A high-performance microwave absorbing coating and its preparation method

Abstract

This invention proposes a high-performance microwave absorbing coating and its preparation method, belonging to the field of microwave absorbing materials technology. The microwave absorbing coating uses porous magnetic alloy composite carbon nanomaterials as the absorbent, resin as the binder, and adds additives, curing agents, and solvents to disperse and form a uniform coating, which is then sprayed onto the surface of a substrate to form the microwave absorbing coating. The absorbent used in this invention is a composite of a metal alloy and carbon nanomaterials, possessing the advantages of being lightweight and corrosion-resistant. The areal density of the microwave absorbing coating is 1.3~2.0 kg / m³. 2 The porous structure facilitates the formation of a complete network structure by the resin in the coating, improving coating adhesion. The destructive strength on various substrates exceeds 14 MPa. Electromagnetic waves entering the coating are reflected multiple times within the porous structure, exhibiting strong absorption of electromagnetic waves in the 1–18 GHz range. When coated on substrate surfaces, it enables stealth coating of large-area, complex structural components, meeting the application requirements of lightweight, corrosion-resistant, and microwave-absorbing coatings for both military and civilian use, and possesses broad market application prospects.

Description

Technical Field

[0001] This invention relates to the field of microwave absorbing materials technology, and in particular to a high-performance microwave absorbing coating and its preparation method. Background Technology

[0002] With the rapid development of information technology, electromagnetic signal detection has become increasingly important. Radar absorbing materials can effectively absorb incident electromagnetic waves and reduce the intensity of target echoes, and are often used on the surfaces of equipment and special devices to achieve electromagnetic protection. As equipment develops, the performance requirements for radar absorbing materials are becoming more and more stringent. In addition to being thin, wide, lightweight, and strong, absorbing materials should also have properties such as corrosion resistance and high adhesion.

[0003] Iron, as an electromagnetic wave absorber, possesses excellent absorption properties. However, iron is easily corroded in its natural state and has a high density. By combining iron with other elements (cobalt, nickel, silicon, manganese, chromium, and aluminum), alloy materials are obtained, improving corrosion resistance. Carbon nanomaterials are chemically stable, have a large specific surface area, are lightweight, possess good dielectric properties, and also absorb electromagnetic waves to a certain degree. Directly mixing the two to prepare an absorbing coating results in delamination of the coating due to the significant density difference between the alloy material and carbon nanomaterials. This delamination reduces the coating's electrical and mechanical properties. Loading a magnetic alloy material onto the surface of carbon nanomaterials and using it as an absorber to prepare an absorbing coating is another method. Chinese patent application CN105670560A provides a nano-cobalt oxide / graphene composite absorbing coating and its preparation method. While the combination of carbon nanomaterials and magnetic alloys provides good corrosion resistance and absorption properties, the high surface density of this coating increases the load on the equipment. Summary of the Invention

[0004] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is the problem of high surface density and poor coating adhesion of the existing microwave absorbing coating.

[0005] The purpose of this invention is to provide a high-performance microwave absorbing coating, which is lightweight, corrosion-resistant, has high adhesion, and exhibits broadband absorption. The absorber has a porous structure, and when applied to a substrate, it can reduce the areal density of the coating to 1.3~2.0 kg / m³. 2 .

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0007] A high-performance microwave absorbing coating comprises the following components: a porous magnetic alloy composite carbon nanomaterial absorber, a binder, an anti-settling agent, a dispersant, a coupling agent, and a solvent.

[0008] Preferably, the high-performance microwave absorbing coating comprises the following components by weight: 50-80 parts of porous magnetic alloy composite carbon nanomaterial absorber, 13-22 parts of binder, 0.5-2 parts of dispersant, 0.5-2 parts of anti-settling agent, 0.5-2 parts of silane coupling agent, 5-10 parts of curing agent, and 14-25 parts of solvent.

[0009] The present invention also discloses the preparation of the porous magnetic alloy composite carbon nanomaterial absorbent as follows: a porous polyurethane foam is impregnated in an ethanol dispersion of carbon nanomaterials, removed and dried, and the impregnation and drying process is repeated; then, a variety of metals are deposited on the surface of the carbon nanomaterials, and finally the porous polyurethane foam is removed to obtain the porous magnetic alloy composite carbon nanomaterial absorbent.

[0010] A further preferred embodiment of the preparation method of the porous magnetic alloy composite carbon nanomaterial absorbent includes the following steps:

[0011] S1 Degreasing: Clean the surface lipids of the polyurethane foam with anhydrous ethanol;

[0012] S2 conductive treatment: The cleaned polyurethane foam is immersed in an ethanol dispersion of carbon nanomaterials, then removed and dried. The immersion and drying process is repeated to ensure that the pores on the surface of the polyurethane foam are completely covered by carbon nanomaterials.

[0013] S3 electrodeposition: Conductive polyurethane foam is placed in an electroplating solution for electroplating.

[0014] S4 Dissolving Substrate: The electroplated material is immersed in the dissolving solution; filtered, cleaned, dried, and ground.

[0015] The porous magnetic alloy composite carbon nanomaterial absorbent is obtained by grinding and sieving.

[0016] Further preferably, the electroplating solution in step S3 includes deionized water, ferrous salt, nickel salt, cobalt salt, chromium salt, molybdenum salt, manganese salt, sodium sulfate, diethylenetriaminepentacarboxylate, and additives; the concentration of ferrous salt in the electroplating solution is 0.01~0.3 mol / L; the concentration of nickel salt in the electroplating solution is 0.01~0.3 mol / L; the concentration of cobalt salt in the electroplating solution is 0.01~0.3 mol / L; the concentration of chromium salt in the electroplating solution is 0.01~0.3 mol / L; and the concentration of molybdenum salt in the electroplating solution is 0.01~0.3 mol / L. The concentration of manganese salt in the electroplating solution is 0.01~0.3 mol / L; the concentration of sodium sulfate in the electroplating solution is 0.01~0.3 mol / L; the concentration of diethylenetriamine pentacarboxylate in the electroplating solution is 0.01~0.3 mol / L; the auxiliary agent is a mixture of sodium dodecyl sulfonate and 1-ethyl-3-methylimidazoline bis(trifluoromethanesulfonyl)imide in a mass ratio of 1-5:3-6; the amount of the auxiliary agent added is 5-10 wt% of the mass of the electroplating solution; the pH value of the electroplating solution is 2.5~5.5.

[0017] Preferably, the ferrous salt is one or a mixture of two or more of ferrous sulfate, ferrous nitrate, ferrous chloride, and other water-soluble ferrous salts containing ferrous ions.

[0018] Preferably, the nickel salt is one or a mixture of two or more of nickel sulfate, hydrated nickel sulfate, nickel chloride, hydrated nickel chloride, and other water-soluble nickel salts containing nickel ions.

[0019] Preferably, the cobalt salt is one or a mixture of two or more of hydrated cobalt sulfate, hydrated cobalt chloride, hydrated cobalt nitrate, and other water-soluble cobalt salts containing cobalt ions.

[0020] Preferably, the chromium salt is one or a mixture of two or more of chromium nitrate, chromium chloride, chromium sulfate, and other water-soluble chromium salts containing chromium ions.

[0021] Preferably, the molybdenum salt is one or a mixture of two or more of molybdenum sulfate, molybdenum chloride, molybdenum nitrate, and other water-soluble molybdenum salts containing molybdenum ions.

[0022] Preferably, the manganese salt is one or a mixture of two or more of manganese sulfate, manganese chloride, manganese nitrate, and other water-soluble manganese salts containing manganese ions.

[0023] More preferably, the carbon nanomaterial in step S2 is one or a mixture of two or more of carbon nanotubes, graphene, and carbon black.

[0024] More preferably, the electroplating conditions in step S3 are as follows: the pH of the electroplating solution is adjusted to 2.5~5.5 with sulfuric acid, the temperature of the plating solution is 40~60℃, the current intensity is 2~8A, and the deposition time is 10~30min.

[0025] More preferably, the dissolving solution in step S4 comprises the following components in parts by weight: 1-3 parts acetone, 4-6 parts dimethylformamide, and 2-4 parts cyclohexanone.

[0026] Preferably, the porous magnetic alloy composite carbon nanomaterial absorber has a size of 8.0~30.0µm and a content of 50~83% in the microwave absorbing coating.

[0027] Preferably, the adhesive is one or a mixture of epoxy-modified polyurethane resin, epoxy-modified acrylic resin, polyurethane resin, epoxy resin, alkanolamine resin, phenolic resin, and silicone resin.

[0028] Preferably, the curing agent is one or a mixture of two or more of dicyandiamide, m-xylenediamine, diaminodiphenylmethane, and adipate dihydrazide.

[0029] Preferably, the solvent is one or a mixture of xylene, cyclohexanone, butyl acetate, n-butanol, and ethyl acetate.

[0030] The present invention also discloses a method for preparing the high-performance microwave absorbing coating, comprising the following steps:

[0031] X1 Weigh out the resin, add solvent and stir until the resin is completely dissolved to obtain the adhesive;

[0032] X2 weigh out the porous magnetic alloy composite carbon nanomaterial absorber, add it to the binder, then add dispersant, anti-settling agent, silane coupling agent for homogenization treatment, and then add curing agent to obtain homogenized microwave absorbing coating.

[0033] X3 applies homogenized microwave absorbing coating to the substrate surface and cures it at 40-80℃ for 40-48 hours.

[0034] Preferably, the coating thickness in step X3 is 0.5~1.8mm.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The porous magnetic alloy composite carbon nanomaterial absorbent prepared by this invention possesses the characteristics of being lightweight, corrosion-resistant, having high adhesion, and exhibiting broadband absorption. The composite of carbon nanomaterials and magnetic alloys forms a porous structure, which can reduce the areal density of the coating to 1.3~2.0 kg / m³. 2It meets the requirements of some devices with stringent weight requirements. Since both carbon nanomaterials and alloys have good corrosion resistance, the resulting microwave absorbing coating has good salt spray resistance and corrosion resistance. The porous structure is conducive to multiple reflections of electromagnetic waves in the coating, which enhances the absorption effect of the coating on electromagnetic waves. It has strong absorption of electromagnetic waves in the range of 1~18GHz. At the same time, due to the presence of the porous structure, the resin can form a complete network structure in the entire coating structure. The destructive strength on different substrates is greater than 14MPa.

[0037] 2. The porous magnetic alloy composite carbon nanomaterial absorber prepared by this invention can achieve homogenization, ensuring the process and performance stability of the coating. The porous magnetic alloy composite carbon nanomaterial, after ball milling, can form a multi-size interactive distribution. After homogenization, it plays a supporting and connecting role in the adhesive system, forming a uniform dispersion within the system, thereby ensuring performance stability. The dielectric loss of the carbon nanomaterial, the magnetic loss of the metal alloy, and the multi-size distribution of the absorber can all be used to control the electromagnetic parameters of the material, giving it a broadband absorption effect.

[0038] 3. By adjusting the parameters in the preparation process of porous magnetic alloy composite carbon nanomaterials, including the type of carbon nanomaterials, the type and content of alloys, the pore size of polyurethane foam, the temperature of electroplating solution, the current intensity, and the grinding time, porous magnetic alloy composite carbon nanomaterial absorbents with different electrical and mechanical properties can be obtained, which have a wide range of applications and good application prospects.

[0039] 4. By adding additives to the electroplating solution, the surface tension of carbon nanomaterials can be improved, the hydrophilicity of carbon nanomaterials can be enhanced, and agglomeration during the deposition of conductive metals can be avoided. This is beneficial for the uniform loading of conductive metals and for the uniform reflection of electromagnetic waves by the absorber. Attached Figure Description

[0040] Figure 1 This is a coating emissivity curve of the high-performance absorbing coating obtained in Example 1 of the present invention.

[0041] Figure 2 The change in reflectivity of the absorbing coating before and after environmental testing in Example 2 of this invention is shown.

[0042] Figure 3 The change in the adhesion of the microwave absorbing coating before and after environmental testing in Example 2 of this invention.

[0043] Figure 4 This is a coating emissivity curve of the high-performance absorbing coating obtained in Example 4 of the present invention. Detailed Implementation

[0044] Example 1

[0045] A method for preparing a high-performance microwave absorbing coating includes the following steps:

[0046] X1. Add 190g of epoxy-modified acrylic resin to a mixed solution of 136g xylene and 34g cyclohexanone and stir until the resin is completely dissolved to obtain an adhesive.

[0047] X2 added 620g of porous magnetic alloy composite carbon nanomaterial absorber to 180g of binder, then added 16g of dispersant, 16g of anti-settling agent, 16g of 3-aminopropyltrimethoxysilane, and 200g of n-butanol for homogenization treatment, and then added 80g of m-xylenediamine to obtain a homogenized microwave absorbing coating; the dispersant was BYK-161 from Germany; the anti-settling agent was 6900-20x;

[0048] X3 uses a pneumatic spray gun to uniformly spray a homogenized microwave absorbing coating onto the steel surface, with a coating thickness of 0.5 mm. The coating is then cured at 60°C for 48 hours to obtain a high-performance microwave absorbing coating. The areal density of the high-performance microwave absorbing coating is 1.3 kg / m³. 2 .

[0049] The preparation method of the porous magnetic alloy composite carbon nanomaterial absorbent is as follows:

[0050] S1 Degreasing: Take a polyurethane foam with a pore size of 5-50μm and put it into a container. Add anhydrous ethanol and place the container into an ultrasonic cleaner. Sonicate for 20 minutes to remove dirt from the surface of the polyurethane foam.

[0051] S2 Conductivity treatment: The cleaned polyurethane foam is immersed in a carbon nanomaterial ethanol dispersion with a concentration of 15 g / L for 10 min. The carbon nanomaterial is carbon nanotubes with a diameter of 2~5 nm and an aspect ratio of 1000~1200. Then the immersed polyurethane foam is taken out and heated and dried. The immersion and drying process is repeated 3 times to make the surface of the polyurethane foam pores completely covered by carbon nanomaterials.

[0052] S3 Electrodeposition: Conductive polyurethane foam is placed in an electroplating solution containing 0.02 mol / L ferrous sulfate, 0.02 mol / L nickel chloride, 0.02 mol / L cobalt nitrate, 0.02 mol / L chromium sulfate, 0.02 mol / L molybdenum nitrate, 0.02 mol / L manganese chloride, 0.2 mol / L sodium sulfate, and 0.2 mol / L diethylenetriamine pentacarboxylate. The amount of additives in the electroplating solution is 8 wt% of the solution mass, and the additives consist of a mixture of sodium dodecyl sulfonate and 1-ethyl-3-methylimidazoline bis(trifluoromethylsulfonyl)imide in a mass ratio of 3:2. The pH of the electroplating solution is adjusted to 3.5 with sulfuric acid, the solution temperature is 50°C, the current intensity is 6A, and the deposition time is 20 min.

[0053] S4 Dissolving Substrate: The electroplated material was placed in a mixed solution of 2000g acetone, 5000g dimethylformamide, and 3000g cyclohexanone and allowed to stand for 20 hours. After the polyurethane foam dissolved, it was filtered. The resulting particles were washed with ethanol, dried, and ball-milled for 0.5 hours. Then, they were passed through an 800-mesh sieve to obtain a porous magnetic alloy composite carbon nanomaterial absorbent with an average size of 8.0~30.0µm. The results are as follows: Figure 1 As shown, when the coating thickness is 0.5 mm, the absorption of electromagnetic waves exceeds 90% in the range of 8.5~13.5 GHz.

[0054] Example 2

[0055] A method for preparing a high-performance microwave absorbing coating includes the following steps:

[0056] X1. Add 150g of epoxy-modified acrylic resin to a mixed solution of 108g xylene and 27g cyclohexanone and stir until the resin is completely dissolved to obtain an adhesive.

[0057] X2 added 500g of porous magnetic alloy composite carbon nanomaterial absorber to 130g of binder, then added 5g of dispersant, 5g of anti-settling agent, 5g of 3-aminopropyltrimethoxysilane, and 140g of cyclohexanone for homogenization treatment, and then added 50g of m-xylenediamine to obtain a homogenized microwave absorbing coating; the dispersant was BYK-161 from Germany; the anti-settling agent was 6900-20x;

[0058] X3 uses a pneumatic spray gun to uniformly spray a homogenized microwave absorbing coating onto the steel surface, with a coating thickness of 1.0 mm. The coating is then cured at 60°C for 48 hours to obtain a high-performance microwave absorbing coating. The areal density of the high-performance microwave absorbing coating is 1.7 kg / m³. 2 .

[0059] The preparation method of the porous magnetic alloy composite carbon nanomaterial absorbent is as follows:

[0060] S1 Degreasing: Take a polyurethane foam with a pore size of 5-50μm and put it into a container. Add anhydrous ethanol and place the container into an ultrasonic cleaner. Sonicate for 20 minutes to remove dirt from the surface of the polyurethane foam.

[0061] S2 Conductivity treatment: The cleaned polyurethane foam is immersed in a carbon nanomaterial ethanol dispersion with a concentration of 2 g / L for 10 min. The carbon nanomaterial is carbon nanotubes with a diameter of 5~10 nm and an aspect ratio of 1300~1700. Then the immersed polyurethane foam is taken out and heated and dried. The immersion and drying process is repeated 3 times to make the surface of the polyurethane foam pores completely covered by carbon nanomaterials.

[0062] S3 Electrodeposition: Conductive polyurethane foam is placed in an electroplating solution containing 0.01 mol / L ferrous sulfate, 0.01 mol / L nickel chloride, 0.01 mol / L cobalt nitrate, 0.01 mol / L chromium sulfate, 0.01 mol / L molybdenum nitrate, 0.01 mol / L manganese chloride, 0.1 mol / L sodium sulfate, and 0.1 mol / L diethylenetriaminepentacarboxylate. The amount of additives in the electroplating solution is 5 wt% of the solution mass, and the additives consist of a mixture of sodium dodecyl sulfonate and 1-ethyl-3-methylimidazoline bis(trifluoromethylsulfonyl)imide in a mass ratio of 1:3. The pH of the electroplating solution is adjusted to 2.5 with sulfuric acid, the solution temperature is 40°C, the current intensity is 2A, and the deposition time is 10 min.

[0063] S4 Dissolving Substrate: The electroplated material was placed in a mixed solution of 1000g acetone, 4000g dimethylformamide, and 2000g cyclohexanone and allowed to stand for 20 hours. After the polyurethane foam dissolved, the solution was filtered. The resulting particles were washed with ethanol, dried, ball-milled for 0.2 hours, and then passed through a 400-mesh sieve to obtain a porous magnetic alloy composite carbon nanomaterial absorbent with an average size of 8.0~30.0µm. Results are as follows... Figure 1 As shown, when the coating thickness is 1.0 mm, the absorption of electromagnetic waves exceeds 90% within the 3~5 GHz range. The coating underwent acid and alkali resistance and humid heat environment tests; the reflectivity remained essentially unchanged, and the adhesion decreased slightly but remained greater than 14 MPa. The results are as follows... Figure 2 , Figure 3 As shown.

[0064] Example 3

[0065] A method for preparing a high-performance microwave absorbing coating includes the following steps:

[0066] X1. Add 240g of epoxy-modified acrylic resin to a mixed solution of 152g xylene and 38g cyclohexanone and stir until the resin is completely dissolved to obtain an adhesive.

[0067] X2 added 800g of porous magnetic alloy composite carbon nanomaterial absorber to 220g of binder, then added 20g of dispersant, 20g of anti-settling agent, 20g of 3-aminopropyltrimethoxysilane, and 200g of xylene for homogenization treatment. Finally, 100g of m-xylenediamine was added to obtain a homogenized microwave absorbing coating. The dispersant was BYK-161 (Germany); the anti-settling agent was 6900-20x.

[0068] X3 uses a pneumatic spray gun to uniformly spray a homogenized microwave absorbing coating onto the steel surface, achieving a coating thickness of 1.2 mm. The coating is then cured at 60°C for 48 hours to obtain a high-performance microwave absorbing coating. The areal density of the high-performance microwave absorbing coating is 2.0 kg / m³. 2 .

[0069] The preparation method of the porous magnetic alloy composite carbon nanomaterial absorbent is as follows:

[0070] S1 Degreasing: Take a polyurethane foam with a pore size of 5-50μm and put it into a container. Add anhydrous ethanol and place the container into an ultrasonic cleaner. Sonicate for 20 minutes to remove dirt from the surface of the polyurethane foam.

[0071] S2 Conductivity Treatment: The cleaned polyurethane foam is impregnated in a 30 g / L ethanol dispersion of carbon nanomaterials for 10 min. The carbon nanomaterials are graphene, with sheet diameters of 1-5 μm, thicknesses of 1-3 nm, and specific surface areas of 850-1100 m² / g. 2 / g, then take out the impregnated polyurethane foam, heat and dry it, and repeat the impregnation and drying process 3 times to make the surface of the polyurethane foam pores completely covered by carbon nanomaterials.

[0072] S3 Electrodeposition: Conductive polyurethane foam is placed in an electroplating solution containing 0.03 mol / L ferrous sulfate, 0.03 mol / L nickel chloride, 0.03 mol / L cobalt nitrate, 0.03 mol / L chromium sulfate, 0.03 mol / L molybdenum nitrate, 0.03 mol / L manganese chloride, 0.3 mol / L sodium sulfate, and 0.3 mol / L diethylenetriaminepentacarboxylate. The amount of additives in the electroplating solution is 10 wt% of the solution mass, and the additives consist of a mixture of sodium dodecyl sulfonate and 1-ethyl-3-methylimidazoline bis(trifluoromethanesulfonyl)imide in a mass ratio of 5:6. The pH of the electroplating solution is adjusted to 3.5 with sulfuric acid, the solution temperature is 50°C, the current intensity is 8A, and the deposition time is 30 min.

[0073] S4 Dissolving Substrate: The electroplated material is placed in a mixed solution consisting of 3000g acetone, 6000g dimethylformamide, and 4000g cyclohexanone and left to stand for 24 hours. After the polyurethane foam dissolves, it is filtered. The resulting particles are washed with ethanol, dried, ball-milled for 1 hour, and then passed through a 1000-mesh sieve to obtain a porous magnetic alloy composite carbon nanomaterial absorber with an average size of 8.0~30.0µm.

[0074] Example 4

[0075] A method for preparing a high-performance microwave absorbing coating is similar to that in Example 1, except that no additives are added to the electroplating solution; and the areal density of the high-performance microwave absorbing coating is 1.3 kg / m³. 2 .like Figure 4 As shown, the coating absorbs less than 80% of electromagnetic waves in the range of 8.5~13.5GHz, and its wave absorption effect is significantly worse than that of the coating with added additives.

[0076] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A high-performance microwave absorbing coating, characterized in that, It includes the following components: porous magnetic alloy composite carbon nanomaterial absorbent, binder, anti-settling agent, dispersant, coupling agent and solvent; The preparation method of the porous magnetic alloy composite carbon nanomaterial absorbent includes the following steps: S1 Degreasing: Clean the surface lipids of the polyurethane foam with anhydrous ethanol; S2 conductive treatment: The cleaned polyurethane foam is immersed in an ethanol dispersion of carbon nanomaterials, then removed and dried. The immersion and drying process is repeated to ensure that the pores on the surface of the polyurethane foam are completely covered by carbon nanomaterials. S3 Electrodeposition: Conductive polyurethane foam is placed in an electroplating solution for electroplating; the electroplating solution includes deionized water, ferrous salt (0.01~0.3 mol / L), nickel salt (0.01~0.3 mol / L), cobalt salt (0.01~0.3 mol / L), chromium salt (0.01~0.3 mol / L), molybdenum salt (0.01~0.3 mol / L), manganese salt (0.01~0.3 mol / L), and [unclear - possibly a specific chemical composition]. The electroplating solution consists of 1 / L sodium sulfate, 0.01-0.3 mol / L diethylenetriamine pentacarboxylate, and an auxiliary agent; the auxiliary agent is a mixture of sodium dodecyl sulfonate and 1-ethyl-3-methylimidazoline bis(trifluoromethanesulfonyl)imide in a mass ratio of 1-5:3-6; the amount of the auxiliary agent added is 5-10 wt% of the electroplating solution mass; the electroplating conditions are: adjusting the pH of the electroplating solution to 2.5-5.5 with sulfuric acid, the solution temperature to 40-60℃, the current intensity to 2-8 A, and the deposition time to 10-30 min; S4 Dissolving Substrate: The electroplated material is immersed in the dissolving solution; The porous magnetic alloy composite carbon nanomaterial absorbent is obtained by filtration, washing, drying, grinding and sieving.

2. The high-performance absorbing coating according to claim 1, characterized in that, It includes the following components by weight: 50-80 parts of porous magnetic alloy composite carbon nanomaterial absorbent, 13-22 parts of binder, 0.5-2 parts of dispersant, 0.5-2 parts of anti-settling agent, 0.5-2 parts of silane coupling agent, 5-10 parts of curing agent, and 14-25 parts of solvent.

3. The high-performance absorbing coating according to claim 1, characterized in that: In step S2, the carbon nanomaterial is one or a mixture of two or more of carbon nanotubes, graphene, and carbon black.

4. The high-performance absorbing coating according to claim 1, characterized in that, The solution in step S4 comprises the following components by weight: 1-3 parts acetone, 4-6 parts dimethylformamide, and 2-4 parts cyclohexanone.

5. The method for preparing the high-performance absorbing coating according to any one of claims 1-4, characterized in that: X1 Weigh out the resin, add solvent and stir until the resin is completely dissolved to obtain the adhesive; X2 weigh out the porous magnetic alloy composite carbon nanomaterial absorber, add it to the binder, then add dispersant, anti-settling agent, and silane coupling agent for homogenization treatment, and then add curing agent to obtain homogenized microwave absorbing coating. X3 applies homogenized microwave absorbing coating to the substrate surface and cures it at 40-80℃ for 40-48 hours.

6. The method for preparing the high-performance absorbing coating according to claim 5, characterized in that: The coating thickness in step X3 is 0.5~1.8mm.

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