Ablation-resistant heat-insulating wave-absorbing coating, composite coating and application thereof

Abstract

The application belongs to the technical field of functional coating, and discloses an ablation-resistant heat-insulating wave-absorbing coating, a composite coating and application thereof, wherein the wave-absorbing coating is a filling powder material composed of modified ceramic hollow microbeads, silicon carbide nanowhiskers, nickel-plated quartz short-cut fibers and cerium oxide nanofibers, and a film-forming material matrix material made of a vinyl acetate-ethylene water-based copolymer emulsion, ethylene glycol and deionized water and a functional additive; the composite coating is obtained by independently spraying single-layer coatings, stacking multiple layers in sequence and finally curing to reach the total thickness. The composite coating has a microstructure constructed with modified ceramic hollow microbeads as a skeleton, and other fillers densely fill the pores around the modified ceramic hollow microbeads, forming three-dimensional heat-insulating channels, so that the composite coating simultaneously has the properties of strong heat insulation, low thermal conductivity, ablation resistance, high mechanical strength and electromagnetic performance, and is widely applied to improving the ablation resistance, heat insulation and radar stealth performance under high-temperature service conditions of targets.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of functional coating, in particular to a kind of ablation-resistant heat-insulating wave-absorbing coating, composite coating and application thereof. BACKGROUND

[0002] High-speed vehicles generate aerodynamic heating when flying dynamically with air friction, and the external temperature can reach above 1000℃ in a very short time, and high-pressure, high-speed airflow scouring effect is formed, which easily leads to the decline of the mechanical properties of the shell and the increase of the cabin temperature, and the internal combustion chamber inner wall and launching stand will also withstand high-speed flame scouring effect, and ablation-resistant heat-insulating materials are important guarantee for normal launching and flying of high-speed vehicles.On the other hand, with the gradual maturity of multi-band, multi-function radar detection technology and the deployment of a global "heavenly net", high-speed vehicles and launching devices are threatened by being discovered, intercepted and destroyed.Wave-absorbing materials can convert incident radar wave energy into other forms of energy mainly thermal energy, which can effectively reduce the radar cross section (RCS) of the target, thereby reducing the probability of being discovered, intercepted and ultimately destroyed by enemy radar.Therefore, an ablation-resistant heat-insulating wave-absorbing integrated material needs to be developed.

[0003] In the prior art, Chinese patents CN 111304578 A, CN 115972695 A and CN 112918025 A respectively disclose a heat-insulating / radar-absorbing integrated composite coating, a titanium alloy material coated with a composite coating and a preparation method thereof, a heat-insulating high-temperature-resistant wave-absorbing material and a preparation method thereof, and an ablation-resistant heat-insulating wave-absorbing integrated composite material and a preparation method thereof, all of which use a multi-layer structure design to achieve heat insulation / wave absorption, but the structure design is complex and the implementation process is difficult.Chinese patent CN 117344262 A discloses a material with high-temperature wave-absorbing heat-insulating coating and a preparation method thereof, which is prepared by spraying lanthanum magnesium aluminum oxide and samarium iron nitrogen mixed powder on the surface of a plate by plasma spraying.The preparation method is harsh.Chinese patents CN 115627119 A and CN 117106372 A respectively disclose a lightweight temperature-resistant heat-insulating stealth coating, a coating and a preparation method thereof, and a coating with the functions of stealth, heat insulation and heat protection, a preparation method thereof and application, which mainly fills the organic film-forming matrix with functional powder to prepare a multifunctional heat-insulating / wave-absorbing coating, but the film-forming matrix material mainly uses silicone rubber and organic solvents, which are expensive and polluting;CN 110885583 A discloses an ablation-resistant wave-absorbing anti-skid wear-resistant composite coating and a preparation method thereof, which includes an anti-corrosion bottom layer, an ablation-resistant wave-absorbing sandwich layer, an anti-skid wear-resistant layer and an anti-aging top layer.The composite coating must be designed with thickness matching among multiple layers to form a multifunctional compatible integrated coating, and the structure and preparation process are complex.

[0004] Therefore, research and development of a low-cost, environmentally friendly, simple construction of ablation-resistant heat-insulating wave-absorbing composite coating and a preparation method thereof have important practical application values for solving the ablation-resistant heat insulation of high-speed aircraft, combustion chambers and launching racks and improving the radar stealth performance thereof. SUMMARY

[0005] The present application aims at solving the problems of the prior art and provides an ablation-resistant heat-insulating wave-absorbing coating, a composite coating and application thereof.

[0006] The present application solves the technical problems by the technical scheme of:

[0007] An ablation-resistant heat-insulating wave-absorbing coating is characterized by comprising the following components: modified ceramic hollow microbeads, silicon carbide nanowhiskers, nickel-plated quartz short-cut fibers, cerium oxide nanofibers, and a film-forming base material made of vinyl acetate-ethylene water-based copolymer emulsion, ethylene glycol and deionized water, and functional additives.

[0008] The mass ratio of the components of the ablation-resistant heat-insulating wave-absorbing coating is as follows: modified ceramic hollow microbeads 5-10 parts, silicon carbide nanowhiskers 10-20 parts, nickel-plated quartz short-cut fibers 6-15 parts, cerium oxide nanofibers 7-15 parts, vinyl acetate-ethylene water-based copolymer emulsion 30-50 parts, ethylene glycol 2-4 parts, deionized water 8-15 parts, and functional additives 2-4 parts.

[0009] The modified ceramic hollow microbeads are one or both of borosilicate ceramic hollow microbeads and aluminosilicate ceramic hollow microbeads, and the surface is modified by coating with a silane coupling agent, and the particle size D50 is 10-50 μm; the silicon carbide nanowhiskers have a beta-type cubic crystal phase structure, a diameter of 20-200 nm, and a length of 0.5-8 μm; the nickel-plated quartz short-cut fibers have a magnetic nickel film chemically plated on the surface, a diameter of 0.5-1 μm, and a length of 6-9 μm; the cerium oxide nanofibers are prepared by electrospinning and high-temperature calcination, have a diameter of 200-400 nm, and a length of 20-50 μm; and the additives include multiple types of fatty hydrocarbon antifoam agent, chloromethyl thiazolinone and methyl isothiazolinone bactericide, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate film-forming aid, polycarboxylic acid sodium salt type dispersant, and acrylate-methacrylate copolymer thickener.

[0010] An ablative heat-insulating wave-absorbing composite coating is prepared by using the aforementioned ablative heat-insulating wave-absorbing coating, and the preparation method comprises the following steps:

[0011] S1, ablative heat-insulating wave-absorbing coating configuration: according to the mass fraction, each filling powder material and film forming material are added to the raw material tank of the vacuum planetary mixer, and each component is uniformly mixed by using the planetary stirring method under vacuum and mechanical bubbles are removed to prepare the ablative heat-insulating wave-absorbing coating;

[0012] S2, single-layer spraying forming: the prepared coating is uniformly sprayed on the metal substrate or carbon composite substrate, and the first layer of coating is obtained after surface drying, and the thickness of the film formed after single-layer spraying is controlled to be 0.3-0.5mm;

[0013] S3, multi-layer spraying forming: the film layer after the first spraying is sprayed again, and the second layer of coating is obtained after surface drying, and the thickness of the film formed after single-layer spraying is controlled to be 0.3-0.5mm, and the interval time between two sprays is controlled to be 2-3h, and the total thickness of the coating is set by multiple spraying;

[0014] S4, drying and curing: the sprayed and formed coating is placed in a constant temperature and humidity environment for deep curing to obtain the ablative heat-insulating wave-absorbing composite coating.

[0015] The application of the ablative heat-insulating wave-absorbing composite coating is characterized in that the ablative heat-insulating wave-absorbing composite coating is sprayed on the surface of a high-speed aircraft with complex shape, a combustion chamber and a launching rack and is cured, so as to improve the ablative, heat-insulating and radar stealth performance of the target under high-temperature service conditions.

[0016] Compared with the prior art, the present application has the following outstanding advantages:

[0017] (1) The coating and the composite coating provided by the present application have a microstructure in which the large-particle-size modified ceramic hollow microsphere particles are used as a skeleton, other filling powder materials are densely filled, and the film forming material is uniformly coated.

[0018] (2) The composite coating product provided by the present application has excellent ablative, heat-insulating and wave-absorbing effects. The cold face temperature is less than 150℃ after being ablated by 1000℃ or above oxyacetylene flame for 5min, and the reflection loss in the frequency range of 2-18GHz is better than-10dB with a bandwidth of 8.6GHz.

[0019] (3) The paint provided by the present application adopts an environmentally-friendly water-based system as a film-forming base material, can be applied by spraying, and the coating can be deeply cured and formed at room temperature after spraying.

[0020] (4) The ablation-resistant heat-insulating wave-absorbing composite coating and the preparation method of the paint thereof provided by the present application are environmentally-friendly, have high production and construction efficiency, low cost, and are more conducive to industrial application. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a schematic diagram of the ablation-resistant heat-insulating wave-absorbing composite coating in Example 1 of the present application;

[0022] Figure 2 is a micro-morphology diagram of the cross section of the ablation-resistant heat-insulating wave-absorbing composite coating in Example 1 of the present application;

[0023] Figure 3 is a temperature change curve of the ablation-resistant heat-insulating wave-absorbing composite coating in Example 1, Example 2 and Example 3 of the present application in an oxygen-ethyne flame test;

[0024] Figure 4 is a reflectivity curve diagram of the ablation-resistant heat-insulating wave-absorbing composite coating in Example 1, Example 2 and Example 3 of the present application in a 2GHz-18GHz frequency band. DETAILED DESCRIPTION

[0025] The present application will be further described below in conjunction with the drawings and specific embodiments. It should be pointed out that the described embodiments are only part of the embodiments of the present application, but not all the embodiments, and these embodiments should not be used to explain the limitation of the scope of protection claimed by the present application. Based on the embodiments in the present application, all other changes or modifications obtained by those skilled in the art without creative labor fall within the scope of protection claimed by the present application.

[0026] Basic Embodiment

[0027] The ablation-resistant heat-insulating wave-absorbing paint provided by the present embodiment is prepared from a filling powder material composed of modified ceramic hollow microbeads, silicon carbide nanowhiskers, nickel-plated quartz short-cut fibers, and cerium oxide nanofibers, and a film-forming base material prepared from a vinyl acetate-ethylene water-based copolymer emulsion, ethylene glycol and deionized water, and a functional additive.

[0028] The mass ratio of the components of the ablation-resistant heat-insulating wave-absorbing coating is: 5-10 parts of modified ceramic hollow microbeads, 10-20 parts of silicon carbide nanowhiskers, 6-15 parts of nickel-plated quartz short-cut fibers, 7-15 parts of cerium oxide nanofibers, 30-50 parts of vinyl acetate-ethylene water-based copolymer emulsion, 2-4 parts of ethylene glycol, 8-15 parts of deionized water, and 2-4 parts of functional additives.

[0029] The modified ceramic hollow microbeads are one or both of borosilicate ceramic hollow microbeads and aluminosilicate ceramic hollow microbeads, and the surface is modified by coating with a silane coupling agent, and the particle size D50 is 10-50 μm; the silicon carbide nanowhiskers have a β-type cubic crystal phase structure, a diameter of 20-200 nm, and a length of 0.5-8 μm; the nickel-plated quartz short-cut fibers have a magnetic nickel film chemically plated on the surface, a diameter of 0.5-1 μm, and a length of 6-9 μm; the cerium oxide nanofibers are prepared by electrospinning and high-temperature calcination, have a diameter of 200-400 nm, and a length of 20-50 μm; and the additives include multiple types of fatty hydrocarbon antifoam agents, chloromethylthiazolinone and methylisothiazolinone bactericides, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate film-forming aids, polycarboxylic acid sodium salt type dispersants, and acrylate-methacrylate copolymer thickening agents.

[0030] An ablation-resistant heat-insulating wave-absorbing composite coating is prepared using the ablation-resistant heat-insulating wave-absorbing coating described above, and the preparation method comprises the following steps:

[0031] S1, ablation-resistant heat-insulating wave-absorbing coating preparation: according to the mass ratio, each filling powder material and film-forming material are added to the raw material tank of a vacuum planetary mixer, and each component is uniformly mixed by using the planetary stirring method under vacuum and mechanical bubbles are removed to prepare the coating; the planetary stirring process parameters are: planetary frame speed 60-130 r / min, dispersing disc speed 300-500 r / min, stirring time 4-6 h, and the ablation-resistant heat-insulating wave-absorbing coating is prepared;

[0032] S2, single-layer spray forming: the prepared coating is uniformly sprayed on a metal substrate or a carbon composite substrate, and the first layer of coating is obtained after surface drying, and the thickness of the film formed after single-layer spraying is controlled to be 0.3-0.5 mm;

[0033] S3, multi-layer spray forming: the film layer after the first spray forming is sprayed again, and the second layer of coating is obtained after surface drying, and the thickness of the film formed after single-layer spraying is controlled to be 0.3-0.5 mm, and the interval time between two sprays is controlled to be 2-3 h, and the process is repeated in turn, and the total thickness of the coating is set by multiple spraying;

[0034] S4, drying and curing: after the spray formed coating is placed in a constant temperature and humidity environment for deep curing, an ablation-resistant heat-insulating wave-absorbing composite coating is obtained; wherein the deep curing conditions are: 23±2℃ constant temperature, 50-60% humidity, and 5-7 days.

[0035] In the thickness of each layer of coating and the composite coating after deep curing, the modified ceramic hollow microsphere with large particle size is used as the framework to construct the microstructure inside the thickness of each coating, and other filling powder materials are used to densely fill the pores around the modified ceramic hollow microsphere, form a three-dimensional heat-insulating path with virtual and real combination, and form a composite coating with strong heat insulation, low thermal conductivity, ablation resistance, high mechanical strength and electromagnetic performance.

[0036] The ablation-resistant heat-insulating wave-absorbing composite coating is applied to the surface of a high-speed aircraft with complex shape, a combustion chamber and a launching stand, and is cured, so as to improve the ablation resistance, heat insulation and radar stealth performance of the target under high temperature service conditions.

[0037] The following is described in detail with multiple specific embodiments.

[0038] Embodiment 1

[0039] Referring to the accompanying drawings, Figures 1-4 The ablation-resistant heat-insulating wave-absorbing coating, composite coating and application thereof provided in the embodiment are specific selections of the foregoing basic embodiment, and the difference lies in that:

[0040] To prepare the ablation-resistant heat-insulating wave-absorbing coating provided in the embodiment, the mass fraction ratio of each component is: borosilicate ceramic hollow microsphere coated with surface silane coupling agent 10 parts, silicon carbide nanowhisker 15 parts, nickel-plated quartz short-cut fiber 8 parts, cerium oxide nanofiber 10 parts, vinyl acetate-ethylene water-based copolymer emulsion 40 parts, ethylene glycol 4 parts, deionized water 10 parts, aliphatic hydrocarbon defoaming agent 0.3 parts, chloromethylthiazolinone and methylisothiazolinone bactericide 0.4 parts, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate film-forming aid 0.4 parts, polycarboxylic acid sodium salt type dispersant 1.2 parts, and acrylate-methacrylate copolymer thickening agent 0.7 parts.

[0041] The preparation method of the ablation-resistant heat-insulating wave-absorbing composite coating comprises the following steps:

[0042] (1) Coating preparation: according to the above mass fraction, the filling powder material and the film-forming material are added to the raw material tank of the vacuum planetary mixer, the rotation speed of the planetary carrier is set to 100 r / min, the rotation speed of the dispersing disc is set to 400 r / min, and the planetary mixer is operated for 5 h to uniformly mix the components and remove mechanical bubbles, thereby preparing the ablation-resistant heat-insulating wave-absorbing coating;

[0043] (2) Spray coating: The prepared coating is manually sprayed onto the aluminum substrate. Spraying is stopped after the thickness reaches 0.4 mm to obtain the first coating layer. After 2 hours of surface drying, spraying is continued. After the thickness reaches 0.4 mm, spraying is stopped to obtain the second coating layer. This process is repeated until the final dried multilayer composite coating reaches the set thickness of 5.0 mm. In this embodiment, the composite coating is formed by stacking multiple layers of coating with a single layer thickness of no more than 0.4 mm to obtain a composite coating with a final total thickness of no less than 5.0 mm.

[0044] (3) Drying and curing: The sprayed composite coating is placed in an environment with a temperature of 23±2℃ and a humidity of 50~60% for 7 days to deeply cure, and the cured ablation-resistant heat insulation and wave-absorbing composite coating is obtained.

[0045] As attached Figure 1 As shown in the top and side views, the obtained ablation-resistant heat-insulating and microwave-absorbing composite coating has a smooth appearance and uniform thickness. The microstructure of the cross-section of the ablation-resistant heat-insulating and microwave-absorbing composite coating was observed using an electron microscope, as shown in the attached figure. Figure 2 As shown, it is evident that the modified ceramic hollow microspheres and solid fibers of various aspect ratios are uniformly distributed within the coating thickness. The microstructure within the composite coating thickness is constructed with large-diameter modified ceramic hollow microspheres as the framework. Other small-scale fillers densely fill the pores around the modified ceramic hollow microspheres, forming a three-dimensional thermal insulation pathway. They are then uniformly coated by the film-forming matrix material and firmly fixed in their respective positions in three-dimensional space. The low thermal conductivity and hollow structure of the ceramic hollow microspheres, together with the solid fillers and the film-forming matrix material, form a microstructure that enhances the thermal insulation and ablation resistance of the composite coating. Various fiber filler materials can also effectively improve the mechanical and electromagnetic properties of the coating, thereby obtaining a composite coating that simultaneously possesses strong thermal insulation, high thermal conductivity, ablation resistance, high mechanical strength, and electromagnetic properties.

[0046] An oxy-acetylene device was constructed to provide a flame exceeding 1000°C. This flame was then directed at the surface of the composite coating prepared according to the embodiments of the present invention for ablation. The temperatures of the coating surface (hot side) and the metal substrate surface (cold side) were measured using two thermocouple probes respectively attached to the coating surface and the metal substrate surface, as shown in the attached figure. Figure 3 As shown, the 5.0mm thick ablation-resistant heat-insulating and microwave-absorbing composite coating product in this embodiment, after being ablated for 5 minutes at a maximum temperature of 1050℃ by an oxy-acetylene flame on the hot side, has a maximum cold side temperature of only 140℃.

[0047] The reflectivity of the ablation-resistant heat-insulating and microwave-absorbing composite coating was tested using a bow-shaped method testing system based on a vector analyzer and a bow-shaped frame, as shown in the attached figure. Figure 4The ablation-resistant heat-insulating wave-absorbing composite coating material obtained in Example 1 has a thickness of 5.0 mm, an effective wave-absorbing bandwidth (reflectivity better than -10 dB) of up to 8.96 GHz, covering 9.04-18 GHz, and a maximum absorption intensity of -17.75 dB at 13.28 GHz.

[0048] Therefore, tests show that the ablation-resistant heat-insulating wave-absorbing composite coating product prepared in the embodiment has a thickness of 5.0 mm, a cold face temperature of less than 150 DEG C after being ablated by an oxygen-ethyne flame of more than 1000 DEG C for 5 min, and a reflectance loss better than -10 dB in a frequency range of 2-18 GHz, with a bandwidth of up to 8.96 GHz, which not only meets the application requirements of high-temperature heat insulation, such as the outer heat protection of a high-speed aircraft or the inner wall heat insulation of a combustion chamber, but also enhances the radar stealth effect of the target.

[0049] Example 2

[0050] Referring to the accompanying drawings, Figures 3-4 The ablation-resistant heat-insulating wave-absorbing coating, composite coating and application thereof provided in the embodiment are basically the same as those in Example 1, and the difference lies in that:

[0051] In the ablation-resistant heat-insulating wave-absorbing coating provided in the embodiment, 8 parts of surface silane coupling agent coated aluminum silicate ceramic hollow microbeads, 12 parts of silicon carbide nanowhiskers, 15 parts of nickel-plated quartz short-cut fibers, 10 parts of cerium oxide nanofibers, 35 parts of vinyl acetate-ethylene water-based copolymer emulsion, 4 parts of ethylene glycol, 13 parts of deionized water, 0.3 parts of aliphatic hydrocarbon defoaming agent, 0.4 parts of chloromethyl thiazolinone and methyl isothiazolinone bactericide, 0.4 parts of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate film-forming aid, 1.2 parts of polycarboxylic acid sodium salt type dispersant and 0.7 parts of acrylate-methacrylate copolymer thickening agent are used.

[0052] The preparation method of the ablation-resistant heat-insulating wave-absorbing composite coating comprises the following steps:

[0053] (1) Coating preparation: the filling powder material and the film-forming material are added into a raw material tank of a vacuum planetary mixer according to the above mass parts, the rotation speed of the planetary frame is set to 120 r / min, the rotation speed of the dispersing disc is set to 400 r / min, and the planetary mixer is operated for 4 h to uniformly mix the components and remove mechanical bubbles;

[0054] (2) Spray forming: the prepared coating is sprayed on the aluminum substrate by hand, and the spraying is stopped when the thickness reaches 0.5 mm, the surface is dried for 3 h, and then the spraying is continued, and the above process is repeated until the final coating reaches 5.0 mm;

[0055] (3) Dry curing: after the spray-formed coating is placed in an environment with a temperature of 23±2℃ and a humidity of 50-60% for deep curing for 7 days, an ablative heat-insulating wave-absorbing composite coating is obtained;

[0056] As shown in the accompanying Figure 3 The 5.0mm-thick ablative heat-insulating wave-absorbing composite coating product prepared in this embodiment has a maximum cold-side temperature of 149℃ after ablating for 5min under a hot-side oxyacetylene flame with a maximum temperature of 1050℃.

[0057] As shown in the accompanying Figure 4 The ablative heat-insulating wave-absorbing composite coating prepared in this embodiment has a thickness of 5.0mm, an effective wave-absorbing bandwidth of 7.36GHz, covering 6.72GHz-14.08GHz, and a maximum absorption intensity of -23.32dB at 8.72GHz.

[0058] Example 3

[0059] As shown in the accompanying Figures 3-4 The ablative heat-insulating wave-absorbing coating, composite coating and application thereof provided in this embodiment are basically the same as those in Examples 1-2, and the difference lies in that:

[0060] In the ablative heat-insulating wave-absorbing coating provided in this embodiment, 8 parts of borosilicate ceramic hollow microbeads coated with a surface silane coupling agent, 12 parts of silicon carbide nanowhiskers, 8 parts of nickel-plated quartz short-cut fibers, 10 parts of cerium oxide nanofibers, 45 parts of a vinyl acetate-ethylene water-based copolymer emulsion, 4 parts of ethylene glycol, 10 parts of deionized water, 0.3 parts of a fatty hydrocarbon defoaming agent, 0.4 parts of chloromethylthiazolinone and methylisothiazolinone bactericides, 0.4 parts of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate film-forming aids, 1.2 parts of polycarboxylic acid sodium salt type dispersants, and 0.7 parts of acrylate-methacrylate copolymer thickening agents are used.

[0061] The preparation method of the ablative heat-insulating wave-absorbing composite coating comprises the following steps:

[0062] (1) Coating preparation: the filling powder materials and film-forming materials are added to the raw material tank of a vacuum planetary mixer according to the above mass parts, the rotation speed of the planetary frame is set to 80r / min, the rotation speed of the dispersing disc is set to 400r / min, and the planetary mixer is operated for 6h to uniformly mix the components and remove mechanical bubbles;

[0063] (2) Spray forming: the prepared coating is sprayed on a metal aluminum substrate by hand, and the spraying is stopped after the thickness reaches 0.4mm, the surface is dried for 2h, and then the spraying is continued, and the above process is repeated until the final coating reaches 5.0mm;

[0064] (3) Drying and curing: After the sprayed coating is placed in an environment with a temperature of 23±2℃ and a humidity of 50~60%, it is deeply cured for 7 days to obtain an ablation-resistant heat insulation and wave-absorbing composite coating.

[0065] As attached Figure 3 As shown, the 5.0mm thick ablation-resistant heat-insulating and microwave-absorbing composite coating product prepared in this embodiment was ablated for 5 minutes at a maximum temperature of 1050℃ on the hot side by an oxy-acetylene flame, and the maximum temperature on the cold side was only 130℃.

[0066] As attached Figure 4 As shown, the ablation-resistant heat-insulating and microwave-absorbing composite coating prepared in this embodiment has an effective absorption bandwidth of 8.16 GHz with a thickness of 5.0 mm, covering 9.28 GHz-17.44 GHz, and a maximum absorption intensity of -25.16 dB at 12.56 GHz.

[0067] In the above embodiments of the present invention, each single-layer coating is constructed with large-diameter modified ceramic hollow microspheres as the framework to build the microstructure of the coating. Other small-scale powders or fiber fillers densely fill the pores around the modified ceramic hollow microspheres, forming a three-dimensional heat insulation channel combining virtual and solid spaces, thus forming a single-layer coating. After multiple single-layer coatings are stacked and cured in sequence, a composite coating with multiple layers of this unique microstructure is finally formed, and the composite coating simultaneously possesses strong heat insulation, low thermal conductivity, ablation resistance, high mechanical strength, and electromagnetic properties.

[0068] It should be noted that the components, proportions and process parameters used in the above specific embodiments of the present invention are only examples. Other different implementation schemes obtained by making specific selections within the scope of the basic embodiments of the present invention can achieve the technical effects described in the present invention. Therefore, the present invention will not list them one by one.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and modifications to the technical solution of the present invention using the methods and techniques disclosed above, or modify it into equivalent embodiments with equivalent changes, without departing from the scope of the present invention. All equivalent changes made to the components, proportions, and processes of the present invention should be covered within the protection scope of the present invention.

Claims

1. An ablative heat-resistant heat-shielding wave-absorbing paint, characterized by: It is a filling powder material composed of modified ceramic hollow microbeads, silicon carbide nanowhiskers, nickel-plated quartz short-cut fibers, and cerium oxide nanofibers, and a film-forming material base material made of vinyl acetate-ethylene water-based copolymer emulsion, ethylene glycol and deionized water, and functional additives; The mass ratio of the components of the ablation-resistant heat-insulating wave-absorbing coating is: modified ceramic hollow microbeads 5-10 parts, silicon carbide nanowhiskers 10-20 parts, nickel-plated quartz short-cut fibers 6-15 parts, cerium oxide nanofibers 7-15 parts, vinyl acetate-ethylene water-based copolymer emulsion 30-50 parts, ethylene glycol 2-4 parts, deionized water 8-15 parts, and functional additives 2-4 parts. The modified ceramic hollow microsphere is one or both of borosilicate ceramic hollow microspheres and aluminosilicate ceramic hollow microspheres, and the surface is coated and modified by a silane coupling agent, and the particle size D50 is 10-50 µm ; The silicon carbide nanowhisker is β a cubic crystal phase structure, with a diameter of 20-200 nm and a length of 0.5-8 µm ; the nickel-plated quartz short-cut fiber is plated with a magnetic nickel film on the surface by electroless plating, with a diameter of 0.5-1 µm and a length of 6-9 µm ; and the cerium oxide nanofiber is prepared by electrospinning and high-temperature calcination, with a diameter of 200-400 nm and a length of 20-50 µm .

2. The ablative heat-resistant wave-absorbing coating of claim 1, wherein the coating is characterized by: The functional additives include: aliphatic hydrocarbon defoaming agent, chloromethyl thiazolinone and methyl isothiazolinone bactericide, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate film-forming aid, polycarboxylic acid sodium salt type dispersant, and acrylate-methacrylate copolymer thickener.

3. A ablative heat-shielded radar-absorbing composite coating, characterized by: It is prepared by using the ablation-resistant heat-insulating wave-absorbing coating of claims 1-2, and the preparation method comprises the following steps: S1, ablation-resistant heat-insulating wave-absorbing coating preparation: according to the mass ratio, each filling powder material and film-forming material are added to the raw material tank of the vacuum planetary mixer, and the components are uniformly mixed by using the planetary stirring method under vacuum and the mechanical bubbles are removed to prepare the ablation-resistant heat-insulating wave-absorbing coating; S2, single layer spray forming: the prepared coating is uniformly sprayed on the metal substrate or carbon composite substrate, and the first layer of coating is obtained after surface drying. The thickness of the film formed after single layer spraying is controlled to be 0.3~0.5 mm ; S3, multi-layer spray forming: re-spraying on the film layer after the first spray forming, and obtaining the second layer of coating after the surface drying, controlling the thickness of the film formed after the single-layer spray to be 0.3-0.5 mm, controlling the interval time between the two sprays to be 2-3 h , and so on, and reaching the set total thickness of the coating through multiple spraying. S4, drying and curing: after placing the sprayed and formed coating in a constant temperature and humidity environment for deep curing, an ablation-resistant heat-insulating wave-absorbing composite coating is obtained.

4. The ablation-resistant, thermally insulating, wave-absorbing composite coating of claim 3, wherein: The planetary stirring process parameters in the step S1 are: planetary gear rotation speed 60~130 r / min , dispersion disc rotation speed 300~500 r / min , stirring time 4~6 h .

5. The ablation-resistant, thermally insulating, wave-absorbing composite coating of claim 3, wherein: The conditions for the deep curing in step S4 are: 23 ± 2 ℃ Normal temperature, 50-60% humidity, time 5-7 days.

6. The use of the ablative heat-resistant wave-absorbing composite coating according to any one of claims 3-5, characterized in that: The ablation-resistant heat-insulating wave-absorbing composite coating is sprayed on the surface of high-speed aircrafts with complex shapes, combustion chambers, and launchers and is cured, which is used to improve the ablation resistance, heat insulation, and radar stealth performance of targets under high-temperature service conditions.

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