A composite absorbent and a corrosion-resistant electromagnetic wave absorbing coating

Abstract

The present invention provides a composite absorbent and a corrosion-resistant wave-absorbing coating, which have excellent corrosion resistance and wave-absorbing performance, and belong to the technical field of the development of wave-absorbing coatings. The present invention provides a composite absorbent, which comprises the following components: modified magnetic iron oxide nanoparticles, silicon carbide, graphene, polydopamine, aluminum oxide and titanium oxide. The present invention solves the technical problem that the wave-absorbing coatings in the prior art cannot achieve both corrosion resistance and wave-absorbing performance. The present invention uses modified magnetic iron oxide nanoparticles, silicon carbide, graphene, polydopamine, aluminum oxide and titanium oxide to be compounded to obtain a composite absorbent, and the wave-absorbing performance can be complementary among the materials, and excellent effects can be produced when used in wave-absorbing coatings. The minimum reflection loss RLmin can reach -61.53 dB, and the wave-absorbing bandwidth range is 10.1 to 14.2 GHz. Moreover, the corrosion-resistant wave-absorbing coating prepared by using the composite absorbent of the present invention has significantly improved corrosion resistance and salt water resistance, can be used in marine substrates, and has broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave absorbing coating development, and particularly relates to a composite absorber and a corrosion-resistant microwave absorbing coating. Background Art

[0002] Microwave absorbing materials refer to a class of materials that can absorb or significantly attenuate the electromagnetic wave energy received on their surfaces, thereby reducing electromagnetic wave interference. In engineering applications, in addition to requiring microwave absorbing materials to have high absorption rates for electromagnetic waves within a relatively wide frequency band, they are also required to have properties such as light weight, temperature resistance, humidity resistance, and corrosion resistance.

[0003] In modern society, with the rapid development of science and technology, various portable and wearable devices emerge in an endless stream, greatly promoting economic development and improving lifestyles. However, at the same time, serious electromagnetic wave pollution has also been generated. In the civilian field, on the one hand, electromagnetic wave pollution interferes with precision instruments, navigation systems, and medical equipment, affecting the normal operation of electronic devices; on the other hand, electromagnetic wave pollution can also cause human nerve decline and induce cell lesions, resulting in health problems. In the military field, radar detection technology and wireless detection technology are becoming increasingly mature, which poses higher requirements for radar stealth technology. Radar stealth technology can effectively avoid detection and attack by reducing the radar scattering and reflection area of the detected target, improving the defense and survival capabilities of combat equipment. However, developing microwave absorbing materials suitable for different environments is one of the main strategies for achieving radar stealth. Therefore, researching new functional materials with strong environmental adaptability and excellent microwave absorbing performance has scientific value and practical significance in multiple fields.

[0004] Chinese Patent CN117106361A discloses a corrosion-resistant microwave absorbing coating and its preparation method, including the following components in parts by weight: 20 - 30 parts of resin; 20 - 40 parts of diluent; 5 - 10 parts of curing agent; 2 - 4 parts of filler; 1 - 2 parts of surfactant; 5 - 10 parts of porous ceramic; 3 - 5 parts of graphene; 1 - 3 parts of carbon fiber. A preparation method of a corrosion-resistant microwave absorbing coating includes the following steps: S1. Mix the resin, diluent, surfactant, porous ceramic, graphene, carbon fiber, and filler to obtain a mixture; S2. Add the curing agent to the mixture and mix to obtain the coating. This corrosion-resistant microwave absorbing coating can be used for coating the surface of metal pipes, and it has the advantages of strong corrosion resistance and strong microwave absorbing performance; the preparation method has the advantages of simple and efficient process and being convenient for industrial scale-up production of the coating.

[0005] Chinese Patent CN117070129A discloses an efficient wave-absorbing coating and its preparation method, which includes the following components in parts by weight: 45-90 parts of resin; 15-30 parts of solvent; 4-9 parts of curing agent; 3-9 parts of filler; 3-5 parts of rare earth oxide; and 20-45 parts of radiation protection composition; the raw materials for preparing the radiation protection composition include porous ceramics, adhesives, radioactive isotopes, and silanes. The prepared coating has excellent corrosion resistance and wave-absorbing performance. When the prepared coating is tested, the reflection loss of the coating is -29.5 dB, and the acid resistance grade reaches grade I. The preparation method of the efficient wave-absorbing coating includes the following steps: S1. Mix the resin, solvent, curing agent, and rare earth oxide to obtain a mixture; S2. Add the radiation protection composition and filler to the mixture and mix to obtain the product. The prepared coating has strong reflection loss ability and excellent corrosion resistance, and can be coated on the surface of metal pipes to improve performance.

[0006] Chinese Patent CN117511338A discloses a lightweight wave-absorbing coating for marine environment and its preparation method. The wave-absorbing coating includes a nano-light density wave-absorbing agent coating pre-dispersion, a nano-dielectric loss type heavy density wave-absorbing agent, and a curing agent; and the nano-light density wave-absorbing agent coating pre-dispersion contains a material for in-situ preparing highly crystalline carbon-coated single-walled carbon nanotubes. The highly crystalline carbon-coated single-walled carbon nanotubes have a stable structure and not only have excellent wave-absorbing characteristics but also have good corrosion resistance. When the thickness of the wave-absorbing coating prepared by the present invention is 10 mm, in the frequency range of 2-18 GHz, the absorption bandwidth with ≤ -10 dB exceeds 11.6 GHz, and at the same time, the reflectivity change after 1200 h under neutral salt spray conditions is within ±5%, which can improve the environmental adaptability and service life of the wave-absorbing coating.

[0007] However, as can be seen from the above prior art, the above wave-absorbing coatings cannot achieve both corrosion resistance and wave-absorbing performance, and there is still a lack of materials with more excellent corrosion resistance and wave-absorbing performance. Summary of the Invention

[0008] The purpose of the present invention is to provide a composite absorber and a corrosion-resistant wave-absorbing coating, which have excellent corrosion resistance and wave-absorbing performance.

[0009] In order to achieve the above invention purpose, the present invention provides the following technical solutions:

[0010] The present invention provides a composite absorber, which includes the following components:

[0011] Modified magnetic iron oxide nanoparticles, silicon carbide, graphene, polydopamine, alumina, and titanium oxide.

[0012] Preferably, the modified magnetic iron oxide nanoparticles are magnetic iron oxide nanoparticles modified with polyethyleneimine.

[0013] Preferably, the weight ratio of the modified magnetic iron oxide nanoparticles, silicon carbide, graphene, polydopamine, alumina and titanium oxide is 8-12:8-12:8-12:4-6:1-3:1-3.

[0014] The present invention also provides the application of the above composite absorbent in the preparation of microwave absorbing coatings.

[0015] The present invention also provides a corrosion-resistant microwave absorbing coating, which comprises the above composite absorbent, a coating matrix material and a coating auxiliary agent.

[0016] Preferably, the corrosion-resistant microwave absorbing coating comprises the following components in parts by weight:

[0017] 50-70 parts of the composite absorbent, 80-120 parts of the coating matrix material and 0.5-5 parts of the coating auxiliary agent.

[0018] Preferably, the coating matrix material is a modified epoxy resin.

[0019] Preferably, the modified epoxy resin is a polyurethane-modified epoxy ester resin.

[0020] Preferably, the coating auxiliary agent is a thickener.

[0021] The present invention also provides the application of the above corrosion-resistant microwave absorbing coating in the preparation of anti-electromagnetic wave pollution materials or radar stealth materials.

[0022] The technical effects and advantages of the present invention:

[0023] The present invention uses a composite absorbent prepared by compounding modified magnetic iron oxide nanoparticles, silicon carbide, graphene, polydopamine, alumina and titanium oxide. The wave absorption performances of these materials can complement each other, and excellent effects can be achieved when used in microwave absorbing coatings. The minimum reflection loss RL min can reach -61.53 dB, and the wave absorption bandwidth ranges from 10.1 to 14.2 GHz. Moreover, the corrosion-resistant microwave absorbing coating prepared by using the composite absorbent of the present invention has significantly improved corrosion resistance and brine resistance, and can be used for marine substrates, having broad application prospects. Detailed embodiments

[0024] The present invention provides a composite absorbent, comprising the following components: modified Fe₃O₄ magnetic nanoparticles, silicon carbide, graphene, polydopamine, alumina and titanium oxide; in the present invention, the modified Fe₃O₄ magnetic nanoparticles are preferably Fe₃O₄ magnetic nanoparticles modified with polyethyleneimine; the weight ratio of the modified Fe₃O₄ magnetic nanoparticles, silicon carbide, graphene, polydopamine, alumina and titanium oxide is preferably 8-12:8-12:8-12:4-6:1-3:1-3.

[0025] The present invention also provides the application of the above composite absorbent in the preparation of wave-absorbing coatings.

[0026] The present invention also provides a corrosion-resistant wave-absorbing coating, comprising the above composite absorbent, a coating matrix material and a coating auxiliary; preferably, the corrosion-resistant wave-absorbing coating comprises the following components in parts by weight: 50-70 parts of the composite absorbent, 80-120 parts of the coating matrix material and 0.5-5 parts of the coating auxiliary; preferably, the coating matrix material is a modified epoxy resin; preferably, the modified epoxy resin is a polyurethane-modified epoxy ester resin; further preferably, the coating auxiliary is a thickener.

[0027] The present invention also provides the application of the above corrosion-resistant wave-absorbing coating in the preparation of anti-electromagnetic wave pollution materials or radar stealth materials, and the coating thickness is preferably above 1.5 mm.

[0028] The technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0029] In the examples, the Chinese name of PEI@Fe₃O₄ is Fe₃O₄ magnetic nanoparticles modified with polyethyleneimine, purchased from Shanghai Buwei Applied Materials Technology Co., Ltd., CAS: 1317-61-9;

[0030] The modified epoxy resin was purchased from Wuhan Shiquanxing New Materials Technology Co., Ltd., with the trade name of polyurethane-modified epoxy ester resin and the product number of SZ-2360;

[0031] The thickener was purchased from Wuhan Runxingyuan Technology Co., Ltd., with the product number of QSC-935.

[0032] Example 1

[0033] Prepare the absorbent:

[0034] Mix all raw materials evenly according to the following weight ratio:

[0035] SiC powder: graphene: PEI@Fe₃O₄: polydopamine: alumina: titanium oxide = 10:10:10:5:3:2.

[0036] Preparation of corrosion-resistant microwave-absorbing coating:

[0037] Weigh 100 parts of modified epoxy resin, 60 parts of absorber, and 0.5 part of thickener. Mix them in an ultracentrifuge at 35 °C for 30 min to obtain the corrosion-resistant microwave-absorbing coating.

[0038] Microwave-absorbing performance test:

[0039] Use the above coating as a sample, and conduct experiments with aluminum alloy as the coating substrate. The coating thickness is 2 mm. Use a vector network analyzer to test the microwave-absorbing performance of the material by the coaxial probe method:

[0040] The results show that the minimum reflection loss RL of the test sample in this experiment min is -61.53 dB, and the microwave-absorbing bandwidth ranges from 10.1 to 14.2 GHz, showing excellent microwave-absorbing performance.

[0041] Corrosion protection performance test:

[0042] Immerse the coated substrate in a 30% sulfuric acid solution. After two weeks, observe and record the corrosion situation of the coating. Evaluate the corrosion degree according to levels 1 - 5, where level 5 indicates that the coating is almost completely damaged and loses its protective ability, indicating the worst corrosion resistance of the coating.

[0043] The results show that the corrosion protection performance of the test sample in this experiment is level 1, and the coating is hardly damaged.

[0044] Salt water resistance test:

[0045] Immerse the coated substrate in a 3% sodium chloride solution and heat it to 40 °C. After two weeks, observe and record the corrosion situation of the coating. Evaluate the corrosion degree according to levels 1 - 5, where level 5 indicates that the coating is almost completely corroded and has the worst salt water resistance.

[0046] The results show that the salt water resistance of the test sample in this experiment is level 1, and the coating is hardly damaged.

[0047] Example 2

[0048] Preparation of absorber:

[0049] Mix all raw materials evenly according to the following weight ratio:

[0050] SiC powder: graphene: PEI@Fe3O4: polydopamine: alumina: titanium oxide = 10:10:8:5:3:2.

[0051] Preparation of corrosion-resistant microwave-absorbing coating:

[0052] Weigh 100 parts of modified epoxy resin, 60 parts of absorbent, and 0.5 part of thickener. Mix them in an ultracentrifuge at 35 °C for 30 min to obtain a corrosion-resistant wave-absorbing coating.

[0053] Wave-absorbing performance test:

[0054] Use the above coating as a sample, and conduct experiments with aluminum alloy as the coating substrate. The coating thickness is 2 mm. Use a vector network analyzer to test the wave-absorbing performance of the material by the coaxial probe method:

[0055] The results show that the minimum reflection loss RL of the test specimen in this experiment min is -59.55 dB, and the wave-absorbing bandwidth range is 10.1 - 14.1 GHz, showing excellent wave-absorbing performance.

[0056] Corrosion protection performance test:

[0057] Immerse the coated substrate in a 30% sulfuric acid solution. After two weeks, observe and record the corrosion situation of the coating. Evaluate the corrosion degree according to levels 1 - 5. Level 5 indicates that the coating is almost completely damaged and loses its protective ability, indicating the worst corrosion resistance of the coating.

[0058] The results show that the corrosion protection performance of the test sample in this experiment is level 1, and the coating is hardly damaged.

[0059] Salt water resistance test:

[0060] Immerse the coated substrate in a 3% sodium chloride solution and heat it to 40 °C. After two weeks, observe and record the corrosion situation of the coating. Evaluate the corrosion degree according to levels 1 - 5. Level 5 indicates that the coating is almost completely corroded and has the worst salt water resistance.

[0061] The results show that the salt water resistance of the test sample in this experiment is level 1, and the coating is hardly damaged.

[0062] Example 3

[0063] Prepare the absorbent:

[0064] Mix all raw materials evenly according to the following weight ratio:

[0065] SiC powder: graphene: PEI@Fe3O4: polydopamine: alumina: titanium oxide = 10:10:12:5:3:2.

[0066] Prepare the corrosion-resistant wave-absorbing coating:

[0067] Weigh 100 parts of modified epoxy resin, 60 parts of absorbent, and 0.5 part of thickener. Mix them in an ultracentrifuge at 35 °C for 30 min to obtain a corrosion-resistant wave-absorbing coating.

[0068] Absorbing performance test:

[0069] Using the above coating as a sample, aluminum alloy was used as the coating substrate for the experiment. The coating thickness was 2 mm. The absorbing performance of the material was tested by the coaxial probe method using a vector network analyzer:

[0070] The results showed that the minimum reflection loss RL min of the sample in this experiment was -59.67 dB, and the absorbing bandwidth range was 10.1 - 14.1 GHz, showing excellent absorbing performance.

[0071] Corrosion resistance test:

[0072] The coated substrate was immersed in a 30% sulfuric acid solution. After two weeks, the corrosion situation of the coating was observed and recorded. The corrosion degree was evaluated according to levels 1 - 5, where level 5 indicated that the coating was almost completely damaged and lost its protective ability, indicating the worst corrosion resistance of the coating.

[0073] The results showed that the corrosion resistance of the sample in this experiment was level 1, and the coating was hardly damaged.

[0074] Salt water resistance test:

[0075] The coated substrate was immersed in a 3% sodium chloride solution and heated to 40°C. After two weeks, the corrosion situation of the coating was observed and recorded. The corrosion degree was evaluated according to levels 1 - 5, where level 5 indicated that the coating was almost completely corroded and had the worst salt water resistance.

[0076] The results showed that the salt water resistance of the sample in this experiment was level 1, and the coating was hardly damaged.

[0077] Example 4

[0078] Preparation of absorbent:

[0079] All raw materials were mixed evenly according to the following weight ratio:

[0080] SiC powder: graphene: PEI@Fe3O4: polydopamine: alumina: titanium oxide = 10:10:10:5:3:2.

[0081] Preparation of corrosion - resistant absorbing coating:

[0082] 100 parts of modified epoxy resin, 55 parts of absorbent, and 0.5 part of thickener were weighed and mixed in an ultra - centrifuge at 35°C for 30 min to obtain the corrosion - resistant absorbing coating.

[0083] Absorbing performance test:

[0084] Using the above coating as a sample, an experiment was carried out with aluminum alloy as the coating substrate. The coating thickness was 2 mm. The wave absorption performance of the material was tested by the coaxial probe method using a vector network analyzer:

[0085] The results showed that the minimum reflection loss RL of the test specimen in this experiment min was -59.39 dB, and the wave absorption bandwidth range was 10.1 - 14.0 GHz, showing excellent wave absorption performance.

[0086] Corrosion resistance test:

[0087] The coated substrate was immersed in a 30% sulfuric acid solution. After two weeks, the corrosion situation of the coating was observed and recorded. The corrosion degree was evaluated according to levels 1 - 5. Among them, level 5 showed that the coating was almost completely damaged and lost its protective ability, indicating the worst corrosion resistance of the coating.

[0088] The results showed that the corrosion resistance of the test sample in this experiment was level 1, and the coating was hardly damaged.

[0089] Salt water resistance test:

[0090] The coated substrate was immersed in a 3% sodium chloride solution and heated to 40°C. After two weeks, the corrosion situation of the coating was observed and recorded. The corrosion degree was evaluated according to levels 1 - 5. Among them, level 5 showed that the coating was almost completely corroded and the salt water resistance of the coating was the worst.

[0091] The results showed that the salt water resistance of the test sample in this experiment was level 1, and the coating was hardly damaged.

[0092] Example 5

[0093] Prepare the absorber:

[0094] Mix all raw materials evenly according to the following weight ratio:

[0095] SiC powder: graphene: PEI@Fe3O4: polydopamine: alumina: titanium oxide = 10:10:10:5:3:2.

[0096] Prepare the corrosion-resistant wave-absorbing coating:

[0097] Weigh 100 parts of modified epoxy resin, 65 parts of absorber, and 0.5 part of thickener, and mix them in an ultracentrifuge at 35°C for 30 min to obtain the corrosion-resistant wave-absorbing coating.

[0098] Wave absorption performance test:

[0099] Using the above coating as a sample, an experiment was carried out with aluminum alloy as the coating substrate. The coating thickness was 2 mm. The wave absorption performance of the material was tested by the coaxial probe method using a vector network analyzer:

[0100] The results show that the minimum reflection loss RL of the test specimens in this experiment min is -60.57 dB, and the wave absorption bandwidth ranges from 10.1 to 14.3 GHz, showing excellent wave absorption performance.

[0101] Corrosion resistance test:

[0102] The coated substrate was immersed in a 30% sulfuric acid solution. After two weeks, the corrosion situation of the coating was observed and recorded, and the corrosion degree was evaluated according to levels 1 to 5. Level 5 indicates that the coating was almost completely damaged and lost its protective ability, indicating the worst corrosion resistance of the coating.

[0103] The results show that the corrosion resistance of the test samples in this experiment is level 1, and the coating was hardly damaged.

[0104] Salt water resistance test:

[0105] The coated substrate was immersed in a 3% sodium chloride solution and heated to 40 °C. After two weeks, the corrosion situation of the coating was observed and recorded, and the corrosion degree was evaluated according to levels 1 to 5. Level 5 indicates that the coating was almost completely corroded and the salt water resistance of the coating was the worst.

[0106] The results show that the salt water resistance of the test samples in this experiment is level 1, and the coating was hardly damaged.

[0107] Comparative example 1

[0108] Prepare the absorbent:

[0109] Mix all raw materials evenly according to the following weight ratio:

[0110] SiC powder: graphene: polydopamine: alumina: titanium oxide = 15:5:5:3:2.

[0111] Prepare the corrosion-resistant wave-absorbing coating:

[0112] Weigh 100 parts of modified epoxy resin, 60 parts of absorbent, and 0.5 part of thickener, and mix them in an ultracentrifuge at 35 °C for 30 min to obtain the corrosion-resistant wave-absorbing coating.

[0113] Wave absorption performance test:

[0114] Using the above coating as the sample, an experiment was carried out with an aluminum alloy as the coated substrate. The coating thickness was 2 mm, and the wave absorption performance of the material was tested by the coaxial probe method using a vector network analyzer:

[0115] The results show that the minimum reflection loss RL of the test specimens in this experiment min is -35.73 dB, and the wave absorption bandwidth ranges from 11.2 to 12.8 GHz.

[0116] Anti-corrosion performance test:

[0117] The coated substrate was immersed in a 30% sulfuric acid solution. After two weeks, the corrosion situation of the coating was observed and recorded. The corrosion degree was evaluated according to levels 1 - 5. Level 5 indicates that the coating was almost completely damaged and lost its protective ability, indicating the worst corrosion resistance of the coating.

[0118] The results showed that the anti-corrosion performance of the experimental samples in this test was level 3.

[0119] Salt water resistance performance test:

[0120] The coated substrate was immersed in a 3% sodium chloride solution and heated to 40°C. After two weeks, the corrosion situation of the coating was observed and recorded. The corrosion degree was evaluated according to levels 1 - 5. Level 5 indicates that the coating was almost completely corroded and the salt water resistance performance of the coating was the worst.

[0121] The results showed that the salt water resistance performance of the experimental samples in this test was level 1.

[0122] Comparative example 2

[0123] Prepare the absorbent:

[0124] Mix all raw materials evenly according to the following weight ratio:

[0125] SiC powder: graphene: PEI@Fe3O4: alumina = 10:10:10:5.

[0126] Prepare the corrosion-resistant absorbing coating:

[0127] Weigh 100 parts of modified epoxy resin, 60 parts of absorbent, and 0.5 parts of thickener. Mix them in an ultracentrifuge at 35°C for 30 minutes to obtain the corrosion-resistant absorbing coating.

[0128] Absorbing performance test:

[0129] Use the above coating as a sample, and use aluminum alloy as the coated substrate for the experiment. The coating thickness is 2 mm. Use a vector network analyzer to test the absorbing performance of the material by the coaxial probe method:

[0130] The results showed that the minimum reflection loss RL min of the experimental specimen in this test was -41.96 dB, and the absorbing bandwidth range was 10.6 - 12.4 GHz.

[0131] Anti-corrosion performance test:

[0132] The coated substrate was immersed in a 30% sulfuric acid solution, and the corrosion of the coating was observed and recorded after two weeks. The degree of corrosion was evaluated on a scale of 1 to 5, where a grade of 5 indicates that the coating was almost completely damaged and lost its protective ability, indicating the poorest corrosion resistance of the coating.

[0133] The results showed that the corrosion protection performance of the experimental samples in this experiment was grade 3.

[0134] Salt water resistance test:

[0135] The coated substrate was immersed in a 3% sodium chloride solution and heated to 40 °C. After two weeks, the corrosion of the coating was observed and recorded. The degree of corrosion was evaluated on a scale of 1 to 5, where a grade of 5 indicates that the coating was almost completely corroded and the salt water resistance of the coating was the worst.

[0136] The results showed that the salt water resistance of the experimental samples in this experiment was grade 2.

[0137] Comparative example 3

[0138] Prepare the absorbent:

[0139] Mix all the raw materials evenly according to the following weight ratio:

[0140] SiC powder: graphene: PEI@Fe3O4: alumina: titanium oxide = 15:5:10:3:2.

[0141] Prepare the corrosion-resistant wave-absorbing coating:

[0142] Weigh 100 parts of modified epoxy resin, 65 parts of absorbent, and 0.5 part of thickener, and mix them in an ultracentrifuge at 35 °C for 30 min to obtain the wave-absorbing coating.

[0143] Wave-absorbing performance test:

[0144] Use the above coating as a sample, and conduct an experiment with an aluminum alloy as the coated substrate. The coating thickness is 2 mm. Use a vector network analyzer to test the wave-absorbing performance of the material by the coaxial probe method:

[0145] The results showed that the minimum reflection loss RL of the test specimens in this experiment min was -46.91 dB, and the wave-absorbing bandwidth range was 10.6 - 13.1 GHz.

[0146] Corrosion protection performance test:

[0147] The coated substrate was immersed in a 30% sulfuric acid solution, and the corrosion of the coating was observed and recorded after two weeks. The degree of corrosion was evaluated on a scale of 1 to 5, where a grade of 5 indicates that the coating was almost completely damaged and lost its protective ability, indicating the poorest corrosion resistance of the coating.

[0148] The results show that the anti-corrosion performance of the experimental samples in this test is Grade 4.

[0149] Salt water resistance performance test:

[0150] The coated substrate was immersed in a 3% sodium chloride solution and heated to 40 °C. After two weeks, the corrosion situation of the coating was observed and recorded, and the corrosion degree was evaluated according to Levels 1-5. Among them, Level 5 indicates that the coating is almost completely corroded and the salt water resistance performance of the coating is the worst.

[0151] The results show that the salt water resistance performance of the experimental samples in this test is Grade 3.

[0152] Comparative Example 4

[0153] Prepare the absorbent:

[0154] Mix all raw materials evenly according to the following weight ratio:

[0155] SiC powder: graphene: PEI@Fe3O4: polydopamine: alumina: titanium oxide = 5:5:15:15:2:3.

[0156] Prepare the corrosion-resistant absorbing coating:

[0157] Weigh 100 parts of modified epoxy resin, 60 parts of absorbent, and 0.5 part of thickener, and mix them in an ultracentrifuge at 35 °C for 30 minutes to obtain the corrosion-resistant absorbing coating.

[0158] Absorbing performance test:

[0159] Use the above coating as the sample, and conduct experiments with an aluminum alloy as the coated substrate. The coating thickness is 2 mm. Use a vector network analyzer to test the absorbing performance of the material by the coaxial probe method:

[0160] The results show that the minimum reflection loss RL of the test specimen in this test min is -38.89 dB, and the absorbing bandwidth range is 11.0 - 13.3 GHz.

[0161] Anti-corrosion performance test:

[0162] Immerse the coated substrate in a 30% sulfuric acid solution. After two weeks, observe and record the corrosion situation of the coating, and evaluate the corrosion degree according to Levels 1-5. Among them, Level 5 indicates that the coating is almost completely damaged and loses its protective ability, indicating that the corrosion resistance of the coating is the worst.

[0163] The results show that the anti-corrosion performance of the experimental samples in this test is Grade 2.

[0164] Salt water resistance performance test:

[0165] The coated substrate was immersed in a 3% sodium chloride solution and heated to 40 °C. After two weeks, the corrosion situation of the coating was observed and recorded, and the corrosion degree was evaluated according to levels 1 - 5, where level 5 indicates that the coating was almost completely corroded and the saltwater resistance of the coating was the worst.

[0166] The results showed that the saltwater resistance of the experimental samples in this experiment was level 2.

[0167] Comparative Example 5

[0168] Prepare the absorbent:

[0169] Mix all raw materials evenly according to the following weight ratio:

[0170] Graphene: PEI@Fe3O4: Alumina: Titanium oxide = 15:15:5:5.

[0171] Prepare the corrosion-resistant wave-absorbing coating:

[0172] Weigh 100 parts of ordinary epoxy resin, 50 parts of absorbent, and 0.5 part of thickener, and mix them in an ultracentrifuge at 35 °C for 30 min to obtain the corrosion-resistant wave-absorbing coating.

[0173] Wave-absorbing performance test:

[0174] Use the above coating as a sample, use aluminum alloy as the coated substrate for the experiment, the coating thickness is 2 mm, and use a vector network analyzer to test the wave-absorbing performance of the material by the coaxial probe method:

[0175] The results showed that the minimum reflection loss RL min of the test specimen in this experiment was -33.20 dB, and the wave-absorbing bandwidth range was 10.7 - 11.9 GHz.

[0176] Corrosion protection performance test:

[0177] Immerse the coated substrate in a 30% sulfuric acid solution. After two weeks, observe and record the corrosion situation of the coating, and evaluate the corrosion degree according to levels 1 - 5, where level 5 indicates that the coating was almost completely damaged and lost its protective ability, indicating that the corrosion resistance of the coating was the worst.

[0178] The results showed that the corrosion protection performance of the experimental samples in this experiment was level 5.

[0179] Saltwater resistance performance test:

[0180] Immerse the coated substrate in a 3% sodium chloride solution and heat to 40 °C. After two weeks, observe and record the corrosion situation of the coating, and evaluate the corrosion degree according to levels 1 - 5, where level 5 indicates that the coating was almost completely corroded and the saltwater resistance of the coating was the worst.

[0181] The results show that the salt water resistance of the experimental samples in this experiment is Grade 5.

[0182] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A corrosion-resistant radar absorbing coating, characterized in that: Including composite absorbent, coating base material and coating additive; The corrosion-resistant wave-absorbing coating comprises the following components in parts by weight: 50 to 70 parts of a composite absorber, 80 to 120 parts of a coating base material, and 0.5 to 5 parts of a coating additive; The composite absorbent comprises the following components: modified ferroferric oxide magnetic nanoparticles, silicon carbide, graphene, polydopamine, aluminum oxide and titanium oxide; The modified ferroferric oxide magnetic nanoparticles are ferroferric oxide magnetic nanoparticles modified by polyethyleneimine; The weight ratio of the modified ferroferric oxide magnetic nanoparticles, silicon carbide, graphene, polydopamine, aluminum oxide and titanium oxide is 8-12:8-12:8-12:4-6:1-3:1-3; The coating matrix material is a modified epoxy resin; The modified epoxy resin is a polyurethane modified epoxy ester resin; The coating additive is a thickener.

2. Use of the corrosion-resistant and radar-absorbing coating according to claim 1 in the preparation of anti-electromagnetic wave pollution materials or radar stealth materials.