Thermal and electromagnetic wave absorbing function integrated ceramic matrix composite structure based on cross-scale porous superstructure

Abstract

The application discloses a ceramic-based composite structure integrating heat-proof and electromagnetic wave absorbing functions based on a cross-scale porous superstructure, which comprises, from bottom to top, a metal bottom plate, a micro-macro cross-scale porous superstructure electromagnetic wave absorbing layer, a micro-nano scale porous structure ceramic heat insulation layer and a high-temperature ceramic ablation-resistant layer. The application is innovative in that different scale porous structures are designed into a dense gradient multi-functional integrated superstructure according to electromagnetic wave absorbing and heat insulation requirements by a cross-scale artificial configuration design method, has the structural and functional integration characteristics, and is convenient for realizing ceramic 3D printing integrated forming, and can provide a new method for realizing electromagnetic protection / thermal protection integration of future high-speed aircraft components.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of multifunctional integrated shell materials of aircraft, and particularly relates to a heat-proof and electromagnetic wave-absorbing function integrated ceramic-based composite structure based on a micro-macro cross-scale porous superstructure. BACKGROUND

[0002] With the rapid development and maturity of aerospace technology, high-speed aircrafts such as manned spaceflight, moon exploration project, deep space exploration, space shuttle, spaceship return capsule and reusable launch vehicle become research hotspots. The heat environment of new high-speed aircrafts is increasingly severe, and the aircrafts need to withstand the extreme high-temperature environment and ablation behavior caused by aerodynamic heating of up to 1000 DEG C or above during flight, which puts forward strict requirements on the heat-proof and heat-insulating performance of the shell materials. Meanwhile, the multifunctionalization and function integration of the thermal protection system are inevitable needs for the future development of advanced spacecrafts, so as to realize the compatibility and integration of multiple functions such as heat-proof, heat-insulating, thermal load bearing and electromagnetic protection. The realization of electromagnetic wave-absorbing function on the aircraft is conducive to reducing electromagnetic pollution and electromagnetic interference, suppressing electromagnetic noise, improving the working stability of the carried electronic equipment, and implementing the function integration design of electromagnetic stealth protection with low scattering target characteristics to evade radar early warning detection. Therefore, the development of heat-proof / heat-insulating / electromagnetic wave-absorbing multifunctional integrated new materials has become a key supporting technology for promoting the development of new high-speed aircrafts.

[0003] The ceramic coating is often used as a heat-proof material in the extremely high-temperature service environment of aerospace due to its excellent performance such as high melting point, high hardness, ablation resistance, high thermal conductivity and good thermal shock resistance. The current ceramic coating mainly includes oxide coating (Al2O3, TiO2, ZrO2, SiO2, etc.), carbide ceramic (SiC, WC, BC, TiC, etc.), nitride ceramic (Si3N4, TiN, BN, AlN, etc.), boride ceramic (TiB, ZrB2, etc.), silicate coating and composite ceramic coating. At the same time, the current porous functional materials are paid much attention, and a large number of types emerge, which have complex microstructure and high porosity, such as foamed materials (such as metal foam, ceramic foam and organic foam), lattice structure (such as corrugated plate structure and honeycomb structure) and aerogel, and have important value in the fields of mechanics, heat insulation and electromagnetic wave-absorbing. SUMMARY

[0004] The present application provides a heat-proof and electromagnetic wave-absorbing function integrated ceramic-based composite structure based on a cross-scale porous superstructure, which can provide a new way for realizing electromagnetic protection / thermal protection integration of future high-speed aircraft components. In order to achieve the above application purposes, the present application discloses the following technical solutions.

[0005] The heat-proof and electromagnetic wave absorbing function integrated ceramic-based composite structure based on a cross-scale porous superstructure comprises, from bottom to top, a metal bottom plate, a micro-macro cross-scale porous superstructure electromagnetic wave absorbing layer, a micro-nano scale porous structure ceramic heat insulation layer and a high-temperature ceramic ablation-resistant layer.

[0006] Further, the micro-macro cross-scale porous superstructure electromagnetic wave absorbing layer is a three-dimensional superstructure of macro-porous structure cells formed by molding micro-nano scale porous ceramics.

[0007] Further, the preparation process of the micro-macro cross-scale porous superstructure electromagnetic wave absorbing layer comprises the following steps:

[0008] (1) mixing a micro-nano scale pore-forming agent into a ceramicizable polymer precursor liquid to form a slurry.

[0009] (2) printing the slurry into a three-dimensional superstructure green body of a periodic array of macro-porous structure cells by using light-cured 3D printing forming, and then performing pyrolysis treatment on the green body in a protective atmosphere.

[0010] Further, in step (1), the ceramicizable polymer precursor comprises at least one of polysilazane, polysilaborazane, polycarbosilane and the like.

[0011] Further, in step (1), the pore-forming agent comprises any one of polystyrene balls, hollow SiO2 and the like. Optionally, the amount of the pore-forming agent is 10-40%.

[0012] Further, in step (2), the pyrolysis treatment is performed at a temperature of 800-1200℃ for 0.5-4 hours.

[0013] Further, the preparation process of the micro-nano scale porous structure ceramic heat insulation layer comprises the following steps: mixing different micro-nano scale pore-forming agents (polystyrene balls, hollow SiO2 and the like) into a ceramicizable polymer precursor to prepare a 3D printing slurry of a porous ceramic layer, and performing light-cured 3D printing forming on the slurry and pyrolyzing the green body at a temperature of 800-1200℃ to finally obtain a micro-nano scale porous ceramic heat insulation layer.

[0014] Further, the thickness of the micro-nano scale porous structure ceramic heat insulation layer is 10-20 mm.

[0015] Further, the material of the high-temperature ceramic ablation-resistant layer comprises any one of SiC, SiBC, SiBCN and the like.

[0016] Further, the thickness of the high-temperature ceramic ablation-resistant layer is 0.5-3 mm.

[0017] Compared with the prior art, the beneficial effects achieved by the present application include: the heat and electromagnetic wave absorption function integrated ceramic matrix composite structure based on the micro-macro cross-scale porous superstructure of the present application realizes the design of different scale pore structures into a dense gradient multi-functional integrated superstructure according to the needs of electromagnetic wave absorption, heat insulation, etc. by a cross-scale artificial configuration design method, has the characteristics of structural and functional integration, and is convenient for realizing ceramic 3D printing integrated forming, and can provide a new way for the electromagnetic protection / thermal protection integration of future high-speed aircraft components. BRIEF DESCRIPTION OF DRAWINGS

[0018] The drawings accompanying the specification of the present application serve to provide a further understanding of the present application, and do not constitute an improper limitation of the present application.

[0019] Figure 1 The following is a schematic diagram of the heat and electromagnetic wave absorption function integrated ceramic matrix composite structure based on the porous superstructure of the following examples.

[0020] Figure 2 The following is a schematic diagram of the preparation process of the electromagnetic wave absorption layer or the heat insulation layer in the following examples.

[0021] Figure 3 The following is a schematic diagram of the electromagnetic reflection simulation results of the Schwarz P porous structure array superstructure in the following examples.

[0022] The marks in the figure represent: 1-metal base plate, 2-micro-macro cross-scale porous superstructure electromagnetic wave absorption layer, 3-micro-nano scale porous structure ceramic heat insulation layer, 4-high temperature ceramic ablation-resistant layer. DETAILED DESCRIPTION

[0023] For the convenience of description, if the words "up", "down", "left" and "right" appear in the present application, they only mean the same as the up, down, left and right directions of the drawings themselves, and do not limit the structure, but only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to have a specific orientation, are constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present application. The present application is further described by the drawings and specific embodiments.

[0024] REFERENCE Figure 1The application discloses a heat-proof and electromagnetic wave absorbing function integrated ceramic matrix composite structure based on a cross-scale porous superstructure, and relates to the technical field of aerospace materials.

[0025] The micro-macro cross-scale porous superstructure electromagnetic wave absorbing layer 2 is a macro-porous structure cell three-dimensional superstructure of micro-nano porous ceramic plastic forming, such as a Gyroid, a Schwarz P and the like. Figure 2 As shown in the figure, the preparation process of the micro-macro cross-scale porous superstructure electromagnetic wave absorbing layer 2 comprises the following steps:

[0026] (1) A micro-nano scale pore-forming agent is added into a ceramicizable polymer precursor liquid to form a slurry. The ceramicizable polymer precursor can be at least one selected from a polysilazane, a polysilaborazane, a polycarbosilane and the like. The pore-forming agent can be any one selected from polystyrene balls, hollow SiO2 and the like. The addition amount of the pore-forming agent ranges from 10% to 40%.

[0027] (2) The slurry is printed into a periodic array three-dimensional superstructure green body of macro-porous structure cells by using a photocuring 3D printing forming, and then the green body is heated to 800-1200 DEG C under the protection of an argon gas atmosphere for 0.5-4 hours. During the process, the ceramicizable polymer precursor is converted into a SiC, SiBC, SiBCN and the like nano ceramic phase at high temperature, and the pore-forming agent is removed at high temperature to form a micro-macro cross-scale porous superstructure. The micro-macro cross-scale porous superstructure realizes multiple scattering and reflection of incident electromagnetic waves through porous structures of different scales, and is beneficial to enhancing electromagnetic loss absorption and electromagnetic low reflection efficiency. Figure 3 The electromagnetic reflection simulation result of the Schwarz P porous structure array superstructure with a SiBC material has a wide frequency domain electromagnetic low reflection characteristic in a 2-40 GHz frequency band.

[0028] The thickness of the micro-nano porous structure ceramic thermal insulation layer 3 is 10-20 mm, and the preparation process comprises the following steps: incorporating different micro-nano scale pore-forming agents (polystyrene balls, hollow SiO2, etc.) into a ceramic polymer precursor to prepare a 3D printing slurry of a porous ceramic layer, and using light-cured 3D printing forming and pyrolyzing the green body at 800-1200 DEG C to finally obtain a micro-nano porous ceramic-based thermal insulation layer. It has high thermal insulation effect through the blocking effect, non-convection effect and infinite loose path effect of the micro-nano porous network structure: ① the micro-nano porous structure is micro-nano porous and has a low density, and each pore wall has the effect of heat shielding plate; ② the air molecules in the pores lose the ability to flow freely and cannot conduct heat convection; ③ the specific surface of the micro-nano porous structure is large and the volume skeleton is loose, heat is conducted along the pore wall, and there are infinite pore walls to form the "infinite loose path" effect, so that the ability of solid heat conduction is reduced.

[0029] The material of the high-temperature ceramic ablation-resistant layer 4 includes any one of SiC, SiBC, SiBCN, etc., and the thickness is 0.5-3 mm, which mainly plays the roles of high-temperature resistance, oxidation resistance and ablation resistance. The high-temperature ceramic ablation-resistant layer 4 can be directly light-cured 3D printed by using a ceramic polymer precursor (such as polysilazane, polysilaborazane, polycarbosilane, etc.) slurry without pore-forming agent doping, and then pyrolyzed by heating the obtained green body to 800-1200 DEG C in an argon protective atmosphere.

[0030] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A ceramic matrix composite structure integrating heat protection and electromagnetic wave absorption functions based on a multi-scale porous metastructure, characterized in that, The composite structure, from bottom to top, comprises: a metal base plate, a micro-to-macro multi-scale porous superstructure electromagnetic absorbing layer, a micro-nano-scale porous ceramic heat insulation layer, and a high-temperature ceramic ablation-resistant layer; wherein: The fabrication process of the micro-macroscale multi-scale porous superstructure electromagnetic absorbing layer includes the following steps: (1) A slurry is formed by incorporating micro- and nano-scale pore-forming agents into a ceramicizable polymer precursor; (2) The slurry is printed into a three-dimensional superstructure green body with a periodic array of macroporous structure cells by photopolymerization 3D printing, and then the green body is pyrolyzed in a protective atmosphere to obtain the desired product. The preparation process of the micro-nano-scale porous ceramic insulation layer includes the following steps: 3D printing slurry for porous ceramic layer is prepared by incorporating pore-forming agents of different micro-nano scales into a ceramicizable polymer precursor, and the green body is pyrolyzed between 800℃ and 1200℃ to finally obtain the micro-nano-scale porous ceramic-based insulation layer.

2. The integrated ceramic matrix composite structure based on a multi-scale porous metastructure with integrated heat protection and electromagnetic wave absorption functions as described in claim 1, characterized in that, The thickness of the micro-macro multiscale porous superstructure electromagnetic absorbing layer is 8~15 mm.

3. The integrated ceramic matrix composite structure based on a multi-scale porous metastructure with integrated heat protection and electromagnetic wave absorption functions as described in claim 1, characterized in that, In step (1), the ceramicizable polymer precursor includes at least one of polysilazane, polysiloborazane, and polycarbosilane.

4. The integrated ceramic matrix composite structure based on a multi-scale porous metastructure with integrated heat protection and electromagnetic wave absorption functions as described in claim 1, characterized in that, In step (1), the pore-forming agent includes any one of polystyrene spheres and hollow SiO2.

5. The integrated ceramic matrix composite structure based on a multi-scale porous metastructure with integrated heat protection and electromagnetic wave absorption functions according to claim 1, characterized in that, In step (1), the amount of the pore-forming agent is 10-40%.

6. The integrated ceramic matrix composite structure based on a multi-scale porous metastructure with integrated heat protection and electromagnetic wave absorption functions according to claim 1, characterized in that, In step (2), the temperature of the pyrolysis treatment is 800~1200℃ and the time is 0.5~4 hours.

7. The integrated ceramic matrix composite structure based on a multi-scale porous metastructure with integrated heat protection and electromagnetic wave absorption functions according to claim 1, characterized in that, In the preparation process of the micro-nano-scale porous ceramic heat insulation layer, the pore-forming agent includes any one of polystyrene spheres and hollow SiO2.

8. The integrated ceramic matrix composite structure based on a multi-scale porous metastructure with integrated heat protection and electromagnetic wave absorption functions according to claim 1, characterized in that, The thickness of the micro-nano porous ceramic insulation layer is 10~20mm.

9. The integrated ceramic matrix composite structure based on a multi-scale porous metastructure with integrated heat protection and electromagnetic wave absorption functions according to any one of claims 1-8, characterized in that, The material of the high-temperature ceramic ablation-resistant layer includes any one of SiC, SiBC, and SiBCN.

10. The integrated ceramic matrix composite structure based on a multi-scale porous metastructure with integrated heat protection and electromagnetic wave absorption functions according to any one of claims 1-8, characterized in that, The thickness of the high-temperature ceramic ablation-resistant layer is 0.5~3 mm.

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