Nano high-temperature anti-oxidation coating for electrolytic aluminum anode carbon and preparation method of nano high-temperature anti-oxidation coating

Abstract

The invention discloses a nanometer high-temperature anti-oxidation coating for electrolytic aluminum anode carbon and a preparation method of the nanometer high-temperature anti-oxidation coating, the nanometer high-temperature anti-oxidation coating comprises a composite adhesive, boron nitride coated aluminum dioxide, modified diatomite, silicon carbide, zirconium dioxide, potassium feldspar, lanthanum oxide, a dispersing agent, a film-forming agent and water, the composite adhesive is prepared from water glass, 3-aminopropyltriethoxysilane and silicon dioxide according to a mass ratio of (7 to 9): (2 to 5): (1 to 2). 3-aminopropyltriethoxysilane can form a network structure with silicon dioxide and water glass through chemical bonding, the interface bonding force of the composite adhesive is improved, and the stability and compatibility of the composite adhesive are improved, so that the adhesive force of the coating is favorably improved, the probability of generating cracks or falling off in a high-temperature environment is reduced, and the service life of the coating is prolonged. And when being applied to electrolytic aluminum anode carbon, the composite material can endow the electrolytic aluminum anode carbon with remarkable high-temperature oxidation resistance, so that the service life of the electrolytic aluminum anode carbon is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and more specifically, to a nano high-temperature anti-oxidation coating for electrolytic aluminum anode carbon and a preparation method thereof. Background Art

[0002] In the production of the aluminum industry, molten cryolite and alumina are mixed as electrolytes, carbon is used as the anode, and graphite is used as the cathode. After passing direct current, electrochemical reactions occur on the two electrodes in the electrolytic cell. The main anode products are carbon dioxide and carbon monoxide gases, and the cathode product is aluminum liquid. The aluminum liquid is pumped out of the cell through a vacuum ladle and sent to the casting workshop. After purification and clarification in the holding furnace, it is cast into aluminum ingots or directly processed into wire blanks, profiles, etc. Carbon is one of the main raw materials in the electrolytic aluminum industry. Since the main component of the carbon body is carbon, it is prone to anode oxidation at high temperatures, which increases the net consumption of the carbon anode; on the other hand, it will cause the electrolytic cell to overheat, resulting in leakage of the cell, and in severe cases, it will trigger safety production accidents. Therefore, the quality and working conditions of the carbon anode have a great impact on the normal production of electrolysis and economic and technical indicators such as current efficiency, power consumption, and primary aluminum grade. Therefore, improving the anti-oxidation property of the carbon anode is of great significance.

[0003] In the prior art, a protective coating is also formed by coating a coating on the surface of carbon to reduce the loss of carbon, but there are still problems such as poor high-temperature anti-oxidation performance and unsatisfactory coating quality. Summary of the Invention

[0004] Based on this, in order to solve the problems of poor high-temperature anti-oxidation performance and unsatisfactory coating quality of the coatings prepared in the prior art, the present invention provides a nano high-temperature anti-oxidation coating for electrolytic aluminum anode carbon and a preparation method thereof. The specific technical solutions are as follows: A nano high-temperature anti-oxidation coating for electrolytic aluminum anode carbon, the nano high-temperature anti-oxidation coating comprising the following raw materials in parts by weight for preparation: 37 parts to 40 parts of a composite binder, 12 parts to 15 parts of aluminum oxide wrapped with boron nitride, 7 parts to 9 parts of modified diatomaceous earth, 10 parts to 13 parts of silicon carbide, 6 parts to 10 parts of zirconium dioxide, 9 parts to 10 parts of potassium feldspar, 3 parts to 5 parts of lanthanum oxide, 6 parts to 9 parts of a dispersant, 1 part to 2 parts of a film-forming agent, 30 parts to 50 parts of water; Wherein, the composite binder is prepared from sodium silicate, 3-aminopropyltriethoxysilane, and silicon dioxide with a mass ratio of (7 to 9):(2 to 5):(1 to 2).

[0005] Further, the preparation of the composite adhesive is as follows: Mix water glass, 3-aminopropyltriethoxysilane, and silica evenly, heat to 75°C to 90°C, and stir at a speed of 500 r / min to 1000 r / min for 1 h to 3 h, and then naturally cool to obtain the composite adhesive.

[0006] Further, the preparation method of boron nitride-coated aluminum oxide is as follows: Add boric acid and urea to a solvent, stir evenly to form a BN precursor sol, then disperse aluminum oxide in the BN precursor sol, stir at a stirring speed of 50 r / min to 100 r / min for 30 min to 60 min, and after drying, obtain a precursor / aluminum oxide composite; Calcinate under the condition of 800°C to 1200°C in a nitrogen atmosphere to obtain boron nitride-coated aluminum oxide.

[0007] Further, the solvent is a mixture of water and methanol with a volume ratio of 1:1.

[0008] Further, the mass ratio of boric acid, urea, and aluminum oxide is (1 to 7):(1 to 5):(1 to 3).

[0009] Further, the dispersant is at least one of sodium silicate, sodium carbonate, sodium stearate, polyacrylamide, and sodium polyacrylate.

[0010] Further, the film-forming agent is at least one of polyurethane, polyacrylate, and polyvinylpyrrolidone.

[0011] In addition, the present application also provides a preparation method of a nano high-temperature anti-oxidation coating, and the preparation method includes the following steps: Add the composite adhesive, dispersant, film-forming agent, and water to a stirring kettle, stir at a magnetic stirring speed of 200 r / min to 500 r / min for 1 h to 2 h to obtain mixture A; Mix boron nitride-coated aluminum oxide, modified diatomite, silicon carbide, zirconium dioxide, potassium feldspar, and lanthanum oxide evenly to obtain mixture B; Under stirring conditions, add mixture B to mixture A, adjust the magnetic stirring speed to 800 r / min to 1000 r / min, stir for 1 h to 3 h, and then perform ultrasonic treatment to obtain a nano high-temperature anti-oxidation coating.

[0012] Further, the frequency of the ultrasonic treatment is 23 KHz to 26 KHz, the power of the ultrasonic treatment is 25 W to 50 W, and the time of the ultrasonic treatment is 15 min to 20 min.

[0013] Further, the density of the nano high-temperature anti-oxidation coating is 1.2 kg / m 3~1.5 kg / m 3 。

[0014] Compared with the prior art, the present application has the following beneficial effects: 1. In the present invention, a composite binder is prepared from sodium silicate, 3-aminopropyltriethoxysilane, and silicon dioxide. 3-aminopropyltriethoxysilane can form a network structure with silicon dioxide and sodium silicate through chemical bonding, improve the interfacial bonding force of the composite binder, enhance its stability and compatibility, and thus contribute to improving the adhesion of the coating and reducing the probability of cracks or peeling in a high-temperature environment.

[0015] 2. By optimizing the composition and component ratio of the nano high-temperature oxidation-resistant coating, a coating with excellent coating performance and remarkable high-temperature oxidation resistance can be obtained. When applied to the electrolytic aluminum anode carbon, it can endow the electrolytic aluminum anode carbon with remarkable high-temperature oxidation resistance, thereby extending its service life. Specifically, boron nitride-coated aluminum oxide has a core-shell structure and has better heat resistance. Acting synergistically with silicon carbide, silicon carbide has extremely strong covalent bonds and can still maintain a relatively high bonding strength at high temperatures, with excellent thermal conductivity, which can significantly improve the high-temperature application performance of the coating; adding modified diatomaceous earth can be used as a filler to increase the mechanical properties of the formed coating and interact with potassium feldspar, which also helps to improve the denseness and mechanical properties of the coating; zirconium dioxide transforms from monoclinic crystals to tetragonal crystals at high temperatures and interacts with lanthanum oxide, making the micro-light structure of the coating denser, which helps to improve the oxidation resistance of the coating.

[0016] 3. The overall preparation process of the nano high-temperature oxidation-resistant coating for electrolytic aluminum anode carbon in the present application is simple, highly controllable, and the obtained coating has better uniformity, which helps to improve the storage stability and use stability. Specific Embodiments

[0017] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with its embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not limit the protection scope of the present invention.

[0018] A nano high-temperature oxidation-resistant coating for electrolytic aluminum anode carbon in one embodiment of the present invention, the nano high-temperature oxidation-resistant coating comprises the following raw materials in parts by weight for preparation: 37 parts to 40 parts of composite binder, 12 parts to 15 parts of boron nitride-coated aluminum oxide, 7 parts to 9 parts of modified diatomaceous earth, 10 parts to 13 parts of silicon carbide, 6 parts to 10 parts of zirconium dioxide, 9 parts to 10 parts of potassium feldspar, 3 parts to 5 parts of lanthanum oxide, 6 parts to 9 parts of dispersant, 1 part to 2 parts of film-forming agent, 30 parts to 50 parts of water; Among them, the composite binder is prepared from sodium silicate, 3-aminopropyltriethoxysilane, and silicon dioxide with a mass ratio of (7-9):(2-5):(1-2).

[0019] In one embodiment, the preparation of the composite binder is as follows: Mix sodium silicate, 3-aminopropyltriethoxysilane, and silicon dioxide evenly, heat to 75°C - 90°C, and stir at a speed of 500 r / min - 1000 r / min for 1 h - 3 h, and then obtain the composite binder after natural cooling.

[0020] In one embodiment, the preparation method of boron nitride-coated aluminum oxide is as follows: Add boric acid and urea to a solvent, stir evenly to form a BN precursor sol, then disperse aluminum oxide in the BN precursor sol, stir at a stirring speed of 50 r / min - 100 r / min for 30 min - 60 min, and after drying, obtain a precursor / aluminum oxide composite; Calcinate under the condition of 800°C - 1200°C in a nitrogen atmosphere to obtain boron nitride-coated aluminum oxide.

[0021] In one embodiment, the solvent is a mixture of water and methanol with a volume ratio of 1:1.

[0022] In one embodiment, the mass ratio of boric acid, urea, and aluminum oxide is (1-7):(1-5):(1-3).

[0023] In one embodiment, the modified diatomite is diatomite modified with a silane coupling agent.

[0024] In one embodiment, the dispersant is at least one of sodium silicate, sodium carbonate, sodium stearate, polyacrylamide, and sodium polyacrylate.

[0025] In one embodiment, the film-forming agent is at least one of polyurethane, polyacrylate, and polyvinylpyrrolidone.

[0026] In addition, the present application also provides a preparation method of a nano high-temperature anti-oxidation coating, and the preparation method includes the following steps: Add the composite binder, dispersant, film-forming agent, and water to a stirring kettle, stir at a magnetic stirring speed of 200 r / min - 500 r / min for 1 h - 2 h to obtain mixture A; Mix boron nitride-coated aluminum oxide, modified diatomite, silicon carbide, zirconium dioxide, potassium feldspar, and lanthanum oxide evenly to obtain mixture B; Under stirring conditions, add the mixture B to the mixture A, adjust the magnetic stirring speed to 800 r / min to 1000 r / min, stir for 1 h to 3 h, and then perform ultrasonic treatment to obtain a nano high-temperature oxidation-resistant coating.

[0027] In one embodiment, the frequency of the ultrasonic treatment is 23 KHz to 26 KHz, the power of the ultrasonic treatment is 25 W to 50 W, and the time of the ultrasonic treatment is 15 min to 20 min.

[0028] In one embodiment, the density of the nano high-temperature oxidation-resistant coating is 1.2 kg / m 3 ~1.5 kg / m 3 .

[0029] In one embodiment, the nano high-temperature oxidation-resistant coating is applied to the surface of the carbon anode for electrolytic aluminum.

[0030] The nano high-temperature oxidation-resistant coating prepared by the above solution has excellent coating properties when applied to the surface of carbon, and the properties are stable, the high-temperature oxidation resistance is remarkable, and it can effectively extend the service life of carbon.

[0031] The present invention will be further described below through specific examples. However, these examples are merely exemplary and do not constitute any limitation to the protection scope of the present invention.

[0032] In the following examples and comparative examples, the reagents, materials, and instruments used can be obtained commercially without special instructions. Example 1

[0033] A preparation method of a nano high-temperature oxidation-resistant coating, the preparation method comprising the following steps: Mix sodium silicate, 3-aminopropyltriethoxysilane, and silicon dioxide with a mass ratio of 7:3:1 evenly, heat to 80 °C, and stir at a speed of 500 r / min for 3 h, and obtain a composite binder after natural cooling; Add boric acid and urea to a solvent (a mixture of water and methanol with a volume ratio of 1:1), stir evenly to form a BN precursor sol, then disperse aluminum oxide in the BN precursor sol, stir at a stirring speed of 100 r / min for 50 min, and after drying, obtain a precursor / aluminum oxide composite; perform calcination treatment at 1000 °C in a nitrogen atmosphere to obtain boron nitride-coated aluminum oxide, and the mass ratio of boric acid, urea, and aluminum oxide is 7:5:2; According to the weight ratio, add 37 parts of the composite binder, 6 parts of sodium silicate, 2 parts of polyacrylate, and 30 parts of water to a stirring kettle, and stir at a magnetic stirring speed of 500 r / min for 2 h; obtain mixture A; Mix 12 parts of boron nitride-coated aluminum oxide, 7 parts of modified diatomaceous earth, 13 parts of silicon carbide, 6 parts of zirconia, 9 parts of potassium feldspar, and 4 parts of lanthanum oxide evenly to obtain mixture B; Under stirring conditions, add the mixture B to the mixture A, adjust the magnetic stirring speed to 800 r / min, and stir for 3 h. Then perform ultrasonic treatment with a frequency of 23 KHz, a power of 25 W, and a time of 15 min to obtain a nano high-temperature oxidation-resistant coating. Example 2

[0034] A preparation method of a nano high-temperature oxidation-resistant coating, the preparation method comprising the following steps: Mix sodium silicate, 3-aminopropyltriethoxysilane, and silicon dioxide with a mass ratio of 9:4:2 evenly, heat to 85 °C, and stir at a speed of 1000 r / min for 1 h. After natural cooling, obtain a composite binder; Add boric acid and urea to a solvent (a mixture of water and methanol with a volume ratio of 1:1), stir evenly to form a BN precursor sol, then disperse aluminum oxide in the BN precursor sol, and stir at a stirring speed of 100 r / min for 60 min. After drying, obtain a precursor / aluminum oxide composite; Under a nitrogen atmosphere, perform calcination treatment at 1200 °C to obtain boron nitride-coated aluminum oxide, and the mass ratio of boric acid, urea, and aluminum oxide is 5:3:2; By weight ratio, add 39 parts of the composite binder, 7 parts of sodium carbonate, 2 parts of polyacrylate, and 32 parts of water to a stirring kettle, and stir at a magnetic stirring speed of 500 r / min for 2 h; obtain mixture A; By weight ratio, mix 15 parts of boron nitride-coated aluminum oxide, 7 parts of modified diatomaceous earth, 11 parts of silicon carbide, 7 parts of zirconia, 9 parts of potassium feldspar, and 4 parts of lanthanum oxide evenly to obtain mixture B; Under stirring conditions, add the mixture B to the mixture A, adjust the magnetic stirring speed to 1000 r / min, and stir for 3 h. Then perform ultrasonic treatment with a frequency of 23 KHz, a power of 25 W, and a time of 15 min to obtain a nano high-temperature oxidation-resistant coating. Example 3

[0035] A preparation method of a nano high-temperature oxidation-resistant coating, the preparation method comprising the following steps: Mix sodium silicate, 3-aminopropyltriethoxysilane, and silicon dioxide with a mass ratio of 8:3:2 evenly, heat to 85 °C, and stir at a speed of 800 r / min for 2 h. After natural cooling, obtain a composite binder; Boric acid and urea were added to a solvent (a mixture of water and methanol with a volume ratio of 1:1), and after stirring evenly, a BN precursor sol was formed. Then, aluminum oxide was dispersed in the BN precursor sol, and it was stirred at a stirring speed of 100 r / min for 45 min. After drying, a precursor / aluminum oxide composite was obtained; under a nitrogen atmosphere, it was calcined at 1200 °C to obtain boron nitride-coated aluminum oxide, and the mass ratio of boric acid, urea, and aluminum oxide was 6:5:2; By weight ratio, 38 parts of a composite binder, 8 parts of sodium carbonate, 2 parts of polyacrylate, and 35 parts of water were added to a stirring kettle and stirred at a magnetic stirring speed of 500 r / min for 1 h; mixture A was obtained; By weight, 13 parts of boron nitride-coated aluminum oxide, 9 parts of modified diatomaceous earth, 10 parts of silicon carbide, 7 parts of zirconium dioxide, 10 parts of potassium feldspar, and 3 parts of lanthanum oxide were mixed evenly to obtain mixture B; Under stirring conditions, mixture B was added to mixture A, the magnetic stirring speed was adjusted to 800 r / min, and it was stirred for 2 h. Then, ultrasonic treatment was carried out. The frequency of the ultrasonic treatment was 25 KHz, the power of the ultrasonic treatment was 25 W, and the time of the ultrasonic treatment was 15 min to obtain a nano high-temperature oxidation-resistant coating.

[0036] Comparative Example 1: Compared with Example 3, the binder in Comparative Example 1 was a single sodium silicate, and the others were the same as in Example 3.

[0037] Comparative Example 2: Compared with Example 3, 3-aminopropyltriethoxysilane was not added to the binder in Comparative Example 2, and the others were the same as in Example 3.

[0038] Comparative Example 3: Compared with Example 3, silicon dioxide was not added to the binder in Comparative Example 3, and the others were the same as in Example 3.

[0039] Comparative Example 4: Compared with Example 3, in Comparative Example 4, a mixture of boron nitride and aluminum oxide with a mass ratio of 5:2 was used to replace boron nitride-coated aluminum oxide, and the others were the same as in Example 3.

[0040] Comparative Example 5: Compared with Example 5, modified diatomaceous earth was not added in Comparative Example 5, and the others were the same as in Example 3.

[0041] Comparative Example 6: Compared with Example 3, silicon carbide was not added in Comparative Example 6, and the others were the same as in Example 3.

[0042] Comparative Example 7: Compared with Example 3, zirconia was not added in Comparative Example 7, and the others were the same as in Example 3.

[0043] Comparative Example 8: Compared with Example 3, potassium feldspar was not added in Comparative Example 8, and the others were the same as in Example 3.

[0044] Comparative Example 9: Compared with Example 3, lanthanum oxide was not added in Comparative Example 9, and the others were the same as in Example 3.

[0045] To further elaborate on the effects brought by the technical invention solution, the following effect verification was conducted.

[0046] I. Verification of the thermal shock resistance of the coating The specific method is as follows: The samples of the nano high-temperature anti-oxidation coatings prepared in Examples 1 to 3 and the comparative samples of the coatings prepared in Comparative Examples 1 to 9 were respectively coated or sprayed on the surface of a graphite rod with a common diameter of 200 mm, dried at room temperature for 48 h, and the nano high-temperature anti-oxidation coating was coated in segments on the same graphite rod, 1 / 2 section was coated with the nano high-temperature anti-oxidation coating, and 1 / 2 section was not coated with the nano high-temperature anti-oxidation coating. Then, it was heated in a muffle furnace at 900 °C for 7 h. After being taken out at high temperature, it was directly impacted with cold water, and the change of the coating was observed. a. Observe whether there is a change in the diameter of the coated area; b. After being taken out at high temperature, directly impact the coating with cold water and observe whether there is any cracking or peeling phenomenon. The evaluation criterion: If there is no obvious change in the diameter of the coated area and no cracking or peeling of the coating, it indicates that the coating has good thermal shock resistance. The results are shown in Table 1 below.

[0047] Table 1: Thermal shock resistance effect

[0048] It can be seen from the data analysis in Table 1 that the coating of the present application can ensure that graphene is not oxidized and can play a significant protective role. The diameter of the graphite has not decreased significantly, and there is no problem of cracking or peeling of the coating, and the application is relatively stable. However, the diameters of the graphite in Comparative Examples 1 to 9 have decreased to varying degrees, indicating that there are interactions between the components. After the components of the present application are compounded, it has better thermal shock resistance.

[0049] II. Anti-oxidation effect The nano high-temperature anti-oxidation coating samples of Examples 1 to 3 and the comparative samples of the coatings of Comparative Examples 1 to 9 were respectively sprayed on the surface of the carbon anode. After spraying, they were stored for 8 h to complete curing and aging, dried at room temperature for 48 h, and then placed in a high-temperature resistance furnace, heated to 900 °C and maintained for 24 h. The weight loss rate of the carbon and the appearance of the coating were tested; a blank control was set under the same conditions. The evaluation criterion: When the final weight loss rate ≤ 2% and the appearance has no cracking or peeling, it indicates that the coating has good anti-oxidation performance. The results are shown in Table 2 below.

[0050] Table 2: Antioxidant effect

[0051] It can be seen from the data analysis in Table 2 that through the optimization of components and their ratios, the oxidation weight loss rate of this application is lower than 1% at 900 °C / 24 h, showing excellent antioxidant performance and excellent coating appearance. However, the changes in the component ratios in Comparative Examples 1 - 9 result in a higher oxidation weight loss rate than that in Example 3, indicating that there is an interaction effect among the components of this application, which can help improve the overall antioxidant performance of the coating and thus extend the service life of carbon.

[0052] The above description of the embodiments is for the convenience of those of ordinary skill in the art to understand and use the present invention. Obviously, those familiar with the art can easily make various modifications to the embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments, and all improvements and modifications made by those skilled in the art without departing from the scope of the present invention as disclosed should be within the protection scope of the present invention.

Claims

1. A nano high temperature anti-oxidation coating for electrolytic aluminum anode carbon, characterized in that: The nano high temperature anti-oxidation coating comprises the following raw materials in parts by weight: 37 to 40 parts of composite binder, 12 to 15 parts of boron nitride coated alumina, 7 to 9 parts of modified diatomaceous earth, 10 to 13 parts of silicon carbide, 6 to 10 parts of zirconium dioxide, 9 to 10 parts of potassium feldspar, 3 to 5 parts of lanthanum oxide, 6 to 9 parts of dispersant, 1 to 2 parts of film-forming agent, and 30 to 50 parts of water; The composite adhesive is prepared from water glass, 3-aminopropyltriethoxysilane and silicon dioxide in a mass ratio of (7-9): (2-5): (1-2).

2. The nano high temperature anti-oxidation coating according to claim 1, characterized in that: The preparation method of the composite adhesive is as follows: water glass, 3-aminopropyltriethoxysilane and silicon dioxide are uniformly mixed, heated to 75° C. to 90° C., stirred at a speed of 500 r / min to 1000 r / min for 1 h to 3 h, and naturally cooled to obtain the composite adhesive.

3. The nano high temperature anti-oxidation coating according to claim 1, characterized in that: The preparation method of the boron nitride-coated aluminum dioxide is as follows: boric acid and urea are added to a solvent, and the mixture is stirred to form a BN precursor sol, and then aluminum dioxide is dispersed in the BN precursor sol, and the mixture is stirred at a stirring speed of 50 r / min to 100 r / min for 30 min to 60 min, and dried to obtain a precursor / aluminum dioxide composite. The calcination treatment is carried out at 800°C to 1200°C in a nitrogen atmosphere to obtain boron nitride-coated alumina.

4. The nano high temperature anti-oxidation coating according to claim 3, characterized in that: The solvent is a mixture of water and methanol in a volume ratio of 1:

1.

5. The nano high temperature anti-oxidation coating according to claim 3, characterized in that: The mass ratio of the boric acid, urea and aluminum dioxide is (1-7): (1-5): (1-3).

6. The nano high temperature anti-oxidation coating according to claim 1, characterized in that: The dispersant is at least one of sodium silicate, sodium carbonate, sodium stearate, polyacrylamide and sodium polyacrylate.

7. The nano high temperature anti-oxidation coating according to claim 1, characterized in that: The film-forming agent is at least one of polyurethane, polyacrylate and polyvinyl pyrrolidone.

8. A method for preparing a nanometer high temperature anti-oxidation coating for electrolytic aluminum anode carbon, characterized in that: The preparation method is used to prepare the nano high temperature anti-oxidation coating according to any one of claims 1 to 7, and the preparation method comprises the following steps: Add the composite binder, dispersant, film-forming agent and water into a stirring kettle, and stir at a magnetic stirring speed of 200 r / min to 500 r / min for 1 h to 2 h to obtain a mixture A; The boron nitride-coated aluminum dioxide, modified diatomaceous earth, silicon carbide, zirconium dioxide, potassium feldspar and lanthanum oxide are uniformly mixed to obtain a mixture B; Under stirring conditions, the mixture B is added to the mixture A, the speed of magnetic stirring is adjusted to 800 r / min-1000 r / min, and stirring is performed for 1 h-3 h, followed by ultrasonic treatment to obtain a nano high-temperature anti-oxidation coating.

9. The preparation method according to claim 8, characterized in that: The frequency of the ultrasonic treatment is 23KHz~26KHz, the power of the ultrasonic treatment is 25W~50W, and the time of the ultrasonic treatment is 15min~20min.

10. The preparation method according to claim 8, characterized in that: The density of the nano high temperature anti-oxidation coating is 1.2 kg / m 3 ~1.5kg / m 3 .

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