Preparation method of super-hydrophobic aluminum profile and application of super-hydrophobic aluminum profile in marine environment

Abstract

The invention discloses a preparation method of a super-hydrophobic aluminum profile and application of the super-hydrophobic aluminum profile in a marine environment, and belongs to the technical field of aluminum alloy materials. Firstly, alloy elements are optimized, secondly, in the key process step-anodic oxidation, composition of an anolyte is optimized, and a basic electrolyte and a modified additive are arranged. A polyethylene glycol-titanium potassium oxalate-citric acid ternary composite additive is adopted, a double-voltage gradient oxidation process is combined, a multi-stage composite structure is constructed in an oxidation film, and meanwhile construction of the aluminum alloy profile with high hardness (larger than or equal to 500 HV) and stable super-hydrophobicity (the contact angle is larger than or equal to 160 degrees) is achieved. The super-hydrophobic aluminum profile prepared through the method is high in corrosion resistance and still keeps excellent performance in the extreme environment, the service life of equipment is remarkably prolonged, and the safety and stability of offshore facilities are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of aluminum alloy materials, and particularly relates to a preparation method of a super-hydrophobic aluminum profile and application thereof in a marine environment. Background Art

[0002] Aluminum is a relatively abundant resource with advantages such as low density, excellent thermal and electrical conductivity, high strength, corrosion resistance, and good processability. It is widely used in industries such as aerospace, shipbuilding, machinery, and instrumentation, and is a key material for lightweight structural design. In atmospheric environments, a self-healing oxide film naturally forms on the surface of pure aluminum, providing excellent corrosion protection. To increase aluminum's strength, it is alloyed. Cast aluminum alloys primarily include Al-Si, Al-Cu, Al-Mg, and Al-Zn. Al-Si aluminum alloys offer excellent casting properties but relatively poor corrosion resistance. The harsh and complex marine environment raises concerns about the safety of various equipment operating within it. In marine environments, aluminum profiles are constantly exposed to issues such as chloride ion corrosion, microbial adhesion, and UV aging.

[0003] Traditional superhydrophobic surfaces rely on chemical plating or fluorination, which presents drawbacks such as complex processes, high environmental toxicity, and poor durability. For example, Chinese patent application CN202010567890.X discloses a method for treating an aluminum alloy surface, comprising the following steps: pretreating the aluminum alloy surface; subjecting the pretreated aluminum alloy to a chemical polishing treatment in a chemical polishing solution comprising the following components in weight fractions: 55%-75% phosphoric acid; 15%-30% sulfuric acid; 10%-25% polyethylene glycol; and 2%-5% copper sulfate; and anodizing the chemically polished aluminum alloy. This aluminum alloy surface treatment method reduces the need for traditional alkaline etching and, by adding copper sulfate and polyethylene glycol to the chemical polishing solution to increase its viscosity, reduces corrosion of the aluminum alloy.

[0004] For example, Chinese patent application CN202311056501.7 discloses a method for surface treatment of aluminum alloys, which includes grinding, polishing, cleaning, and etching the surface of the aluminum alloy, immersing the aluminum alloy in a silane coupling agent solution, taking it out and heating and curing it, and in situ generating a super-hydrophobic film layer with a micro-nano structure on the surface of the aluminum alloy. The aluminum alloy treated by this method exhibits super-hydrophobic properties and corrosion resistance due to the micro-nanoscale composite rough structure of the surface coating.

[0005] Therefore, with the current existing technology, these coatings are easy to fall off, and the construction of micro-nano structures mostly relies on chemical etching or template methods, which makes it difficult to accurately control the morphology. Therefore, a method for preparing super-hydrophobic aluminum profiles with high mechanical stability, environmental protection and high durability is developed. Summary of the Invention

[0006] The present invention addresses the problems existing in the prior art by developing a polyethylene glycol-potassium titanium oxalate-citric acid ternary composite additive and combining it with a dual-voltage gradient oxidation process to construct a multi-level composite structure in the oxide film. This allows for the construction of aluminum alloy profiles with high hardness (≥500 HV) and stable superhydrophobicity (contact angle ≥160°), making them particularly suitable for marine environments. The materials can effectively resist chloride ion corrosion, microbial attachment, and ultraviolet aging, significantly improving equipment safety and service life.

[0007] In order to achieve the above technical objectives, the technical solution adopted by the present invention is: A method for preparing a super-hydrophobic aluminum profile comprises the following steps: (1) Ingredients and smelting: Ingredients are prepared according to mass percentage: Cu 3-8%, Fe 2-5%, Mn 5-9%, Mg 1-2%, Zn 1-2%, Si 0.5-0.8%, Ni 0.1%, Ti 0.05%, Zr 0.05-0.1%, Y 0.02-0.05%, Sc 0.01-0.03%, and the rest are Al and unavoidable impurities, with the total amount of unavoidable impurities ≤ 0.1%. Smelt at high temperature for 6h-8h to obtain aluminum alloy melt; then refine and cast to obtain cast rods; (2) placing the cast rod obtained in step (1) in a soaking furnace at a temperature of 480-550°C for 10-15 hours, and cooling after homogenization; extruding and aging the cast rod to obtain an aluminum alloy profile; (3) Immerse the aluminum alloy profile in an alkaline degreasing solution at 55-60°C for 3-5 minutes to remove oil stains, take it out, and wash it with water; (4) Then soak it in an acidic solution at 50-55°C for 30-40 seconds to improve the surface finish; (5) Anodizing treatment: The aluminum alloy substrate treated in step (4) is anodized in an electrolyte, with the aluminum alloy as the anode and the aluminum plate as the cathode, wherein the oxidation voltage is 15-20V and the current density is 1-2A / dm 2 , the electrolyte temperature is 10-20℃, the oxidation time is 20-40 minutes; then the voltage is increased to 80-100V, oxidation is carried out for 20-30 minutes, and air stirring is used during the anodic oxidation process; (6) Post-treatment: The anodized profile is treated with hot air at 100-120°C for 30 minutes; then the treated aluminum alloy substrate is immersed in a passivation solution at 80-85°C for 15-30 minutes, taken out to drain the surface moisture, and dried at 80-90°C for 2-4 hours to obtain a super-hydrophobic aluminum profile.

[0008] Furthermore, in the aging treatment of step (2), the aging temperature is 165-175° C., and the aging treatment time is 10-12 h.

[0009] Furthermore, the composition of the alkaline degreasing solution in step (3) is: NaOH 50 g / L, Na3PO4 20 g / L, and the solvent is water.

[0010] Furthermore, the acidic solution in step (4) is a mixed solution of phosphoric acid and nitric acid, wherein the mass concentration of phosphoric acid is 70% and the mass concentration of nitric acid is 30%, and the two are mixed in a volume ratio of 1:1.

[0011] Furthermore, the electrolyte in step (5) comprises a basic electrode solution and a modifying additive, wherein the basic electrode solution comprises oxalic acid, phosphoric acid and sulfuric acid, the oxalic acid concentration is 40 g / L, the phosphoric acid concentration is 20 g / L, and the sulfuric acid concentration is 5 g / L; the modifying additive comprises polyethylene glycol, potassium titanium oxalate and citric acid, the polyethylene glycol concentration is 10 g / L, the potassium titanium oxalate concentration is 10 g / L, and the citric acid concentration is 10 g / L.

[0012] Furthermore, the passivation solution in step (6) consists of chromic anhydride, sodium fluoride and water, the chromic anhydride concentration is 200 g / L, the sodium fluoride concentration is 20 g / L, and the solvent is water.

[0013] A method for preparing a super-hydrophobic aluminum profile. The aluminum alloy profile prepared by the method is processed according to actual needs and applied to deep-sea equipment and offshore wind power facilities.

[0014] Beneficial effects: (1) First, the present invention optimizes the alloying elements. The main elements work together: core metal elements such as Cu (3-8%) and Mn (5-9%) form Al2CuMg and Al6Mn strengthening phases to improve strength; Fe (2-5%) refines the grains, and Mg and Zn enhance the aging hardening effect; the addition of Zr and Sc forms nano-Al3 (Sc, Zr) dispersed phases, which inhibit recrystallization and improve high-temperature stability; the Si content is controlled to avoid coarse silicon phases, and the total amount of impurities ≤0.1% can effectively prevent grain boundary segregation.

[0015] (2) In the key process step - anodization, the composition of the anolyte is optimized, and the basic electrolyte and modified additives are set. Oxalic acid in the basic electrolyte promotes the growth of the porous layer, phosphoric acid expands the pores, and sulfuric acid enhances the reaction activity. At the same time, the modified additives are added, and the three work together to improve the corrosion resistance of the material. Polyethylene glycol (PEG1000): As a surfactant, it reduces the surface tension of the electrolyte, promotes the penetration of the electrolyte in the micropores, and inhibits the film defects caused by bubble retention; potassium titanium oxalate releases TiO during the anodization process. 2+, by driving the electric field to embed into the alumina lattice, forming Ti-O-Al bonds, which improves the microhardness of the film layer; while citric acid and Al 3+ The formation of a stable complex ([Al(C6H5O7)]⁻) slows the deposition rate of alumina and induces directional micropore growth. Simultaneously, its carboxylic acid groups carbonize during the hot air post-treatment phase, generating hydrophobic carbon chains (-CH2-), further enhancing the superhydrophobic properties of the profile surface. The three elements achieve optimal effects when applied at equal concentrations.

[0016] (3) Dual voltage gradient oxidation is used simultaneously. In the first stage (15-20V), low voltage is used to generate a dense barrier layer (about 2-3μm thick) to reduce the active dissolution of the matrix Al; in the second stage (80-100V), high voltage is used to induce an "electrical breakdown effect" to epitaxially grow a multi-level microporous structure on the dense layer (increasing the specific surface area).

[0017] (4) Finally, the passivation liquid is used for sealing treatment. Chromic anhydride (200 g / L) and sodium fluoride (20 g / L) work together to form a Cr-OF-Al passivation film to fill the microcracks in the oxide layer.

[0018] (5) The super-hydrophobic aluminum profiles prepared by this method are not only highly corrosion-resistant, but also maintain excellent performance in extreme environments, significantly extending the service life of the equipment and improving the safety and stability of offshore facilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Figure 1 shows the microscopic morphology and energy spectrum analysis of the aluminum alloy in Example 1 of the present invention after 2000 hours of experiment in simulated seawater, where (a) is the morphology of the aluminum alloy before corrosion, (b) is the morphology of the aluminum alloy after corrosion, and (c) is the EDS energy spectrum analysis diagram of the corrosion surface. DETAILED DESCRIPTION

[0020] The technical solution of the present invention will be further described below with reference to specific embodiments, but is not limited thereto.

[0021] Example 1 A method for preparing a super-hydrophobic aluminum profile comprises the following steps: (1) Ingredients and smelting: Ingredients are prepared according to mass percentage: Cu 3%, Fe 2%, Mn 5%, Mg 1%, Zn 1%, Si 0.5%, Ni 0.1%, Ti 0.05%, Zr 0.1%, Y 0.05%, Sc 0.03%, and the rest is Al and unavoidable impurities, with the total amount of unavoidable impurities ≤ 0.1%. Smelt at high temperature for 6 h to 8 h to obtain aluminum alloy melt; then refine and cast to obtain cast rods; (2) placing the cast rod obtained in step (1) in a soaking furnace at a temperature of 480° C. for 10 h, and cooling after homogenization; extruding and aging the cast rod to obtain an aluminum alloy profile; (3) Immerse the aluminum alloy profile in an alkaline degreasing solution at 55-60°C for 3 minutes to remove oil stains, take it out, and wash it with water; (4) Then soak it in an acidic solution at 50-55°C for 30 seconds to improve the surface finish; (5) Anodizing treatment: The aluminum alloy substrate treated in step (4) is anodized in an electrolyte, with the aluminum alloy as the anode and the aluminum plate as the cathode, wherein the oxidation voltage is 15V and the current density is 1A / dm 2 , the electrolyte temperature is 10-20℃, the oxidation time is 20 minutes; then the voltage is increased to 80V, oxidation is carried out for 20 minutes, and air stirring is used during the anodic oxidation process; (6) Post-treatment: The anodized profile is treated with hot air at 100-120°C for 30 minutes; then the treated aluminum alloy substrate is immersed in a passivation solution at 80-85°C for 15 minutes, taken out to drain the surface moisture, and dried at 80-90°C for 2 hours to obtain a super-hydrophobic aluminum profile.

[0022] In step (2) aging treatment, the aging temperature is 165-175°C and the aging treatment time is 10 hours.

[0023] The composition of the alkaline degreasing solution in step (3) is: NaOH 50g / L, Na3PO4 20g / L, and the solvent is water.

[0024] The acidic solution in step (4) is a mixed solution of phosphoric acid and nitric acid, wherein the mass concentration of phosphoric acid is 70% and the mass concentration of nitric acid is 30%, and the two are mixed in a volume ratio of 1:1.

[0025] In step (5), the electrolyte comprises a basic electrode solution and a modifying additive, wherein the basic electrode solution comprises oxalic acid, phosphoric acid and sulfuric acid, wherein the oxalic acid concentration is 40 g / L, the phosphoric acid concentration is 20 g / L and the sulfuric acid concentration is 5 g / L; the modifying additive comprises polyethylene glycol, potassium titanium oxalate and citric acid, wherein the polyethylene glycol concentration is 10 g / L, the potassium titanium oxalate concentration is 10 g / L and the citric acid concentration is 10 g / L.

[0026] Step (6) The passivation solution consists of chromic anhydride, sodium fluoride and water, the chromic anhydride concentration is 200 g / L, the sodium fluoride concentration is 20 g / L, and the solvent is water.

[0027] Example 2 A method for preparing a super-hydrophobic aluminum profile comprises the following steps: (1) Ingredients and smelting: Ingredients are prepared according to mass percentage: Cu 5%, Fe 3%, Mn 7%, Mg 2%, Zn 2%, Si 0.6%, Ni 0.1%, Ti 0.05%, Zr 0.1%, Y 0.02%, Sc 0.01%, and the rest is Al and unavoidable impurities, with the total amount of unavoidable impurities ≤ 0.1%. Smelt at high temperature for 6 h to 8 h to obtain aluminum alloy melt; then refine and cast to obtain cast rods; (2) placing the cast rod obtained in step (1) in a soaking furnace at a temperature of 500° C. for 12 h, and cooling after homogenization; extruding and aging the cast rod to obtain an aluminum alloy profile; (3) Immerse the aluminum alloy profile in an alkaline degreasing solution at 55-60°C for 3 minutes to remove oil stains, take it out, and wash it with water; (4) Then soak it in an acidic solution at 50-55°C for 30 seconds to improve the surface finish; (5) Anodizing treatment: The aluminum alloy substrate treated in step (4) is anodized in an electrolyte, with the aluminum alloy as the anode and the aluminum plate as the cathode, wherein the oxidation voltage is 20 V and the current density is 1 A / dm 2 , the electrolyte temperature is 10-20℃, the oxidation time is 30 minutes; then the voltage is increased to 90V, oxidation is carried out for 25 minutes, and air stirring is used during the anodic oxidation process; (6) Post-treatment: The anodized profile is treated with hot air at 100-120°C for 30 minutes; then the treated aluminum alloy substrate is immersed in a passivation solution at 80-85°C for 20 minutes, taken out and drained of surface moisture, and dried at 80-90°C for 3 hours to obtain a super-hydrophobic aluminum profile.

[0028] In step (2) aging treatment, the aging temperature is 165-175°C and the aging treatment time is 11 hours.

[0029] The composition of the alkaline degreasing solution in step (3) is: NaOH 50g / L, Na3PO4 20g / L, and the solvent is water.

[0030] The acidic solution in step (4) is a mixed solution of phosphoric acid and nitric acid, wherein the mass concentration of phosphoric acid is 70% and the mass concentration of nitric acid is 30%, and the two are mixed in a volume ratio of 1:1.

[0031] In step (5), the electrolyte comprises a basic electrode solution and a modifying additive, wherein the basic electrode solution comprises oxalic acid, phosphoric acid and sulfuric acid, wherein the oxalic acid concentration is 40 g / L, the phosphoric acid concentration is 20 g / L and the sulfuric acid concentration is 5 g / L; the modifying additive comprises polyethylene glycol, potassium titanium oxalate and citric acid, wherein the polyethylene glycol concentration is 10 g / L, the potassium titanium oxalate concentration is 10 g / L and the citric acid concentration is 10 g / L.

[0032] Step (6) The passivation solution consists of chromic anhydride, sodium fluoride and water, the chromic anhydride concentration is 200 g / L, the sodium fluoride concentration is 20 g / L, and the solvent is water.

[0033] Example 3 A method for preparing a super-hydrophobic aluminum profile comprises the following steps: (1) Ingredients and smelting: Ingredients are prepared according to mass percentage: Cu 8%, Fe 5%, Mn 9%, Mg 2%, Zn 2%, Si 0.8%, Ni 0.1%, Ti 0.05%, Zr 0.1%, Y 0.05%, Sc 0.03%, and the rest is Al and unavoidable impurities, with the total amount of unavoidable impurities ≤ 0.1%. Smelt at high temperature for 6 h to 8 h to obtain aluminum alloy melt; then refine and cast to obtain cast rods; (2) placing the cast rod obtained in step (1) in a soaking furnace at a temperature of 550° C. for 15 h, and cooling after homogenization; extruding and aging the cast rod to obtain an aluminum alloy profile; (3) Immerse the aluminum alloy profile in an alkaline degreasing solution at 55-60°C for 5 minutes to remove oil stains, take it out, and wash it with water; (4) Then soak it in an acidic solution at 50-55°C for 40 seconds to improve the surface finish; (5) Anodizing treatment: The aluminum alloy substrate treated in step (4) is anodized in an electrolyte, with the aluminum alloy as the anode and the aluminum plate as the cathode, wherein the oxidation voltage is 20 V and the current density is 2 A / dm 2 , the electrolyte temperature is 10-20℃, the oxidation time is 40 minutes; then the voltage is increased to 80-100V, oxidation is carried out for 30 minutes, and air stirring is used during the anodic oxidation process; (6) Post-treatment: The anodized profile is treated with hot air at 100-120°C for 30 minutes; then the treated aluminum alloy substrate is immersed in a passivation solution at 80-85°C for 30 minutes, taken out to drain the surface moisture, and dried at 80-90°C for 4 hours to obtain a super-hydrophobic aluminum profile.

[0034] In step (2) aging treatment, the aging temperature is 165-175°C and the aging treatment time is 12 hours.

[0035] The composition of the alkaline degreasing solution in step (3) is: NaOH 50g / L, Na3PO4 20g / L, and the solvent is water.

[0036] The acidic solution in step (4) is a mixed solution of phosphoric acid and nitric acid, wherein the mass concentration of phosphoric acid is 70% and the mass concentration of nitric acid is 30%, and the two are mixed in a volume ratio of 1:1.

[0037] In step (5), the electrolyte comprises a basic electrode solution and a modifying additive, wherein the basic electrode solution comprises oxalic acid, phosphoric acid and sulfuric acid, wherein the oxalic acid concentration is 40 g / L, the phosphoric acid concentration is 20 g / L and the sulfuric acid concentration is 5 g / L; the modifying additive comprises polyethylene glycol, potassium titanium oxalate and citric acid, wherein the polyethylene glycol concentration is 10 g / L, the potassium titanium oxalate concentration is 10 g / L and the citric acid concentration is 10 g / L.

[0038] Step (6) The passivation solution consists of chromic anhydride, sodium fluoride and water, the chromic anhydride concentration is 200 g / L, the sodium fluoride concentration is 20 g / L, and the solvent is water.

[0039] Comparative Example 1 In this comparative example, except that Zr element is not added to the alloy composition, the rest of the raw materials and process methods are the same as those of Example 3. A method for preparing a super-hydrophobic aluminum profile comprises the following steps: (1) Ingredients and smelting: Ingredients are prepared according to mass percentage: Cu 8%, Fe 5%, Mn 9%, Mg 2%, Zn 2%, Si 0.8%, Ni 0.1%, Ti 0.05%, Y 0.05%, Sc 0.03%, and the rest is Al and unavoidable impurities, with the total amount of unavoidable impurities ≤ 0.1%. Smelt at high temperature for 6 h to 8 h to obtain aluminum alloy melt; then refine and cast to obtain cast rods.

[0040] Comparative Example 2 In this comparative example, except that Sc element is not added to the alloy composition, the rest of the raw materials and process methods are the same as those in Example 3. A method for preparing a super-hydrophobic aluminum profile comprises the following steps: (2) Ingredients and smelting: Ingredients are prepared according to mass percentage: Cu 8%, Fe 5%, Mn 9%, Mg 2%, Zn 2%, Si 0.8%, Ni 0.1%, Ti 0.05%, Zr 0.1%, Y 0.05%, and the rest is Al and unavoidable impurities, with the total amount of unavoidable impurities ≤ 0.1%. Smelt at high temperature for 6h-8h to obtain aluminum alloy melt; then refine and cast to obtain cast rods.

[0041] Comparative Example 3 In this comparative example, except for changing the electrolyte composition, that is, not using the modifying additive, the rest of the raw materials and process steps are the same as in Example 1. That is, in step (5): In step (5), the electrolyte is a basic electrode solution, wherein the basic electrode solution contains oxalic acid, phosphoric acid and sulfuric acid, with the oxalic acid concentration being 40 g / L, the phosphoric acid concentration being 20 g / L and the sulfuric acid concentration being 5 g / L.

[0042] Comparative Example 4 In this comparative example, except for changing the electrolyte composition, that is, not using polyethylene glycol in the modified additive, the rest of the raw materials and process steps are the same as in Example 1. That is, in step (5): In step (5), the electrolyte comprises a basic electrode solution and a modifying additive, wherein the basic electrode solution comprises oxalic acid, phosphoric acid and sulfuric acid, with the oxalic acid concentration being 40 g / L, the phosphoric acid concentration being 20 g / L and the sulfuric acid concentration being 5 g / L; and the modifying additive comprises potassium titanium oxalate and citric acid, with the potassium titanium oxalate concentration being 10 g / L and the citric acid concentration being 10 g / L.

[0043] Comparative Example 5 In this comparative example, except for changing the electrolyte composition, that is, not using potassium titanium oxalate in the modified additive, the remaining raw materials and process steps are the same as those in Example 1. That is, in step (5): In step (5), the electrolyte comprises a basic electrode solution and a modifying additive, wherein the basic electrode solution comprises oxalic acid, phosphoric acid and sulfuric acid, with the oxalic acid concentration being 40 g / L, the phosphoric acid concentration being 20 g / L and the sulfuric acid concentration being 5 g / L; and the modifying additive comprises polyethylene glycol and citric acid, with the polyethylene glycol concentration being 10 g / L and the citric acid concentration being 10 g / L.

[0044] Comparative Example 6 In this comparative example, except for changing the electrolyte composition, that is, not using citric acid in the modified additive, the rest of the raw materials and process steps are the same as in Example 1. That is, in step (5): In step (5), the electrolyte comprises a basic electrode solution and a modifying additive, wherein the basic electrode solution comprises oxalic acid, phosphoric acid and sulfuric acid, with the oxalic acid concentration being 40 g / L, the phosphoric acid concentration being 20 g / L and the sulfuric acid concentration being 5 g / L; and the modifying additive comprises polyethylene glycol and potassium titanium oxalate, with the polyethylene glycol concentration being 10 g / L and the potassium titanium oxalate concentration being 10 g / L.

[0045] Comparative Example 7 In this comparative example, except for changing the electrolyte composition, that is, reducing the concentration of each raw material in the modified additive, the remaining raw materials and process steps are the same as those in Example 1. That is, in step (5): In step (5), the electrolyte comprises a basic electrode solution and a modifying additive, wherein the basic electrode solution comprises oxalic acid, phosphoric acid and sulfuric acid, with the oxalic acid concentration being 40 g / L, the phosphoric acid concentration being 20 g / L and the sulfuric acid concentration being 5 g / L; the modifying additive comprises polyethylene glycol, potassium titanium oxalate and citric acid, with the polyethylene glycol concentration being 8 g / L, the potassium titanium oxalate concentration being 8 g / L and the citric acid concentration being 8 g / L.

[0046] Comparative Example 8 In this comparative example, except for changing the electrolyte composition, that is, increasing the concentration of each raw material in the modified additive, the remaining raw materials and process steps are the same as those in Example 1. That is, in step (5): The electrolyte in step (5) comprises a basic electrode solution and a modifying additive, wherein the basic electrode solution comprises oxalic acid, phosphoric acid and sulfuric acid, wherein the oxalic acid concentration is 40 g / L, the phosphoric acid concentration is 20 g / L and the sulfuric acid concentration is 5 g / L; the modifying additive comprises polyethylene glycol, potassium titanium oxalate and citric acid, wherein the polyethylene glycol concentration is 12 g / L, the potassium titanium oxalate concentration is 12 g / L and the citric acid concentration is 12 g / L.

[0047] Performance Testing The performance tests were conducted on the aluminum alloy materials obtained in Examples 1-3 and Comparative Examples 1-8. The test indicators and methods are as follows: Oxide film thickness measurement: Based on ISO 2360:2017, "Measurement of thickness of non-conductive coatings on non-magnetic metal substrates — Eddy current method," five measurement points were taken for each sample and the average value was calculated. Test instrument: Eddy Current Coating Thickness Gauge (Model: Surfix SFN, accuracy ±0.5 μm).

[0048] Hardness: The hardness test of the alloy sample is carried out in accordance with GB / T23.1 standard.

[0049] Contact angle, static contact angle: according to ASTM D7334-21 "Standard Practice for Evaluating Surface Wettability by Contact Angle Measurement", the deionized water drop volume is 4 μL.

[0050] Salt spray test: A salt spray test chamber (Q-FOG CCT1100, compliant with ASTM B117-22) was used. The test conditions were: 5% NaCl solution, pH 6.5-7.2, temperature 35±2°C, spray pressure 0.8-1.2 bar, continuous spray mode. Tests were conducted according to ISO 10289:2021, "Corrosion test methods for conversion and anodic oxide coatings on metal substrates." The time to the first appearance of substrate corrosion was recorded.

[0051] Mechanical properties testing was performed using a universal testing machine (Instron 5985, load accuracy ±0.5%) according to ASTM E8 / E8M-22, "Metallic Materials, Tensile Test Methods." Specimen dimensions conformed to ISO 6892-1:2020, No. 5 scale specimens (gauge length 50 mm, width 12.5 mm). All performance tests were repeated 10 times, and the results were averaged.

[0052] Table 1 Performance test results The data in the table demonstrate that the aluminum alloy materials obtained from the examples of the present invention significantly outperform the comparative examples in terms of oxide film thickness, hardness, contact angle, and tensile strength, demonstrating excellent overall performance and corrosion resistance. In particular, the examples far outlasted the comparative examples in salt spray testing, further demonstrating their stability in complex environments. However, comparative examples 1-2, which varied the alloying element composition, and comparative examples 3-8, which varied the composition of the modifying additives, failed to achieve the excellent results of the examples. This demonstrates that the alloy proportions and the use and composition of the modifiers of the present invention are crucial for improving the overall performance of the material. Depletion of Zr or Sc reduces the alloy's high-temperature stability and leads to inadequate homogenization, resulting in coarsened grains (average size >20μm) after extrusion, poor oxide film uniformity, and reduced thickness (18-20μm), which in turn compromises corrosion resistance and mechanical strength. Without the addition of modifying additives, the oxide film exhibits high brittleness, a hardness of only 320 HV, and exhibits pitting corrosion after 800 hours of salt spray testing. When polyethylene glycol was omitted from the modifying additive (Comparative Example 4), the micropore distribution was uneven, and the contact angle dropped to 152°. When potassium titanium oxalate was omitted (Comparative Example 5), the film had insufficient hardness, the surface was easily abraded, and the contact angle was 148°. When citric acid was omitted (Comparative Example 6), the hydrophobic carbon chain was missing, and the contact angle was only 142°. Adjusting the modifying additive concentration (8 g / L or 12 g / L) resulted in slightly lower overall performance than in Example 1, indicating that the optimal synergistic effect was achieved at the same concentration (10 g / L). Adjusting the concentration too high or too low affected the overall performance of the material, confirming that 10 g / L was the optimal ratio, ensuring the material's long-term stability in high-temperature, high-humidity environments.

[0053] Deep sea simulation corrosion resistance test: Test conditions: Solution: 5% NaCl solution (simulated seawater salinity), pH 7.2±0.1.

[0054] Pressure: 5 MPa (simulating 5000m deep-sea hydrostatic pressure), using a high-pressure reactor (model: PARR 4575).

[0055] Temperature: 10±1℃ (simulating deep sea low temperature environment).

[0056] Cyclic shock: pressure fluctuation range is 5±0.5 MPa, frequency is 1 Hz (60 cycles per minute), and the total test time is 2000 hours.

[0057] Reference standard: ISO 11489:2021 "Metallic materials - High-pressure corrosion test methods".

[0058] Detection indicators: Weight loss rate: calculated according to ASTM G31-21 "Metal Immersion Corrosion Test Standard", sample size 50×25×3 mm, 10 samples were repeated in each experimental group, and the results were averaged.

[0059] Surface morphology: SEM was used to observe pitting corrosion, and EDS was used to analyze corrosion products.

[0060] Table 2 Results of deep sea simulation corrosion resistance test The data in Table 2 show that Example 1's weight loss (0.04 mg / cm²) is much lower than that of the comparative example, attributed to the denseness of its oxide film and its excellent corrosion resistance. SEM analysis reveals no surface pitting, and a dense structure before and after corrosion. The primary surface corrosion products are AlO(OH), or Al₂O₃·H₂O.

[0061] It should be noted that the above embodiments are only some of the preferred embodiments of the present invention, and not all of them. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present invention.

Claims

1. A method for preparing a super-hydrophobic aluminum profile, characterized in that: The method comprises the following preparation steps: (1) Ingredients and smelting: Ingredients are prepared according to mass percentage: Cu3-8%, Fe2-5%, Mn5-9%, Mg1-2%, Zn1-2%, Si0.5-0.8%, Ni0.1%, Ti0.05%, Zr0.05-0.1%, Y0.02-0.05%, Sc0.01-0.03%, and the rest are Al and unavoidable impurities, with the total amount of unavoidable impurities ≤0.1%. Smelt at high temperature for 6h-8h to obtain aluminum alloy melt; then refine and cast to obtain cast rods; (2) placing the cast rod obtained in step (1) in a soaking furnace at a temperature of 480-550°C for 10-15 hours, and cooling after homogenization; extruding and aging the cast rod to obtain an aluminum alloy profile; (3) Immerse the aluminum alloy profile in an alkaline degreasing solution at 55-60°C for 3-5 minutes to remove oil stains, take it out, and wash it with water; (4) Then soak it in an acidic solution at 50-55°C for 30-40 seconds to improve the surface finish; (5) Anodizing treatment: The aluminum alloy substrate treated in step (4) is anodized in an electrolyte, with the aluminum alloy as the anode and the aluminum plate as the cathode, wherein the oxidation voltage is 15-20V and the current density is 1-2A / dm 2 , the electrolyte temperature is 10-20℃, and the oxidation time is 20-40 minutes; Then increase the voltage to 80-100V and oxidize for 20-30 minutes, using air stirring during the anodizing process; (6) Post-treatment: The anodized profile is treated with hot air at 100-120°C for 30 minutes; then the treated aluminum alloy substrate is immersed in a passivation solution at 80-85°C for 15-30 minutes, taken out to drain the surface moisture, and dried at 80-90°C for 2-4 hours to obtain a super-hydrophobic aluminum profile.

2. The method for preparing a super-hydrophobic aluminum profile according to claim 1, wherein In step (2) aging treatment, the aging temperature is 165-175°C and the aging treatment time is 10-12h.

3. The method for preparing a super-hydrophobic aluminum profile according to claim 1, wherein The composition of the alkaline degreasing solution in step (3) is: NaOH 50g / L, Na3PO4 20g / L, and the solvent is water.

4. The method for preparing a super-hydrophobic aluminum profile according to claim 1, wherein The acidic solution in step (4) is a mixed solution of phosphoric acid and nitric acid, wherein the mass concentration of phosphoric acid is 70% and the mass concentration of nitric acid is 30%, and the two are mixed in a volume ratio of 1:

1.

5. The method for preparing a super-hydrophobic aluminum profile according to claim 1, wherein In step (5), the electrolyte comprises a basic electrode solution and a modifying additive, wherein the basic electrode solution comprises oxalic acid, phosphoric acid and sulfuric acid, wherein the oxalic acid concentration is 40 g / L, the phosphoric acid concentration is 20 g / L and the sulfuric acid concentration is 5 g / L; the modifying additive comprises polyethylene glycol, potassium titanium oxalate and citric acid, wherein the polyethylene glycol concentration is 10 g / L, the potassium titanium oxalate concentration is 10 g / L and the citric acid concentration is 10 g / L.

6. The method for preparing a super-hydrophobic aluminum profile according to claim 1, wherein: Step (6) The passivation solution consists of chromic anhydride, sodium fluoride and water, the chromic anhydride concentration is 200 g / L, the sodium fluoride concentration is 20 g / L, and the solvent is water.

7. A method for preparing a super-hydrophobic aluminum profile according to any one of claims 1 to 6, characterized in that: The aluminum alloy profiles prepared by this method are processed according to actual needs and used in deep-sea equipment and offshore wind power facilities.

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