Corrosion-resistant graphene aerogel coating and use method thereof

Abstract

The invention discloses a corrosion-resistant graphene aerogel coating and a use method thereof. The use method comprises the following steps: 1, selecting polyvinyl alcohol with the alcoholysis degree of 85-99%; 2, polyvinyl alcohol is weighed and added into ultrapure water, and a polyvinyl alcohol solution with the concentration being 0.5-5.0 g / ml is prepared; 3, pouring out the prepared solution, and cooling the polyvinyl alcohol solution to room temperature; 4, pouring 1mg-10mg / ml of the graphene oxide solution into the cooled polyvinyl alcohol solution, and stirring to completely separate the graphene oxide into the polyvinyl alcohol solution; 5, stirring the solution to uniformly disperse all solutes; and 6, adding polyethylene glycol diglycidyl ether into the obtained solution, so that the polyethylene glycol diglycidyl ether and the polyvinyl alcohol are crosslinked to form gel. The graphene aerogel coating disclosed by the invention not only can effectively make up the defects of the existing coating technology, but also can improve the corrosion resistance in multiple aspects.

Description

Technical Field

[0001] The present invention relates to the technical field of new material coatings, and particularly to a corrosion-resistant graphene aerogel coating and its usage method. Background Art

[0002] Currently, the most widely used coating in the market is the micro-arc oxidation (MAO) coating. It is a treatment technology widely applied to the surfaces of materials such as aluminum alloys, titanium alloys, and magnesium alloys in recent years, with strong wear resistance, high temperature resistance, and good corrosion protection performance. Although the micro-arc oxidation coating has achieved good application effects in some fields, there are still some obvious drawbacks, mainly reflected in the following aspects: 1. The main feature of the micro-arc oxidation coating is its high hardness, but its brittleness is also relatively strong. Especially when processing substrates with complex shapes, the coating is prone to cracking or peeling. This is because tiny pores and cracks are generated during the micro-arc oxidation process. Although these pores help improve the adhesion of the coating, they also lead to the brittleness of the coating and reduce its stability under impact and friction. Therefore, the micro-arc oxidation coating has poor durability when facing relatively harsh working environments. 2. The thickness of the micro-arc oxidation coating is usually not easily controlled uniformly. In practical applications, the thickness of the coating is often affected by factors such as the surface state of the substrate, current density, and processing time, resulting in non-uniformity of the coating thickness. Especially on substrates with complex geometric shapes, the coating is prone to local over-thickness or under-thickness, which will affect the overall performance of the coating and reduce its corrosion resistance and wear resistance. 3. During the production process of the micro-arc oxidation coating, high voltage and current are required, consuming a large amount of electrical energy, and the process equipment and processing process are relatively complex. Therefore, its production cost is relatively high. In addition, the formation time of the micro-arc oxidation coating is relatively long, and repeated processing is required during the formation process, which further increases the overall cost. 4. The micro-arc oxidation coating is mainly applicable to light metal materials such as aluminum alloys, titanium alloys, and magnesium alloys. For some highly corrosive environments, such as acidic and strongly alkaline environments, its corrosion resistance still has certain limitations. Although the micro-arc oxidation coating has good protection performance in some neutral and weak acid environments, its anti-corrosion effect is still insufficient under relatively harsh working conditions. 5. Although the micro-arc oxidation coating can obtain different surface effects of different colors by adjusting process parameters, due to the structural characteristics of the coating, there are often obvious pores and textures on its surface, which limits its application in some high-end decorative uses. Moreover, the smoothness and uniformity of the coating surface are relatively poor, affecting the aesthetics of the coating. Summary of the Invention

[0003] The purpose of the present invention is to provide a corrosion-resistant graphene aerogel coating. By combining graphene with aerogel, it can not only significantly improve the corrosion resistance of the aerogel, but also enhance its mechanical strength, thermal stability, and multifunctionality.

[0004] The above technical objectives of the present invention are achieved through the following technical solutions: A corrosion-resistant graphene aerogel coating, comprising the following steps:

[0005] Step 1: Select polyvinyl alcohol with an alcoholysis degree of 85-99%.

[0006] Step 2: Weigh polyvinyl alcohol and add it to ultrapure water to prepare a polyvinyl alcohol solution with a concentration of 0.5-5.0 g / ml.

[0007] Step 3: Pour out the solution prepared in Step 2 and let the polyvinyl alcohol solution cool to room temperature.

[0008] Step 4: Pour a 1 mg-10 mg / ml graphene oxide solution into the cooled polyvinyl alcohol solution and stir to completely disperse the graphene oxide in the polyvinyl alcohol solution.

[0009] Step 5: Stir the solution in Step 4 to evenly disperse all the solutes.

[0010] Step 6: Add polyethylene glycol diglycidyl ether to the solution obtained in Step 5 to crosslink the polyethylene glycol diglycidyl ether with polyvinyl alcohol to form a gel.

[0011] Further preferably, in Step 2, the solution is stirred and prepared at 70-95 °C.

[0012] Further preferably, in Step 4, a sodium hydroxide solution is used to adjust the pH of the liquid to make the solution neutral.

[0013] Further preferably, in Step 6, after adding polyethylene glycol diglycidyl ether, the solution is stirred at a temperature of 30-90 °C.

[0014] The present invention also discloses a method for using a corrosion-resistant graphene aerogel coating, comprising the following steps:

[0015] Step 1: Grind the surface of the substrate and place it at room temperature in a dry place for later use.

[0016] Step 2: Drop the prepared aerogel coating onto the surface of the ground substrate. After it is in complete contact with the substrate surface, the whole is moved into a freeze dryer so that the aerogel coating is coated on the surface of the substrate.

[0017] In summary, the present invention has the following beneficial effects:

[0018] 1. Graphene aerogel coatings have extremely strong corrosion resistance, especially outstanding performance in harsh environments such as strong acids, strong alkalis, and seawater. Graphene itself has very high chemical stability, which can effectively prevent the penetration of corrosion media such as moisture and salts.

[0019] 2. The high porosity of the aerogel coating enables the coating surface to adsorb and isolate corrosive substances, reducing the damage of corrosion media to the substrate. The two-dimensional structure and high specific surface area of graphene also endow the coating with a more solid protective film, effectively delaying the occurrence and expansion of corrosion.

[0020] 3. The low density of graphene aerogel coatings makes them extremely light, which gives them significant advantages in fields such as aerospace and marine that require lightweight. Despite the light weight of the coating, due to the high strength of graphene and the unique structure of the aerogel, the coating can still provide excellent mechanical strength and wear resistance to meet high-strength protection requirements.

[0021] 4. The preparation process of graphene aerogel coating materials is relatively environmentally friendly, avoiding the use of toxic substances and solvents that may exist in traditional coatings. Graphene and aerogel materials themselves also have good sustainability and do not release harmful gases or chemical substances during use. Therefore, graphene aerogel coatings meet the current requirements of environmental protection and can effectively reduce environmental pollution.

[0022] 5. High graphene aerogel coatings have good adhesion and can firmly adhere to metal substrates, avoiding problems such as coating peeling or falling off. Due to its uniform pore structure and nanoscale coating technology, the aerogel coating can form a uniform and stable coating surface, avoiding the phenomenon of uneven thickness in traditional coatings. In addition, the graphene aerogel coating has a relatively high surface smoothness, which can not only improve the aesthetics of the coating but also reduce surface friction and enhance wear resistance.

[0023] 6. Graphene aerogel coatings can not only resist chemical corrosion but also have strong electrochemical stability. In electrolyte solutions such as sodium chloride solution, graphene aerogel coatings can effectively prevent the occurrence of electrochemical reactions on metal substrates and avoid the occurrence of corrosion cell effects. This makes graphene aerogel coatings particularly suitable for applications such as ocean engineering and chemical reactors that require prevention of electrochemical corrosion.

[0024] 7. Graphene aerogel coatings not only have basic properties such as corrosion resistance, high temperature resistance, and wear resistance but can also be functionally customized according to different requirements. Description of the Drawings

[0025] Figure 1 is the surface morphology diagram of the aerogel coating;

[0026] Figure 2It is a comparison of the hydrogen release rates of magnesium alloy sheets and micro-arc oxidized aerogel coatings in sodium chloride solution;

[0027] Figure 3 It is the hydrophilicity test result of this aerogel. Specific implementation manners

[0028] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below in conjunction with embodiments. Those skilled in the art will understand that the following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention.

[0029] Embodiment 1

[0030] A corrosion-resistant graphene aerogel coating, comprising the following steps:

[0031] Step 1. First, we need to select polyvinyl alcohol with an alcoholysis degree of 85-99%. This is the first key step in preparing the aerogel, and selecting a suitable polyvinyl alcohol material.

[0032] Step 2. Weigh polyvinyl alcohol and pour it into the prepared ultrapure water, and stir at 70-95°C to prepare a polyvinyl alcohol solution with a concentration of 0.5-5.0 g / ml.

[0033] Step 3. Pour out the solution prepared in Step 2, and wait for the polyvinyl alcohol solution to cool to room temperature. This is to slow down the molecular movement and slow down the reaction of the solute.

[0034] Step 4. We need to take out graphene oxide. Pour 10 ml of a graphene oxide solution with a concentration of 1 mg-10 mg / ml into the cooled polyvinyl alcohol solution, and stir to completely disperse the graphene oxide in the polyvinyl alcohol solution. At the same time, it is necessary to use 1 M sodium hydroxide solution to adjust the pH of the liquid to make the solution neutral, to prevent the solution itself from corroding the magnesium alloy sheet in an acidic or alkaline environment.

[0035] Step 5. Stir the solution in Step 4 to make all the solutes disperse evenly, to prevent the phenomenon of uneven diffusion of solutes during the formation of the aerogel.

[0036] Step 6: Add polyethylene glycol diglycidyl ether to the solution obtained in Step 5. This is a crucial step in turning the solution into a gel. This uses the chemical cross-linking method to cross-link polyethylene glycol diglycidyl ether with polyvinyl alcohol to form a gel. After adding polyethylene glycol diglycidyl ether, set the temperature of the solution between 30 - 90°C and stir to accelerate molecular movement, enabling better cross-linking between polyethylene glycol diglycidyl ether and polyvinyl alcohol. Polyethylene glycol diglycidyl ether can improve the anti-corrosion performance of the aerogel when the aerogel is formed.

[0037] Example 2

[0038] A method for using a corrosion-resistant graphene aerogel coating, comprising the following steps:

[0039] Step 1: Preparation of the coating substrate. First, the required magnesium alloy sheet needs to be polished. Use different sandpapers (such as 180#, 320#, 1200# sandpapers) to polish the magnesium alloy sheet. This is to enable the coating to better contact the surface of the magnesium alloy sheet, thus having a larger contact area and allowing the coating to further adhere to the magnesium alloy material. Place the polished magnesium alloy sheet at room temperature in a dry place for later use.

[0040] Step 2: Drop the prepared liquid onto the surface of the prepared magnesium alloy sheet. After it is in complete contact with the surface of the magnesium alloy sheet, transfer the whole into a freeze-drying oven. This is to evaporate the liquid in the solution, making the prepared aerogel coating coated on the surface of the magnesium alloy sheet to achieve the anti-corrosion effect.

[0041] Figure 1 Shows a material with a complex microstructure on its surface, whose morphology is composed of flaky, wrinkled, and fine granular features. This irregular microstructure indicates that the material may have undergone special surface treatment or a self-forming nano-scale growth mechanism, thus showing certain advantages in terms of anti-corrosion performance. The flaky structure on the surface of the material forms a tightly interlaced barrier layer that can effectively prevent the penetration of corrosive media. The fine particles in the microstructure can enhance the anti-corrosion performance of the material. These particles may be composed of specific anti-corrosion compounds, such as oxides, sulfides, or other substances with higher stability, which can form a protective film to improve the material's tolerance to acid-base, moisture, or salt spray environments. In addition, the high specific surface area of this surface may improve the adhesion of the anti-corrosion coating, making the coating more stable and durable.

[0042] Figure 1The presented material morphology indicates its great advantages in terms of anti-corrosion performance. The dense microstructure can provide a barrier effect to inhibit the intrusion of corrosive media. Meanwhile, the complexity of the surface morphology may also contribute to enhancing the durability of the material, making it suitable for application scenarios requiring high anti-corrosion performance, such as marine environments, chemical equipment, or metal substrates exposed to harsh environments for a long time.

[0043] This invention includes two core technologies (exponentially reducing the hydrogen release rate and hydrophilicity). Compared with the corresponding prior art, the specific advantages are described as follows:

[0044] 1. Exponentially reducing the hydrogen release rate

[0045] Magnesium is an active metal that easily loses electrons to form magnesium ions. This active property makes magnesium prone to electrochemical reactions in water or aqueous solutions. When magnesium comes into contact with a sodium chloride solution, the electrons on the surface of the magnesium metal are attracted by the water or chloride ions in the solution, leading to the oxidation of the magnesium metal. The reaction to generate hydrogen occurs on the surface of the magnesium metal. Hydrogen ions (H+) in water react with the electrons lost by magnesium to produce hydrogen:

[0046] 2H + (aq) + 2e - →H2(g)

[0047] This reaction causes bubbles (hydrogen) to escape from the surface of the magnesium metal, thus forming the hydrogen we observe.

[0048] Therefore, observing the hydrogen release rate is a key technology for studying anti-corrosion coatings.

[0049] The following is a comparison of the hydrogen release rates of magnesium alloy sheets, commercially available micro-arc oxidation coatings, and newly prepared aerogel coatings. It can be seen that the aerogel coating can exponentially reduce the hydrogen release rate of magnesium alloy sheets, indicating the unique anti-corrosion effect of this aerogel coating.

[0050] Figure 2 It shows the trend of the volume of hydrogen evolution varying with time during the immersion process of different materials, indicating their corrosion resistance in a corrosive environment. The vertical axis represents the volume of hydrogen evolution per unit area, and the horizontal axis represents the immersion time (h). The figure includes the test results of three different materials: WE43 (black squares), MAO (green triangles), and aerogel (blue diamonds).

[0051] As can be seen from the figure, the hydrogen evolution rate of the WE43 alloy is the highest and increases rapidly within 24 hours, indicating that a severe corrosion reaction has occurred in the immersion environment. A large amount of hydrogen evolution means that the material has suffered serious metal dissolution during corrosion and has poor corrosion resistance.

[0052] In contrast, the hydrogen evolution rate of the MAO sample decreased significantly. Although there was still a certain amount of hydrogen evolution within the first 24 hours, it then tended to stabilize. This indicates that the MAO coating can inhibit the corrosion of the substrate metal to a certain extent, but there is still a certain degree of corrosion activity. The aerogel coating sample exhibited the best corrosion resistance, with the hydrogen evolution volume remaining at an extremely low level throughout the immersion process and showing almost no obvious increase. This shows that the aerogel coating forms an extremely effective barrier on the material surface, which can effectively prevent the penetration of corrosive media (such as water and oxygen), thereby greatly reducing the corrosion rate of the material.

[0053] In summary, Figure 2 it shows that the aerogel coating significantly improves the corrosion resistance of the material, while the untreated WE43 alloy exhibits poor corrosion resistance. MAO treatment enhances the corrosion resistance to a certain extent, but it is still not as ideal as the Aerogel coating. Therefore, the aerogel coating may be a highly potential anti-corrosion technology, suitable for application scenarios with high requirements for corrosion resistance, such as biomedical implants or structural materials in marine environments.

[0054] 2. Hydrophilicity

[0055] The prepared aerogel coating is a highly hydrophilic coating material. This hydrophilicity can help reduce water accumulation and lower the corrosion risk. Principle: Hydrophilicity refers to the ability of a material to attract and interact with water molecules. The hydrophilicity of the aerogel coating enables its surface to adsorb water instead of allowing water to stay on the surface. This means that water will be "absorbed" into the coating structure rather than accumulating into water droplets or water films. Traditional coatings sometimes form water films, especially in humid environments, and these water films can act as catalysts for corrosion reactions. Through the hydrophilicity of the aerogel, water is effectively dispersed or adsorbed, reducing the chance of water accumulation, thereby lowering the corrosion risk caused by water retention on the surface of metals or other substrates. By adsorbing water, the aerogel coating avoids the long-term presence of water on the surface, thus effectively reducing the probability of corrosion.

[0056] Figure 3 The results of a contact angle measurement experiment are shown, indicating the wettability of the liquid droplet on the material surface. The image shows a liquid droplet deposited on the solid surface, and its contact angle is measured optically. Judging from the size of the contact angle, the material surface shows a certain degree of hydrophilicity towards the liquid. Generally, a contact angle less than 90° indicates that the material is hydrophilic, while a contact angle greater than 90° means hydrophobicity. Figure 3The contact angle of the liquid droplets is approximately 30°, indicating that the liquid can spread well on the surface, suggesting that the surface energy of the material is relatively high and the interaction with the liquid is strong. From an application perspective, the hydrophilicity of this material may have an important impact on its applications in the fields of anti-corrosion, coatings, medical implants, or water treatment. For example, in biocompatible materials, hydrophilic surfaces usually help reduce protein adsorption, thereby reducing the risk of biofouling. In anti-corrosion coatings, moderate hydrophilicity may help reduce the retention of corrosive media on the material surface.

[0057] Therefore, this material exhibits obvious hydrophilic characteristics. This property may have a positive impact on its applications in multiple industrial and biomedical fields, especially in situations where liquid wetting behavior needs to be controlled.

[0058] The above embodiments are merely explanations of the present invention and do not limit the present invention. Those skilled in the art can make modifications to these embodiments without creative contributions according to their needs after reading this specification, but as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A corrosion-resistant graphene aerogel coating, characterized in that, It includes the following steps: Step 1: Select polyvinyl alcohol with a degree of alcoholysis of 85-99%; Step 2: Weigh polyvinyl alcohol and add it to ultrapure water to prepare a polyvinyl alcohol solution with a concentration of 0.5-5.0 g / ml; Step 3: Pour out the solution prepared in Step 2 and let the polyvinyl alcohol solution cool to room temperature; Step 4: Pour a 1 mg-10 mg / ml graphene oxide solution into the cooled polyvinyl alcohol solution and stir to completely disperse the graphene oxide in the polyvinyl alcohol solution; Step 5: Stir the solution in Step 4 to make all solutes evenly dispersed; Step 6: Add polyethylene glycol diglycidyl ether to the solution obtained in Step 5 to crosslink polyethylene glycol diglycidyl ether with polyvinyl alcohol to form a gel.

2. The corrosion-resistant graphene aerogel coating according to claim 1, characterized in that, In Step 2, stir and prepare the solution at 70-95 °C.

3. The corrosion-resistant graphene aerogel coating according to claim 1, characterized in that: In Step 4, use sodium hydroxide solution to adjust the pH of the liquid to make the solution neutral.

4. The corrosion-resistant graphene aerogel coating according to claim 1, characterized in that: In Step 6, after adding polyethylene glycol diglycidyl ether, stir the solution at a temperature of 30-90 °C.

5. The method of using the corrosion-resistant graphene aerogel coating according to claims 1-4, characterized in that, It includes the following steps: Step 1: Polish the surface of the substrate and place it at room temperature in a dry place for standby; Step 2: Drop the prepared aerogel coating onto the surface of the polished substrate. After it is in complete contact with the substrate surface, transfer the whole into a freeze-drying oven to coat the aerogel coating on the surface of the substrate.

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