A high-temperature resistant, corrosion-resistant, and thermally conductive coating, its preparation method, and its application.

Abstract

This invention provides a high-temperature resistant, corrosion-resistant, and thermally conductive coating, its preparation method, and its application. The raw materials include 20-30 parts phenolic epoxy resin, 20-50 parts thermal conductive agent, 20-45 parts organic solvent, 2-3 parts silane coupling agent, 15-20 parts epoxy curing agent, 5-30 parts filler, and 1.5-2.5 parts additives. Compared with existing technologies, this invention uses silver-doped aluminum nitride as the thermal conductive agent. Silver powder can effectively inhibit the agglomeration of aluminum nitride, resulting in a high thermal conductivity coating with improved resistance to 90℃ 3.5wt% NaCl solution. An epoxy curing agent is prepared by nucleophilic addition of styrene and p-phenylenediamine. After curing, the coating film exhibits strong toughness, good water resistance, and high temperature resistance. The coating of this invention has a salt spray resistance ≥5000h, a resistance to 90℃ 3.5wt% NaCl solution ≥8000h, and a thermal conductivity of 21.3 W / (m·K) on carbon steel.

Description

Technical Field

[0001] This invention belongs to the field of metal protection and coatings, specifically relating to a high-temperature resistant, corrosion-resistant, and thermally conductive coating, its preparation method, and its application. Background Technology

[0002] Heat exchangers are common chemical equipment in refining, thermal power, pharmaceutical, machinery, and many other industrial sectors. Their main function is to transfer heat from a higher-temperature fluid to a lower-temperature fluid. Because heat exchangers typically operate in corrosive environments such as high temperatures, acids, and salt spray, they often suffer from corrosion problems such as acid corrosion, high-temperature corrosion, wear, and perforation, severely affecting their efficiency and lifespan. To reduce the drawbacks of corrosion, some chemical plants use corrosion-resistant materials such as stainless steel and alloys to manufacture heat exchangers, but this significantly increases equipment manufacturing costs.

[0003] In the development of anti-corrosion technology, coating the surface of heat exchangers with corrosion-resistant, high-temperature-resistant, and high-thermal-conductivity coatings has become an important way to improve and solve the corrosion problem of heat exchangers.

[0004] Patent CN 107267033 A, published on October 20, 2017, discloses a graphene-doped heat exchanger tube bundle coating and its preparation method. The coating comprises component A: 35-50 parts of mixed resin, 1.2-8 parts of graphene dispersion, 30-50 parts of filler, 0.2-2 parts of coupling agent, 0.5-3 parts of thixotropic agent, 0.1-0.5 parts of defoamer, and 10-30 parts of solvent; component B includes a mixed curing agent. The coating exhibits corrosion resistance, hydrophobicity, and resistance to high-temperature and high-pressure steam purging through the synergistic effect of phenolic epoxy resin, epoxy-modified silicone resin, and graphene dispersion. However, its acid and alkali resistance test temperature is relatively low, only tested at 60℃, which cannot meet the requirements for higher temperature applications.

[0005] Patent CN 114075402 A, published on February 22, 2022, discloses a high-temperature resistant and corrosion-resistant coating for sulfur-containing heat exchangers and its preparation method, specifically for corrosion-resistant shell-and-tube heat exchangers. This high-temperature resistant and corrosion-resistant coating mainly consists of component A and component B. Component A comprises coating additives, pigments, solvents, and the following components by weight: 40-75 parts of silicone-modified epoxy resin, 11-18 parts of nano-reinforced anti-corrosion filler, and 8-20 parts of nano-flake carbon powder. The silicone-modified epoxy resin is prepared by reacting 30-50 parts of linear phenolic epoxy resin and 10-25 parts of silicone resin. The nano-reinforced anti-corrosion filler is a compound of nano-titanium dioxide, nano-alumina, and nano-silicon carbide in a mass ratio of 1:1:2. Component B is an organic amine curing agent. This high-temperature resistant and corrosion-resistant coating exhibits high adhesion, sulfur corrosion resistance, high temperature resistance, and high thermal conductivity. However, its salt spray resistance is relatively low and does not meet the requirements. Summary of the Invention

[0006] The purpose of this invention is to provide a high-temperature resistant, corrosion-resistant, and thermally conductive coating and its preparation method. Phenolic epoxy is used as the main film-forming substance, silver-doped aluminum nitride as the thermally conductive agent, and modified amine as the epoxy curing agent. The prepared high-temperature resistant, corrosion-resistant, and heat-dissipating coating provides excellent high-temperature corrosion resistance and thermal conductivity for metal protection. The maximum temperature resistance is 260℃, salt spray resistance is ≥5000h, and resistance to 90℃ 3.5wt% NaCl solution is ≥8000h. The thermal conductivity reaches 21.3 W / (m·K) on a carbon steel substrate with a film thickness of 50 micrometers.

[0007] Another objective of this invention is to provide an application of a high-temperature resistant, corrosion-resistant, and thermally conductive coating in the field of metal protection, particularly for heat exchangers, to improve long-term high-temperature corrosion resistance and thermal conductivity.

[0008] The specific technical solution of this invention is as follows:

[0009] A high-temperature resistant, corrosion-resistant, and thermally conductive coating comprises the following raw materials in parts by weight: 20-30 parts phenolic epoxy resin, 20-50 parts thermally conductive agent, 20-45 parts organic solvent, 2-3 parts silane coupling agent, 15-20 parts epoxy curing agent, 5-30 parts filler, and 1.5-2.5 parts additives.

[0010] The phenolic epoxy resin has a solid content of ≥80%;

[0011] The thermal conductive agent is silver-doped aluminum nitride, which is prepared by a high-temperature reduction reaction.

[0012] The method for preparing the silver-doped aluminum nitride is as follows:

[0013] Alumina, silver powder, and high-purity graphite were ball-milled and mixed, heated under an inert atmosphere, and a catalyst was added to maintain the temperature for reaction. Nitrogen gas was then introduced and the temperature was raised to carry out a nitriding reaction to obtain silver-doped aluminum nitride.

[0014] In the method for preparing silver-doped aluminum nitride: the mass ratio of alumina, silver powder, and high-purity graphite is 100-150:1-2:50-80; the catalyst is 1 / 100-1.5 / 100 of the total mass of alumina, silver powder, and high-purity graphite; the catalyst is yttrium oxide, used to accelerate the reaction rate and lower the reaction temperature; the ball milling mixing time is 2-3 hours; the inert atmosphere is argon, helium, or a combination thereof; the heating refers to heating to 800-1200℃; the heat preservation reaction refers to reacting at 800-1200℃ for 5-8 hours; the nitriding reaction by raising the temperature refers to raising the temperature to 1300-1450℃ and performing a high-temperature nitriding reaction for 5-10 hours.

[0015] In this invention, alumina, silver powder, and high-purity graphite are ball-milled and mixed. Under an inert gas atmosphere, a high-temperature reduction reaction catalyzed by yttrium oxide is performed to prepare elemental aluminum. Then, the newly generated aluminum powder and elemental silver undergo a nitriding reaction with nitrogen to prepare silver-doped aluminum nitride. During the reaction, the mixture is heated to 800–1200°C under an inert gas atmosphere, and the high-temperature reduction reaction under yttrium oxide catalysis lasts for 5–8 hours to generate elemental aluminum. Then, nitrogen gas is introduced, and the temperature is raised to 1300–1450°C, followed by a high-temperature nitriding reaction for 5–10 hours to obtain silver-doped aluminum nitride.

[0016] The preparation method of the epoxy curing agent is as follows: the catalyst is added to p-phenylenediamine, heated and stirred under a protective atmosphere, styrene is added dropwise, the temperature is raised to react, and the mixture is separated and purified to obtain the epoxy curing agent.

[0017] In the preparation method of the epoxy curing agent, the catalyst is sodium hexamethyldisilamide; the protective atmosphere is nitrogen; the heating and stirring mixing refers to stirring at 600 r / min for 50-60 min in a constant temperature water bath at 78℃; the heating reaction refers to the nucleophilic addition reaction in a constant temperature water bath at 90℃ for 60-80 min; the amount of catalyst added is 0.05 / 100-0.1 / 100 of the total mass of styrene and p-phenylenediamine, and the molar ratio of styrene to p-phenylenediamine is 0.6-1.0:1.

[0018] In this invention, the epoxy curing agent is prepared by nucleophilic addition reaction of styrene with p-phenylenediamine. After the reaction is completed, separation and purification are carried out, specifically: excess styrene is removed by vacuum distillation, and then the filtrate is obtained by filtration, which is the epoxy curing agent.

[0019] The organic solvent is one or a combination of xylene, n-butanol, and acetone.

[0020] The silane coupling agent is one or a combination of KH550, KH560 and KH570.

[0021] The filler is one or a combination of aluminum tripolyphosphate, iron oxide red, and talc.

[0022] The additive is one or a combination of the following: anti-settling agent fumed silica, dispersant EFKA4010, and leveling agent BYK333.

[0023] The present invention provides a method for preparing a high-temperature resistant, corrosion-resistant, and thermally conductive coating, specifically comprising:

[0024] Add the formulated amount of phenolic epoxy resin to an organic solvent, mix well, then add the thermal conductive agent and filler, stir and disperse, then add the additives and silane coupling agent, stir, and finally add the epoxy curing agent and stir evenly to obtain a high-temperature resistant, corrosion-resistant, and thermally conductive coating.

[0025] The preparation process was carried out at room temperature and pressure.

[0026] The preparation method of the high-temperature resistant, corrosion-resistant, and thermally conductive coating is as follows: the stirring and dispersion refers to dispersing at 500-800 r / min for 10-15 min; after adding the additives and silane coupling agent, stirring at 2000 r / min for 30 min.

[0027] This invention provides an application of a high-temperature resistant, corrosion-resistant, and thermally conductive coating in the field of metal protection, particularly for heat exchangers. The coating is sprayed or coated onto a metal substrate and cured at 100°C for 4 hours, resulting in a film thickness of 100±5μm, thus achieving long-lasting high-temperature corrosion protection and heat dissipation for the substrate.

[0028] Aluminum nitride (ANH3) is a diamond-like nitride, stable up to 2200℃. It has high room temperature strength, and its strength decreases slowly with increasing temperature. ANH3 has good thermal conductivity and a low coefficient of thermal expansion, making it an excellent material for thermal shock resistance and also possessing superior corrosion resistance. Elemental silver is chemically stable, has excellent thermal and electrical conductivity, is not easily corroded by chemicals, is soft, and highly ductile. Silver's thermal and electrical conductivity are among the highest of all metals. By doping aluminum nitride with silver, its thermal conductivity and thermal stability can be improved. This invention provides a method for preparing a high-temperature resistant, corrosion-resistant, and thermally conductive coating. Using phenolic epoxy as the main film-forming substance, silver-doped aluminum nitride as the thermal conductive agent, and modified amine as the epoxy curing agent, the prepared high-temperature resistant, corrosion-resistant, and heat-dissipating coating provides excellent high-temperature corrosion resistance and thermal conductivity for metal protection (heat exchangers). The high-temperature resistant, corrosion-resistant, and thermally conductive coating provided by this invention exhibits salt spray resistance ≥5000h and resistance to 90℃ 3.5wt% NaCl solution ≥8000h. On a carbon steel substrate with a film thickness of 100 micrometers, the thermal conductivity is 21.3 W / (m·K). After being held in a muffle furnace at 260℃ for 2000h, the coating showed slight fading but no overall change.

[0029] Compared with existing technologies, this invention uses silver-doped aluminum nitride as a thermal conductive agent. Silver powder effectively inhibits aluminum nitride agglomeration. This thermal conductive agent exhibits high temperature resistance and good thermal stability, resulting in a high thermal conductivity coating with improved resistance to 90℃ 3.5wt% NaCl solution. An epoxy curing agent prepared by the nucleophilic addition reaction of styrene and p-phenylenediamine produces a cured film with strong toughness, good water resistance, and high temperature resistance. The high-temperature corrosion-resistant thermal conductive coating provided by this invention has a salt spray resistance ≥5000h, a 90℃ 3.5wt% NaCl solution resistance ≥8000h, and a thermal conductivity of 21.3 W / (m·K) on a carbon steel substrate with a film thickness of 100 micrometers. Attached Figure Description

[0030] Figure 1 This is a schematic diagram illustrating the preparation of silver-doped aluminum nitride in Example 1;

[0031] Figure 2 The image shows a scanning electron microscope (SEM) image of silver-doped aluminum nitride prepared in Example 1. The left image is magnified 600 times, and the right image is magnified 1200 times.

[0032] Figure 3 Example 1: Schematic diagram of the preparation of epoxy curing agent;

[0033] Figure 4 The infrared spectrum of the epoxy curing agent prepared in Example 1 of this invention;

[0034] Figure 5 The images show the high-temperature resistant, corrosion-resistant, and thermally conductive coating prepared for Example 2, applied to the surface of carbon steel and then immersed in a 3.5 wt% NaCl solution at 90°C for 8000 hours. The left image shows the coating before the experiment, and the right image shows the coating after immersion in the 3.5 wt% NaCl solution at 90°C for 8000 hours. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available.

[0037] Unless otherwise specified in the embodiments, the techniques or conditions described in the literature in this field or in accordance with the product manual may be followed.

[0038] Example 1

[0039] A method for preparing a high-temperature resistant, corrosion-resistant, and thermally conductive coating includes the following steps:

[0040] 1) Preparation of silver-doped aluminum nitride:

[0041] For a detailed schematic diagram of the preparation of silver-doped aluminum nitride, please refer to [link / reference]. Figure 1 100g of alumina powder, 1.5g of silver powder and 60g of high-purity graphite were ball-milled for 2.5h and then transferred to a tubular reactor. 1.8g of yttrium oxide powder was added as a catalyst, and then high-purity argon gas was introduced and heated to 1100℃. The high-temperature reduction reaction was carried out for 6h to produce elemental aluminum. Then, high-purity nitrogen gas was introduced and the temperature was raised to 1400℃. The high-temperature nitriding reaction was carried out for 8h to obtain silver-doped aluminum nitride. Figure 2To prepare scanning electron microscope images of silver-doped aluminum nitride, it was found that the silver-doped aluminum nitride exhibits a layered structure which is beneficial for heat transfer, with a sheet diameter of 30–60 μm. No agglomeration was observed after the addition of silver powder, which is beneficial for improving the dispersion performance of aluminum nitride.

[0042] 2) Preparation of epoxy curing agent:

[0043] 0.41 g of sodium hexamethyldisilamide was added as a catalyst to 2 mol of p-phenylenediamine. Under nitrogen protection, the mixture was stirred at 600 rpm for 55 min in a 78°C constant temperature water bath. Then, 1.3 mol of styrene was added dropwise, followed by a nucleophilic addition reaction in a 90°C constant temperature water bath for 70 min. Excess styrene was removed by vacuum distillation, and the filtrate was filtered to obtain the epoxy curing agent. A schematic diagram of the epoxy curing agent preparation is shown below. Figure 3 The byproducts do not affect the curing performance of the coating and can be used as corrosion inhibitors to improve the anti-corrosion performance of the coating. Figure 4 The infrared spectrum of the self-made epoxy curing agent is shown at 3436 cm⁻¹. -1 and 3390cm -1 The absorption peak at 2952 cm⁻¹ originates from the stretching vibration absorption peak of primary amines. -1 The absorption peak at 1365 cm⁻¹ originates from the stretching vibration of the unsaturated CH bond in the benzene ring. -1 1248cm -1 and 1207cm -1 The absorption peak at 793 cm⁻¹ originates from the vibration of the benzene ring skeleton. -1 and 711cm -1 The absorption peak at that position is a characteristic absorption peak of a monosubstituted benzene ring, and the infrared spectroscopy results indicate that styrene has been successfully grafted onto p-phenylenediamine through a nucleophilic addition reaction.

[0044] 3) Preparation of high-temperature resistant, corrosion-resistant, and thermally conductive coatings

[0045] Add 16g xylene and 14g n-butanol to 20g phenolic epoxy resin (purchased from Shandong Deyuan Epoxy Technology Co., Ltd., brand name 638), stir at 500r / min until homogeneous, then add 25g thermal conductive silver-doped aluminum nitride, 5g aluminum tripolyphosphate, and 5g iron oxide red, disperse at 800r / min for 15min, then add 0.5g anti-settling agent fumed silica, 1.5g dispersant EFKA4010, and 2g silane coupling agent KH560, stir at 2000r / min for 30min, and finally add 16g epoxy curing agent (the above-mentioned self-made styrene-modified p-phenylenediamine), stir until homogeneous, and the high-temperature resistant, corrosion-resistant, and thermally conductive coating is obtained.

[0046] 4) Basic performance characterization of high-temperature resistant, corrosion-resistant, and thermally conductive coatings

[0047] The coating was sprayed onto a carbon steel plate (substrate sandblasted to Sa2.5 grade) using compressed air and cured at 100℃ for 4 hours, with the film thickness controlled at 100±5μm, thus obtaining a high-temperature resistant, corrosion-resistant, and thermally conductive coating. The coating's adhesion, impact resistance, resistance to 90℃ 3.5wt% NaCl solution, salt spray performance, and thermal conductivity are shown in Table 1. After the coating prepared in Example 1 was held in a muffle furnace at 260℃ for 2000 hours, the film showed slight fading, but no overall change.

[0048] Example 2

[0049] A method for preparing a high-temperature resistant, corrosion-resistant, and thermally conductive coating includes the following steps:

[0050] The process was carried out according to Example 1, except that 20g of silver-doped aluminum nitride and 10g of aluminum tripolyphosphate were added during the preparation of the coating, while other parameters remained unchanged. The adhesion, impact resistance, resistance to 90°C 3.5wt% NaCl solution, salt spray performance, and thermal conductivity of the coating prepared in Example 2 are shown in Table 1. After being held in a muffle furnace at 260°C for 2000 hours, the coating prepared in Example 2 showed slight fading, but no overall change.

[0051] Figure 5 The image shows a high-temperature resistant, corrosion-resistant, and thermally conductive coating prepared in Example 2. After being applied to a carbon steel surface, the coating was immersed in a 3.5 wt% NaCl solution at 90°C for 8000 hours. After immersion in the 3.5 wt% NaCl solution at 90°C for 8000 hours, the coating prepared in Example 2 showed no corrosion, peeling, or chalking. The coating film exhibited good adhesion to the carbon steel substrate, indicating that the self-made coating possesses excellent high-temperature corrosion resistance on the carbon steel substrate.

[0052] Comparative Example 1

[0053] A method for preparing a high-temperature resistant, corrosion-resistant, and thermally conductive coating includes the following steps:

[0054] The method described in Example 1 was followed, except that the 16g of self-made epoxy curing agent was replaced with a commercially available polyamide epoxy curing agent (purchased from Dongguan Zhenhe Resin Technology Co., Ltd.), while all other aspects remained unchanged. The adhesion, impact resistance, resistance to 90°C 3.5wt% NaCl solution, salt spray performance, and thermal conductivity of the coating in Comparative Example 1 are shown in Table 1. After being heated in a muffle furnace at 260°C for 100 hours, the coating in Comparative Example 1 showed significant fading and peeling.

[0055] Comparative Example 2

[0056] A method for preparing a high-temperature resistant, corrosion-resistant, and thermally conductive coating includes the following steps:

[0057] The method described in Example 1 was followed, except that no thermal conductive agent was added and the amount of aluminum tripolyphosphate added was increased to 30g, while other parameters remained unchanged. The adhesion, impact resistance, resistance to 90°C 3.5wt% NaCl solution, salt spray performance, and thermal conductivity of the coating prepared in Comparative Example 2 are shown in Table 1.

[0058] Comparative Example 3

[0059] A method for preparing a high-temperature resistant, corrosion-resistant, and thermally conductive coating includes the following steps:

[0060] The method described in Example 1 was followed, except that 25g of commercially available aluminum nitride was added as the thermally conductive agent, while all other aspects remained unchanged. The coating adhesion, impact resistance, resistance to 90°C 3.5wt% NaCl solution, salt spray performance, and thermal conductivity of Comparative Example 3 are shown in Table 1.

[0061] Comparative Example 4

[0062] A method for preparing a high-temperature resistant, corrosion-resistant, and thermally conductive coating includes the following steps:

[0063] The method described in Example 1 was followed, except that 20g of phenolic epoxy resin was used instead of commercially available epoxy resin E20 (purchased from Shandong Deyuan Epoxy Technology Co., Ltd.), while all other aspects remained unchanged. The adhesion, impact resistance, resistance to 90°C 3.5wt% NaCl solution, salt spray performance, and thermal conductivity of the coating in Comparative Example 4 are shown in Table 1. After being heated in a muffle furnace at 260°C for 300 hours, the coating in Comparative Example 4 showed significant fading and peeling.

[0064] Table 1 shows the overall physical properties of the coatings used on carbon steel surfaces in the examples and comparative examples.

[0065]

[0066] By comparing the test results of Example 1 and Comparative Example 1, it is shown that the self-made epoxy curing agent can significantly improve the salt spray resistance, high temperature resistance, and resistance to 90℃ 3.5wt% NaCl solution of the high temperature resistant, corrosion resistant, and thermally conductive coating.

[0067] By comparing the test results of Example 1 and Comparative Example 2, it was found that using silver-doped aluminum nitride as a thermal conductive agent can significantly improve the thermal conductivity of the paint film on carbon steel.

[0068] By comparing the test results of Example 1 and Comparative Example 3, it is shown that the self-made silver-doped aluminum nitride has better thermal conductivity than the high-temperature corrosion-resistant and thermally conductive coating prepared by commercially available aluminum nitride, and the coating film has better resistance to 90℃ 3.5wt% NaCl solution.

[0069] Comparing the test results of Example 1 and Comparative Example 4, it is shown that phenolic epoxy resin has better temperature resistance and salt spray resistance than epoxy resin E20. At the same time, using phenolic epoxy resin as the main film-forming material, the cross-cut adhesion of the high-temperature resistant, anti-corrosion and thermally conductive coating is better.

[0070] The above description of the embodiments is intended to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A high-temperature resistant, corrosion-resistant, and thermally conductive coating, characterized in that, The high-temperature resistant, corrosion-resistant, and thermally conductive coating comprises the following raw materials in parts by weight: 20-30 parts phenolic epoxy resin, 20-50 parts thermally conductive agent, 20-45 parts organic solvent, 2-3 parts silane coupling agent, 15-20 parts epoxy curing agent, 5-30 parts filler, and 1.5-2.5 parts additives. The thermal conductive agent is silver-doped aluminum nitride; The method for preparing the silver-doped aluminum nitride is as follows: Alumina, silver powder, and high-purity graphite are ball-milled and mixed, heated under an inert atmosphere, and a catalyst is added to maintain the temperature for reaction. Nitrogen gas is then introduced and the temperature is raised to carry out a nitriding reaction to obtain silver-doped aluminum nitride. The mass ratio of alumina, silver powder, and high-purity graphite is 100~150:1~2:50~80. The preparation method of the epoxy curing agent is as follows: the catalyst is added to p-phenylenediamine, heated and stirred under a protective atmosphere, styrene is added dropwise, the temperature is raised to react, and the mixture is separated and purified to obtain the epoxy curing agent.

2. The high-temperature resistant, corrosion-resistant, and thermally conductive coating according to claim 1, characterized in that, In the method for preparing silver-doped aluminum nitride, the catalyst is yttrium oxide; the catalyst is 1 / 100 to 1.5 / 100 of the total mass of aluminum oxide, silver powder and high-purity graphite.

3. The high-temperature resistant, corrosion-resistant, and thermally conductive coating according to claim 1 or 2, characterized in that, In the method for preparing silver-doped aluminum nitride, the heating refers to heating to 800~1200℃; the heat preservation reaction refers to reacting at 800~1200℃ for 5~8 hours; and the nitriding reaction by raising the temperature refers to raising the temperature to 1300~1450℃ and performing a high-temperature nitriding reaction for 5~10 hours.

4. The high-temperature resistant, corrosion-resistant, and thermally conductive coating according to claim 1, characterized in that, In the preparation method of the epoxy curing agent, the catalyst is sodium hexamethyldisilamide; the amount of catalyst added is 0.05 / 100 to 0.1 / 100 of the total mass of styrene and p-phenylenediamine, and the molar ratio of styrene to p-phenylenediamine is 0.6 to 1.0:

1.

5. The high-temperature resistant, corrosion-resistant, and thermally conductive coating according to claim 1, characterized in that, In the preparation method of the epoxy curing agent, the heating and stirring mixing refers to stirring at 600 r / min for 50 to 60 min in a constant temperature water bath at 78℃; the heating reaction refers to nucleophilic addition reaction in a constant temperature water bath at 90℃ for 60 to 80 min.

6. The high-temperature resistant, corrosion-resistant, and thermally conductive coating according to claim 1, characterized in that, The silane coupling agent is one or a combination of KH550, KH560 and KH570.

7. A method for preparing the high-temperature resistant, corrosion-resistant, and thermally conductive coating according to any one of claims 1-6, characterized in that, The preparation method of the high-temperature resistant, anti-corrosion, and thermally conductive coating is as follows: add the formulated amount of phenolic epoxy resin to an organic solvent, mix well, add thermal conductive agent and filler, stir and disperse, then add additives and silane coupling agent, stir, and finally add epoxy curing agent and stir evenly to obtain the high-temperature resistant, anti-corrosion, and thermally conductive coating.

8. The application of the high-temperature resistant, corrosion-resistant, and thermally conductive coating according to any one of claims 1-6, characterized in that, Applications in the field of metal protection.

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