completely immersing the aluminum alloy treated in step (1) in an organic acid solution having a concentration of 0.005 to 0.01 mol / L for 10 to 15 minutes, then heating the solution to 90 to 95° C. at a rate of 2 to 3° C. per minute, maintaining the solution at 90 to 95° C. for 25 to 30 minutes, and then naturally cooling the solution to room temperature to obtain an aluminum alloy treated with an organic acid;

[0023] (3) uniformly mixing a methyl-containing amide compound with an organic polar solvent and a surfactant in a volume ratio of 1:1.5-2:0.01-0.02, then heating to 85-90° C., completely immersing the aluminum alloy treated with the organic acid in step (2) in the aqueous solution of the methyl-containing amide compound and heat-treating for 10-12 hours, taking out, washing with anhydrous ethanol 2-3 times, and drying to obtain an aluminum alloy with a nanocolumn structure on the surface;

[0024] (4) A sulfur-containing silane coupling agent is mixed and hydrolyzed with deionized water at a mass-liquid ratio of 1 g: 15-20 ml to obtain a silane aqueous solution. An aluminum alloy having a nanocolumn structure on its surface is completely immersed in the silane aqueous solution, and microwaved for 1-3 times at a power of 400-600 W for 10-20 min. The aluminum alloy is taken out and washed with anhydrous ethanol for 2-3 times and dried to obtain an aluminum alloy having an ultra-long nanocolumn structure.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The antibacterial aluminum alloy prepared by the present invention has a nano-antibacterial layer prepared on the surface by a chemical etching method. The nano-antibacterial layer is composed of a protruding nano-pillar structure. The nano-pillar structure has a suitable gap, height and top size, so that it can effectively adsorb bacteria while piercing the bacterial cell membrane or cell wall, thereby effectively killing Gram-negative and Gram-positive bacteria.

[0027] 2. Since the nano antibacterial layer of the present invention does not contain any additional antibacterial components, there is no need to worry about the antibacterial components falling off due to long-term light aging of the aluminum alloy, nor is there any need to worry about the emergence of drug-resistant bacteria that reduces the antibacterial effect.

[0028] 3. The raw materials of the present invention are sufficient in China and are reasonably priced, so that there is no high cost limit for large-scale production; at the same time, the antibacterial aluminum alloy is simple and the overall production cost is not high, which is conducive to large-scale industrial production. DETAILED DESCRIPTION

[0029] Example 1

[0030] Weigh the specific raw materials according to Table 1. The preparation steps are as follows:

[0031] (1) Ultrasonic cleaning of 7075 aluminum alloy was performed with anhydrous ethanol and deionized water at 20°C for 15 min at an ultrasonic power of 100 Hz. After cleaning, the alloy was taken out and dried naturally for later use.

[0032] (2) placing the aluminum alloy treated in step (1) into an organic acid solution and completely immersing it for 10 minutes, then heating it to 90°C at a rate of 2 to 3°C per minute, keeping it at 90°C for 30 minutes, then taking it out and naturally cooling it to room temperature to obtain an organic acid-treated aluminum alloy;

[0033] (3) uniformly mixing the methyl-containing amide compound with an organic polar solvent and a surfactant, and then heating to 85° C., completely immersing the aluminum alloy treated with the organic acid in step (2) in the aqueous solution of the methyl-containing amide compound and keeping the mixture warm for 12 hours, taking the mixture out, washing it with anhydrous ethanol 2 to 3 times, and drying it to obtain an aluminum alloy having a nanocolumn structure on the surface;

[0034] (4) A sulfur-containing silane coupling agent is mixed with deionized water and hydrolyzed to obtain a silane aqueous solution. The aluminum alloy having a nanocolumn structure on the surface is completely immersed in the silane aqueous solution, microwave-treated three times, taken out and washed with anhydrous ethanol for 2 to 3 times, and dried to obtain an aluminum alloy having an ultra-long nanocolumn structure.

[0035] Example 2

[0036] Weigh the specific raw materials according to Table 1. The preparation steps are as follows:

[0037] (1) Ultrasonic cleaning of 7075 aluminum alloy was performed with anhydrous ethanol and deionized water at 25°C for 10 min at an ultrasonic power of 150 Hz. After cleaning, the alloy was taken out and dried naturally for later use.

[0038] (2) placing the aluminum alloy treated in step (1) into an organic acid solution and completely immersing it for 10 to 15 minutes, then heating it to 95°C at a rate of 2 to 3°C per minute, keeping it at 95°C for 30 minutes, then taking it out and naturally cooling it to room temperature to obtain an organic acid-treated aluminum alloy;

[0039] (3) uniformly mixing the methyl-containing amide compound with an organic polar solvent and a surfactant, and then heating to 90° C., completely immersing the aluminum alloy treated with the organic acid in step (2) in the aqueous solution of the methyl-containing amide compound and keeping the mixture warm for 10 hours, taking the mixture out, washing it with anhydrous ethanol 2 to 3 times, and drying it to obtain an aluminum alloy having a nanocolumn structure on the surface;

[0040] (4) A sulfur-containing silane coupling agent is mixed with deionized water and hydrolyzed to obtain a silane aqueous solution. The aluminum alloy having a nanocolumn structure on the surface is completely immersed in the silane aqueous solution and microwave-treated twice. The aluminum alloy is taken out and washed with anhydrous ethanol 2 to 3 times and dried to obtain an aluminum alloy having an ultra-long nanocolumn structure.

[0041] Example 3

[0042] Weigh the specific raw materials according to Table 1. The preparation steps are as follows:

[0043] (1) Ultrasonic cleaning of 7075 aluminum alloy was performed with anhydrous ethanol and deionized water at 25°C for 15 min at an ultrasonic power of 150 Hz. After cleaning, the alloy was taken out and dried naturally for later use.

[0044] (2) placing the aluminum alloy treated in step (1) into an organic acid solution and completely immersing it for 15 minutes, then heating it to 95°C at a rate of 2 to 3°C per minute, keeping it at 95°C for 30 minutes, then taking it out and naturally cooling it to room temperature to obtain an organic acid-treated aluminum alloy;

[0045] (3) uniformly mixing the methyl-containing amide compound with an organic polar solvent and a surfactant, and then heating to 90° C., completely immersing the aluminum alloy treated with the organic acid in step (2) in the aqueous solution of the methyl-containing amide compound and keeping the mixture warm for 12 hours, taking the mixture out, washing it with anhydrous ethanol 2 to 3 times, and drying it to obtain an aluminum alloy having a nanocolumn structure on the surface;

[0046] (4) A sulfur-containing silane coupling agent is mixed with deionized water and hydrolyzed to obtain a silane aqueous solution. The aluminum alloy having a nanocolumn structure on the surface is completely immersed in the silane aqueous solution, microwave-treated once, taken out and washed with anhydrous ethanol 2 to 3 times, and dried to obtain an aluminum alloy having an ultra-long nanocolumn structure.

[0047] Comparative Example 1

[0048] Specific raw materials were weighed according to Table 1. The difference from Example 3 was that no surfactant was added in step (3). The remaining preparation steps were the same as in Example 3.

[0049] Comparative Example 2

[0050] The specific raw materials were weighed according to Table 1. The difference from Example 3 was that in step (2), organic acid solution was not used but deionized water was used instead. The mixture was heated to 100° C. The remaining preparation steps were the same as those in Example 3.

[0051] Comparative Example 3

[0052] The specific raw materials were weighed according to Table 1. Unlike Example 3, mercaptopropyl triethoxysilane was used instead of 3-thiocyanatopropyl triethoxysilane aqueous solution. The remaining preparation steps were the same as those in Example 3.

[0053] Comparative Example 4

[0054] The specific raw materials were weighed according to Table 1. Unlike Example 3, step (4) was omitted. The remaining preparation steps were the same as in Example 3.

[0055] Comparative Example 5

[0056] The specific raw materials were weighed according to Table 1. The difference from Example 3 was that the concentration of the organic acid was 0.02 mol / L. The remaining preparation steps were the same as those in Example 3.

[0057] Table 1

[0058]

[0059] Performance evaluation

[0060] Antibacterial performance test: The antibacterial aluminum alloys prepared in Examples 1 to 3 and Comparative Examples 1 to 5 were tested for their antibacterial performance using a film-sticking method to obtain the antibacterial rate, referring to the "Test method for antibacterial performance of plastic surfaces" (GB / T31402-2015 / ISO22196:2007). First, the bacteria in the test tube were transferred to a conical flask containing a bacterial suspension and glass beads using a bacterial loop, so that the bacterial concentration in the bacterial suspension was about 10 5 -107 CFU / mL, and different concentration gradients were used to count and verify the bacterial concentration; each test sample was placed flat on a culture dish, and 0.2 mL of bacterial solution was added to each sample, taking care not to allow the bacterial solution to overflow the sample. PE film was then attached to the bacterial solution and carefully pressed against the sample with tweezers, taking care not to allow the bacterial solution to overflow; the culture dish was placed in an incubator for 18 to 24 hours, and the bacteria were then eluted from the sample surface with an eluent. 0.1 mL of the eluted bacterial solution was then added to the agar plate and evenly dispersed using a push rod. The agar plate was then placed in an incubator for 18 to 24 hours, and the bacterial count was calculated. The antibacterial R was calculated according to formula (1): R = (BA) / B × 100%, where R is the antibacterial rate (%), B is the number of bacteria grown in the blank control sample, and A is the number of bacteria grown in the antibacterial sample. Gram-positive bacteria were represented by Staphylococcus aureus, and Gram-negative bacteria were represented by Escherichia coli. Specific results are shown in Table 2.

[0061] Microstructure Testing: The surface and side morphologies of the aluminum alloys obtained in Examples 1-3 and Comparative Examples 1-5 were observed using an InspectF scanning electron microscope. Nanoparticle size measurement software was used to roughly measure the height, interprotrusion spacing, and protrusion tip dimensions of the nanoprotrusion structures. Specific results are shown in Table 3.

[0062] Table 2

[0063]

[0064] Table 3

[0065]

[0066]

[0067] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. An antibacterial aluminum alloy, characterized in that: The antibacterial aluminum alloy is prepared by the following steps: (1) Ultrasonic cleaning of aluminum alloy was performed with anhydrous ethanol and deionized water at 20-25°C for 10-15 min, with an ultrasonic power of 100-150 Hz. After cleaning, the aluminum alloy was taken out and dried naturally for later use. (2) The aluminum alloy treated in step (1) is completely immersed in an organic acid solution with a concentration of 0.005-0.01 mol / L and soaked for 10-15 minutes, then heated to 90-95°C at a rate of 2-3°C per minute, kept at 90-95°C for 25-30 minutes, and then taken out and naturally cooled to room temperature to obtain an aluminum alloy treated with organic acid; (3) uniformly mixing a methyl-containing amide compound and an organic polar solvent in a volume ratio of 1:1.5-2, then heating to 85-90°C, completely immersing the aluminum alloy treated with the organic acid in step (2) in the methyl-containing amide compound solution and heat-treating for 10-24 hours, taking out and washing with anhydrous ethanol 2-3 times, and drying to obtain an aluminum alloy with a nanocolumn structure on the surface; (4) Take a sulfur-containing silane coupling agent, dissolve it in deionized water at a mass-liquid ratio of 1g:15~20ml to obtain a silane aqueous solution, completely immerse the aluminum alloy with a nano-pillar structure on the surface in the silane aqueous solution, microwave it for 1~3 times at a power of 400~600W, for 10~15min, take it out and wash it with anhydrous ethanol for 2~3 times, and dry it to obtain an aluminum alloy with an ultra-long nano-pillar structure; The organic acid includes one or a combination of two or more of phytic acid, tannic acid, gallic acid, fumaric acid, and tartaric acid; the organic polar solvent includes one of dimethyl sulfoxide, pyridine, tetramethylethylenediamine, and isopropyl alcohol; the sulfur-containing silane coupling agent includes one of 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-thiocyanatopropyltriethoxysilane; the methyl-containing amide compound includes one of N,N-dimethylacrylamide, N-isopropylacrylamide, N,N-dimethylformamide, and N-dimethylformamide; a surfactant is further added in step (3), and the volume ratio of the surfactant added to the methyl-containing amide compound is 0.01~0.02:1; the surfactant is one of anionic surfactant, nonionic surfactant, and zwitterionic surfactant.

2. The antibacterial aluminum alloy according to claim 1, characterized in that The sulfur-containing silane coupling agent is 3-thiocyanatopropyltriethoxysilane.

3. The antibacterial aluminum alloy according to claim 1, characterized in that It is characterized by: The aluminum alloy is a 7 series aluminum alloy.

4. The antibacterial aluminum alloy according to claim 1, characterized in that The antibacterial aluminum alloy is prepared by the following steps: (1) Ultrasonic cleaning of aluminum alloy was performed with anhydrous ethanol and deionized water at 20-25°C for 10-15 min, with an ultrasonic power of 100-150 Hz. After cleaning, the aluminum alloy was taken out and dried naturally for later use. (2) The aluminum alloy treated in step (1) is completely immersed in an organic acid solution with a concentration of 0.005-0.01 mol / L and soaked for 10-15 minutes, then heated to 90-95°C at a rate of 2-3°C per minute, kept at 90-95°C for 25-30 minutes, and then taken out and naturally cooled to room temperature to obtain an aluminum alloy treated with organic acid; (3) uniformly mixing a methyl-containing amide compound with an organic polar solvent and a surfactant in a volume ratio of 1:1.5-2:0.01-0.02, then heating to 85-90°C, completely immersing the aluminum alloy treated with the organic acid in step (2) in the methyl-containing amide compound solution and heat-treating for 10-12 hours, taking out, washing with anhydrous ethanol 2-3 times, and drying to obtain an aluminum alloy with a nanocolumn structure on the surface; (4) Take a sulfur-containing silane coupling agent, mix it with deionized water and hydrolyze it at a mass-liquid ratio of 1g:15~20ml to obtain a silane aqueous solution. Completely immerse the aluminum alloy with a nanocolumn structure on the surface in the silane aqueous solution, microwave it for 1~3 times at a power of 400~600W and a time of 10~20min, take it out and wash it with anhydrous ethanol for 2~3 times, and dry it to obtain an aluminum alloy with an ultra-long nanocolumn structure.

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