Reusable light thermal insulation material as well as preparation method and application thereof

Abstract

The invention discloses a reusable light heat-proof and heat-insulating material and application thereof, and the heat-proof and heat-insulating material is designed according to the anti-radiation / heat-proof / heat-insulating gradient thought for a thermal environment profile of a reusable aircraft. The surface of the material is a ceramic-based heat-proof coating with high emissivity, so that radiation heat flux permeation on the surface of the material is reduced; the interior of the material is a silicon-based heat-proof material, so that the material has a non-ablation / low-ablation effect; the innermost layer of the material is a light thermal insulation material to reduce the structural temperature of the aircraft. According to the thermal protection material spraying integrated forming method, the binding force between the material and the surface of the metal matrix is high, the interface is stable, the process implementation performance is good, the material has the capacity of being repeatedly used for a certain number of times, and the thermal protection and insulation requirements of repeatedly used aircrafts are met.

Description

Technical Field

[0001] The present invention relates to the field of thermal insulation materials for aerospace vehicles, and particularly to a reusable lightweight thermal insulation material, its preparation method and application. Background Art

[0002] The thermal environment profile of reusable vehicles is complex, which poses higher requirements for thermal protection materials. Currently, the mainstream thermal protection materials are resin-based and silicon-based thermal protection materials. After being heated, the ablation surface of these materials carbonizes, becomes loose, and the strength weakens. The residual layer can only play an insulating role and cannot be reused. Currently, the thermal protection materials that can meet the requirements of reusability are connected to the sidewall structure of the vehicle by bonding or mechanical snap connection. The bonding reliability is not high, the mechanical snap connection is relatively cumbersome, the process efficiency is not high, and it additionally brings interface reliability problems. Therefore, it is of great significance to develop a lightweight thermal insulation material with strong bonding force to the metal matrix surface, stable interface, good processability, and reusable performance. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a reusable lightweight thermal insulation material, its preparation method and application. This material is designed for the thermal environment profile of reusable vehicles, adopting an anti-radiation / thermal protection / thermal insulation gradient design. Its surface is a ceramic-based thermal protection coating with a high emissivity, which can reduce the infiltration of radiant heat flux; the interior is a silicon-based thermal protection material with no ablation or low ablation effect; the innermost layer is a thermal insulation material, which can reduce the temperature of the vehicle structure, so that the material can achieve a certain number of reuse capabilities. This thermal insulation material is an integrated gradient material, which is integrally formed by spraying. The anti-radiation, thermal protection, and thermal insulation layers are co-prepared and co-cured, and the system is compatible. Moreover, this material has a strong bonding force to the metal matrix surface, a stable interface, and good processability.

[0004] The purpose of the present invention is achieved by the following technical solutions: <First Aspect> A preparation method of a reusable lightweight thermal insulation material, comprising the following steps: S1. Preparation of the thermal insulation layer; S2. Preparation of the thermal protection layer on the thermal insulation layer; S3. Preparation of the anti-radiation layer on the thermal protection layer; S4. Densification treatment on the surface of the anti-radiation layer.

[0005] As an implementation scheme, the preparation steps of the thermal insulation layer are as follows: S11. Mix a silicone rubber solvent, expanded particles, porous ceramic microspheres, coupling agent, dispersant, and process solvent to obtain a uniform first slurry; S12. Add a diluent to the first slurry to adjust the viscosity to 1000 - 2000 mPa·s, obtaining a second slurry; S13. Apply the second slurry onto the surface of the metal substrate in a multi - layer spraying manner to coat a wet film, and perform surface drying.

[0006] As an embodiment, the preparation steps of the heat - resistant layer are as follows: S21. Mix a silicone rubber solvent, an inorganic ablation - resistant flame - retardant filler, high - performance chopped fibers, a silicon - based reinforcing material, a coupling agent, a dispersant, and a process solvent to obtain a uniform third slurry; S22. Add a diluent to the third slurry to adjust the viscosity to 1000 - 2000 mPa·s, obtaining a fourth slurry; S23. Apply the fourth slurry onto the surface of the heat - insulating layer in a multi - layer spraying manner to coat a wet film, and perform surface drying.

[0007] As an embodiment, the preparation steps of the radiation - resistant layer are as follows: S31. Mix an emissive material, high - performance chopped fibers, an inorganic ablation - resistant flame - retardant filler, and a ceramic gel to obtain a uniform fifth slurry; S32. Spray the fifth slurry onto the surface of the heat - resistant layer in a multi - layer spraying manner, and perform surface drying.

[0008] As an embodiment, in step S11, the mass ratio of the silicone rubber solvent, the expandable particles, the porous ceramic microspheres, the coupling agent, the dispersant, and the process solvent is: 25 - 35:12 - 18:21 - 35:0.8 - 1.2:0.8 - 1.2:42 - 58.

[0009] In some embodiments, in step S11, the mass ratio of the silicone rubber solvent, the expandable particles, the porous ceramic microspheres, the coupling agent, the dispersant, and the process solvent is 30:15:25 - 30:1:1:50.

[0010] As an embodiment, in step S21, the mass ratio of the silicone rubber solvent, the inorganic ablation - resistant flame - retardant filler, the high - performance chopped fibers, the silicon - based reinforcing material, the coupling agent, the dispersant, and the process solvent is: 25 - 35:10 - 14:8 - 12:1.5 - 2.5:0.8 - 1.2:0.8 - 1.2:40 - 60.

[0011] In some embodiments, in step S21, the mass ratio of the silicone rubber solvent, the inorganic ablation - resistant flame - retardant filler, the high - performance chopped fibers, the coupling agent, the dispersant, and the process solvent is 30:10 - 12:10:2:1:1:50.

[0012] As an implementation solution, in step S31, the mass ratio of the emission material, high-performance chopped fibers, inorganic ablation-resistant flame retardant filler, and ceramic gel is: 4 to 6: 8 to 12: 4 to 6: 12 to 18.

[0013] In some embodiments, in step S31, the mass ratio of the emission material, high-performance chopped fibers, inorganic ablation-resistant flame retardant filler, and ceramic gel is 5: 10: 5: 15.

[0014] As an implementation solution, the silicone rubber-containing solvent is selected from one or more of 107 and GD-401 liquid methyl silicone rubber.

[0015] In some embodiments, the silicone rubber-containing solvent is selected as 107 silicone rubber.

[0016] As an implementation solution, the coupling agent is selected from one or more of KH-550 and KH-560.

[0017] In some embodiments, the coupling agent is selected as KH-550.

[0018] As an implementation solution, the dispersant is selected from one or more of mica powder with a particle size of 10 to 50 μm and boron nitride with a particle size of 1 to 10 μm.

[0019] In some embodiments, the dispersant is selected as mica powder with a particle size of 30 to 45 μm.

[0020] As an implementation solution, the process solvent is selected from one or more of acetone, ethyl acetate, cyclohexanone, and xylene solvent.

[0021] As an implementation solution, the process solvent is a mixture of acetone and ethyl acetate with a mass ratio of 3 to 1: 1.

[0022] In some embodiments, the process solvent is a mixture of acetone and ethyl acetate with a mass ratio of 3: 1.

[0023] As an implementation solution, the diluent is selected from one or more of ethyl acetate and acetone.

[0024] In some embodiments, the diluent is selected as ethyl acetate.

[0025] As an implementation solution, the expanded particles are selected from one or more of expanded perlite, expanded vermiculite, and expanded graphite.

[0026] As an implementation solution, the expanded particles are selected as a mixture of expanded perlite and expanded vermiculite with a mass ratio of 2 to 3: 1.

[0027] In some embodiments, the expanded particles are a mixture of expanded perlite and expanded vermiculite with a mass ratio of 2:1.

[0028] As an embodiment, the porous ceramic microspheres are selected from one or more of zirconia, silica, mullite, and hollow glass microspheres.

[0029] As an embodiment, the porous ceramic microspheres are a mixture of zirconia and silica with a mass ratio of 2 - 3:1, the particle size range of zirconia is 1 - 10 μm, and the particle size range of silica is 10 - 40 nm.

[0030] In some embodiments, the porous ceramic microspheres are a mixture of zirconia and silica with a mass ratio of 3:1.

[0031] In some embodiments, the particle size of zirconia is 3 - 4 μm, and the particle size of silica is 25 - 30 nm.

[0032] As an embodiment, the silica-based reinforcing material is selected from one or more of white carbon black, SiC particles, and silicone resin reinforcing fillers.

[0033] In some embodiments, the silica-based reinforcing material is white carbon black.

[0034] As an embodiment, the inorganic ablation-resistant and flame-retardant filler is selected from one or more of iron oxide, montmorillonite, wollastonite, alumina fiber, and graphite.

[0035] As an embodiment, the inorganic ablation-resistant and flame-retardant filler is a mixture of iron oxide, montmorillonite, and alumina fiber with a mass ratio of 2.5 - 3.5:0.8 - 1.2:1.6 - 2.4.

[0036] In some embodiments, the inorganic ablation-resistant and flame-retardant filler is a mixture of iron oxide, montmorillonite, and alumina fiber with a mass ratio of 3:1:2.

[0037] As an embodiment, the inorganic ablation-resistant and flame-retardant filler is a mixture of iron oxide, wollastonite, and alumina fiber with a mass ratio of 2.5 - 3.5:0.8 - 1.2:1.6 - 2.4.

[0038] In some embodiments, the inorganic ablation-resistant and flame-retardant filler is a mixture of iron oxide, wollastonite, and alumina fiber with a mass ratio of 3:1:2.

[0039] As an embodiment, the high-performance chopped fibers are ceramic fiber mixtures.

[0040] As an embodiment, the high-performance chopped fibers are a mixture of alumina and silica fibers with a mass ratio of 6-8:4.

[0041] As an embodiment, the high-performance chopped fibers are ceramic fibers with a single filament diameter of 5–15 μm and a chopped length of 50–200 μm.

[0042] As an embodiment, the emission material is one or more of silicon carbide, zirconium boride, zirconia, molybdenum disilicide, and high-entropy ceramics with a particle size of 0.4~2 μm.

[0043] In some embodiments, the emission material contains silicon carbide with a particle size of 0.4~1 μm.

[0044] In some embodiments, the emission material contains zirconium boride with a particle size of 0.5~2 μm.

[0045] In some embodiments, the emission material contains zirconia with a particle size of 0.5~1 μm.

[0046] In some embodiments, the emission material contains molybdenum disilicide with a particle size of 0.5~1 μm.

[0047] As an embodiment, the emission material is a mixture of silicon carbide, zirconium boride, and zirconia with a mass ratio of 2~3 : 5~6 : 1~2.

[0048] In some embodiments, the emission material is a mixture of silicon carbide, zirconium boride, and zirconia with a mass ratio of 3 : 5 : 2.

[0049] As an embodiment, the emission material is a mixture of molybdenum disilicide, zirconium boride, and zirconia with a mass ratio of 3~4 : 5~6 : 1~2.

[0050] In some embodiments, the emission material is a mixture of molybdenum disilicide, zirconium boride, and zirconia with a mass ratio of 4 : 5 : 2.

[0051] As an embodiment, the ceramic gel is one or more of alumina ceramic aerogel, tetraethyl orthosilicate sol, and zirconyl chloride sol.

[0052] In some embodiments, the ceramic gel is alumina ceramic aerogel.

[0053] As an embodiment, the multi-layer spraying is carried out by plasma spraying.

[0054] As an embodiment, the parameters of the plasma spraying are as follows: plasma power 30–80 kW, spraying distance 80~140 mm, gun speed 0.3~1 m / s, and path overlap 25%~50% during repeated spraying.

[0055] As an embodiment, in step S1, the parameters of the plasma spraying are as follows: plasma power 50~60 kW, spraying distance 80~120 mm, gun speed 0.3~1 m / s, and path overlap 25%~40% during repeated spraying.

[0056] As an embodiment, in step S2, the parameters of the plasma spraying are as follows: plasma power 60~70 kW, spraying distance 90~140 mm, gun speed 0.3~1 m / s, and path overlap 25%~40% during repeated spraying.

[0057] As an embodiment, in step S3, the parameters of the plasma spraying are as follows: plasma power 50~60 kW, spraying distance 80~150 mm, gun speed 0.3~0.8 m / s, and path overlap 30%~50% during repeated spraying.

[0058] As an embodiment, in the multi-layer spraying, the single-layer thickness is 30~150 μm, one layer is sprayed every 5~25 min, and the multi-layer spraying thickness is 0.2~7 mm.

[0059] As an embodiment, in step S1, in the multi-layer spraying, the single-layer thickness is 50~150 μm, one layer is sprayed every 5~10 min, and the multi-layer spraying thickness is 3~7 mm.

[0060] As an embodiment, in step S2, in the multi-layer spraying, the single-layer thickness is 100~150 μm, one layer is sprayed every 10~15 min, and the multi-layer spraying thickness is 2~5 mm.

[0061] As an embodiment, in step S3, in the multi-layer spraying, the single-layer thickness is 30~50 μm, one layer is sprayed every 5~15 min, and the multi-layer spraying thickness is 200~500 μm.

[0062] As an embodiment, the surface drying is as follows: drying for 2~3 days at 10-40°C and humidity ≤30%.

[0063] As an embodiment, the steps of the densification treatment are as follows: coating a nano-ceramic sol on the surface of the radiation-resistant layer, and performing heat treatment to convert the sol into a gel, and repeating the steps of coating and heat treatment until the porosity <5%.

[0064] As an embodiment, the heat treatment temperature is 300~350°C.

[0065] As an embodiment, the ceramic sol is one or more of silica sol, alumina sol, zirconia sol, and zirconium boride sol.

[0066] In some embodiments, the ceramic sol is silica and alumina sol.

[0067] As an embodiment, the concentration of the ceramic sol is 5–25 wt%.

[0068] As an embodiment, the mass ratio of silica to alumina in the ceramic sol is 1.5~3:1, the concentration of SiO2 sol is 10wt.%~15wt.%, and the concentration of Al2O3 sol is 5wt.%~10wt.%.

[0069] In some embodiments, the mass ratio of silica to alumina in the ceramic sol is 2:1, the concentration of SiO2 sol is 10wt.%, and the concentration of Al2O3 sol is 5wt.%.

[0070] <Second aspect> The present invention provides a reusable lightweight heat-insulating and heat-protecting material, which is prepared by the above method.

[0071] As an embodiment, the heat-insulating and heat-protecting material includes a heat-insulating layer, a heat-protecting layer, and a radiation-resistant layer arranged in sequence.

[0072] As an embodiment, the heat-insulating layer is a silicon-based heat-insulating material with low thermal conductivity.

[0073] As an embodiment, the heat-protecting layer is a silicon-based heat-insulating material resistant to ablation.

[0074] As an embodiment, the radiation-resistant layer is a ceramic-based heat-insulating material.

[0075] As an embodiment, the heat-insulating and heat-protecting material further includes filling the pores on one side of the radiation-resistant layer with nano-ceramic gel as a local densification treatment.

[0076] As an embodiment, the heat-insulating layer contains expanded particles and porous ceramic microspheres.

[0077] As an embodiment, the heat-protecting layer contains inorganic ablation-resistant and flame-retardant fillers and high-performance chopped fibers.

[0078] As an embodiment, the radiation-resistant layer contains emissive materials, high-performance chopped fibers, and inorganic ablation-resistant and flame-retardant fillers.

[0079] As an embodiment, the radiation-resistant layer further contains nano-ceramic gel.

[0080] <Third aspect> The present invention provides an application of the above reusable lightweight heat-insulating and heat-protecting material on the structural surface of a spacecraft.

[0081] Compared with the prior art, the present invention has the following beneficial effects: 1) Break through the limitations of the semi-passive heat protection system and achieve high-efficiency ablation resistance and reusability By introducing an inorganic ablation-resistant flame-retardant filler and a chopped porous ceramic fiber reinforcement system into the heat protection layer, the present invention constructs a composite structure of high-temperature resistant skeleton - layered barrier - fiber reinforcement. Compared with the passive heat protection mechanism of traditional resin-based / silicon-based materials relying on ablation phase change, the material of the present invention inhibits surface carbonization and loosening when heated, maintains the integrity of the residual layer structure and mechanical strength, avoids the decline of heat protection performance caused by material mass loss, realizes multiple reuse, and solves the core defect of "ablation failure and non-reusability" of semi-passive materials.

[0082] 2) Integrate heat protection and heat insulation functions and simplify the design of the multi-layer heat protection system Through the collaborative design of a high-performance emission material and a composite structure of porous ceramic microspheres / expanded particles in the anti-radiation layer and the heat insulation layer, an integrated thermal protection mechanism of radiative heat dissipation - high-temperature resistant barrier - ultra-low thermal conductivity is formed. Compared with the complex structure of traditional ceramic-based heat protection materials that require an additional heat insulation layer, the present invention optimizes the material components and couples the multi-layer structure, enabling the heat protection layer to have both high ablation resistance (tolerating a high temperature of 1200 °C) and the ultra-low thermal conductivity characteristics of the heat insulation layer (significantly reducing the thermal conductivity at room temperature). There is no need to add an independent heat insulation layer on the back of the ceramic material, thus simplifying the overall heat protection system structure, reducing the system weight and improving the reliability.

[0083] 3) Optimize the compatibility between the material and the structural interface, and improve the connection reliability and process efficiency The material system of the present invention (especially the composite design of a silicon-based glue-containing solvent and an inorganic filler) can be integrally bonded or structurally integrated with the side wall structure of the aircraft through an in-situ forming process, avoiding the reliability hidden dangers of traditional bonding processes. At the same time, the high flexibility of the material itself (synergistic reinforcement of chopped fibers and silicone rubber matrix) and structural adaptability can simplify complex connection methods such as mechanical buckles, reduce the problem of interface stress concentration, realize efficient process assembly and long-term reliable connection, and solve the problems of "complicated process and high risk of interface failure" of traditional connection methods.

[0084] 4) Comprehensive performance improvement and application expansion Through the gradient functional design and material synergy of the heat insulation layer, heat protection layer, and radiation resistance layer, the thermal protection system constructed by the present invention has the following characteristics: ① Wide temperature range adaptability: It can withstand extreme temperatures from -50°C to 1500°C; ② Lightweight characteristics: The density is significantly lower than that of traditional ceramic matrix materials; ③ Multifunctional integration: Heat protection, heat insulation, radiation resistance, and structural load-bearing are integrated. It provides an efficient, reliable, and easy-to-maintain thermal protection solution for fields such as reusable aircraft and high-temperature industrial equipment, breaking through the technical bottlenecks of traditional materials such as "single function, complex system, and poor reliability". BRIEF DESCRIPTION OF THE DRAWINGS

[0085] By reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings, other features, objects, and advantages of the present invention will become more apparent: Figure 1 To show the attenuation of the heat protection performance of the heat insulation and heat protection materials prepared in Example 1 and the comparative example of the present invention under repeated heat tests. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0086] The present invention will be described in detail below with reference to the embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several adjustments and improvements can be made. These all fall within the protection scope of the present invention.

[0087] For easy understanding, first, the abbreviations or nouns mentioned in the following text are explained: 107 silicone rubber: α,ω-dihydroxy polydimethylsiloxane is the base rubber of two-component and one-component condensation silicone rubber, which is usually called 107 glue in the market. In the present invention, the viscosity of 5000 - 15000 mPa·s is selected; High-performance chopped fibers: A ceramic fiber mixture with a mass ratio of Al2O3:SiO2 = 3:2, a single filament diameter of 5 - 15 μm, and a chopped length of 50 - 200 μm; Expanded perlite: The particle size is 50 - 100 μm, and the thermal conductivity is 0.05 W / (m·K); Expanded vermiculite: 75μm - 200μm, and the thermal conductivity is 0.08 W / (m·K); Nanoceramic sol (SiO2 and Al2O3 sol): The mass ratio of SiO2 and Al2O3 is 2:1, the concentration of SiO2 sol is 10wt.%, and the concentration of Al2O3 sol is 5wt.%.

[0088] Example 1 This example provides a preparation method of a reusable lightweight heat insulation and heat protection material, including the following steps: S1. Preparation of the heat insulation layer The raw materials required are: Containing silicone rubber solvent: 107 silicone rubber; Expanded particles: a mixture of expanded perlite and expanded vermiculite in a mass ratio of 2:1; Porous ceramic microspheres: A porous hollow ceramic microsphere mixture composed of ZrO2 and SiO2 in a mass ratio of 3:1, with a zirconium oxide particle size range of 3-4 μm and a silicon oxide particle size range of 25-30 nm; Coupling agent: KH-550; Dispersant: mica powder with a particle size of 30-45 μm; Process solvent: acetone and ethyl acetate in a mass ratio of 3:1.

[0089] The preparation method is: By weight, 30 parts of silicone rubber solvent, 15 parts of expanded particles, 25 parts of porous ceramic microspheres, 1 part of coupling agent, 1 part of dispersant, and 50 parts of process solvent were mixed at 25±3°C for 0.5h to obtain a uniform slurry; Then, 30 to 50 phr (30 phr in this embodiment) of ethyl acetate is added to the slurry to adjust the viscosity to 1000 to 2000 mPa·s (the viscosity in this embodiment is 1200 mPa·s); Then, a multi-layer spraying method is adopted: the thickness of a single layer is 50-150 μm (100 μm in this embodiment), and the next layer is sprayed after an interval of 5-10 minutes (8 minutes in this embodiment). A wet film with a thickness of 3-7 mm (5 mm in this embodiment) is coated on the surface of the aluminum metal substrate. The spraying parameters are a plasma power of 50-60 kW (50 kW in this embodiment), a spraying distance of 80-120 mm (100 mm in this embodiment), a spray gun speed of 0.3-1.0 m / s (0.5 m / s in this embodiment), an overlap rate of 25%-40% (30% in this embodiment), and then the wet film is surface-dried to obtain a thermal insulation layer with a thickness of 5±0.5 mm.

[0090] S2. Preparation of heat protection layer The raw materials required are: Containing silicone rubber solvent: 107 silicone rubber; Inorganic ablation-resistant flame-retardant filler: a combination of iron oxide (5 μm particle size, 95% purity, granular), montmorillonite (10-20 μm, 85% purity, layered), and alumina fiber (6 μm diameter, 50-200 μm length, 95% purity, fibrous), with a mass ratio of 3:1:2; High-performance chopped fiber: ceramic fiber (Al2O3-SiO2) mixture; Silicon-based reinforcing filler: fumed silica; Coupling agent: KH-550; Dispersant: mica powder with a particle size of 30 - 45 μm; Process solvent: acetone and ethyl acetate with a mass ratio of 3:1.

[0091] The preparation method is as follows: By mass fraction, mix 30 parts of silicone rubber solvent, 12 parts of inorganic ablative-resistant flame retardant filler, 10 parts of high-performance chopped fibers, 2 parts of silicon-based reinforcing filler, 1 part of coupling agent, 1 part of dispersant, and 50 parts of process solvent at 25 ± 3 °C for 0.5 h to obtain a uniformly mixed slurry; Then add 30 - 50 phr parts (30 parts in this example) of ethyl acetate to the slurry to adjust the viscosity to 1000 - 2000 mPa·s (the viscosity is 1200 mPa·s in this example); Next, adopt the multi-layer spraying method: spray the next layer with a single-layer thickness of 100 - 150 μm (120 μm in this example), at an interval of 10 - 15 minutes (12 minutes in this example), to form a wet film with a thickness of 2 - 5 mm (4 mm in this example) on the surface of the heat-insulating layer. The spraying parameters are plasma power of 60 - 70 kW (60 kW in this example), spraying distance of 90 - 140 mm (110 mm in this example), gun moving speed of 0.3 - 1.0 m / s (0.8 m / s in this example), and overlap rate of 25% - 40% (30% in this example). Then surface-dry the wet film to obtain a heat-resistant layer with a thickness of 4 ± 0.4 mm.

[0092] S3. Preparation of the radiation-resistant layer The raw materials are as follows: High-performance emission material: a combination of SiC with a particle size of 0.4 - 1 μm, ZrB2 with a particle size of 0.5 - 2 μm, and ZrO2 with a particle size of 0.5 - 1 μm, and the mass ratio of the three is 3:5:2; High-performance chopped fibers: a mixture of ceramic fibers (Al2O3 - SiO2); Inorganic ablative-resistant flame retardant filler: a combination of iron oxide (particle size 5 μm, purity 95%, granular), montmorillonite (10 - 20 μm, purity 85%, layered), and alumina fibers (diameter 6 μm, length 50 - 200 μm, purity 95%, fibrous), and the mass ratio of the three is 3:1:2; Ceramic gel: alumina ceramic aerogel prepared by the sol - gel method, with a pore size of 20 nm and a compressive strength of 2 MPa.

[0093] The preparation method is as follows: By mass fraction, mix 5 parts of high-performance emission material, 10 parts of high-performance chopped fibers, 5 parts of inorganic ablative-resistant flame retardant filler, and 15 parts of ceramic gel, and stir well to obtain the spraying raw material; The spraying raw materials are sprayed on the outer side of the heat-insulating layer by a plasma spraying device in a multi-layer spraying manner. The parameters are as follows: plasma power is 50 - 60 kW (50 kW in this embodiment), spraying distance is 80 - 150 mm (100 mm in this embodiment), spray gun speed is 300 - 800 mm / s (500 mm / s in this embodiment), the path overlap is 30% - 50% (45% in this embodiment) during repeated spraying, the single-layer thickness is 30 - 50 μm (30 μm in this embodiment), and the next layer is sprayed after an interval of 5 - 15 minutes (10 min in this embodiment), obtaining a wet film with a thickness of 200 - 500 μm (300 μm in this embodiment). Then, the wet film is surface-dried to obtain an anti-radiation layer with a thickness of 0.3 ± 0.05 mm.

[0094] S4. Local densification treatment Sol-gel sealing is used to assist densification. The nano-ceramic sol (SiO2 and Al2O3 sol) is dip-coated or sprayed onto the surface of the anti-radiation layer, and heat treatment is carried out at 300 - 350 °C (300 °C in this embodiment) to convert the sol into a gel and fill the micropores. This step is repeated for densification until the porosity is < 5%.

[0095] It should be noted that the parameters for surface-drying treatment are as follows: at 10 - 40 °C (room temperature in this embodiment) and a humidity of ≤ 30%, drying for 2 - 3 days (3 days in this embodiment).

[0096] It should be noted that when the prepared heat-insulating and heat-protecting material is connected to the substrate, the innermost layer (heat-insulating layer) is treated with a coupling agent to prepare an interface layer connected to the substrate.

[0097] Example 2 This embodiment provides a preparation method of a reusable lightweight heat-insulating and heat-protecting material, including the following steps: S1. Preparation of the heat-insulating layer The required raw materials are: Silicone rubber solvent: 107 silicone rubber; Expanded particles: a mixture of expanded perlite and expanded vermiculite in a mass ratio of 2:1; Porous ceramic microspheres: a mixture of porous hollow ceramic microspheres composed of ZrO2 and SiO2 in a mass ratio of 3:1, with the particle size range of zirconia being 3 - 4 μm and the particle size range of silica being 25 - 30 nm; Coupling agent: KH-550; Dispersant: mica powder with a particle size of 30 - 45 μm; Process solvent: acetone and ethyl acetate in a mass ratio of 3:1.

[0098] The preparation method is as follows: By mass, 30 parts of silicone rubber solvent, 15 parts of expanded particles, 30 parts of porous ceramic microspheres, 1 part of coupling agent, 1 part of dispersant, and 50 parts of process solvent are mixed at 25 ± 3°C for 0.5 h to obtain a uniformly mixed slurry; Then, 30 - 50 phr (30 parts in this example) of ethyl acetate is added to the slurry to adjust the viscosity to 1000 - 2000 mPa·s (the viscosity is 1200 mPa·s in this example); Next, the multi - layer spraying method is adopted: the single - layer thickness is 50 - 150 μm (100 μm in this example), the next layer is sprayed after an interval of 5 - 10 minutes (8 minutes in this example), a wet film with a thickness of 3 - 7 mm (5 mm in this example) is coated on the aluminum metal substrate. The spraying parameters are plasma power of 50 - 60 kW (50 kW in this example), spraying distance of 80 - 120 mm (100 mm in this example), spray gun moving speed of 0.3 - 1.0 m / s (0.5 m / s in this example), and overlap rate of 25% - 40% (30% in this example). Then, the wet film is surface - dried to obtain a heat - insulating layer with a thickness of 5 ± 0.5 mm.

[0099] S2. Preparation of the heat - resistant layer The required raw materials are: Silicone rubber solvent: 107 silicone rubber; Inorganic ablative - resistant flame - retardant filler: a combination of iron oxide (particle size 5 μm, purity 95%, granular), wollastonite (40 - 60 μm, purity 85%, 90% lamellar, 10% fibrous), and alumina fiber (diameter 6 μm, length 50 - 200 μm, purity 95%, fibrous), and the mass ratio of the three is 3:1:2; High - performance chopped fiber: ceramic fiber (Al2O3 - SiO2) mixture; Silicone - based reinforcing filler: fumed silica; Coupling agent: KH - 550; Dispersant: mica powder with a particle size of 30 - 45 μm; Process solvent: acetone and ethyl acetate with a mass ratio of 3:1.

[0100] The preparation method is as follows: By mass, 30 parts of silicone rubber solvent, 10 parts of inorganic ablative - resistant flame - retardant filler, 10 parts of high - performance chopped fiber, 2 parts of silicone - based reinforcing filler, 1 part of coupling agent, 1 part of dispersant, and 50 parts of process solvent are mixed at 25 ± 3°C for 0.5 h to obtain a uniformly mixed slurry; Then, 30 to 50 phr (30 parts in this embodiment) of ethyl acetate is added to the slurry and formulated to a viscosity of 1000 to 2000 mPa·s (the viscosity is 1200 mPa·s in this embodiment); Next, the multi-layer spraying method is adopted: the single-layer thickness is 100 - 150 μm (120 μm in this embodiment), and the next layer is sprayed at intervals of 10 - 15 minutes (12 min in this embodiment). A wet film with a thickness of 2 - 5 mm (4 mm in this embodiment) is formed on the surface of the heat insulation layer. The spraying parameters are: plasma power 60 - 70 kW (60 kW in this embodiment), spraying distance 90 - 140 mm (110 mm in this embodiment), spray gun moving speed 0.3 - 1.0 m / s (0.8 m / s in this embodiment), overlap rate 25% - 40% (30% in this embodiment). Then, the wet film is surface-dried to obtain a heat-proof layer with a thickness of 4 ± 0.4 mm.

[0101] S3. Preparation of the anti-radiation layer The raw materials are as follows: High-performance emission materials: a combination of MoSi2 with a particle size of 0.5 - 1 μm, ZrB2 with a particle size of 0.5 - 2 μm, and ZrO2 with a particle size of 0.5 - 1 μm, and the mass ratio of the three is 4:5:2; High-performance chopped fibers: a mixture of ceramic fibers (Al2O3 - SiO2); Inorganic ablation-resistant and flame-retardant fillers: a combination of iron oxide (particle size 5 μm, purity 95%, granular), wollastonite (40 - 60 μm, purity 85%, 90% lamellar, 10% fibrous), and alumina fibers (diameter 6 μm, length 50 - 200 μm, purity 95%, fibrous), and the mass ratio of the three is 3:1:2; Ceramic gel: alumina ceramic aerogel prepared by the sol-gel method, with a pore diameter of 20 nm and a compressive strength of 2 MPa.

[0102] The preparation method is as follows: By mass, 5 parts of high-performance emission materials, 10 parts of high-performance chopped fibers, 5 parts of inorganic ablation-resistant and flame-retardant fillers, and 15 parts of ceramic gel are mixed and stirred evenly to obtain the spraying raw materials; The spraying raw materials are sprayed on the outer side of the heat-insulating layer by using a plasma spraying device in a multi-layer spraying manner. The parameters are as follows: plasma power is 50 - 60 kW (50 kW in this embodiment), spraying distance is 80 - 150 mm (100 mm in this embodiment), spray gun speed is 300 - 800 mm / s (500 mm / s in this embodiment), the path overlap during repeated spraying is 30% - 50% (45% in this embodiment), the single-layer thickness is 30 - 50 μm (30 μm in this embodiment), and the next layer is sprayed after an interval of 5 - 15 minutes (10 min in this embodiment), obtaining a wet film with a thickness of 200 - 500 μm (300 μm in this embodiment), and then the wet film is surface-dried to obtain an anti-radiation layer with a thickness of 0.3 ± 0.05 mm.

[0103] S4. Local densification treatment Sol-gel sealing is used to assist densification. The nano-ceramic sol (SiO2 and Al2O3 sol) is dip-coated or sprayed onto the surface of the anti-radiation layer, and heat treatment is carried out at 300 - 350 °C (300 °C in this embodiment) to convert the sol into a gel and fill the micropores; This step is repeated for densification until the porosity < 5%.

[0104] Example 3 This embodiment provides a preparation method of a reusable lightweight heat-insulating and heat-shielding material, including the following steps: S1. Preparation of the heat-insulating layer The required raw materials are: Silicone rubber solvent: 107 silicone rubber; Expanded particles: a mixture of expanded perlite and expanded vermiculite in a mass ratio of 2:1; Porous ceramic microspheres: a mixture of porous hollow ceramic microspheres composed of ZrO2 and SiO2 in a mass ratio of 3:1, with the particle size range of zirconia being 3 - 4 μm and the particle size range of silica being 25 - 30 nm; Coupling agent: KH-550; Dispersant: mica powder with a particle size of 30 - 45 μm; Process solvent: acetone and ethyl acetate in a ratio of 3:1.

[0105] The preparation method is as follows: By mass fraction, 30 parts of the silicone rubber solvent, 15 parts of the expanded particles, 25 parts of the porous ceramic microspheres, 1 part of the coupling agent, 1 part of the dispersant, and 50 parts of the process solvent are mixed at 2 * 5 ± 3 °C for 0.5 h to obtain a uniformly mixed slurry; Then, 30 to 50 phr (30 parts in this embodiment) of ethyl acetate is added to the slurry and formulated to a viscosity of 1000 to 2000 mPa·s (the viscosity in this embodiment is 1200 mPa·s); Next, the multi-layer spraying method is adopted: the single-layer thickness is 50 to 150 μm (100 μm in this embodiment), and the next layer is sprayed after an interval of 5 to 10 minutes (8 minutes in this embodiment). A wet film with a thickness of 3 to 7 mm (3 mm in this embodiment) is coated on the surface of the substrate. The spraying parameters are plasma power of 50 to 60 kW (50 kW in this embodiment), spraying distance of 80 to 120 mm (100 mm in this embodiment), spray gun moving speed of 0.3 - 1.0 m / s (0.5 m / s in this embodiment), and overlap rate of 25% to 40% (30% in this embodiment). Then, the wet film is surface-dried to obtain a heat-insulating layer with a thickness of 3 ± 0.3 mm.

[0106] S2. Preparation of the heat-resistant layer The raw materials required are: Silicone rubber-containing solvent: 107 silicone rubber; Inorganic ablation-resistant flame retardant filler: a combination of iron oxide (particle size 5 μm, purity 95%, granular), montmorillonite (10 - 20 μm, purity 85%, layered), and alumina fiber (diameter 6 μm, length 50 - 200 μm, purity 95%, fibrous), and the mass ratio of the three is 3:1:2; High-performance chopped fiber: ceramic fiber (Al2O3 - SiO2) mixture; Silicone-based reinforcing filler: fumed silica; Coupling agent: KH-550; Dispersant: mica powder with a particle size of 30 - 45 μm; Process solvent: acetone and ethyl acetate with a mass ratio of 3:1.

[0107] The preparation method is as follows: By mass, 30 parts of silicone rubber-containing solvent, 12 parts of inorganic ablation-resistant flame retardant filler, 10 parts of high-performance chopped fiber, 2 parts of silicone-based reinforcing filler, 1 part of coupling agent, 1 part of dispersant, and 50 parts of process solvent are mixed at 25 ± 3 °C for 0.5 h to obtain a uniformly mixed slurry; Then, 30 to 50 phr (30 parts in this embodiment) of ethyl acetate is added to the slurry and formulated to a viscosity of 1000 to 2000 mPa·s (the viscosity in this embodiment is 1200 mPa·s); Next, a multi-layer spraying method is adopted: the thickness of a single layer is 100-150 μm (1200 μm in this embodiment), and the next layer is sprayed at an interval of 10-15 minutes (12 minutes in this embodiment). A wet film with a thickness of 2-5 mm (2 mm in this embodiment) is formed on the surface of the heat insulation layer. The spraying parameters are: plasma power of 60-70 kW (60 kW in this embodiment), spraying distance of 90-140 mm (110 mm in this embodiment), gun moving speed of 0.3-1.0 m / s (0.8 m / s in this embodiment), overlap rate of 25%-40% (30% in this embodiment). Then, the wet film is surface-dried to obtain a heat-resistant layer with a thickness of 2 ± 0.2 mm.

[0108] S3. Preparation of the anti-radiation layer The raw materials are as follows: High-performance emission materials: a combination of SiC with a particle size of 0.4-1 μm, ZrB2 with a particle size of 0.5-2 μm, and ZrO2 with a particle size of 0.5-1 μm, and the mass ratio of the three is 3:5:2; High-performance chopped fibers: a mixture of ceramic fibers (Al2O3-SiO2); Inorganic ablation-resistant and flame-retardant fillers: a combination of iron oxide (particle size 5 μm, purity 95%, granular), montmorillonite (10-20 μm, purity 85%, layered), and alumina fibers (diameter 6 μm, length 50-200 μm, purity 95%, fibrous), and the mass ratio of the three is 3:1:2; Ceramic gel: alumina ceramic aerogel prepared by the sol-gel method, with a pore diameter of 20 nm and a compressive strength of 2 MPa.

[0109] The preparation method is as follows: By mass, 5 parts of high-performance emission materials, 10 parts of high-performance chopped fibers, 5 parts of inorganic ablation-resistant and flame-retardant fillers, and 15 parts of ceramic gel are mixed and stirred evenly to obtain the spraying raw materials; The spraying raw materials are sprayed on the outside of the heat-resistant layer by using a plasma spraying device in a multi-layer spraying manner. The parameters are: plasma power of 50-60 kW (50 kW in this embodiment), spraying distance of 80-150 mm (100 mm in this embodiment), gun speed: 300-800 mm / s (500 mm / s in this embodiment), path overlap of 30%-50% (45% in this embodiment) during repeated spraying, single-layer thickness of 30-50 μm (30 μm in this embodiment), and the next layer is sprayed after an interval of 5-15 minutes (10 minutes in this embodiment) to obtain a wet film with a thickness of 200-500 μm (300 μm in this embodiment). Then, the wet film is surface-dried to obtain an anti-radiation layer with a thickness of 0.3 ± 0.05 mm.

[0110] S4. Local densification treatment Sol-gel sealing-assisted densification is adopted. The nano-ceramic sol (SiO2 and Al2O3 sol) is dip-coated or spray-coated on the surface of the anti-radiation layer, and heat treatment is carried out at 300~350°C (300°C in this embodiment) to convert the sol into a gel, filling the micropores. This step is repeated for densification until the porosity is <5%.

[0111] Comparative example In this comparative example, the method provided in Reference Example 1 was used to prepare the heat-insulating and anti-heat materials, but the inorganic ablative-resistant and flame-retardant filler was replaced with metal hydroxide (Al(OH)3). However, it was found during the preparation process that the metal hydroxide decomposed with endothermic reaction and released water vapor at high temperature. Although it could reduce the temperature and retard the flame, it would cause a sharp increase in the internal pores of the heat-insulating material, affecting the internal bonding force of the heat-insulating material and further affecting the internal interface stability of the heat-insulating material.

[0112] Performance detection: (1) Bond with the metal substrate and detect the interfacial bonding force The detection method of the interfacial bonding force of the heat-insulating coating adopts the generally accepted and authoritative test method in the industry: GB / T 5210 "Determination of Coating Adhesion - Pull-off Test".

[0113] (2) Heat flux assessment Single ablation: Ablate the outer layer of the heat-insulating coating, with a peak heat flux of 500 kW / m 2 for 30 s, and then continuously ablate at a heat flux of 80 kW / m 2 for 200 s.

[0114] Multiple ablations: Repeat the above ablation steps 5 times.

[0115] Under the above assessment heat flux, the surface temperature of the heat-insulating material is about 1200°C at most. Monitor the back temperature and comprehensive thermal conductivity at a heat-insulating material thickness of 10 mm.

[0116] Back temperature of the 10-mm-thick heat-insulating material: Five temperature sensor measuring points are arranged at the back temperature of the heat-insulating material, and the average value of these 5 temperature measuring points is taken as the back temperature of the heat-insulating material.

[0117] Comprehensive thermal conductivity: The test and calculation method of the comprehensive thermal conductivity of the heat-insulating coating adopts the generally accepted and authoritative test method in the industry: GB / T 10295 "Determination of Steady-State Thermal Resistance and Related Characteristics of Thermal Insulation Materials - Heat Flow Meter Method", and the thermal conductivity is calculated by measuring the steady-state heat flow and temperature difference (λ = Q·d / (A·ΔT)).

[0118] Attenuation of heat-insulating performance: Calculate the attenuation of heat-insulating performance by statistically analyzing the changes in the back temperature and comprehensive thermal conductivity of the material during multiple heat assessment tests.

[0119] (3) Compressive strength The detection method of the compressive strength of the heat insulation coating adopts the generally accepted and authoritative test method in the industry: GB / T 5072 "Refractory materials - Test method for cold crushing strength".

[0120] Table 1 Comparison of heat insulation material parameters

[0121] (1)Excellent heat insulation performance The heat insulation layer adopts an effective combination of inorganic ablative-resistant and flame-retardant fillers and high-performance chopped fibers, which has high stability below 800°C. Combined with the anti-radiation layer coated on the surface and local densification treatment, it can effectively resist the radiant heat flux of the aerospace vehicle engine. It can withstand the combined action of a peak heat flux of 500 kW / m 2 (for 30 s continuously) and a long-term heat flux of 80 kW / m 2 (for 200 s continuously). At a thickness of 10 mm, the back temperature ≤ 150°C, and the comprehensive thermal conductivity of the material ≤ 0.3 W / mK. Compared with traditional heat insulation materials, at the same test heat flux, the back temperature at a thickness of 10 mm reaches 200 - 300°C. The present invention greatly improves the heat insulation effect and can better protect the matrix material.

[0122] (2)Excellent reusability As Figure 1 shown, under the predetermined test heat flux, the heat insulation material provided by the present invention (Example 1) is repeatedly tested 5 times, and the heat insulation performance decays by about 16%. After the traditional heat insulation material (comparative example) is tested once, the heat insulation performance decays by > 50% when tested again. This enables it to maintain stable and reliable performance in the reusable scenario, significantly reducing the use cost and improving the resource utilization rate.

[0123] (3)Good system compatibility The material components of the heat insulation layer, heat protection layer, and anti-radiation layer do not chemically react with each other during the curing process, and the performance of the raw materials will not deteriorate; the interfaces between the metal substrate, heat insulation layer, and heat protection layer are treated with coupling agents to achieve strong bonding and prevent delamination or peeling; the surface densification material of the anti-radiation layer and the raw material components of the anti-radiation layer are of the same system and will not chemically react either. This good system compatibility ensures the stability and reliability of the overall performance of the material and extends the service life of the material.

[0124] (4)Scientific gradient design Coordinate gradient design is carried out on the thermal conductivity and coefficient of thermal expansion of the heat insulation layer, heat protection layer, and radiation resistance layer. The thermal conductivity of the outer layer is high, and that of the inner layer is low. The coefficient of thermal expansion decreases from the inside to the outside. The gradient design of thermal conductivity enables the outer layer to dissipate heat quickly, the inner layer to effectively block heat, prolong the tolerance time of the base material, and improve the heat protection efficiency; the gradient design of the coefficient of thermal expansion avoids stress concentration or cracking in the heat protection material caused by temperature changes (interface 20°C to 800°C), enhancing the structural stability and durability of the material.

[0125] (5) High-efficiency spray forming process It is integrally formed by spraying, reducing interface treatment, avoiding the complex process and instability of gluing, and achieving strong interface bonding; at the same time, spray construction has good adaptability to complex surfaces, does not require molds, has low loss, and high implementation efficiency. Compared with traditional processes, it can reduce process complexity, improve production efficiency, and reduce production costs.

[0126] (6) Low-cost co-preparation and co-curing process The spraying methods for the three layers of the radiation resistance layer / heat protection layer / heat insulation layer are the same or similar, without the need to replace spraying equipment, sites, personnel, etc.; and there is no need to completely cure the previous layer before spraying the next layer. It only needs to continue spraying after surface drying, and the heat insulation and heat protection materials can be cured together. This co-preparation and co-curing process greatly reduces the process cost, improves the implementation efficiency, and is conducive to large-scale industrial production.

[0127] (7) Lightweight The comprehensive density of the heat insulation and heat protection material provided by the present invention is about 0.5 g / cm 3 , which is lower than the density of traditional heat insulation and heat protection materials, 0.7 - 1.0 g / cm 3 . While ensuring excellent performance, lightweight is achieved, which can be widely applied to fields with strict weight requirements, such as aerospace, etc., reducing the overall equipment mass, lowering energy consumption, and improving operation efficiency.

[0128] (8) Strong bonding force and stable interface The bonding force and interface bonding force between the heat insulation and heat protection material provided by the present invention and metal substrates (such as aluminum alloy, magnesium alloy, etc.) are not less than 0.5 MPa, which is higher than the cross-section bonding force of 0.3 MPa of traditional heat insulation and heat protection materials. The strong bonding force and stable interface ensure the firm connection between the material and the body. In complex environments such as high temperature and vibration, problems such as delamination and shedding are not likely to occur, improving the reliability and safety of the overall structure.

[0129] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific implementation manners, and those skilled in the art can make various deformations or modifications within the scope of the claims, which does not affect the essence of the present invention.

Claims

1. A preparation method of a reusable lightweight heat-insulating material, characterized in that, The following steps are involved: S1. Preparation of a thermal insulation layer, wherein the thermal insulation layer contains expanded particles and porous ceramic microspheres; S2. preparing a heat-proof layer on the heat-insulating layer, wherein the heat-proof layer contains an inorganic ablation-resistant flame-retardant filler and high-performance chopped fibers; S3. Preparing an anti-radiation layer on the heat protection layer, wherein the anti-radiation layer contains an emissive material, high-performance chopped fibers, and an inorganic ablation-resistant flame-retardant filler; S4, performing densification treatment on the surface of the anti-radiation layer.

2. The method according to claim 1, characterized in that Step S1 comprises: mixing a silicone rubber solvent, expanded particles, porous ceramic microspheres, a coupling agent, a dispersant, and a process solvent to obtain a uniform first slurry; adding a diluent to the first slurry to adjust the viscosity to 1000-2000 mPa·s to obtain a second slurry; and applying the second slurry to the surface of the metal substrate by multi-layer spraying to form a wet film, and drying the film to obtain the thermal insulation layer. Step S2 comprises: mixing a silicone rubber solvent, an inorganic ablation-resistant flame-retardant filler, high-performance chopped fibers, a silicon-based reinforcing material, a coupling agent, a dispersant, and a process solvent to obtain a uniform third slurry; adding a diluent to the third slurry to adjust the viscosity to 1000-2000 mPa·s to obtain a fourth slurry; and applying the fourth slurry to the surface of the thermal insulation layer in a multi-layer spraying manner to form a wet film, and allowing the surface to dry to obtain the thermal insulation layer. Step S3 comprises: mixing an emitting material, high-performance chopped fibers, an inorganic ablation-resistant flame-retardant filler, and a ceramic gel to obtain a uniform fifth slurry; spraying the fifth slurry on the surface of the heat-resistant layer by multi-layer spraying, and drying the slurry to obtain the radiation-resistant layer; Step S4 is: coating the surface of the anti-radiation layer with nano-ceramic sol, and performing heat treatment to convert the sol into gel, and repeating the coating and heat treatment steps until the porosity is less than 5%.

3. The method according to claim 2, wherein Also includes at least one of the following technical features: A1. In step S11, the mass ratio of the silicone rubber solvent, the expanded particles, the porous ceramic microspheres, the coupling agent, the dispersant, and the process solvent is: 25-35: 12-18: 21-35: 0.8-1.2: 0.8-1.2: 42-58; B1. In step S21, the mass ratio of the silicone rubber solvent, the inorganic ablation-resistant flame-retardant filler, the high-performance chopped fiber, the silicon-based reinforcing material, the coupling agent, the dispersant, and the process solvent is: 25-35: 10-14: 8-12: 1.5-2.5: 0.8-1.2: 0.8-1.2: 40-60; C1. In step S31, the mass ratio of the emissive material, the high-performance chopped fiber, the inorganic ablation-resistant flame-retardant filler, and the ceramic gel is: 4-6: 8-12: 4-6: 12-18.

4. The method according to claim 2, wherein Also includes at least one of the following technical features: A2. The silicone rubber-containing solvent is selected from one or more of 107 and GD-401 liquid methyl silicone rubber; B2. The dispersant is selected from one or more of mica powder with a particle size of 10-50 μm and boron nitride with a particle size of 1-10 μm; C2. The expanded particles are selected from one or more of expanded perlite, expanded vermiculite, and expanded graphite; D2. The porous ceramic microspheres are selected from one or more of zirconia, silica, mullite, and hollow glass microspheres; E2. The silicon-based reinforcing material is selected from one or more of silica white carbon black, SiC particles, and silicone resin reinforcing fillers; F2. The inorganic ablation-resistant and flame-retardant filler is selected from one or more of iron oxide, montmorillonite, wollastonite, alumina fiber, and graphite; G2. The high-performance chopped fibers are a ceramic fiber mixture; H2. The emission material is selected from one or more of silicon carbide, zirconium boride, zirconia, molybdenum disilicide, and high-entropy ceramics; I2. The ceramic gel is selected from one or more of alumina ceramic aerogel, tetraethyl orthosilicate sol, and zirconium oxychloride sol.

5. The method according to claim 2, characterized in that It further includes at least one of the following technical features: A3. The coupling agent is selected from one or more of KH-550 and KH-560; B3. The process solvent is selected from one or more of acetone, ethyl acetate, cyclohexanone, and xylene solvent; C3. The diluent is selected from one or more of ethyl acetate and acetone.

6. The method according to claim 2, characterized in that It further includes at least one of the following technical features: A4. The expanded particles are a mixture of expanded perlite and expanded vermiculite with a mass ratio of 2-3:1; B4. The porous ceramic microspheres are a mixture of zirconia and silica with a mass ratio of 2-3:1, the particle size range of zirconia is 1-10 μm, and the particle size range of silica is 10-40 nm; C4. The inorganic ablation-resistant and flame-retardant filler is a mixture of iron oxide, montmorillonite, and alumina fiber with a mass ratio of 2.5-3.5:0.8-1.2:1.6-2.4; D4. The inorganic ablation-resistant and flame-retardant filler is a mixture of iron oxide, wollastonite, and alumina fiber with a mass ratio of 2.5-3.5:0.8-1.2:1.6-2.4; E4. The high-performance chopped fibers are a mixture of alumina and silica fibers with a mass ratio of 6-8:4; F4. The emission material is a mixture of silicon carbide, zirconium boride, and zirconia with a mass ratio of 2-3:5-6:1-2; G4. The emission material is a mixture of molybdenum disilicide, zirconium boride, and zirconia with a mass ratio of 3-4:5-6:1-2; H4. In the ceramic sol, the mass ratio of silicon dioxide to alumina is 1.5-3:1, the concentration of SiO2 sol is 10wt.% - 15wt.%, and the concentration of Al2O3 sol is 5wt.% - 10wt.%.

7. The method according to claim 2, characterized in that It further includes at least one of the following technical features: A5. The multi-layer spraying adopts plasma spraying, and the parameters are: plasma power 30–80 kW, spraying distance 80~140mm, spray gun speed 0.3~1m / s, and the path overlap is 25%~50% during repeated spraying; B5. In the multi-layer spraying, the single-layer thickness is 30~150μm, one layer is sprayed every 5~25min, and the multi-layer spraying thickness is 0.2~7mm thick.

8. The method according to claim 2, wherein The heat treatment temperature is 300~350°C.

9. A heat-insulating and heat-proof material, characterized in that, It is prepared by the method according to any one of claims 1 to 8, and includes a heat insulation layer, a heat protection layer and a radiation resistant layer arranged in sequence, and the radiation resistant layer is subjected to local densification treatment.

10. An application of the heat insulation and heat protection material according to claim 9 on the structural surface of a spacecraft.

Images