Preparation method for low-temperature synthesis of high-entropy spinel oxide coating with electromagnetic wave absorption and corrosion resistance

Abstract

The invention discloses a preparation method for low-temperature synthesis of a high-entropy spinel oxide coating with electromagnetic wave absorption and corrosion resistance, a hydrothermal method is adopted to prepare a high-entropy spinel oxide, the process is simple and easy to implement, the synthesis temperature is low, the operation is simple and convenient, the cost is low, and the prepared high-entropy spinel oxide powder material is high in purity and good in electromagnetic wave absorption and corrosion resistance. The material can be directly sintered and molded and realizes an electromagnetic wave absorption function; meanwhile, the high-entropy spinel oxide powder is doped into the resin coating, so that the corrosion resistance of the coating is effectively improved, a novel coating with electromagnetic wave absorption and corrosion resistance is obtained, and the problem that an electromagnetic wave absorption coating on the surface of a metal base material is easy to corrode in the prior art is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic wave absorbing materials technology, and in particular to a method for preparing a high-entropy spinel oxide coating with electromagnetic wave absorption and corrosion resistance properties through low-temperature synthesis. Background Technology

[0002] With the continuous advancement of technology and the increasing demands of people's lives, it is necessary to coat the surfaces of military equipment and civilian devices (such as the surfaces of ships, torpedoes, and mobile phone inner casings) with coatings that absorb electromagnetic waves. However, when the electromagnetic wave absorbing coating on the substrate surface is exposed to harsh environments such as humidity, acids, alkalis, and salts for extended periods, the performance of the absorbing material will deteriorate or its service life will be affected. Therefore, there is an urgent need to develop coatings that combine electromagnetic wave absorption and corrosion resistance to solve this technical challenge. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a high-entropy spinel oxide coating with electromagnetic wave absorption and corrosion resistance at low temperature, so as to effectively solve the problem that electromagnetic wave absorbing coatings on the surface of metal substrates are easily corroded in the prior art.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] This invention provides a method for preparing a high-entropy spinel oxide coating with electromagnetic wave absorption and corrosion resistance through low-temperature synthesis, comprising the following steps:

[0006] (1) Preparation of nickel-copper-zinc-manganese-cobalt salt high-entropy spinel oxide precursor liquid

[0007] (1-1) According to the molar ratio of cobalt:nickel:copper:zinc:manganese = 6~10:1~3:1~3:1~3:1~3, the cobalt source, nickel source, copper source, zinc source and manganese source are dissolved in water and stirred evenly to obtain a mixed solution;

[0008] (1-2) Add urea to the mixed solution according to the molar ratio of cobalt:urea = 1:3-6, stir for 30-60 min until the solution is mixed evenly to obtain nickel copper zinc manganese cobaltate precursor solution;

[0009] (2) Preparation of high-entropy spinel oxide powder materials of nickel copper zinc manganese cobalt salt

[0010] (2-1) The nickel copper zinc manganese cobalt salt precursor liquid was placed in a hydrothermal reactor and subjected to hydrothermal reaction at a temperature of 95-145°C for 6-30 hours to obtain the reaction product.

[0011] (2-2) The reaction product is centrifuged, washed and dried, and then heated to 300-600℃ at a rate of 2-5℃ / min for sintering treatment. The holding time is 1-3h to obtain high-entropy spinel oxide powder material.

[0012] (3) Preparation of high-entropy spinel oxide coatings with both electromagnetic wave absorption and corrosion resistance properties

[0013] (3-1) The high-entropy spinel oxide powder material is added to the coating and stirred evenly to obtain a mixed coating with a high-entropy spinel oxide powder material content of 2-10%.

[0014] (3-2) After grinding, washing and drying the surface of the metal substrate, the mixed coating is applied to the surface of the metal substrate. After static curing, a high-entropy spinel oxide coating with both electromagnetic wave absorption and corrosion resistance is obtained.

[0015] Further, in step (1) of the present invention, the stirring time is 20–40 min. In step (2-2), the reaction product is washed with water by centrifugation 3–5 times, then washed with anhydrous ethanol by centrifugation 3–5 times, and dried at 60–80°C for 10–24 h. In step (3-2), the coating thickness of the mixed coating is 90–110 μm, and it is allowed to cure at room temperature for 8–24 h.

[0016] In the above scheme, the cobalt source of the present invention is cobalt nitrate, cobalt chloride, cobalt acetate, or cobalt sulfate; the nickel source is nickel nitrate, nickel chloride, nickel acetate, or nickel sulfate; the copper source is copper nitrate, copper chloride, copper acetate, or copper sulfate; the zinc source is zinc nitrate, zinc chloride, zinc acetate, or zinc sulfate; and the manganese source is manganese nitrate, manganese chloride, manganese acetate, or manganese sulfate. The high-entropy spinel oxide powder material obtained in step (2) of the present invention has a fuzzy spherical morphology, with O, Co, Zn, Cu, Ni, and Mn uniformly distributed; its microwave absorption performance is as follows: at a frequency of 16.86–17.98 GHz and a matching thickness of 1.70–2.07 mm, the absorption loss is -55.75–-18.56 dB; at a matching thickness of 2.04–2.79 mm, the effective absorption bandwidth is 7.13–8.11 GHz.

[0017] In the above scheme, the high-entropy spinel oxide coating is subjected to salt spray testing under the condition of 5% sodium chloride solution, and the salt spray corrosion resistance time is at least 9 days.

[0018] The present invention has the following beneficial effects:

[0019] (1) This invention uses a hydrothermal method to prepare high-entropy spinel oxide, which is not only simple and easy to implement, with low synthesis temperature, convenient operation, and low cost, but also produces high-entropy spinel oxide powder with high purity, which can be directly sintered. The spherical structure of nickel, zinc, copper, manganese, cobalt, and oxygen atoms in the high-entropy spinel oxide forms a three-dimensional network, providing more paths for electron hopping, thereby increasing conductivity loss; the oxide powder has a fuzzy spherical morphology with a large number of interfaces, thus having greater microwave absorption advantages. At the same time, due to the continuous increase in magnetic loss, the high-entropy spinel oxide achieves microwave absorption (RL≤-10 dB) under the combined effect of multiple losses.

[0020] (2) This invention involves doping high-entropy spinel oxide powder into a resin coating to form a mixed coating. After adding the powder, the powder particles fill the voids and pores in the resin, making the path of the corrosive medium to the metal substrate more tortuous, thereby effectively improving the corrosion resistance of the coating. Therefore, the prepared coating is a novel coating that combines electromagnetic wave absorption and corrosion resistance. Attached Figure Description

[0021] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings:

[0022] Figure 1 This is the XRD pattern of the nickel-copper-zinc-manganese-cobaltate high-entropy spinel oxide powder material prepared in Example 1 of this invention;

[0023] Figure 2 The images show the SEM images and EDS test results of the nickel-copper-zinc-manganese-cobaltate high-entropy spinel oxide powder material prepared in Example 1 of this invention.

[0024] Figure 3 This is a schematic diagram of the microwave reflection loss of the nickel-copper-zinc-manganese cobaltate high-entropy spinel oxide powder material prepared in Example 1 of the present invention at different thicknesses.

[0025] Figure 4 The images show the nickel-copper-zinc-manganese-cobaltate high-entropy spinel oxide coating prepared in Example 1 of this invention, and a salt spray test diagram of a comparative example.

[0026] Figure 5 This is the XRD pattern of the nickel-copper-zinc-manganese-cobaltate high-entropy spinel oxide powder material prepared in Example 2 of this invention;

[0027] Figure 6 The images show the SEM images and EDS test results of the nickel-copper-zinc-manganese-cobaltate high-entropy spinel oxide powder material prepared in Example 2 of this invention.

[0028] Figure 7This is a schematic diagram of the microwave reflection loss of the nickel-copper-zinc-manganese cobaltate high-entropy spinel oxide powder material prepared in Example 2 of the present invention at different thicknesses;

[0029] Figure 8 The images show the nickel-copper-zinc-manganese-cobaltate high-entropy spinel oxide coating prepared in Example 2 of this invention, and a salt spray test diagram of a comparative example.

[0030] Figure 9 This is the XRD pattern of the nickel-copper-zinc-manganese-cobaltate high-entropy spinel oxide powder material prepared in Example 3 of this invention;

[0031] Figure 10 The images show the SEM images and EDS test results of the nickel-copper-zinc-manganese-cobaltate high-entropy spinel oxide powder material prepared in Example 3 of this invention.

[0032] Figure 11 This is a schematic diagram of the microwave reflection loss of the nickel-copper-zinc-manganese cobaltate high-entropy spinel oxide powder material prepared in Example 3 of the present invention at different thicknesses;

[0033] Figure 12 The images show the nickel-copper-zinc-manganese cobaltate high-entropy spinel oxide coating prepared in Example 3 of this invention, and a comparative example of a salt spray test. Detailed Implementation

[0034] Example 1:

[0035] This embodiment describes a method for preparing a high-entropy spinel oxide coating with electromagnetic wave absorption and corrosion resistance through low-temperature synthesis. The steps are as follows:

[0036] (1) Preparation of nickel-copper-zinc-manganese-cobalt salt high-entropy spinel oxide precursor liquid

[0037] (1-1) Dissolve 2.9105 g cobalt nitrate hexahydrate, 0.3635 g nickel nitrate hexahydrate, 0.3020 g copper nitrate trihydrate, 0.3719 g zinc nitrate hexahydrate, and 0.4474 g manganese nitrate tetrahydrate in 50.0 mL of water and stir for 30 min to obtain a mixed solution;

[0038] (1-2) Add 2.9105 g of urea to the above mixed solution and stir for 30 min to obtain nickel copper zinc manganese cobaltate precursor solution;

[0039] (2) Preparation of high-entropy spinel oxide powder materials of nickel copper zinc manganese cobalt salt

[0040] (2-1) The above nickel-copper-zinc-manganese-cobaltate precursor liquid was placed in a hydrothermal reactor and then placed in a drying oven for heating. The temperature of the drying oven was 105℃ and the hydrothermal reaction time was 12h to obtain the reaction product.

[0041] (2-2) The above reaction product was washed three times by centrifugation with water, then washed three times by centrifugation with anhydrous ethanol, dried at 80℃ for 24h, and then placed in a muffle furnace and heated to 400℃ at a rate of 5℃ / min for sintering treatment. The holding time was 2h to obtain high-entropy spinel oxide powder material.

[0042] (3) Preparation of high-entropy spinel oxide coatings with both electromagnetic wave absorption and corrosion resistance properties

[0043] (3-1) Add the above high-entropy spinel oxide powder material to the epoxy resin coating (and add the curing agent polyamide 650 with the same mass as the epoxy resin), stir evenly, and obtain a mixed coating with a high-entropy spinel oxide powder material content of 5wt%.

[0044] (3-2) The Q235 carbon steel substrate was repeatedly polished with 400# and 1000# sandpaper, ultrasonically cleaned with anhydrous ethanol for 15 min, and dried. The above mixed coating was then applied to the Q235 carbon steel substrate by scraping method. The coating thickness was 100±10μm. After standing and curing at room temperature for 24 h, a high-entropy spinel oxide coating with both electromagnetic wave absorption and corrosion resistance was obtained.

[0045] The high-entropy spinel oxide powder material obtained in step (2) of this embodiment, such as Figure 1 As shown, its characteristic diffraction peaks match those of the standard cards for nickel cobaltate, copper cobaltate, zinc cobaltate, and manganese cobaltate, indicating that the detected substance is nickel-copper-zinc-manganese cobaltate. Figure 2 As shown, the oxide powder material exhibits a bouncy, spherical shape, with O, Co, Zn, Cu, Ni, and Mn uniformly distributed throughout the sample. Due to the abundance of interfaces, the bouncy, spherical material possesses greater microwave absorption advantages. Figure 3 As shown, the oxide powder material has an effective electromagnetic wave absorption band in the frequency range of 2 to 18 GHz. At a frequency of 16.86 GHz and a thickness of 2.07 mm, the absorption loss of the sample reaches -55.75 dB; when the sample thickness is 2.79 mm, the effective absorption bandwidth is 8.03 GHz.

[0046] The nickel-copper-zinc-manganese-cobaltate high-entropy spinel oxide coating prepared in this embodiment was subjected to salt spray testing in a salt spray chamber under 5% (w / w) sodium chloride solution conditions. A coating made of pure epoxy resin on a Q235 surface and a pure Q235 carbon steel substrate (uncoated) were used as comparative examples. The test results are as follows: Figure 4As shown (samples 1#, 2#, and 3# in the figure are parallel samples of this embodiment), with the increase of time in the salt spray environment, when the salt spray time is 1 day, the uncoated pure Q235 carbon steel substrate begins to be corroded over a large area, forming a large amount of reddish-brown corrosion products; when the salt spray time is 5 days, the pure epoxy resin coating begins to show pitting corrosion (as shown in the red circle in the figure); when the salt spray time is 9 days, the 3# nickel copper zinc manganese cobalt salt high-entropy spinel oxide coating begins to show blistering (as shown in the red circle in the figure).

[0047] Example 2:

[0048] This embodiment describes a method for preparing a high-entropy spinel oxide coating with electromagnetic wave absorption and corrosion resistance through low-temperature synthesis. The steps are as follows:

[0049] (1) Preparation of nickel-copper-zinc-manganese-cobalt salt high-entropy spinel oxide precursor liquid

[0050] (1-1) Dissolve 2.9105 g cobalt nitrate hexahydrate, 0.3635 g nickel nitrate hexahydrate, 0.3020 g copper nitrate trihydrate, 0.3719 g zinc nitrate hexahydrate, and 0.4474 g manganese nitrate tetrahydrate in 50.0 mL of water and stir for 30 min to obtain a mixed solution;

[0051] (1-2) Add 2.9105 g of urea to the above mixed solution and stir for 30 min to obtain nickel copper zinc manganese cobaltate precursor solution;

[0052] (2) Preparation of high-entropy spinel oxide powder materials of nickel copper zinc manganese cobalt salt

[0053] (2-1) The above nickel-copper-zinc-manganese-cobaltate precursor liquid was placed in a hydrothermal reactor and then placed in a drying oven for heating. The temperature of the drying oven was 105℃ and the hydrothermal reaction time was 18h to obtain the reaction product.

[0054] (2-2) The above reaction product was washed three times by centrifugation with water, then washed three times by centrifugation with anhydrous ethanol, dried at 80℃ for 24h, and then placed in a muffle furnace and heated to 400℃ at a rate of 5℃ / min for sintering treatment. The holding time was 2h to obtain high-entropy spinel oxide powder material.

[0055] (3) Preparation of high-entropy spinel oxide coatings with both electromagnetic wave absorption and corrosion resistance properties

[0056] (3-1) Add the above high-entropy spinel oxide powder material to the epoxy resin coating (and add the curing agent polyamide 650 with the same mass as the epoxy resin), stir evenly, and obtain a mixed coating with a high-entropy spinel oxide powder material content of 5wt%.

[0057] (3-2) The Q235 carbon steel substrate was repeatedly polished with 400# and 1000# sandpaper, ultrasonically cleaned with anhydrous ethanol for 15 min, and dried. The above mixed coating was then applied to the Q235 carbon steel substrate by scraping method. The coating thickness was 100±10μm. After standing and curing at room temperature for 24 h, a high-entropy spinel oxide coating with both electromagnetic wave absorption and corrosion resistance was obtained.

[0058] The high-entropy spinel oxide powder material obtained in step (2) of this embodiment, such as Figure 5 As shown, its characteristic diffraction peaks match those of the standard cards for nickel cobaltate, copper cobaltate, zinc cobaltate, and manganese cobaltate, indicating that the detected substance is nickel-copper-zinc-manganese cobaltate. Figure 6 As shown, the oxide powder material exhibits a bouncy, spherical shape, with O, Co, Zn, Cu, Ni, and Mn uniformly distributed throughout the sample. Due to the abundance of interfaces, the bouncy, spherical material possesses greater microwave absorption advantages. Figure 7 As shown, the oxide powder material has an effective electromagnetic wave absorption band in the frequency range of 2 to 18 GHz. When the frequency is 17.62 GHz and the thickness is 1.86 mm, the absorption loss of the sample reaches -21.21 dB; when the sample thickness is 2.29 mm, the effective absorption bandwidth is 8.11 GHz.

[0059] The nickel-copper-zinc-manganese-cobaltate high-entropy spinel oxide coating prepared in this embodiment was subjected to salt spray testing in a salt spray chamber under 5% (w / w) sodium chloride solution conditions. A coating made of pure epoxy resin on a Q235 surface and a pure Q235 carbon steel substrate (uncoated) were used as comparative examples. The test results are as follows: Figure 8 As shown (samples 1#, 2#, and 3# in the figure are parallel samples of this embodiment), with the increase of time in the salt spray environment, when the salt spray time is 1 day, the uncoated pure Q235 carbon steel substrate begins to be corroded over a large area, forming a large amount of reddish-brown corrosion products; when the salt spray time is 5 days, the pure epoxy resin coating begins to show pitting corrosion (as shown in the red circle in the figure); when the salt spray time is 10 days, the #3 nickel copper zinc manganese cobalt salt high-entropy spinel oxide coating begins to show pitting corrosion (as shown in the red circle in the figure).

[0060] Example 3:

[0061] This embodiment describes a method for preparing a high-entropy spinel oxide coating with electromagnetic wave absorption and corrosion resistance through low-temperature synthesis. The steps are as follows:

[0062] (1) Preparation of nickel-copper-zinc-manganese-cobalt salt high-entropy spinel oxide precursor liquid

[0063] (1-1) Dissolve 2.9105 g cobalt nitrate hexahydrate, 0.3635 g nickel nitrate hexahydrate, 0.3020 g copper nitrate trihydrate, 0.3719 g zinc nitrate hexahydrate, and 0.4474 g manganese nitrate tetrahydrate in 50.0 mL of water and stir for 30 min to obtain a mixed solution;

[0064] (1-2) Add 2.9105 g of urea to the above mixed solution and stir for 30 min to obtain nickel copper zinc manganese cobaltate precursor solution;

[0065] (2) Preparation of high-entropy spinel oxide powder materials of nickel copper zinc manganese cobalt salt

[0066] (2-1) The above nickel-copper-zinc-manganese-cobaltate precursor liquid was placed in a hydrothermal reactor and then placed in a drying oven for heating. The temperature of the drying oven was 105℃ and the hydrothermal reaction time was 24h to obtain the reaction product.

[0067] (2-2) The above reaction product was washed three times by centrifugation with water, then washed three times by centrifugation with anhydrous ethanol, dried at 80℃ for 24h, and then placed in a muffle furnace and heated to 400℃ at a rate of 5℃ / min for sintering treatment. The holding time was 2h to obtain high-entropy spinel oxide powder material.

[0068] (3) Preparation of high-entropy spinel oxide coatings with both electromagnetic wave absorption and corrosion resistance properties

[0069] (3-1) Add the above high-entropy spinel oxide powder material to the epoxy resin coating (and add the curing agent polyamide 650 with the same mass as the epoxy resin), stir evenly, and obtain a mixed coating with a high-entropy spinel oxide powder material content of 5wt%.

[0070] (3-2) The Q235 carbon steel substrate was repeatedly polished with 400# and 1000# sandpaper, ultrasonically cleaned with anhydrous ethanol for 15 min, and dried. The above mixed coating was then applied to the Q235 carbon steel substrate by scraping method. The coating thickness was 100±10 μm. After standing and curing at room temperature for 24 h, a high-entropy spinel oxide coating with both electromagnetic wave absorption and corrosion resistance was obtained.

[0071] The high-entropy spinel oxide powder material obtained in step (2) of this embodiment, such as Figure 9 As shown, its characteristic diffraction peaks match those of the standard cards for nickel cobaltate, copper cobaltate, zinc cobaltate, and manganese cobaltate, indicating that the detected substance is nickel-copper-zinc-manganese cobaltate. Figure 10 As shown, the oxide powder material exhibits a bouncy, spherical shape, with O, Co, Zn, Cu, Ni, and Mn uniformly distributed throughout the sample. Due to the abundance of interfaces, the bouncy, spherical material possesses greater microwave absorption advantages. Figure 11As shown, the oxide powder material has an effective electromagnetic wave absorption band in the frequency range of 2 to 18 GHz. At a frequency of 17.98 GHz and a thickness of 1.70 mm, the absorption loss of the sample reaches -18.56 dB; when the sample thickness is 2.04 mm, the effective absorption bandwidth is 7.13 GHz.

[0072] The nickel-copper-zinc-manganese-cobaltate high-entropy spinel oxide coating prepared in this embodiment was subjected to salt spray testing in a salt spray chamber under 5% (w / w) sodium chloride solution conditions. A coating made of pure epoxy resin on a Q235 surface and a pure Q235 carbon steel substrate (uncoated) were used as comparative examples. The test results are as follows: Figure 12 As shown (samples 1#, 2#, and 3# in the figure are parallel samples of this embodiment), with the increase of time in the salt spray environment, when the salt spray time is 1 day, the uncoated pure Q235 carbon steel substrate begins to be corroded over a large area, forming a large amount of reddish-brown corrosion products; when the salt spray time is 5 days, the pure epoxy resin coating begins to show pitting corrosion (as shown in the red circle in the figure); when the salt spray time is 10 days, the #3 nickel copper zinc manganese cobalt salt high-entropy spinel oxide coating begins to show pitting corrosion and blistering (as shown in the red circle in the figure).

Claims

1. A method for preparing a high-entropy spinel oxide coating with electromagnetic wave absorption and corrosion resistance properties through low-temperature synthesis, characterized in that... Includes the following steps: (1) Preparation of nickel-copper-zinc-manganese-cobalt salt high-entropy spinel oxide precursor liquid (1-1) According to the molar ratio of cobalt:nickel:copper:zinc:manganese = 6~10:1~3:1~3:1~3:1~3, the cobalt source, nickel source, copper source, zinc source and manganese source are dissolved in water and stirred evenly to obtain a mixed solution; (1-2) Add urea to the mixed solution according to the molar ratio of cobalt:urea = 1:3-6, stir for 30-60 min until the solution is mixed evenly to obtain nickel copper zinc manganese cobaltate precursor solution; (2) Preparation of nickel-copper-zinc-manganese-cobalt high-entropy spinel oxide powder materials (2-1) The nickel copper zinc manganese cobalt salt precursor liquid was placed in a hydrothermal reactor and subjected to hydrothermal reaction at a temperature of 95-145°C for 6-30 hours to obtain the reaction product. (2-2) The reaction product is centrifuged, washed and dried, and then heated to 300-600℃ at a rate of 2-5℃ / min for sintering treatment. The holding time is 1-3h to obtain high-entropy spinel oxide powder material. (3) Preparation of high-entropy spinel oxide coatings with both electromagnetic wave absorption and corrosion resistance properties (3-1) The high-entropy spinel oxide powder material is added to the coating and stirred evenly to obtain a mixed coating with a high-entropy spinel oxide powder material content of 2-10%. (3-2) After grinding, washing and drying the surface of the metal substrate, the mixed coating is applied to the surface of the metal substrate. After static curing, a high-entropy spinel oxide coating with both electromagnetic wave absorption and corrosion resistance is obtained.

2. The method for preparing a high-entropy spinel oxide coating with electromagnetic wave absorption and corrosion resistance properties by low-temperature synthesis according to claim 1, characterized in that: The stirring time in step (1) is 20 to 40 minutes.

3. The method for preparing a high-entropy spinel oxide coating with electromagnetic wave absorption and corrosion resistance properties by low-temperature synthesis according to claim 1, characterized in that: In step (2-2), the reaction product is washed with water by centrifugation 3-5 times, then washed with anhydrous ethanol by centrifugation 3-5 times, and dried at 60-80℃ for 10-24 hours.

4. The method for preparing a high-entropy spinel oxide coating with electromagnetic wave absorption and corrosion resistance properties by low-temperature synthesis according to claim 1, characterized in that: In step (3-2), the coating thickness of the mixed coating is 90-110 μm, and it is allowed to cure at room temperature for 8-24 hours.

5. The method for preparing a high-entropy spinel oxide coating with electromagnetic wave absorption and corrosion resistance properties by low-temperature synthesis according to claim 1, characterized in that: The cobalt source is cobalt nitrate, cobalt chloride, cobalt acetate, or cobalt sulfate; the nickel source is nickel nitrate, nickel chloride, nickel acetate, or nickel sulfate; the copper source is copper nitrate, copper chloride, copper acetate, or copper sulfate; the zinc source is zinc nitrate, zinc chloride, zinc acetate, or zinc sulfate; and the manganese source is manganese nitrate, manganese chloride, manganese acetate, or manganese sulfate.

6. The method for preparing a high-entropy spinel oxide coating with electromagnetic wave absorption and corrosion resistance properties by low-temperature synthesis according to claim 1, characterized in that: The high-entropy spinel oxide powder material obtained in step (2) has a fuzzy ball-like morphology and uniform distribution of O, Co, Zn, Cu, Ni, and Mn.

7. The method for preparing a high-entropy spinel oxide coating with electromagnetic wave absorption and corrosion resistance properties by low-temperature synthesis according to claim 1, characterized in that: The high-entropy spinel oxide powder material obtained in step (2) has the following microwave absorption performance: at a frequency of 16.86 to 17.98 GHz and a matching thickness of 1.70 to 2.07 mm, the absorption loss is -55.75 to -18.56 dB; at a matching thickness of 2.04 to 2.79 mm, the effective absorption bandwidth is 7.13 to 8.11 GHz.

8. The method for preparing a high-entropy spinel oxide coating with electromagnetic wave absorption and corrosion resistance properties by low-temperature synthesis according to claim 1, characterized in that: The high-entropy spinel oxide coating was subjected to a salt spray test under a 5% (w / w) sodium chloride solution, and the salt spray corrosion resistance time was at least 9 days.

Images