A high-temperature resistant lightweight stealth coating material and its preparation method

Abstract

A high-temperature resistant lightweight stealth coating material and a preparation method thereof belong to the technical field of functional materials. The raw material composition of the high-temperature resistant lightweight stealth coating material includes boride, silicide, titanate flux, metal-coated carbide, zinc oxide-coated nano-carbon material, and sintering aid. For the high-temperature resistant lightweight stealth coating material prepared by the present invention, the infrared emissivity at a wavelength of 3 - 5 μm is 0.231 - 0.245, the infrared emissivity at a wavelength of 8 - 14 μm is 0.424 - 0.441, the tensile bonding strength is 40.8 - 46.4 MPa, and the number of thermal shock resistance times is 153 - 167.

Description

Technical Field

[0001] The present invention relates to a high-temperature resistant lightweight stealth coating material and a preparation method thereof, belonging to the technical field of functional materials. Background Art

[0002] With the development of military technology, the role and status of aircraft in the battlefield have been continuously improved. Correspondingly, modern reconnaissance and aiming technologies have also been continuously improved, which has severely tested the survival ability of aircraft. In order to improve the survival ability of aircraft, stealth technology has emerged. Stealth technology refers to a comprehensive technology that reduces the risk of being detected, tracked, and attacked by changing the detectable characteristic information emitted by the target and suppressing the signals it emits, thereby improving the survival ability of military targets. Stealth technology mainly includes infrared stealth, radar stealth, visible light stealth, and magnetic stealth, etc. Among them, in the guided detection weaponry used by various military powers, infrared guidance dominates, reaching more than 90%, and the proportion of infrared detection also reaches more than 30%. It has become a necessary method for military reconnaissance and is related to national defense security.

[0003] Infrared stealth technology reduces the energy of the target's infrared radiation by changing the structural design or using infrared physical principles, thereby achieving the purpose of reducing the detectability of the target. Its technical means mainly include changing the infrared radiation characteristics of the target, reducing the infrared radiation intensity of the target, and adjusting the propagation path of infrared radiation, etc. Usually, the infrared radiation sources of aircraft mainly include the thermal radiation of the engine, the high-temperature gas ejected from the tail nozzle, the infrared radiation of the aircraft skin, and the reflection of the environment, etc. For example, an aeroengine generally operates under high pressure, high speed, and high temperature during operation, thus becoming one of the main infrared radiation sources of the aircraft. The technical approaches to achieve infrared stealth usually include cooling, shielding, or coating with infrared low-emissivity coating materials, etc. Among them, coating with an infrared low-emissivity coating is a simple, convenient, and effective technical approach to improve the infrared stealth performance of aircraft.

[0004] Infrared rays are electromagnetic waves with frequencies between microwaves and visible light, and their wavelengths are between 760 nm and 1 mm. According to infrared physics, objects above absolute zero (-273.15 °C) inevitably radiate infrared energy to the outside world. The infrared radiation energy of an object conforms to the Stefan-Boltzmann law, that is, W = σET 4 , where W is the total radiation energy of the object, σ is the Boltzmann constant of 5.67032×10 -8 W·m -2 ·k -4 , E is the infrared emissivity of the object, T is the absolute temperature of the object, and the infrared emissivity of the object surface also conforms to the Hagen-Ruben law, that is, E≈2×(2ε0ωρ) ½, where ε0 is the dielectric constant of the object, ω is the angular frequency of the electromagnetic wave, and ρ is the resistivity of the object. The radiation ability of an object is determined by the emissivity and temperature. Therefore, reducing the surface emissivity of the object and controlling the surface temperature of the object are the basic ways to achieve infrared stealth. However, in order to ensure that the aircraft has sufficient power and thrust-to-weight ratio, the method of reducing the surface temperature is not very feasible. Therefore, surface engineering technology is usually used to cover a layer of high-temperature resistant and low-infrared-emission coating on the target surface to reduce the surface emissivity of the target and achieve infrared stealth. The lower the resistivity of the material, the better its conductivity and the lower its infrared emissivity.

[0005] Currently, the infrared low-emissivity coating materials with application potential in medium and high-temperature environments are roughly divided into two categories: metal-based coating materials and inorganic low-reflectivity coating materials. Although metal-based coating materials have significant advantages such as low price, good conductivity, and low infrared emissivity, the heat resistance of metal materials is generally poor, and the working temperature can generally only be in the range of 600-800 °C, which is not suitable for serving in higher-temperature environments, or can only be used in high-temperature environments for a short time. This limits its use for infrared stealth in the engine parts of aircraft. Inorganic low-emissivity coatings generally use ceramic materials with high temperature resistance and low thermal conductivity as the surface layer, and are compounded on the surface of high-temperature components in the form of coatings or thin films to achieve the effect of reducing the infrared emissivity of the target surface. Such materials have extremely high heat resistance and can be used for a long time at high temperatures. Especially in the 3-5 μm wavelength band, they have a low infrared emissivity, and the infrared emissivity changes little with temperature, and can also achieve the compatibility of multiple stealth functions. Therefore, inorganic low-emissivity coating materials are a type of material reported more and with more significant effects at present, and dominate the field of infrared stealth materials. However, compared with metal-based coating materials, inorganic low-emissivity coating materials also have very obvious deficiencies in infrared stealth. First of all, the conductivity of inorganic low-emissivity coating materials is difficult to match that of metal-based coating materials, especially high-temperature resistant ceramic coatings. Therefore, their infrared emissivity is generally higher than that of metal coatings, which will inevitably cause a decrease in the infrared stealth effect. Secondly, inorganic low-emissivity coating materials generally have the disadvantages of being too brittle and insufficient bonding strength with the substrate, resulting in poor high-temperature thermal shock resistance, limited service life in high-temperature environments, and a high risk of sudden failure. Finally, due to the above two defects, inorganic low-emissivity coating materials often need to maintain a certain thickness to make up for the above two deficiencies. Therefore, it is difficult for inorganic low-emissivity coating materials to achieve a relatively thin thickness to meet the lightweight requirements of aircraft. Therefore, developing inorganic low-emissivity coating materials with high temperature resistance, good high-temperature thermal shock resistance, light weight, high conductivity, and good infrared stealth effect is the key to solving the infrared stealth problem of the high-temperature power propulsion parts of aircraft.

[0006] Chinese Patent CN117230399A discloses a dispersion-strengthened composite powder for infrared stealth materials, its preparation method, and an infrared stealth coating. The preparation method includes: mixing metal powder, ceramic powder, polyvinyl alcohol, and water, followed by ball milling and granulation to obtain agglomerated powder; subjecting the agglomerated powder to high-frequency plasma treatment to obtain the dispersion-strengthened composite powder for infrared stealth materials; the metal powder includes one or more of Al, Cu, Au, Ag, Ni, and Pt; the ceramic powder is a nano-negative temperature coefficient thermosensitive semiconductor ceramic, and the nano-negative temperature coefficient thermosensitive semiconductor ceramic includes a high-temperature type ceramic powder and a medium-low temperature type ceramic powder. This dispersion-strengthened composite powder for infrared stealth materials has extremely high density, sphericity, and fluidity. The ceramic phase is uniformly dispersed in the metal, enhancing the hardness, wear resistance, temperature resistance, and other properties of the metal material. It can be used for 3D printing infrared stealth equipment or spraying infrared stealth coatings. The infrared stealth coating prepared by this patent adds a large amount of metal powder, and its high-temperature resistance performance is definitely not particularly good. In the data disclosed in its examples, it only clearly states that there is no abnormality in the coating after 50 high-temperature cycle thermal shocks at 900°C. Whether it can be used at higher temperatures is not disclosed in this patent. However, judging from the powder composition and preparation method described in the patent, since the ceramic phase is uniformly dispersed in the metal in this patent, it can be generally judged that the metal is the main phase in this coating, so the metal content will not be too low, and thus the high-temperature resistance performance is definitely limited.

[0007] Chinese Patent CN110002900A discloses an environmental barrier-infrared stealth integrated coating, a coated composite material, and its preparation method. The coating is a multi-layer stacked structure, and the multi-layer stacked structure sequentially includes a silicon bonding layer, an antioxidant layer, and a low infrared emissivity / sealing layer from the inside to the outside. The antioxidant layer is a mullite single coating or a mullite / BSAS composite coating, and the low infrared emissivity / sealing layer is a Bi2O3-ZnO-based glass coating containing noble metal fillers. The present invention also correspondingly provides a coated composite material and its preparation method. The environmental barrier-infrared stealth integrated coating of the present invention adopts a multi-layer stacked structure, and the thermal expansion coefficients of each functional layer gradually change slowly, weakening the thermal mismatch between layers and endowing the coating with excellent thermal shock resistance performance. The infrared stealth coating designed in this patent has a very complex structure, and it is conceivable that its preparation process is cumbersome and the difficulty of precise control of the preparation process is high. Moreover, in the low infrared emissivity / sealing layer, it also contains noble metal fillers such as Ag, Pd, Au, and Pt, and its manufacturing cost is relatively high.

[0008] As can be seen from the above, the infrared stealth coating materials used in the high-temperature parts of current aircraft still have prominent problems such as poor high-temperature resistance, unsatisfactory high-temperature thermal shock resistance, high infrared emissivity caused by low conductivity, and difficulty in achieving lightweight. Therefore, developing a high-temperature resistant and lightweight stealth coating material is crucial for enhancing the anti-strike ability of military aircraft. Summary of the Invention

[0009] Aiming at the deficiencies of the above-mentioned existing technologies, the present invention provides a high-temperature resistant lightweight stealth coating material and a preparation method thereof, achieving the following invention objectives: preparing a high-temperature resistant lightweight stealth coating material with good high-temperature resistance, excellent high-temperature thermal shock resistance, high conductivity and low infrared emissivity.

[0010] To achieve the above invention objectives, the present invention adopts the following technical solutions:

[0011] A high-temperature resistant lightweight stealth coating material and a preparation method thereof, the raw material composition of the high-temperature resistant lightweight stealth coating material includes boride, silicide, titanate flux, metal-coated carbide, zinc oxide-coated nano-carbon material, and sintering aid;

[0012] The mass ratio of the boride, silicide, titanate flux, metal-coated carbide, zinc oxide-coated nano-carbon material, and sintering aid is 20~100:30~150:1~5:1~10:1~8:1~4;

[0013] The boride is one of titanium boride, zirconium boride, calcium boride, hafnium boride, vanadium boride, chromium boride, silicon boride, manganese monoboride, manganese diboride, manganese tetraboride, molybdenum monoboride, molybdenum diboride, molybdenum pentaboride, any two or any combination of two or more of them;

[0014] The particle size of the boride is 0.5~3μm;

[0015] The silicide is one of titanium silicide, zirconium silicide, tantalum silicide, tungsten silicide, molybdenum trisilicide, pentamolybdenum trisilicide, molybdenum disilicide, any two or any combination of two or more of them;

[0016] The particle size of the silicide is 0.5~3μm;

[0017] The titanate flux is one of potassium titanate, lithium titanate, magnesium titanate, barium titanate, lead titanate, zinc titanate, any two or any combination of two or more of them;

[0018] The particle size of the titanate flux is 0.1~1μm;

[0019] In the metal-coated carbide, the metal is one of nickel, cobalt or a combination of nickel and cobalt, and the carbide is one of zirconium carbide, titanium carbide, vanadium carbide, tungsten carbide, any two or any combination of two or more of them;

[0020] The particle size of the carbide is 1~100nm;

[0021] In the zinc oxide-coated nanocarbon material, the nanocarbon material is one of carbon nanotubes, carbon nanofibers, nanocarbon spheres, graphene, nanoscale conductive carbon black, and nanoscale graphite powder, any two of them, or a combination of any two or more of them;

[0022] The particle size of the nanocarbon material is 1 to 100 nm;

[0023] The sintering aid is one of silicon phosphate and boron phosphate or a combination of the two;

[0024] The particle size of the sintering aid is 0.1 to 1 μm;

[0025] The following is a further improvement of the above technical solution:

[0026] Step 1: Preparation of metal-coated carbide

[0027] For the preparation of the metal-coated carbide, one of electroless plating, hydrothermal hydrogen reduction, and precipitation reduction methods is used;

[0028] In the electroless plating method, the carbide powder is dispersed in the electroless plating solution at the nanoscale, and then by controlling the temperature of the plating solution, the pH value of the plating solution, and the stirring rate, nickel ions, cobalt ions, or a mixture of nickel and cobalt ions contained in the electroless plating solution are controllably reduced to elemental nickel, elemental cobalt, or a mixture of the two elemental substances under the action of a reducing agent and adhere to and coat the surface of the carbide powder to form a metal-coated carbide;

[0029] The electroless plating solution is composed of one or a mixture of nickel salts and cobalt salts, a complexing agent, a stabilizer, a reducing agent, and a dispersant;

[0030] The complexing agent is an aliphatic carboxylic acid;

[0031] The stabilizer is one of thiocyanate and thiourea;

[0032] The reducing agent is one of sodium hypophosphite, hydrazine, and sodium borohydride;

[0033] The dispersant is a non-ionic surfactant that promotes the dispersion of the carbide powder, specifically one of alkyl glycoside surfactants, long-chain fatty alcohol polyoxyethylene ether surfactants, and alkyl phenol polyoxyethylene ether surfactants, any two of them, or a combination of any two or more of them;

[0034] In the hydrothermal hydrogen reduction method, the carbide powder, a catalyst, a dispersant, and a nickel salt solution or a cobalt salt solution or a mixed solution of nickel salt and cobalt salt are added to an autoclave, and the appropriate reaction temperature and reaction pressure are controlled, and hydrogen is used to reduce and deposit nickel ions, cobalt ions, or a mixture of nickel and cobalt ions on the surface of the carbide powder to form a metal-coated carbide;

[0035] The catalyst is one of palladium chloride and anthraquinone;

[0036] The dispersant is one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and polyethylene glycol monooctyl phenyl ether, any two of them, or any combination of two or more of them;

[0037] The reaction temperature is 110~160°C;

[0038] The reaction pressure is 1~5 MPa;

[0039] In the precipitation reduction method, one or a mixture of nickel salts and cobalt salts is dissolved in deionized water to form an aqueous solution. The temperature of the aqueous solution is controlled, and then carbide powder is added. After strong stirring and uniform dispersion, ammonia water is added to form nickel hydroxide or cobalt hydroxide precipitate adsorbed on the surface of the carbide powder. After the reaction is completed, the carbide powder is dried, and the dried powder is reduced at high temperature with hydrogen to obtain metal-coated carbide;

[0040] The nickel salt is one of nickel chloride, nickel nitrate, nickel sulfate, nickel phosphate, and nickel acetate, any two of them, or any combination of two or more of them;

[0041] The cobalt salt is one of cobalt chloride, cobalt nitrate, cobalt sulfate, cobalt phosphate, and cobalt acetate, any two of them, or any combination of two or more of them.

[0042] Step 2. Preparation of zinc oxide-coated nanocarbon material

[0043] First, the nanocarbon material is oxidized, then added to anhydrous monohydric alcohol. After the nanocarbon material is dispersed into nano single-particle state, an alkaline aqueous solution is added to adjust the pH value, and then an alcohol solution of zinc salt is added. After stirring at room temperature until the reaction is complete, filtration is carried out. The filtered solid is washed with deionized water and anhydrous ethanol until neutral, and then dried to obtain zinc oxide-coated nanocarbon material;

[0044] For the oxidation treatment, the method is as follows: The nanocarbon material is added to a mixed solution of concentrated nitric acid and hydrogen peroxide, heated to 70~90°C, stirred and refluxed for 1~2 hours, then filtered. The filtered solid is washed with deionized water until neutral, and then dried to obtain the oxidized nanocarbon material;

[0045] The alkaline aqueous solution is one of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, and ammonia water;

[0046] For the pH value adjustment, the pH value is adjusted to 10~12;

[0047] The alcohol solution of zinc salt is composed of zinc salt, alcohol amine substance, and anhydrous monohydric alcohol;

[0048] The zinc salt is one of zinc stearate, zinc acetate, and zinc salicylate;

[0049] The alkanolamine is one of isobutanolamine, monoethanolamine, diethanolamine, and triethanolamine;

[0050] The anhydrous monohydric alcohol is one of methanol and ethanol or a mixture of methanol and ethanol.

[0051] Step 3: Preparation of the high-temperature resistant lightweight stealth coating material

[0052] The high-temperature resistant lightweight stealth coating material is prepared by using the atmospheric plasma spraying technology, which has the advantages of high automation degree, a layered structure of the coating, and simple operation;

[0053] The surface of the substrate to be sprayed must be rust-removed, degreased, and sandblasted in advance. Then, according to the mass ratio of the raw material composition of the high-temperature resistant lightweight stealth coating material, the raw material powders are mixed evenly to obtain a mixed powder. After adding the mixed powder into the spraying equipment, control the arc voltage at 60 - 90V, the arc current at 500 - 700A, the main gas argon flow rate at 50 - 65L / min, the secondary gas hydrogen flow rate at 20 - 35L / min, the powder feeding speed at 10 - 20g / min, and the spraying distance at 90 - 120mm. Spray the mixed powder evenly onto the surface of the substrate to finally obtain a high-temperature resistant lightweight stealth coating material with a thickness of 120 - 260μm.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] 1. The high-temperature resistant lightweight stealth coating material prepared by the present invention uses micron-scale borides and silicides as the main raw materials. All the micron-scale borides and silicides defined in the specification have very high melting points (all above 1800°C) and very good electrical conductivity, which ensures that the prepared stealth coating has very good high-temperature resistance. At the same time, due to the good electrical conductivity, according to the Hagen-Ruben law, that is, E≈2×(2ε0ωρ) ½ , it can also be inferred that these micron-scale borides and silicides with good electrical conductivity will reduce the infrared emissivity of the coating material by reducing the resistivity of the coating;

[0056] 2. The present invention enhances the bonding strength between the melted thermal spray powder and the substrate through the design of coating nanoscale carbides with two metals, nickel and cobalt. The main principle is that the melting points of the two metal elements, nickel and cobalt, are not particularly high, and their reaction activities are relatively high. They are particularly prone to forming metal alloys or metal cermet alloys with the metal elements on the surface of the metal substrate or the non-metal elements on the surface of the ceramic substrate. Moreover, in the present invention, the carbide is limited to the nanoscale, mainly to utilize the huge specific surface area of the nanoscale carbide to increase the contact area between the metal-coated nanoscale carbide and the substrate, and to enhance the reaction degree between the metal-coated nanoscale carbide and the substrate surface by increasing the contact area. In addition, the carbides defined in the present invention, namely zirconium carbide, titanium carbide, vanadium carbide, and tungsten carbide, all have very good electrical conductivity. These strongly conductive nanoparticles can not only enhance the bonding strength but also effectively fill the gaps between micron-scale borides and silicides, improving the overall electrical conductivity of the coating and thus reducing the overall infrared emissivity of the coating.

[0057] 3. The main purpose of the zinc oxide-coated nanocarbon material prepared in the present invention is to further enhance the overall electrical conductivity and density of the coating by utilizing the strong electrical conductivity of the nanocarbon material and the size complementary effect between the nanoscale particles of the nanocarbon material and micron-scale borides and silicides. Since the coating preparation method selected in the present invention is thermal spraying, the powder transported by this process method can reach a high temperature of 1500 °C and above. During this high-temperature process, the nanocarbon material is extremely prone to oxidation and combustion. Therefore, the present invention coats the surface of the nanocarbon material with zinc oxide. The melting point of zinc oxide is as high as 1975 °C, and it also has semiconductor electrical conductivity. Therefore, on the premise of effectively protecting the nanocarbon material from high-temperature oxidation, it has no substantial impact on the high-temperature electrical conductivity of the nanocarbon material in the coating. So, the zinc oxide-coated nanocarbon material prepared in the present invention plays a very crucial role in reducing the infrared emissivity of the coating.

[0058] 4. The titanate flux added in the present invention has a relatively low melting point. During the thermal spraying process, when the powder is close to the substrate surface, the titanate can wrap the high-melting-point powder in a molten liquid or semi-liquid form. Therefore, it can effectively transfer the heat generated by the thermal spraying equipment to the high-melting-point powder, promoting the melting on the surface of the high-melting-point powder and further promoting the bonding force between the high-melting-point powder and the substrate surface. In addition, the liquid or semi-liquid substance generated by the melting of the titanate itself also has very good bonding strength with the substrate surface. Therefore, the titanate flux can effectively improve the bonding strength between the coating material and the substrate surface.

[0059] 5. The silicon phosphate and boron phosphate added in the present invention are both viscous vitreous substances after high-temperature melting. Therefore, they can effectively adhere to the surface of the substrate after melting, and the liquid viscous melt formed by these two substances can transfer heat relatively faster than high-melting-point powders. Therefore, it can effectively enhance the transfer of heat generated by the thermal spraying equipment to the surface of the substrate, and thus can play a role in assisting the sintering of high-melting-point powders on the surface of the substrate, ultimately promoting the hot melt bonding strength between the high-melting-point powders and the surface of the substrate;

[0060] 6. The high-temperature resistant lightweight stealth coating material prepared by the present invention has an infrared emissivity of 0.231 - 0.245 at a wavelength of 3 - 5 μm, an infrared emissivity of 0.424 - 0.441 at a wavelength of 8 - 14 μm, a tensile bonding strength of 40.8 - 46.4 MPa, and the number of thermal shock resistance is 153 - 167. Description of the Drawings

[0061] Figure 1 Scanning electron microscope photograph of the surface of the high-temperature resistant lightweight stealth coating material obtained in Example 1 magnified 1000 times;

[0062] Figure 2 Scanning electron microscope photograph of the surface of the high-temperature resistant lightweight stealth coating material obtained in Example 1 magnified 10000 times. Detailed Embodiments

[0063] The following are the preferred embodiments of the present invention. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0064] Example 1: Preparation Method of a High-Temperature Resistant Lightweight Stealth Coating Material

[0065] Step 1: Preparation of Metal-Coated Carbide

[0066] Prepare metal-coated carbide by electroless plating;

[0067] Disperse carbide powder at the nanoscale in the electroless plating solution, and then by controlling the temperature of the plating solution, the pH value of the plating solution and the stirring rate, the nickel ions contained in the electroless plating solution are controllably reduced to elemental nickel under the action of a reducing agent and adhere to coat on the surface of the carbide powder to form metal-coated carbide;

[0068] The carbide powder is zirconium carbide;

[0069] The particle size of the zirconium carbide is 30 nm;

[0070] The electroless plating solution is composed of nickel salt, complexing agent, stabilizer, reducing agent, and dispersant;

[0071] The mass ratio of the carbide powder, nickel salt, complexing agent, stabilizer, reducing agent, dispersant, and deionized water is 15:20:0.5:0.06:3:0.3:160;

[0072] The complexing agent is citric acid;

[0073] The stabilizer is sodium thiocyanate;

[0074] The reducing agent is sodium hypophosphite;

[0075] The dispersant is alkyl polyglycoside APG0810;

[0076] The nickel salt is nickel sulfate;

[0077] The temperature of the plating solution is 65 °C, the pH value of the plating solution is 5.6, and the stirring rate is 200 revolutions per minute.

[0078] Step 2: Preparation of zinc oxide-coated nano-carbon material

[0079] First, the nano-carbon material is oxidized, then added to anhydrous monohydric alcohol. After the nano-carbon material is dispersed into nano-single particle state, an alkaline aqueous solution is added to adjust the pH value, and then an alcohol solution of zinc salt is added. After the reaction is complete with stirring at room temperature, filtration is carried out. The filtered solid is washed with deionized water and anhydrous ethanol until neutral, and then dried to obtain the zinc oxide-coated nano-carbon material;

[0080] The nano-carbon material is carbon nanotubes;

[0081] The particle size of the carbon nanotubes is 30 nm;

[0082] For the oxidation treatment, the method is: adding the nano-carbon material into a mixed solution of concentrated nitric acid and hydrogen peroxide, keeping the temperature constant at 80 °C, stirring and refluxing for 1.5 hours, then filtering. The filtered solid is washed with deionized water until neutral, and then dried to obtain the oxidized nano-carbon material;

[0083] The mass ratio of the concentrated nitric acid to the hydrogen peroxide is 3:10;

[0084] The mass concentration of hydrogen peroxide in the hydrogen peroxide solution is 10%;

[0085] The alkaline aqueous solution is sodium hydroxide aqueous solution;

[0086] For the pH value adjustment, the pH value is adjusted to 11;

[0087] The alcohol solution of zinc salt is composed of zinc salt, alcohol amine substance, and anhydrous monohydric alcohol;

[0088] The mass ratio of the zinc salt, alcohol amine substance, and anhydrous monohydric alcohol is 5:0.3:45;

[0089] The zinc salt is zinc stearate;

[0090] The alkanolamine is isobutanolamine;

[0091] The anhydrous monohydric alcohol is ethanol.

[0092] Step 3. Preparation of the high-temperature resistant lightweight stealth coating material

[0093] The raw material composition of the high-temperature resistant lightweight stealth coating material includes boride, silicide, titanate flux, metal-coated carbide, zinc oxide-coated nano-carbon material, and sintering aid;

[0094] The mass ratio of the boride, silicide, titanate flux, metal-coated carbide, zinc oxide-coated nano-carbon material, and sintering aid is 80:50:2:6:5:2;

[0095] The boride is titanium boride;

[0096] The particle size of the boride is 2 μm;

[0097] The silicide is titanium silicide;

[0098] The particle size of the silicide is 1 μm;

[0099] The titanate flux is potassium titanate;

[0100] The particle size of the titanate flux is 0.6 μm;

[0101] In the metal-coated carbide, the metal is nickel and the carbide is zirconium carbide;

[0102] The particle size of the carbide is 30 nm;

[0103] In the zinc oxide-coated nano-carbon material, the nano-carbon material is carbon nanotube;

[0104] The particle size of the nano-carbon material is 30 nm;

[0105] The sintering aid is silicon phosphate;

[0106] The particle size of the sintering aid is 0.3 μm;

[0107] The high-temperature resistant lightweight stealth coating material is prepared by atmospheric plasma spraying technology, which has the advantages of high automation degree, layered coating structure, and simple operation;

[0108] The surface of the substrate to be sprayed must be rust-removed, degreased, and sandblasted in advance. Then, according to the mass ratio of the raw material composition of the high-temperature resistant lightweight stealth coating material, the raw material powders are mixed evenly to obtain a mixed powder. After adding the mixed powder into the spraying equipment, control the arc voltage at 80V, the arc current at 650A, the main gas argon gas flow rate at 60L / min, the auxiliary gas hydrogen gas flow rate at 30L / min, the powder feeding speed at 16g / min, and the spraying distance at 110mm. Spray the mixed powder evenly onto the surface of the substrate to finally obtain a high-temperature resistant lightweight stealth coating material with a thickness of 200μm.

[0109] Example 2: A preparation method of a high-temperature resistant lightweight stealth coating material

[0110] Step 1: Preparation of metal-coated carbide

[0111] The metal-coated carbide is prepared by a hydrothermal hydrogen reduction method;

[0112] In the hydrothermal hydrogen reduction method, the carbide powder, catalyst, dispersant, and nickel salt solution are added into an autoclave. Control the appropriate reaction temperature and reaction pressure, and use hydrogen to reduce and deposit nickel ions on the surface of the carbide powder to form a metal-coated carbide;

[0113] The carbide powder is titanium carbide;

[0114] The particle size of the titanium carbide is 1nm;

[0115] The catalyst is palladium chloride;

[0116] The dispersant is sodium dodecylbenzenesulfonate;

[0117] The mass ratio of the carbide powder, catalyst, dispersant, and nickel salt solution is 10:0.3:1:90;

[0118] In the nickel salt solution, the mass fraction of the nickel salt is 15%;

[0119] The reaction temperature is 120°C;

[0120] The reaction pressure is 2MPa;

[0121] The nickel salt is nickel nitrate.

[0122] Step 2: Preparation of zinc oxide-coated nano-carbon material

[0123] First, the nano-carbon material is oxidized, and then added to anhydrous monohydric alcohol. After dispersing the nano-carbon material into a nano-single particle state, then add an alkaline aqueous solution to adjust the pH value, and then add an alcoholic solution of zinc salt. After stirring and reacting completely at room temperature, filter. The filtered solid is washed with deionized water and anhydrous ethanol until neutral, and then dried to obtain a zinc oxide-coated nano-carbon material;

[0124] The nano-carbon material is graphene;

[0125] The particle size of the graphene is 1 nm;

[0126] For the oxidation treatment, the method is as follows: Add the nano-carbon material into the mixed solution of concentrated nitric acid and hydrogen peroxide, keep the temperature constant at 70 °C, stir and reflux for 1 hour, then filter. The filtered solid is washed with deionized water until neutral, and then dried to obtain the oxidized nano-carbon material;

[0127] The mass ratio of the concentrated nitric acid to the hydrogen peroxide is 3:10;

[0128] The mass concentration of hydrogen peroxide in the hydrogen peroxide solution is 10%;

[0129] The alkaline aqueous solution is a potassium hydroxide aqueous solution;

[0130] For the pH value adjustment, the pH value is adjusted to 10;

[0131] The alcoholic solution of the zinc salt is composed of a zinc salt, an alkanolamine substance, and a monohydric alcohol without water;

[0132] The zinc salt is zinc acetate;

[0133] The alkanolamine substance is diethanolamine;

[0134] The monohydric alcohol without water is methanol.

[0135] Step 3: Preparation of the high-temperature lightweight stealth coating material

[0136] The raw material composition of the high-temperature lightweight stealth coating material includes a boride, a silicide, a titanate flux, a metal-coated carbide, a zinc oxide-coated nano-carbon material, and a sintering aid;

[0137] The mass ratio of the boride, the silicide, the titanate flux, the metal-coated carbide, the zinc oxide-coated nano-carbon material, and the sintering aid is 20:30:1:1:1:1;

[0138] The boride is zirconium boride;

[0139] The particle size of the boride is 0.5 μm;

[0140] The silicide is zirconium silicide;

[0141] The particle size of the silicide is 0.5 μm;

[0142] The titanate flux is lithium titanate;

[0143] The particle size of the titanate flux is 0.1 μm;

[0144] In the metal-coated carbide, the metal is nickel and the carbide is titanium carbide;

[0145] The particle size of the carbide is 1 nm;

[0146] In the zinc oxide-coated nano-carbon material, the nano-carbon material is graphene;

[0147] The particle size of the nano-carbon material is 1 nm;

[0148] The sintering aid is boron phosphate;

[0149] The particle size of the sintering aid is 0.1 μm;

[0150] The high-temperature resistant lightweight stealth coating material is prepared by atmospheric plasma spraying technology, which has the advantages of high automation degree, layered coating structure, simple operation, etc.;

[0151] The surface of the substrate to be sprayed must be rust-removed, degreased and sandblasted in advance. Then, according to the mass ratio of the raw material composition of the high-temperature resistant lightweight stealth coating material, the raw material powders are mixed evenly to obtain a mixed powder. After adding the mixed powder into the spraying equipment, control the arc voltage at 60 V, the arc current at 500 A, the main gas argon flow rate at 50 L / min, the secondary gas hydrogen flow rate at 20 L / min, the powder feeding speed at 10 g / min, and the spraying distance at 90 mm. Spray the mixed powder evenly onto the surface of the substrate to finally obtain a high-temperature resistant lightweight stealth coating material with a thickness of 120 μm.

[0152] Example 3: A preparation method of a high-temperature resistant lightweight stealth coating material

[0153] Step 1: Preparation of metal-coated carbide

[0154] The metal-coated carbide is prepared by the precipitation reduction method;

[0155] In the precipitation reduction method, nickel salt is dissolved in deionized water to form an aqueous solution. Control the temperature of the aqueous solution, then add carbide powder. After strong stirring and uniform dispersion, add ammonia water to make nickel form nickel hydroxide precipitation and adsorb on the surface of the carbide powder. After the reaction is completed, the carbide powder is dried, and the dried powder is reduced at high temperature by hydrogen to obtain the metal-coated carbide;

[0156] The carbide powder is vanadium carbide;

[0157] The particle size of the vanadium carbide is 100 nm;

[0158] The nickel salt is dissolved in deionized water to form an aqueous solution, and the mass concentration of the nickel salt is 13%;

[0159] The nickel salt is nickel acetate;

[0160] The nickel salt is dissolved in deionized water to form an aqueous solution, carbide powder, and ammonia water, and the mass ratio of the three is 20:2:11;

[0161] The mass concentration of ammonia monohydrate in the ammonia water is 4%;

[0162] After high-temperature reduction with hydrogen, the reduction temperature is 160 °C.

[0163] Step 2: Preparation of zinc oxide-coated nano-carbon material

[0164] First, the nano-carbon material is oxidized, then added to anhydrous monohydric alcohol. After the nano-carbon material is dispersed into nano-single particle state, then an alkaline aqueous solution is added to adjust the pH value, and then an alcohol solution of zinc salt is added. After the reaction is completely stirred at room temperature, filtration is carried out. The filtered solid is washed with deionized water and anhydrous ethanol until neutral, and then dried to obtain zinc oxide-coated nano-carbon material;

[0165] The nano-carbon material is nano-scale conductive carbon black;

[0166] The particle size of the nano-scale conductive carbon black is 100 nm;

[0167] For the oxidation treatment, the method is: adding the nano-carbon material into a mixed solution of concentrated nitric acid and hydrogen peroxide, heating to 90 °C under constant temperature, stirring and refluxing for 2 hours, then filtering, washing the filtered solid with deionized water until neutral, and then drying to obtain the oxidized nano-carbon material;

[0168] The alkaline aqueous solution is ammonia water;

[0169] When adjusting the pH value, the pH value is adjusted to 12;

[0170] The alcohol solution of zinc salt is composed of zinc salt, alkanolamine, and anhydrous monohydric alcohol;

[0171] The mass ratio of the zinc salt, alkanolamine, and anhydrous monohydric alcohol is 5:0.3:45;

[0172] The zinc salt is zinc salicylate;

[0173] The alkanolamine is triethanolamine;

[0174] The anhydrous monohydric alcohol is ethanol.

[0175] Step 3: Preparation of high-temperature resistant lightweight stealth coating material

[0176] The raw material composition of the high-temperature resistant lightweight stealth coating material includes boride, silicide, titanate flux, metal-coated carbide, zinc oxide-coated nano-carbon material, and sintering aid;

[0177] The mass ratio of the boride, silicide, titanate flux, metal-coated carbide, zinc oxide-coated nano-carbon material, and sintering aid is 100:150:5:10:8:4;

[0178] The boride is calcium boride;

[0179] The particle size of the boride is 3 μm;

[0180] The silicide is tantalum silicide;

[0181] The particle size of the silicide is 3 μm;

[0182] The titanate flux is magnesium titanate;

[0183] The particle size of the titanate flux is 1 μm;

[0184] In the metal-coated carbide, the metal is nickel and the carbide is vanadium carbide;

[0185] The particle size of the carbide is 100 nm;

[0186] In the zinc oxide-coated nano-carbon material, the nano-carbon material is nano-conductive carbon black;

[0187] The particle size of the nano-carbon material is 100 nm;

[0188] The sintering aid is silicon phosphate;

[0189] The particle size of the sintering aid is 1 μm;

[0190] The high-temperature resistant lightweight stealth coating material is prepared by atmospheric plasma spraying technology, which has the advantages of high automation degree, layered coating structure, and simple operation;

[0191] The surface of the substrate to be sprayed must be rust-removed, degreased, and sandblasted in advance. Then, according to the mass ratio of the raw material composition of the high-temperature resistant lightweight stealth coating material, the raw material powders are mixed evenly to obtain a mixed powder. After adding the mixed powder to the spraying equipment, the arc voltage is controlled at 90 V, the arc current is 700 A, the main gas argon flow rate is 65 L / min, the secondary gas hydrogen flow rate is 35 L / min, the powder feeding speed is 20 g / min, and the spraying distance is 120 mm. The mixed powder is evenly sprayed onto the surface of the substrate, and finally a high-temperature resistant lightweight stealth coating material with a thickness of 260 μm is obtained.

[0192] Example 4: A preparation method of a high-temperature resistant lightweight stealth coating material

[0193] Step 1. Preparation of metal-coated carbide

[0194] On the basis of Example 1, nickel salt, that is, nickel sulfate, is replaced with cobalt sulfate, and other operations are the same as those in Example 1;

[0195] The operations of Steps 2 and 3 are the same as those in Example 1.

[0196] Comparative Example 1: Based on Example 1, without performing Step 1, the preparation of metal-coated carbide, in Step 3, the preparation of high-temperature resistant lightweight stealth coating material, 6 parts of metal-coated carbide are replaced with 6 parts of carbide in equal amount. The specific operations are as follows:

[0197] Without performing Step 1, the preparation of metal-coated carbide

[0198] The operation of Step 2 is the same as that in Example 1;

[0199] Step 3, the preparation of high-temperature resistant lightweight stealth coating material

[0200] 6 parts of metal-coated carbide are replaced with 6 parts of carbide in equal amount, and other operations are the same as those in Example 1;

[0201] The carbide is zirconium carbide;

[0202] The particle size of the carbide is 30 nm.

[0203] Comparative Example 2: Based on Example 1, without performing Step 2, the preparation of zinc oxide-coated nano-carbon material, in Step 3, the preparation of high-temperature resistant lightweight stealth coating material, 5 parts of zinc oxide-coated nano-carbon material are replaced with 5 parts of nano-carbon material in equal amount. The specific operations are as follows:

[0204] The operation of Step 1 is the same as that in Example 1;

[0205] Without performing Step 2, the preparation of zinc oxide-coated nano-carbon material;

[0206] Step 3, the preparation of high-temperature resistant lightweight stealth coating material

[0207] 5 parts of zinc oxide-coated nano-carbon material are replaced with 5 parts of nano-carbon material in equal amount, and other operations are the same as those in Example 1;

[0208] The nano-carbon material is carbon nanotube;

[0209] The particle size of the nano-carbon material is 30 nm.

[0210] Comparative Example 3: Based on Example 1, in Step 3, the preparation of high-temperature resistant lightweight stealth coating material, without adding titanate flux, 2 parts of titanate flux are replaced with 2 parts of boride in equal amount. The specific operations are as follows:

[0211] The operations of Steps 1 and 2 are the same as those in Example 1;

[0212] Step 3, the preparation of high-temperature resistant lightweight stealth coating material

[0213] Replace 2 parts of titanate flux with 2 parts of boride in equal amounts, and other operations are the same as in Example 1.

[0214] Comparative Example 4: On the basis of Example 1, in Step 3, the preparation of the high-temperature resistant lightweight stealth coating material, without adding a sintering aid, replace 2 parts of the sintering aid with 2 parts of boride in equal amounts. The specific operation is as follows:

[0215] The operations in Steps 1 and 2 are the same as in Example 1;

[0216] Step 3, Preparation of the high-temperature resistant lightweight stealth coating material

[0217] Replace 2 parts of the sintering aid with 2 parts of boride in equal amounts, and other operations are the same as in Example 1.

[0218] Performance test:

[0219] For the high-temperature resistant lightweight stealth coating materials obtained in Examples 1, 2, 3, 4 and Comparative Examples 1, 2, 3, 4, conduct tests on indicators such as infrared emissivity and tensile bonding strength:

[0220] 1. Infrared emissivity: Heat the specimen of the high-temperature resistant lightweight stealth coating material to 1100 °C, and measure the hemispherical infrared radiation intensity of the specimen and the standard blackbody in the range of 3 - 5 μm and 8 - 14 μm under the same conditions to obtain the infrared emissivity;

[0221] 2. Tensile bonding strength: Conduct the test according to "GB / T 8642 - 2002 Thermal spraying - Determination of tensile bonding strength";

[0222] 3. Number of thermal shock resistance: Adopt the water quenching method. Heat the specimen in a box-type resistance furnace at a set temperature of 1100 °C for 10 minutes, then quickly take it out and quench it into clean water at about 20 °C. When the specimen cools to room temperature in the water, take it out and dry it with a hair dryer, which completes one thermal shock experiment. Repeat this cycle until visible cracks, peeling or flaking appear on the surface of the specimen. Record the number of thermal shocks experienced at this time, which is the number of thermal shock resistance;

[0223] The results are shown in Table 1:

[0224] Table 1

[0225] As can be seen from the data in Table 1, the infrared emissivities of Examples 1-4 at a wavelength of 3-5 μm are all below 0.25, and the infrared emissivities at a wavelength of 8-14 μm do not exceed 0.5. Moreover, the tensile bonding strength of the coating is greater than 40 MPa, and the number of thermal shock resistance is more than 150 times. This shows that the high-temperature resistant lightweight stealth coating material obtained by the present invention has remarkable advantages such as good high-temperature resistance, excellent high-temperature thermal shock resistance, and low infrared emissivity; the carbide added in Comparative Example 1 was not metal-coated, and the infrared emissivity of Comparative Example 1 increased significantly, the tensile bonding strength decreased particularly sharply, and the number of thermal shock resistance also decreased to the lowest. This shows that after the carbide is metal-coated, it can mainly improve the bonding strength between the coating material and the substrate surface, and improve the thermal shock resistance by enhancing the bonding strength. Moreover, the carbide after metal coating may improve the overall conductivity of the coating by increasing the density of the coating during the coating formation process, and thus the carbide after metal coating can also reduce the infrared emissivity; the nano-carbon material added in Comparative Example 2 was not zinc oxide-coated, and the infrared emissivity of Comparative Example 2 increased to the maximum, and the tensile bonding strength and the number of thermal shock resistance also decreased significantly. This shows that zinc oxide coating the nano-carbon material can prevent the nano-carbon material from being oxidized and ablated during high-temperature spraying, and thus can ensure that the nano-carbon material enters the coating material matrix with a relatively complete nano-structure, playing the role of enhancing the coating conductivity and reducing the infrared emissivity; in Comparative Example 3, no titanate flux was added, and the infrared emissivity of Comparative Example 3 increased significantly, and the tensile bonding strength and the number of thermal shock resistance decreased greatly. It can be seen that the titanate flux plays a very important role in improving the interfacial adhesion between the coating and the substrate, and also plays a role in reducing the infrared emissivity of the coating; in Comparative Example 4, no sintering aid was added, and the infrared emissivity of Comparative Example 4 increased significantly, and the tensile bonding strength and the number of thermal shock resistance decreased sharply. This shows that the sintering aid plays a very crucial role in the bonding strength between the coating and the substrate, and may affect the infrared emissivity of the coating by influencing the density of the coating.

[0226] In the attached drawings Figure 1 and Figure 2 are respectively the scanning electron microscope photos of the surface of the high-temperature resistant lightweight stealth coating material obtained in Example 1 magnified 1000 times and 10000 times. From the Figure 1 view of the 1000-fold magnification, the surface of the coating is very flat, relatively dense as a whole, without pore defects. From the Figure 2 view of the 10000-fold magnification, various raw material powders in the coating are fused together, and the pores formed after fusion are extremely tiny, almost all in the sub-micron to nano level. This shows that the high-temperature resistant lightweight stealth coating material prepared by the present invention has a very high density.

[0227] As described above, it is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent replacements or changes should be covered within the protection scope of the present invention.

Claims

1. A high-temperature resistant lightweight stealth coating material, characterized in that: The raw material composition of the high-temperature resistant lightweight stealth coating material includes boride, silicide, titanate flux, metal-coated carbide, zinc oxide-coated nano-carbon material, and sintering aid; The boride is one of titanium boride, zirconium boride, calcium boride, hafnium boride, vanadium boride, chromium boride, silicon boride, manganese monoboride, manganese diboride, manganese tetraboride, molybdenum monoboride, molybdenum diboride, molybdenum pentaboride, or any combination of two or more of them; The silicide is one of titanium silicide, zirconium silicide, tantalum silicide, tungsten silicide, molybdenum trisilicide, pentamolybdenum trisilicide, molybdenum disilicide, or any combination of two or more of them; The titanate flux is one of potassium titanate, lithium titanate, magnesium titanate, barium titanate, lead titanate, zinc titanate, or any combination of two or more of them; In the metal-coated carbide, the metal is one of nickel, cobalt, or a combination of nickel and cobalt, and the carbide is one of zirconium carbide, titanium carbide, vanadium carbide, tungsten carbide, or any combination of two or more of them; The particle size of the carbide is 1 - 100 nm; In the zinc oxide-coated nano-carbon material, the nano-carbon material is one of carbon nanotubes, carbon nanofibers, nano-carbon spheres, graphene, nano-scale conductive carbon black, nano-scale graphite powder, or any combination of two or more of them; The sintering aid is one of silicon phosphate, boron phosphate, or a combination of the two.

2. The high-temperature resistant lightweight stealth coating material according to claim 1, characterized in that: For the metal-coated carbide, the preparation method adopts one of electroless plating method, hydrothermal hydrogen reduction method, and precipitation reduction method; For the zinc oxide-coated nano-carbon material, the preparation method is as follows: First, the nano-carbon material is oxidized, then added to anhydrous monohydric alcohol, and the nano-carbon material is dispersed to the nano-single particle state. Then, an alkaline aqueous solution is added to adjust the pH value, and then an alcohol solution of zinc salt is added. After stirring at room temperature until the reaction is complete, filtration is carried out. The filtered solid is washed with deionized water and anhydrous ethanol until neutral, and then dried to obtain the zinc oxide-coated nano-carbon material.

3. The high-temperature resistant lightweight stealth coating material according to claim 2, characterized in that: In the electroless plating method, the carbide powder is dispersed in the electroless plating solution at the nano-scale, and then by controlling the temperature of the plating solution, the pH value of the plating solution, and the stirring rate, the nickel ions, cobalt ions, or a mixture of nickel and cobalt ions contained in the electroless plating solution are controllably reduced to elemental nickel, elemental cobalt, or a mixture of elemental nickel and cobalt under the action of a reducing agent and adhere to coat the surface of the carbide powder to form a metal-coated carbide; The electroless plating solution is composed of one or a mixture of two of nickel salt and cobalt salt, complexing agent, stabilizer, reducing agent, and dispersant; The complexing agent is aliphatic carboxylic acid; The stabilizer is one of thiocyanate and thiourea; The reducing agent is one of sodium hypophosphite, hydrazine, and sodium borohydride; The dispersant is a non-ionic surfactant that promotes the dispersion of the carbide powder, specifically one of alkyl glycoside surfactants, long-chain fatty alcohol polyoxyethylene ether surfactants, and alkylphenol polyoxyethylene ether surfactants, or any combination of two or more of them.

4. The high-temperature resistant lightweight stealth coating material according to claim 2, characterized in that: In the hydrothermal hydrogen reduction method, carbide powder, a catalyst, a dispersant, a nickel salt solution or a cobalt salt solution or a mixed solution of nickel salt and cobalt salt are added into an autoclave, and appropriate reaction temperature and reaction pressure are controlled. Hydrogen is used to reduce and deposit nickel ions, cobalt ions or both nickel and cobalt ions on the surface of the carbide powder to form metal-coated carbide; The catalyst is one of palladium chloride and anthraquinone; The dispersant is one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and polyethylene glycol monooctyl phenyl ether or any combination of two or more of them; The reaction temperature is 110~160°C; The reaction pressure is 1~5 MPa.

5. The high-temperature resistant lightweight stealth coating material according to claim 2, characterized in that: In the precipitation reduction method, one or a mixture of nickel salt and cobalt salt is dissolved in deionized water to form an aqueous solution. The temperature of the aqueous solution is controlled, and then carbide powder is added. After being strongly stirred and dispersed evenly, ammonia water is added to make nickel or cobalt generate nickel hydroxide or cobalt hydroxide precipitation and adsorb on the surface of the carbide powder. After the reaction is completed, the carbide powder is dried, and the dried powder is reduced at high temperature by hydrogen to obtain metal-coated carbide; The nickel salt is one of nickel chloride, nickel nitrate, nickel sulfate, nickel phosphate, and nickel acetate or any combination of two or more of them; The cobalt salt is one of cobalt chloride, cobalt nitrate, cobalt sulfate, cobalt phosphate, and cobalt acetate or any combination of two or more of them.

6. The high-temperature resistant lightweight stealth coating material according to claim 2, characterized in that: In the oxidation treatment, the method is: adding nano-carbon material into a mixed solution of concentrated nitric acid and hydrogen peroxide, keeping the temperature constant at 70~90°C, stirring and refluxing for 1~2 hours, then filtering. The filtered solid is washed with deionized water until neutral, and then dried to obtain the oxidized nano-carbon material; The alkaline aqueous solution is one of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, and ammonia water; For adjusting the pH value, the pH value is adjusted to 10~12; The alcoholic solution of zinc salt is composed of zinc salt, alkanolamine, and anhydrous monohydric alcohol; The zinc salt is one of zinc stearate, zinc acetate, and zinc salicylate; The alkanolamine is one of isobutanolamine, monoethanolamine, diethanolamine, and triethanolamine; The anhydrous monohydric alcohol is one of methanol and ethanol or a mixture of methanol and ethanol.

7. The high-temperature resistant lightweight stealth coating material according to claim 1, characterized in that: The mass ratio of the boride, silicide, titanate flux, metal-coated carbide, zinc oxide-coated nano-carbon material, and sintering aid is 20~100:30~150:1~5:1~10:1~8:1~4.

8. The high-temperature resistant lightweight stealth coating material according to claim 1, characterized in that: The particle size of the boride is 0.5~3 μm; The particle size of the silicide is 0.5~3 μm.

9. The high-temperature resistant lightweight stealth coating material according to claim 1, characterized in that: The particle size of the titanate flux is 0.1~1 μm; The particle size of the nano-carbon material is 1 to 100 nm; The particle size of the sintering aid is 0.1 to 1 μm.

10. The preparation method of the high-temperature resistant lightweight stealth coating material according to claim 1, wherein: The surface of the substrate to be sprayed must be rust-removed, degreased, and sandblasted in advance. Then, according to the mass ratio of the raw material composition of the high-temperature resistant lightweight stealth coating material, the raw material powders are mixed evenly to obtain a mixed powder. After adding the mixed powder into the spraying equipment, control the arc voltage at 60 to 90 V, the arc current at 500 to 700 A, the main gas argon gas flow rate at 50 to 65 L / min, the auxiliary gas hydrogen gas flow rate at 20 to 35 L / min, the powder feeding speed at 10 to 20 g / min, and the spraying distance at 90 to 120 mm. Spray the mixed powder evenly onto the surface of the substrate to finally obtain a high-temperature resistant lightweight stealth coating material with a thickness of 120 to 260 μm.

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