Photo-thermal self-repairing super-smooth coating and application thereof in field of magnesium alloy surface corrosion prevention

Abstract

The invention provides a photo-thermal self-repairing super-smooth coating and application of the photo-thermal self-repairing super-smooth coating in the field of magnesium alloy surface corrosion prevention. The photo-thermal self-repairing super-smooth coating is prepared by a method comprising the following steps: (1) adding nano ferroferric oxide, an amino silane coupling agent and simethicone into ethyl acetate, and uniformly stirring and mixing; (2) adding epoxy resin and paraffin into ethyl acetate, and uniformly stirring and mixing; and (3) mixing the solutions obtained in the step (1) and the step (2) to obtain the photo-thermal self-repairing super-smooth coating. The photo-thermal self-repairing super-smooth coating has the characteristics of high economy and simple and convenient preparation process, and can greatly improve the corrosion protection capability of the magnesium alloy and effectively prolong the service life of the magnesium alloy when being applied to corrosion prevention of the surface of the magnesium alloy.

Description

TECHNICAL FIELD

[0001] The present application relates to magnesium alloy coating technology, in particular to a photo-thermal self-repairing super-smooth coating and its application in the field of magnesium alloy surface corrosion protection. BACKGROUND

[0002] Magnesium alloy has important engineering applications in product lightweight material selection due to its low density, high specific strength and specific stiffness. However, magnesium alloy has a low electrode potential, so it is prone to corrosion in corrosive media, and compared with other metal materials such as aluminum alloy and steel, the corrosion product of magnesium alloy is loose and porous magnesium oxide, which does not have a dense structure and corrosion resistance similar to aluminum oxide. Therefore, the poor corrosion resistance of magnesium alloy is one of the important reasons for limiting its application in practical engineering applications, and the corrosion resistance of magnesium alloy in engineering applications still needs to be solved by surface coating protection.

[0003] Micro-arc oxidation treatment is an important technical method commonly used to improve the corrosion resistance of magnesium alloy. However, due to the inevitable generation of micropores and microcracks during micro-arc oxidation, corrosive media can easily corrode the substrate surface through micropores and microcracks, so further protection is generally needed to seal the micropores and microcracks on the surface of the micro-arc oxidation film.

[0004] Introducing a super-hydrophobic coating on the surface of micro-arc oxidation is one of the commonly used sealing methods, because the super-hydrophobic coating can not only seal the pores on the surface of micro-arc oxidation, but also prevent water droplets from staying on the surface of the micro-arc oxidation film for a long time. However, since the super-hydrophobic coating itself relies on a fragile micro-nano structure on the surface, this structure is easily damaged by the external environment, resulting in coating failure. This seriously affects the application potential of super-hydrophobic coatings in practical situations. SUMMARY

[0005] The purpose of the present application is to provide a photo-thermal self-repairing super-smooth coating that has the characteristics of high economy and simple preparation process, which can greatly improve the corrosion protection ability of magnesium alloy and effectively prolong the service life of magnesium alloy when applied to magnesium alloy surface corrosion protection.

[0006] It should be noted that in the present application, unless otherwise specified, the specific meaning of "including" involved in the composition limitation and description includes both open-ended "including", "containing" and the like, and closed "consisting of", "consisting of" and the like.

[0007] To achieve the above purpose, the technical solution adopted by the present application is: a photo-thermal self-repairing super-smooth coating prepared by the following method:

[0008] (1). Add nano-Fe3O4, amino silane coupling agent and dimethyl silicone oil (polydimethylsiloxane) into ethyl acetate and stir to mix uniformly;

[0009] (2). Add epoxy resin and paraffin into ethyl acetate and stir to mix uniformly;

[0010] (3). Mix the solutions obtained in steps (1) and (2) to obtain a light-heat self-repairing super-smooth coating.

[0011] The steps (1) and (2) have no sequence.

[0012] Further, in step (1), the mass ratio of the nano-Fe3O4, amino silane coupling agent, dimethyl silicone oil and ethyl acetate is 1.5-3:1-2:3-4:30-40. The present application can further improve the super-smooth and self-repairing ability of the super-smooth coating by controlling the ratio of the above raw materials.

[0013] Further, the amino silane coupling agent is γ-aminopropyl triethoxysilane (KH-550) and / or γ-(2,3-epoxypropoxy) propyl trimethoxysilane (KH-560).

[0014] Further, the particle size of the nano-Fe3O4 is 20-40 nm.

[0015] Further, the stirring speed in step (1) is 300-500 r / min, and the stirring time is 3-4 h.

[0016] Further, the mass ratio of the epoxy resin, paraffin and ethyl acetate in step (2) is 0.5-1:1-2:10-20.

[0017] Further, the stirring speed in step (2) is 300-500 r / min, and the stirring time is 10-12 h.

[0018] Further, the epoxy resin is one or more of epoxy resin E44, epoxy resin E51 and hydantoin epoxy resin.

[0019] Further, in step (3), the mass ratio of the solutions obtained in steps (1) and (2) is 1-2:1-2.

[0020] Preparation of the light-heat self-repairing super-smooth coating of the present application: first, graft dimethyl silicone oil to the surface of nano-Fe3O4 through a silane coupling agent; then, introduce the modified nano-Fe3O4 into epoxy resin to form a uniform mixed solution. The present application utilizes the excellent light-heat conversion performance of nano-Fe3O4 and the synergistic effect with paraffin to make the coating have light-heat responsive self-repairing ability.

[0021] Another object of the present application also discloses an application of the photo-thermal self-repairing super-smooth coating in the field of corrosion prevention on the surface of magnesium alloy. The photo-thermal self-repairing super-smooth coating can greatly improve the corrosion prevention ability of the magnesium alloy and prolong the service life of the magnesium alloy.

[0022] The magnesium-lithium alloy substrate has poor corrosion resistance, and corrosion occurs in 1 day in a salt spray test if no coating is applied. After the coating is applied, the corrosion resistance is significantly improved, and no corrosion occurs after 7 days of salt spray test. In this experiment, the impedance modulus is used to quantitatively analyze the corrosion resistance, and the results show that the impedance modulus of the coating sample is improved by about 5 orders of magnitude compared with the substrate. The salt spray test is usually used to simulate the actual working condition, and the test period is usually 7 days, so the test period of this experiment is also set to 7 days.

[0023] Another object of the present application also discloses a preparation method of the photo-thermal self-repairing corrosion prevention composite coating, comprising the following steps:

[0024] N1. Preparing a micro-arc oxidation film layer on the surface of the magnesium alloy;

[0025] N2. Coating the photo-thermal self-repairing super-smooth coating on the surface of the micro-arc oxidation film layer (micro-arc oxidation ceramic film layer), and standing for 24-36 h to obtain the photo-thermal self-repairing corrosion prevention composite coating.

[0026] Further, the magnesium alloy includes but is not limited to LA81 magnesium-lithium alloy or rare earth magnesium alloy WE43.

[0027] Further, the magnesium alloy in step N1 is pretreated before use; the pretreatment is sequentially polishing, cleaning and drying. Pretreating the magnesium alloy can remove stains and oxide layers on the surface of the magnesium alloy.

[0028] Further, the polishing sequentially uses 100#, 400#, 800#, 1500# and 2000# silicon carbide sandpaper.

[0029] Further, the cleaning is ultrasonic cleaning.

[0030] Further, the cleaning is sequentially ultrasonic cleaning with deionized water and alcohol.

[0031] Further, the drying is vacuum drying, which is performed by using a vacuum oven; the temperature of the vacuum oven is 50℃, and the vacuum degree is kept below 0.1 MPa.

[0032] Further, the step N1 of preparing the micro-arc oxidation film layer on the surface of the magnesium alloy comprises: immersing the magnesium alloy in an electrolyte and applying electricity, the alternating current voltage is 250-400 V, the pulse frequency is 400-500 Hz, the oxidation time is 3-5 min, and the oxidation temperature is 30-42℃.

[0033] Further, the electrolyte comprises the following components and concentrations: sodium hydroxide 7-9 g / L, sodium silicate 9-11 g / L, potassium fluoride 4-6 g / L, and deionized water.

[0034] Alternatively, the electrolyte comprises the following components and concentrations: potassium hydroxide 1-1.5 g / L, sodium silicate 6-7 g / L, potassium fluoride 3-4 g / L, and deionized water.

[0035] Further, the electrolyte preferably comprises the following components and concentrations: sodium hydroxide 8 g / L, sodium silicate 10 g / L, potassium fluoride 5 g / L, and deionized water.

[0036] Further, the thickness of the micro-arc oxidation film layer in step N1 is 15-30 μm.

[0037] Further, the coating amount of the photo-thermal self-repairing super-smooth coating in step N2 is 0.5-1 g / cm 2 .

[0038] Further, the thickness of the photo-thermal self-repairing corrosion-resistant composite coating in step N2 is 20-40 μm.

[0039] Another object of the present application also discloses a photo-thermal self-repairing corrosion-resistant composite coating prepared by the above method.

[0040] In practical applications, the micro-arc oxidation film layer will inevitably have pores or damage due to external force, affecting its performance and service life. To solve this problem, the present application introduces a self-repairing super-smooth coating on the surface of the micro-arc oxidation film layer for pore sealing. Although traditional self-repairing coatings can cope with external damage, they mostly rely on thermal stimulation to achieve repair, and their use is limited. As a green and pollution-free choice, photo-thermal materials provide a new direction for self-repairing coating technology. Based on this, the present application innovatively introduces ferroferric oxide nanoparticles and paraffin while constructing a super-smooth structure, endowing the coating with photo-thermal self-repairing ability and significantly improving the durability of the substrate alloy. Ferroferric oxide has excellent photo-thermal performance, and paraffin is a commonly used phase change self-repairing material. Both of them not only have low cost and wide sources, but also have good synergistic effect, effectively improving the self-repairing performance of the coating and significantly enhancing the practicality and economy of the technology

[0041] The photo-thermal self-repairing super-smooth coating and its application in the field of corrosion prevention on the surface of magnesium alloy have the following advantages compared with the prior art:

[0042] 1) The photothermal self-repairing super-slick coating formula of the present application is scientific and reasonable, and can form a long-term corrosion-resistant composite coating on the surface of magnesium alloy. The synergistic effect of the porous structure of the micro-arc oxidation surface and the phase change characteristics of the photothermal self-repairing coating makes the composite coating have excellent bonding strength; the physical barrier effect of the micro-arc oxidation film layer and the super-slick performance of the photothermal self-repairing super-slick coating are tightly coupled, and together give the composite coating excellent long-term corrosion resistance.

[0043] 2) The photothermal self-repairing corrosion-resistant composite coating on the surface of magnesium alloy has a double protection mechanism: on the one hand, the micro-arc oxidation film layer is treated by sealing, which significantly improves the corrosion resistance of the substrate alloy; on the other hand, its unique photothermal self-repairing property can automatically repair the damaged part of the coating under sunlight, effectively preventing the magnesium alloy substrate from being directly exposed to the corrosion environment. This double protection mechanism makes the coating have significant application advantages in the field of engineering corrosion protection, and provides an innovative solution for the corrosion protection of magnesium alloy.

[0044] The photothermal self-repairing super-slick coating of the present application is a material surface corrosion-resistant coating material, and has good application prospect and large-scale promotion potential in the field of magnesium alloy surface corrosion protection. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 A is the optical microscope picture of the micro-arc oxidation film layer in Example 1; Figure 1 B is the optical microscope picture of the photothermal self-repairing corrosion-resistant composite coating in Example 1.

[0046] Figure 2 A is the static contact angle picture of the photothermal self-repairing corrosion-resistant composite coating in Example 1; 2B-F are the rolling angle pictures of the photothermal self-repairing corrosion-resistant composite coating.

[0047] Figure 3 The impedance values of the photothermal self-repairing corrosion-resistant composite coating before damage, after damage and after self-repairing.

[0048] Figure 4 A is the photo of the photothermal self-repairing corrosion-resistant composite coating under natural light, Figure 4 B and 4C are the comparison photos before and after self-repairing, respectively. DETAILED DESCRIPTION

[0049] Hereinafter, the present application will be further described in conjunction with examples. The description of the technical features described below is based on representative embodiments, specific examples of the present application, but the present application is not limited to these embodiments, specific examples. It should be noted that:

[0050] The units used in the specification are international standard units unless otherwise specified, and the numerical values, numerical ranges appearing in the present application should be understood to include inevitable systematic errors in industrial production.

[0051] In the specification, the numerical range indicated using "numerical value A to numerical value B" means a range including the end point numerical values A and B.

[0052] In the specification, the numerical range indicated using "above" or "below" means a numerical range including the number.

[0053] In the specification, the meaning indicated using "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0054] In the specification, "optional" or "optionally" means that the use or non-use of certain substances, components, execution steps, applied conditions, and the like factors.

[0055] In the specification, when "room temperature" or "room temperature" is used, the temperature can be 15-25℃.

[0056] In the specification, the reagents or instruments used without specifying the manufacturer are all conventional products that can be obtained by purchase.

[0057] The present application will be further illustrated by the following examples, but is not limited to the following examples.

[0058] Example 1:

[0059] This example discloses a photothermal self-repairing super-smooth coating prepared by the following method:

[0060] (1) Fe3O4 nanoparticles (particle size 20-40 nm), silane coupling agent KH550 and dimethyl silicone oil are simultaneously added to ethyl acetate and stirred to mix uniformly, and the mass ratio of Fe3O4, silane coupling agent, dimethyl silicone oil and ethyl acetate is 1.5:1:3:30.

[0061] (2) Epoxy resin E44 and paraffin are dissolved in ethyl acetate solution, and the mass ratio of epoxy resin E44, paraffin and ethyl acetate is 0.5:1:10.

[0062] (3) The solutions obtained in steps (1) and (2) are mixed and stirred to obtain a photothermal self-repairing super-smooth coating, wherein the mass of the epoxy resin is twice that of the nano-Fe3O4.

[0063] The steps of preparing a photothermal self-repairing corrosion-resistant composite coating on the surface of a magnesium alloy using the photothermal self-repairing super-smooth coating are as follows:

[0064] N1. The LA81 magnesium-lithium alloy is polished with 100#, 400#, 800#, 1500# and 2000# silicon carbide sandpaper in sequence, and then the surface of the LA81 magnesium-lithium alloy is ultrasonically cleaned with deionized water and alcohol in sequence to achieve the purpose of degreasing and decontamination, and then the LA81 magnesium-lithium alloy is placed in a 50℃ oven for drying.

[0065] N2. The magnesium-lithium alloy obtained in step N1 is subjected to micro-arc oxidation to prepare a micro-arc oxidation film layer on the surface; wherein the micro-arc oxidation film layer is prepared using a silicate electrolyte system containing components and contents of sodium hydroxide 8g / L, sodium silicate 10g / L, potassium fluoride 5g / L and deionized water, and the process parameters of the micro-arc oxidation method are 250V alternating current, 400Hz pulse frequency, oxidation time 3min, and oxidation temperature 30℃, and then the surface is cleaned with deionized water and alcohol in sequence, and dried in a 50℃ oven to obtain a micro-arc oxidation film layer with a thickness of 15μm;

[0066] N3. The photo-thermal self-repairing super-smooth coating is coated on the surface of the micro-arc oxidation film layer prepared in N2 at a rate of 0.5g / cm 2 The photo-thermal self-repairing corrosion-resistant composite coating is obtained after standing for 24h.

[0067] Example 2:

[0068] This embodiment discloses a photo-thermal self-repairing super-smooth coating prepared by the following method:

[0069] (1) Fe3O4 nanoparticles (particle size 20-40nm), silane coupling agent KH550 and dimethyl silicone oil are simultaneously added to ethyl acetate and stirred to mix uniformly, and the mass ratio of the Fe3O4, silane coupling agent, dimethyl silicone oil and ethyl acetate is 1.5:1:3:30.

[0070] (2) Epoxy resin E44 and paraffin are dissolved in ethyl acetate solution, and the mass ratio of the epoxy resin E44, paraffin and ethyl acetate is 0.5:1:10.

[0071] (3) The solutions obtained in steps (1) and (2) are mixed and stirred to obtain the photo-thermal self-repairing super-smooth coating, wherein the mass of the epoxy resin is twice that of the nano-Fe3O4.

[0072] The steps of preparing a photo-thermal self-repairing corrosion-resistant composite coating on the surface of a magnesium alloy using the photo-thermal self-repairing super-smooth coating are as follows:

[0073] N1. The rare earth magnesium alloy WE43 is polished with 100#, 400#, 800#, 1500# and 2000# silicon carbide sandpaper in sequence, and then the surface of the rare earth magnesium alloy is ultrasonically cleaned with deionized water and alcohol in sequence to achieve the purpose of degreasing and decontamination, and then the rare earth magnesium alloy is placed in a 50℃ oven for drying.

[0074] N2. The rare earth magnesium alloy obtained in N1 is subjected to micro-arc oxidation to prepare a micro-arc oxidation film layer on the surface; wherein the micro-arc oxidation film layer is prepared using a silicate electrolyte system containing components and contents of sodium hydroxide 8g / L, sodium silicate 10g / L, potassium fluoride 5g / L and deionized water, and the process parameters of the micro-arc oxidation method are an alternating current of 250V, a pulse frequency of 400Hz, an oxidation time of 3min, and an oxidation temperature of 30℃, and then the micro-arc oxidation film layer is cleaned with deionized water and alcohol in sequence and dried in a 50℃ oven to obtain a micro-arc oxidation film layer with a thickness of 15μm;

[0075] N3. The photo-thermal self-repairing super-smooth coating is coated on the surface of the micro-arc oxidation film layer prepared in N2 at a coating amount of 0.5g / cm 2 The photo-thermal self-repairing corrosion-resistant composite coating is obtained after standing for 24h.

[0076] Example 3:

[0077] The present embodiment discloses a photo-thermal self-repairing super-smooth coating prepared by the following method:

[0078] (1) Fe3O4 nanoparticles (particle size 20-40nm), silane coupling agent KH550 and dimethyl silicone oil are simultaneously added to ethyl acetate and stirred to mix uniformly, and the mass ratio of the Fe3O4, silane coupling agent, dimethyl silicone oil and ethyl acetate is 3:2:4:40.

[0079] (2) Epoxy resin E44 and paraffin are dissolved in ethyl acetate solution, and the mass ratio of the epoxy resin E44, paraffin and ethyl acetate is 0.5:1:10.

[0080] (3) The solutions obtained in steps (1) and (2) are mixed and stirred to obtain the photo-thermal self-repairing super-smooth coating, wherein the mass of the epoxy resin is twice that of the nano-Fe3O4.

[0081] The steps of preparing a photo-thermal self-repairing corrosion-resistant composite coating on the surface of a magnesium alloy using the photo-thermal self-repairing super-smooth coating are as follows:

[0082] N1. The rare earth magnesium alloy WE43 is polished with 100#, 400#, 800#, 1500# and 2000# silicon carbide sandpaper in sequence, and then the surface of the rare earth magnesium alloy is ultrasonically cleaned with deionized water and alcohol in sequence to achieve the purpose of degreasing and decontamination, and then the rare earth magnesium alloy is placed in a 50℃ oven for drying.

[0083] N2. The rare earth magnesium alloy obtained in N1 is subjected to micro-arc oxidation to prepare a micro-arc oxidation film layer on the surface; wherein the micro-arc oxidation film layer is prepared by using a silicate electrolyte system containing sodium hydroxide 8 g / L, sodium silicate 10 g / L, potassium fluoride 5 g / L and deionized water, and the process parameters of the micro-arc oxidation method are 250 V alternating current, 400 Hz pulse frequency, 3 min oxidation time, and 30℃ oxidation temperature, and then the micro-arc oxidation film layer is cleaned with deionized water and alcohol in sequence, dried in a 50℃ oven, and a micro-arc oxidation film layer with a thickness of 15 μm is obtained;

[0084] N3. The photo-thermal self-repairing super-smooth coating is coated on the surface of the micro-arc oxidation film layer prepared in N2 at a thickness of 0.5 g / cm 2 After standing for 24 h, a photo-thermal self-repairing corrosion-resistant composite coating is obtained.

[0085] Comparative Example:

[0086] In order to evaluate the effect of the photo-thermal self-repairing corrosion-resistant composite coating in the present application, the following comparative example is provided, i.e. a solid-like super-smooth composite coating without ferroferric oxide nanoparticles and paraffin is used as the comparative example. The preparation steps of the comparative example are as follows:

[0087] Preparation of the magnesium alloy sample in the comparative example:

[0088] The LA81 magnesium-lithium alloy is only subjected to micro-arc oxidation treatment (the micro-arc oxidation treatment method is the same as that in Example 1). The surface of the alloy is not coated with the photo-thermal self-repairing super-smooth coating, i.e. a solid-like super-smooth coating without ferroferric oxide nanoparticles and paraffin.

[0089] The photo-thermal self-repairing corrosion-resistant composite coatings of Examples 1-3 and the coating of the comparative example are tested respectively, and the testing methods and testing results are as follows:

[0090] Corrosion resistance test: the magnesium alloy sample of the comparative example and the magnesium alloy sample treated with the composite coating of Example 1 are simultaneously exposed to a corrosion medium, and the corrosion rate and the formation of corrosion products are recorded.

[0091] Result comparison: the efficiency of the composite coating of the present application is evaluated by comparing the corrosion rate, the morphology and amount of corrosion products, and the durability and self-repairing ability of the coatings of the magnesium alloy samples in the comparative example and Example 1. The corrosion degree of the two samples in the same time, including the weight loss and the surface morphology change, is recorded and analyzed.

[0092] Figure 1 A is the optical microscope image of the micro-arc oxidation film layer in Example 1. From the image, it can be seen that the surface of the micro-arc oxidation film layer is smooth and uniform, and the coating is not cracked or peeled off. Figure 1It can be seen that the micro-arc oxidation film layer coating surface is a volcanic hole structure, and the holes are distributed with micro-cracks of different sizes, which is not conducive to the long-term corrosion prevention of the coating. The solid-like super-smooth anti-corrosion composite coating prepared by vacuum adsorption has no hole structure, which is conducive to its long-term corrosion prevention.

[0093] Figure 1 B is the optical microscope picture of the light-heat self-repairing anti-corrosion composite coating in Example 1. It can be seen that the micro-arc oxidation hole is covered by the light-heat self-repairing super-smooth coating.

[0094] Figure 2 A is the water droplet static contact angle picture of the light-heat self-repairing super-smooth anti-corrosion composite coating in Example 1. 2B-F are the sliding angle pictures of the light-heat self-repairing anti-corrosion composite coating. From Figure 2 As can be seen from A, the static contact angle of the self-repairing solid-like super-smooth coating is greater than 90°, from Figure 2 As can be seen from B-F, the sliding angle is less than 10°, meeting the requirements of the static contact angle and dynamic contact angle in the definition of super-smooth.

[0095] As can be seen from A, the static contact angle of the self-repairing solid-like super-smooth coating is greater than 90°, from Figure 3 It can be seen that the modulus of the light-heat self-repairing super-smooth anti-corrosion composite coating prepared by the present application is the largest, and the corrosion resistance is the best. Compared with the LA81 magnesium-lithium alloy bare substrate, it can be improved by six orders of magnitude, indicating that the coating has excellent corrosion resistance. After scratching, the impedance value returns to the level of the bare substrate, and after self-repairing, the impedance value is improved by three orders of magnitude.

[0096] Figure 4 A is the electronic photo of the light-heat self-repairing anti-corrosion composite coating placed in the natural environment, combined with Figure 4 B-C can be seen that the light-heat self-repairing super-smooth anti-corrosion composite coating prepared by the present application can be self-repaired under natural light, and the scratches can be self-healed under sunlight.

[0097] In summary, the comparative example magnesium alloy sample shows a faster corrosion rate and more corrosion products, while the magnesium alloy sample of Example 1 exhibits significantly improved corrosion resistance and self-repairing ability. The present application prepares a micro-arc oxidation film layer on the surface of the magnesium alloy, which can effectively resist the erosion of corrosive media in a corrosive environment. At the same time, the micro-arc oxidation film layer with micro-porous structure can provide pinning sites for the light-heat self-repairing super-smooth coating, so that the micro-arc oxidation film layer and the self-repairing super-smooth coating form a mechanical chain, improving the adhesion of the coating. At the same time, the light-heat self-repairing super-smooth coating has phase change characteristics, and in the initial state, it is in a liquid phase, which can better immerse the porous structure of the micro-arc oxidation. By vacuum adsorption, the capillary action of the micro-pores is reduced, further improving the adhesion of the composite coating.

[0098] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A photothermal self-repairing super-slip coating, characterized in that: Prepared by the following method: (1) Add nano-ferroferric oxide, aminosilane coupling agent and dimethyl silicone oil to ethyl acetate and stir to mix evenly; (2) Add epoxy resin and paraffin wax to ethyl acetate and stir to mix evenly; (3) The solutions obtained in step (1) and step (2) are mixed to obtain a photothermal self-repairing super-slip coating.

2. The photothermal self-repairing super-slip coating according to claim 1, characterized in that: The mass ratio of the nano-ferrosoferric oxide, aminosilane coupling agent, dimethyl silicone oil and ethyl acetate in step (1) is 1.5-3:1-2:3-4:30-40; And / or, the aminosilane coupling agent is γ-aminopropyltriethoxysilane and / or γ-(2,3-epoxypropoxy)propyltrimethoxysilane; And / or, the particle size of the nano-ferrosoferric oxide is 20 to 40 nanometers.

3. The photothermal self-repairing super-slip coating according to claim 1, characterized in that: The mass ratio of the epoxy resin, paraffin wax and ethyl acetate in step (2) is 0.5-1:1-2:10-20; And / or, the epoxy resin is one or more of epoxy resin E44, epoxy resin E51 and hydantoin epoxy resin.

4. The photothermal self-repairing super-slip coating according to claim 1, characterized in that: In step (3), the mass ratio of the solutions obtained in step (1) to those obtained in step (2) is 1-2:1-2.

5. An application of the photothermal self-repairing super-slip coating according to any one of claims 1 to 4 in the field of corrosion protection of magnesium alloy surfaces.

6. A method for preparing a photothermal self-repairing anti-corrosion composite coating, characterized in that: The following steps are involved: N1. Preparation of micro-arc oxidation film on magnesium alloy surface; N2. Apply the photothermal self-repairing super-slip coating described in any one of claims 1 to 4 to the surface of the micro-arc oxidation film layer, and let it stand for 24 to 36 hours to obtain a photothermal self-repairing anti-corrosion composite coating.

7. The method for preparing the photothermal self-repairing anti-corrosion composite coating according to claim 6, characterized in that: The step N1 of preparing a micro-arc oxidation film on the surface of the magnesium alloy includes: immersing the magnesium alloy in an electrolyte and applying power, wherein the AC voltage is 250-400V, the pulse frequency is 400-500Hz, the oxidation time is 3-5min, and the oxidation temperature is 30-42°C.

8. The method for preparing the photothermal self-repairing anti-corrosion composite coating according to claim 7, characterized in that: The electrolyte comprises the following components and concentrations: sodium hydroxide 7-9 g / L, sodium silicate 9-11 g / L, potassium fluoride 4-6 g / L and deionized water; Alternatively, the electrolyte comprises the following components and concentrations: 1-1.5 g / L potassium hydroxide, 6-7 g / L sodium silicate, 3-4 g / L potassium fluoride and deionized water.

9. The method for preparing the photothermal self-repairing anti-corrosion composite coating according to claim 6, characterized in that: The thickness of the micro-arc oxidation film layer in step N1 is 15 to 30 μm; And / or, the thickness of the photothermal self-repairing anti-corrosion composite coating in step N2 is 20-40 μm.

10. A photothermal self-repairing anti-corrosion composite coating, prepared by the method according to any one of claims 6 to 9.

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