A super-hydrophobic self-cleaning aluminum alloy coating and a method of making the same

Abstract

The application provides a super-hydrophobic self-cleaning aluminum alloy coating and a preparation method thereof, and belongs to the technical field of super-hydrophobic material preparation. The SiO2 / CuO composite particles with a core-shell structure are prepared by using a hydrothermal method, then the SiO2 / CuO composite particles are modified by using hexadecyl trimethoxysilane, and are sprayed on the surface of a substrate to obtain a super-hydrophobic self-cleaning coating with photocatalytic capacity. The preparation method is simple, no chemicals are used except for ethanol and a small amount of hexadecyl trimethoxysilane, the prepared coating has photocatalytic antibacterial capacity, and the coating surface shows good super-hydrophobicity and excellent corrosion resistance to water, acid and alkali.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of super-hydrophobic material preparation, in particular to a super-hydrophobic self-cleaning aluminum alloy coating and a preparation method thereof. BACKGROUND

[0002] Aluminum alloy has high strength, hardness and excellent welding performance, and is the main material for manufacturing large thin-walled high-precision complex solid and hollow profiles, and is widely used in aerospace, vehicle engineering and other fields. Powder plus glue can form a coating on the surface of aluminum alloy, which can endow the aluminum alloy with excellent surface properties such as corrosion resistance and super-hydrophobicity. For example, the document "Preparation and Performance Research of Silica / Epoxy Resin / Silicone Rubber Super-hydrophobic Coating" reports that a super-hydrophobic coating is successfully prepared on the surface of aluminum alloy under the synergistic action of epoxy resin and nano-SiO2, which has excellent corrosion resistance.

[0003] Super-hydrophobic coating is a new and environmentally friendly metal surface treatment technology. Compared with traditional corrosion protection methods such as organic coating, surface oxidation treatment and corrosion inhibitor, the preparation process of super-hydrophobic coating is simpler, has higher cost performance and causes less pollution. For example, the patent 202211023236.8 "Construction Method of Solid Super-smooth Surface" discloses a construction method of solid super-smooth surface. The method constructs a metal oxide layer on the surface of a metal substrate by anodic oxidation, and fills the light-heat nanoparticles and solid paraffin organic fusion on the surface of the super-hydrophobic coating to obtain the solid super-smooth surface. However, it needs to first prepare a "nanopin" multi-level micro-nano structure CuO surface on the surface of copper by anodic oxidation, which has a complex preparation process and is not conducive to large-scale practical application. SUMMARY

[0004] Therefore, the present application aims to provide a super-hydrophobic self-cleaning aluminum alloy coating and a preparation method thereof. The preparation method provided by the present application is simple, and the super-hydrophobic self-cleaning aluminum alloy coating obtained by the method has excellent super-hydrophobic self-cleaning performance, corrosion resistance and photocatalytic performance.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solution: a preparation method of a super-hydrophobic self-cleaning aluminum alloy coating, comprising the following steps:

[0006] (1) mixing and stirring anhydrous ethanol, deionized water, ammonia water and tetraethyl orthosilicate to react, and collecting the solid to obtain nano-silicon dioxide;

[0007] (2) performing hydrothermal reaction on the obtained nano-silicon dioxide, copper nitrate hydrate, polyethylene glycol, melamine, water and hydrogen peroxide, collecting the precipitate after the reaction is completed, and obtaining nano-SiO2 / CuO composite particles;

[0008] (3) modifying the obtained nano-SiO2 / CuO composite particles with hexadecyltrimethoxysilane to obtain nano-SiO2 / CuO@HDTMS composite particles;

[0009] (4) mixing the obtained nano-SiO2 / CuO@HDTMS composite particles with epoxy resin, a curing agent and dimethylbenzene, and then spraying to obtain a super-hydrophobic self-cleaning coating.

[0010] Preferably, the volume ratio of anhydrous ethanol, deionized water, ammonia water and tetraethyl orthosilicate in step (1) is (122-124):(41-43):(17-20):(6-9).

[0011] Preferably, the stirring reaction temperature in step (1) is 25-30℃, and the reaction time is 2-3h.

[0012] Preferably, the weight ratio of copper nitrate hydrate, nano-silica, polyethylene glycol, melamine, water and hydrogen peroxide in step (2) is (3-4):(1-1.5):(0.5-1.2):(1.7-2.3):(11-14):(7-8).

[0013] Further preferably, the concentration of the hydrogen peroxide is preferably 25%-30%.

[0014] Preferably, the hydrothermal reaction temperature in step (2) is 180-200℃, and the hydrothermal reaction time is 10-12h.

[0015] Preferably, the step (3) further comprises a solvent, and the solvent is ethanol and water.

[0016] Further preferably, the weight ratio of nano-silica, nano-copper oxide, hexadecyltrimethoxysilane, ethanol and water is (1-4):(0.3-0.7):(1-4):(45-50):(8-12).

[0017] Preferably, the reaction temperature for modification in step (3) is 25-30℃, and the reaction time is 20-24h.

[0018] The application also provides a super-hydrophobic self-cleaning aluminum alloy coating prepared by the preparation method.

[0019] Beneficial technical effects:

[0020] The present application adopts hydrothermal method to prepare SiO2 / CuO composite particles with core-shell structure, then modifies them with hexadecyltrimethoxysilane, sprays them on the surface of a substrate to obtain a super-hydrophobic self-cleaning coating with photocatalytic ability. The prepared coating not only has photocatalytic ability, but also shows the same super-hydrophobicity to water, acid and alkali. In addition, no chemicals are used in the process of preparing the coating except ethanol and a small amount of hexadecyltrimethoxysilane. This strategy overcomes the shortcomings of super-hydrophobic coatings in the preparation process, such as strict preparation conditions, use of a large amount of toxic chemicals, multi-step process, and the resulting difficulties in large-scale application. Therefore, the SiO2 / CuO@HDTMS coating has significant advantages in terms of cost and environmental protection. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 SEM image of the SiO2 / CuO@HDTMS coating obtained in Example 2;

[0022] Figure 2 Nyquist plot of the coating of Example 2 and Comparative Example 1 measured after immersion in 3.5wt.% NaCl solution for 24h;

[0023] Figure 3 Fitting circuit diagram, wherein figure a represents the fitting circuit of the epoxy resin coated aluminum alloy plate, and figure b represents the fitting circuit of the SiO2 / CuO@HDTMS super-hydrophobic composite coating;

[0024] Figure 4 Tafel polarization curve diagram of the coating of Comparative Example 1 and Example 2 measured after immersion in 3.5wt.% NaCl solution for 24h;

[0025] Figure 5 Bacteriostatic effect diagram of the coating of Example 2 and Comparative Examples 1 and 2. DETAILED DESCRIPTION

[0026] The present application provides a preparation method of a super-hydrophobic self-cleaning aluminum alloy coating, comprising the following steps:

[0027] (1) mixing and stirring anhydrous ethanol, deionized water, ammonia water and tetraethyl orthosilicate to react, and collecting the solid to obtain nanosilica;

[0028] (2) performing hydrothermal reaction on the obtained nanosilica and copper nitrate hydrate, polyethylene glycol, melamine, water and hydrogen peroxide, collecting the precipitate after the reaction to obtain nanometer SiO2 / CuO composite particles;

[0029] (3) modifying the obtained nano-SiO2 / CuO composite particles with hexadecyltrimethoxysilane to obtain nano-SiO2 / CuO@HDTMS composite particles;

[0030] (4) mixing the obtained nano-SiO2 / CuO@HDTMS composite particles with epoxy resin, curing agent and dimethylbenzene, and then spraying to obtain a super-hydrophobic self-cleaning coating.

[0031] The anhydrous ethanol, deionized water, ammonia and tetraethyl orthosilicate are mixed and stirred to react, and the solid is collected to obtain nano-silica.

[0032] In the present application, the volume ratio of the anhydrous ethanol, deionized water, ammonia and tetraethyl orthosilicate is preferably (122-124):(41-43):(17-20):(6-9), and more preferably 122.5:42.5:18:8; the stirring reaction temperature is preferably 25-30℃, and more preferably 30℃; and the reaction time is preferably 2-3h, and more preferably 2h.

[0033] In the present application, after the reaction is completed, centrifugation, washing and drying are further included; the washing reagent is a mixed solution of ethanol and water, the volume ratio of the ethanol and water is 1:1, the centrifuged product is washed five times with the mixed solution of ethanol and water to remove the ammonia and other impurities in the product; and the drying temperature is 50-60℃, and the drying time is 2-3h.

[0034] After obtaining the nano-silica, the obtained nano-silica, copper nitrate hydrate, polyethylene glycol, melamine, water and hydrogen peroxide are subjected to hydrothermal reaction, and the precipitate is collected after the reaction to obtain nano-SiO2 / CuO composite particles.

[0035] In the present application, the copper nitrate hydrate, nano-silicon dioxide, polyethylene glycol, melamine and water are first stirred by magnetic stirring under a constant temperature water bath at a speed of 500 rpm for 6 hours. Then hydrogen peroxide is added and stirred for 2 hours, and finally transferred into a hydrothermal kettle for hydrothermal reaction. In the present application, the weight ratio of the copper nitrate hydrate, nano-silicon dioxide, polyethylene glycol, melamine, water, hydrogen peroxide is preferably (3-4):(1-1.5):(0.5-1.2):(1.7-2.3):(11-14):(7-8), more preferably 3:1:1:2:12:8; the concentration of the hydrogen peroxide is preferably 25%-30%, more preferably 30%; the hydrothermal reaction temperature is preferably 180-200℃, more preferably 200℃, and the hydrothermal reaction time is preferably 10-12h, more preferably 12h. In the present application, after the reaction is completed, the reaction solution is also subjected to washing, centrifugal precipitation.

[0036] After obtaining the nano-SiO2 / CuO composite particles, the present application modifies the obtained nano-SiO2 / CuO composite particles using hexadecyl trimethoxysilane to obtain nano-SiO2 / CuO@HDTMS composite particles.

[0037] In the present application, during the modification process, a solvent is also added for reaction, and the solvent is ethanol and water; in the present application, the weight ratio of the nano-silicon dioxide, nano-copper oxide, hexadecyl trimethoxysilane, ethanol, water is preferably (1-4):(0.3-0.7):(1-4):(45-50):(8-12), more preferably 3:0.3:1.7:50:10; the reaction temperature for modification is preferably 25-30℃, more preferably 30℃, and the reaction time is preferably 20-24h, more preferably 24h. In the present application, after the modification reaction is completed, centrifugal washing and drying are also included, and the drying temperature is 60℃ and the drying time is 3h.

[0038] The present application mixes the particles with epoxy resin, curing agent and xylene, and then sprays to obtain a super-hydrophobic self-cleaning coating.

[0039] In the present application, the weight ratio of the nano-SiO2 / CuO@HDTMS composite particles, epoxy resin, curing agent and xylene is 10:1:3:100.

[0040] The present application also provides a super-hydrophobic self-cleaning aluminum alloy coating prepared by the preparation method of the above technical solution.

[0041] In order to better understand the present application, the content of the present application is further illustrated by combining the following examples, but the content of the present application is not limited to the following examples.

[0042] Example 1

[0043] (1) Take 32.5 ml of anhydrous ethanol, 42.5 ml of deionized water, and 18 ml of ammonia water, and prepare A liquid in a 30°C constant temperature water bath with magnetic stirring at a speed of 400 rpm; then take 8 ml of tetraethyl orthosilicate and 90 ml of anhydrous ethanol, and prepare B liquid in a 30°C constant temperature water bath with magnetic stirring; increase the stirring speed of A liquid to 600 rpm, and then add B liquid within one minute; adjust the stirring speed of the mixture back to 400 rpm, and keep the reaction for 2 h. After obtaining the mixed solution, volatilize the ammonia water, and then perform differential centrifugation on the suspension, and clean the mixture with an alcohol-water mixture (v:v = 1:1) for five times to remove the ammonia water and other impurities. Then, place the treated sample in a constant temperature drying box at 60°C for drying for 3 h to obtain nano-silicon dioxide;

[0044] (2) Take 0.001 mol of copper nitrate hydrate, 0.1 g of silicon dioxide, 0.1 g of polyethylene glycol, 0.2 g of melamine, and 12 ml of water, and perform magnetic stirring at a speed of 500 rpm for 6 h in a 30°C constant temperature water bath, then add 8 ml of 30% hydrogen peroxide, and stir for 2 h; then transfer the solution into a hydrothermal kettle, and perform reaction at 200°C for 12 h; then wash and centrifuge the precipitate to obtain nano-SiO2 / CuO composite particles;

[0045] (3) Add the prepared SiO2 / CuO composite particles into 10 ml of water, 50 ml of ethanol, and 1 ml of hexadecane trimethoxysilane, and perform reaction for 24 h in a 30°C constant temperature water bath; then take out the mixture, wash and centrifuge the precipitate, and dry at 60°C for 3 h to obtain nano-SiO2 / CuO@HDTMS composite particles;

[0046] (4) Add 1 g of the obtained nano-SiO2 / CuO@HDTMS composite particles, 0.1 g of epoxy resin, and 0.3 g of curing agent into 10 g of dimethylbenzene, and mix; then perform ultrasonic treatment for 10 min, and then spray the mixture with an airbrush. The coating is denoted as SiO2 / CuO@HDTMS coating.

[0047] Example 2

[0048] The same as in Example 1, except that the amount of hexadecane trimethoxysilane used is 2 ml.

[0049] Figure 1 The SEM image of the coating of Example 2, and the micro / nano hierarchical structure is the key to the super-hydrophobic surface. The morphology of the SiO2 / CuO@HDTMS composite particles is observed by scanning electron microscopy and transmission electron microscopy, and the CuO is uniformly loaded on the surface of the SiO2 to form a micro / nano structure.

[0050] Example 3

[0051] The same as in Example 1, except that the amount of hexadecane trimethoxysilane used is 3 ml.

[0052] Example 4

[0053] The same as example 1, except that the amount of hexadecyltrimethoxysilane used is 4ml.

[0054] Comparative Example 1

[0055] 0.1g of epoxy resin and 0.3g of curing agent were added to 10g of xylene, mixed and ultrasonically dispersed, and then sprayed onto the surface of an aluminum alloy using an airbrush.

[0056] Comparative Example 2

[0057] The SiO2 / CuO composite particles were prepared in the same manner as in example 1.

[0058] 1g of SiO2 / CuO composite particles were added to a mixture of 0.1g of epoxy resin and 0.3g of curing agent in 10g of xylene, mixed and ultrasonically dispersed, and then sprayed onto the surface of an aluminum alloy using an airbrush, and then heated and cured to obtain an aluminum alloy coating. The coating is referred to as the SiO2 / CuO coating.

[0059] Test

[0060] 1) Hydrophobic angle test

[0061] The coatings obtained in examples 1-4 and comparative examples 1-2 were subjected to a hydrophobic angle test, and the test results are shown in Table 1.

[0062] Table 1 Hydrophobic angle of the coatings obtained in examples 1-4 and comparative examples 1-2

[0063] Sample No. Amount of hexadecyltrimethoxysilane used Hydrophobic angle Example 1 1ml 157.4±3.0° Example 2 2ml 167.4±3.0° Example 3 3ml 164.4±3.0° Example 4 4ml 160.4±3.0° Comparative Example 1 0ml 65±3.0° Comparative Example 2 0ml 66±3.0°

[0064] As can be seen from Table 1, the contact angle of the pure epoxy coating in comparative example 1 is 65±3.0°, which is hydrophilic. The contact angle of the SiO2 / CuO coating is 66±3.0°, and the contact angle of the SiO2 / CuO@HDTMS coating is 157.4±3.0°. It can be seen that the surface of the SiO2 / CuO nanoparticles has a lower surface energy after modification with hexadecyltrimethoxysilane, and the nanoparticles of SiO2 and CuO are bonded to each other, which significantly increases the surface roughness of the coating, and the contact angle is also greatly increased, which exhibits excellent superhydrophobicity.

[0065] 2) Photocatalytic degradation

[0066] In the field of photocatalysis, copper oxide (CuO) is an important p-type semiconductor with catalytic, optical, antibacterial and low cost properties. CuO-based nanoparticles are suitable for photocatalytic applications due to their band gap (1.2-2.1 eV), easy availability, good toxicity, conductivity and thermal conductivity. The addition of CuO allows the coating to decompose certain organic pollutants. Rhodamine b solution and methylene blue solution were used to simulate organic pollutants. Example 2 was selected as the experimental group, and Comparative Example 1 and Comparative Example 2 as the control group. The degradation rate is shown in Table 2.

[0067] Table 2 Degradation rate of coating of Example 2 and Comparative Examples 1 and 2 on rhodamine b solution and methylene blue solution

[0068] Sample No. 300 min rhodamine b solution C / C0 value Degradation rate Example 2 0.14 86％ Comparative Example 1 0.98 2％ Comparative Example 2 0.40 60％

[0069] Sample No. 300 min methylene blue solution C / C0 value Degradation rate Example 2 0.20 80％ Comparative Example 1 0.97 3％ Comparative Example 2 0.44 56％

[0070] As can be seen from Table 2, the epoxy resin coating of Comparative Example 1 has no degradation function on the above two solutions, and the C / C0of the solution is 0.98 and 0.97 respectively within 300 min, and the degradation rate is 2% and 3% respectively. The SiO2 / CuO coating of Comparative Example 2 can degrade the rhodamine b solution, and the C / C0of the solution is 0.40 within 300 min, and the degradation rate is 60%. The SiO2 / CuO coating can degrade the methylene blue solution, and the C / C0of the solution is 0.44 within 300 min, and the degradation rate is 56%. The SiO2 / CuO@HDTMS coating of Example 2 can also degrade the above two organic dyes, and the C / C0of the two solutions is 0.14 and 0.20 respectively within 300 min, and the degradation rate is 86% and 80% respectively.

[0071] 3) Abrasion resistance analysis of SiO2 / CuO@HDTMS superhydrophobic composite coating

[0072] The SiO2 / CuO@HDTMS superhydrophobic composite coating of Example 2 was modified on the cotton fabric, then the modified cotton fabric was fixed on a 200g weight and placed on a 600 mesh sandpaper, and dragged 10cm straight and 10cm vertically at a speed of 4cm / s, as one cycle. After 80 cycles of friction, the contact angle was still above 148°, indicating that the superhydrophobic composite coating had good abrasion resistance.

[0073] 4) Superhydrophobicity

[0074] The superhydrophobicity of the coating of Example 2 on water, acid drop (pH=2), and base drop (pH=11) was tested, and the test results are shown in Table 3.

[0075] Table 3 Superhydrophobicity test results

[0076] Solution Water HC1 (pH = 2) NaOH (pH = 11) Hydrophobic angle 167.4° 162.5° 163.4°

[0077] The droplets formed on the SiO2 / CuO@HDTMS coating surface were spherical and exhibited the same liquid repellency towards these liquids. The contact angle of water on the coating was 167.4°, that of HCl solution was 162.5°, and that of NaOH solution was 163.4°.

[0078] 5) Corrosion resistance analysis

[0079] The corrosion resistance performance of the SiO2 / CuO@HDTMS superhydrophobic composite coating prepared in Example 2 is analyzed below.

[0080] (1) In the electrochemical performance test, an electrochemical workstation was used to test the corrosion resistance of the sample. Electrochemical measurements were performed in a suitable three-electrode cell under ventilated conditions using a potentiostat-galvanistat / EISAmetek PARSTA 4000. The test area was calculated to be 9 cm². 2 An epoxy-coated aluminum alloy sample (30 mm × 30 mm × 1.5 mm) was used as the working electrode (WE), and a Pt grid was used as the counter electrode. All potentials were measured using a saturated calomel electrode (SCE) in 3.5 wt.% NaCl solution. Electrochemical impedance spectroscopy (EIS) was performed near the open-circuit voltage (OCP) in the frequency domain (10). -2 (Hz-10kHz), with an amplitude of ±10mV.

[0081] By testing the AC impedance of different coatings and using equivalent circuits for data fitting, the corrosion mechanism and anti-corrosion performance of the coatings can be analyzed more accurately. Figure 2 The Nyquist plots of each coating were obtained after immersion in 3.5 wt.% NaCl solution for 24 hours. It can be seen that each sample's Nyquist plot shows only one capacitive arc. The diameter of the capacitive arc represents the resistance to charge transfer during corrosion; its diameter is directly proportional to the coating's corrosion resistance—a larger diameter indicates better corrosion resistance. Therefore, the SiO2 / CuO@HDTMS superhydrophobic composite coating significantly improves the corrosion resistance of aluminum alloys.

[0082] To further analyze the corrosion mechanism of the coatings, equivalent circuit fitting was performed on each coating using Zview software, such as... Figure 3 As shown. Figure 3 Figure a in the diagram shows the fitted circuit for an epoxy resin coated aluminum alloy plate. Figure 3 Figure b shows the fitted circuit of the SiO2 / CuO@HDTMS superhydrophobic composite coating, and its fitting data can be found in Table 4. R0 s For the resistance of the solution, Cb C is the capacitance of the coating dl R is the double layer capacitance between the electrolyte and the interface c and R ct are the coating resistance and the solution charge transfer resistance, respectively. R ct is one of the important indicators for evaluating the corrosion rate, and its value is usually inversely proportional to the corrosion rate of the coating sample. As can be seen from Table 4, the R ct of the modified SiO2 / CuO@HDTMS superhydrophobic composite coating is much higher than that of bare aluminum alloy. This result shows that the barrier effect of the composite coating on the corrosion medium is significantly improved. The air in the coating can protect the substrate from the invasion of corrosion ions and inhibit the charge transfer between the corrosion medium and the substrate, thereby providing effective protection for the substrate.

[0083] Table 4 EIS fitting circuit parameters of different coatings

[0084]

[0085] (2) Tafel polarization curve is one of the important electrochemical analysis methods for judging the corrosion protection mechanism according to the corrosion current density and the corrosion potential. Figure 4 Tafel polarization curves of Comparative Example 1 and Example 2 after immersion in 3.5 wt.% NaCl solution for 24 h. Then, the corrosion efficiency η is calculated according to the polarization curve data and formula (1), and formula (1) is as follows:

[0086]

[0087] As can be seen from Table 4, compared with Comparative Example 1, the E coor of Example 2 is shifted from -0.67 V to 0.93 V, and the potential difference is 0.26 V, and the corrosion potential decreases; compared with Comparative Example 1, the I coor of Example 2 is reduced from 3.437 x 10 -5 A·cm -2 to 9.568 x 10 -7 A·cm -2 , and the corrosion current density is reduced by two orders of magnitude, and the protection efficiency is 97.22%. The smaller the corrosion current density, the better the corrosion resistance of the coating.

[0088] Table 4 Tafel polarization curve parameters of different samples in 3.5 wt.% NaCl solution

[0089] Sample I coor (Acm -2 )]]> E coor (V)]]> η Example 2 9.568 x 10 -7 ]] -0.93 / Comparative Example 1 3.437 x 10 -5 ]]> -0.67 97.22％

[0090] 6) Antibacterial ability

[0091] Co-culture and plate coating counting test. The bacteria solution was diluted to 105 CFU / mL. 32 mL of the diluted bacteria solution was added to the corresponding numbered disposable petri dish to submerge the sample. The petri dish was placed in a constant temperature incubator at 37°C and incubated for 72 h. Photographs were taken at 0 h; at 24 h, 48 h, the culture solution was aspirated and the sample was gently rinsed with 25 mL of PBS, then the PBS was aspirated, 25 mL of fresh LB medium was added and a photograph was taken; at 72 h, the culture solution was aspirated and the sample was gently rinsed with 25 mL of PBS, then the PBS was aspirated, 5 mL of PBS was used to rinse the residual bacteria solution at the non-sample area, then 25 mL of PBS medium was added and a photograph was taken. The co-culture solution was ultrasonically rinsed, 10-fold gradient dilution was performed with sterile PBS, and 100 μL of the dilution was uniformly spread on LB solid medium. The petri dish was placed in a constant temperature incubator at 37°C and incubated for 18 h, then taken out, photographed, and the number of bacteria was recorded.

[0092] The bacterial suspension flushed from different samples was diluted at a certain ratio and then cultured, and the number of bacteria of different samples was as follows Figure 5 As can be seen from Table 5, the antibacterial effect of Example 2 is the best, and the inhibition of bacteria is stronger. The "air cushion" of the super-hydrophobic coating surface hinders the direct contact of the bacterial solution and the surface of the coating, and the CuO in Comparative Example 2 also has a certain bactericidal ability. The antibacterial effect of the super-hydrophobic coating and CuO, the synergy of the two makes the coating have stronger bactericidal performance.

[0093] Table 5 antibacterial ability test of different samples

[0094] Group Number of colonies Dilution factor Total number of colonies Example 2 30 10 4 ]] 7.50 x 10 6 ]] Comparative Example 1 211 10 4 ]] 1.45 x 10 8 ]]> Comparative Example 2 58 10 4 ]] 5.28 x 10 7 ]]>

[0095] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should be considered as the protection scope of the present application.

Claims

1. A method for preparing a superhydrophobic self-cleaning aluminum alloy coating, characterized in that, The method comprises the following steps: (1) mixing and stirring anhydrous ethanol, deionized water, ammonia water and tetraethyl orthosilicate to react, collecting the solid to obtain nano-silicon dioxide; (2) performing hydrothermal reaction on the obtained nano-silicon dioxide, copper nitrate hydrate, polyethylene glycol, melamine, water and hydrogen peroxide, collecting the precipitate after the reaction to obtain nano-SiO2 / CuO composite particles; (3) modifying the obtained nano-SiO2 / CuO composite particles with hexadecyl trimethoxysilane (HDTMS) to obtain nano-SiO2 / CuO@HDTMS composite particles; (4) mixing the obtained nano-SiO2 / CuO@HDTMS composite particles with epoxy resin, curing agent and dimethylbenzene, and then performing spraying to obtain a super-hydrophobic self-cleaning coating.

2. The production method according to claim 1, characterized by, In the step (1), the volume ratio of anhydrous ethanol, deionized water, ammonia water and tetraethyl orthosilicate is (122-124):(41-43):(17-20):(6-9).

3. The preparation method according to claim 1, characterized in that, In the step (1), the stirring reaction temperature is 25-30℃, and the reaction time is 2-3h.

4. The method of claim 1, wherein, In the step (2), the weight ratio of copper nitrate hydrate, nano-silicon dioxide, polyethylene glycol, melamine, water and hydrogen peroxide is (3-4):(1-1.5):(0.5-1.2):(1.7-2.3):(11-14):(7-8).

5. The production method according to claim 1 or 4, characterized by, The concentration of the hydrogen peroxide is 25%-30%.

6. The method of claim 1, wherein, In the step (2), the hydrothermal reaction temperature is 180-200℃, and the hydrothermal reaction time is 10-12h.

7. The preparation method according to claim 1, characterized in that, The step (3) further comprises a solvent, which is ethanol and water.

8. The preparation method according to claim 7, characterized in that, The weight ratio of nano-silicon dioxide, nano-copper oxide, hexadecyl trimethoxysilane, ethanol and water is (1-4):(0.3-0.7):(1-4):(45-50):(8-12).

9. The method of claim 1, wherein, In the step (3), the reaction temperature for modification is 25-30℃, and the reaction time is 20-24h.

10. The super-hydrophobic self-cleaning aluminum alloy coating prepared by the method according to any one of claims 1-9.

Images