A grid type ceramic-based wave-absorbing composite material, a preparation method and application thereof

Abstract

The application discloses a grid type ceramic base wave absorbing composite material and a preparation method and application thereof, and relates to the technical field of wave absorbing materials. The grid type ceramic base wave absorbing composite material comprises a grid structure formed by a plurality of ceramic base composite plates through longitudinal and transverse interlacing. Each ceramic base composite plate is a cuboid. A plurality of grooves are equally and regularly arranged on one side of each ceramic base composite plate along the long side direction. When the plurality of ceramic base composite plates are longitudinally and transversely interlaced, the grooves on the longitudinal ceramic base composite plates and the grooves on the transverse ceramic base composite plates are embedded in each other, thereby forming an interlocked grid structure. The grid structure wave absorbing material prepared by the application has good high-temperature resistance, and meanwhile, excellent room-temperature and high-temperature wave absorbing performance can be realized through material design of fibers, interfaces and substrates and grid structure design.

Description

Technical Field

[0001] This invention relates to the field of microwave absorbing materials technology, specifically to a grid-type ceramic-based microwave absorbing composite material, its preparation method, and its application. Background Technology

[0002] Traditional absorbing materials have narrow absorption bands and low operating temperatures, making it difficult to meet the high-temperature stealth requirements of hot-end components of hypersonic vehicles. Therefore, there is an urgent need to study a high-temperature resistant broadband absorbing material.

[0003] Continuous fiber reinforced ceramic matrix composites possess characteristics such as low density, high strength, oxidation resistance, and high temperature resistance, making them an ideal choice for high-temperature components. Currently, layup designs are mainly used to improve the high-temperature microwave absorption performance of ceramic matrix composites. However, due to limitations in the manufacturing process, the materials have a weak absorption capacity for low-frequency electromagnetic waves, making it difficult to achieve broadband microwave absorption.

[0004] As a metamaterial, the grid-like absorbing structure can achieve broadband absorption of electromagnetic waves through material and structural design, while also possessing excellent mechanical properties such as light weight and high strength, making it a superior integrated load-bearing and absorbing structure. Currently, grid-like absorbing materials are typically composed of conductive carbon fibers and resin-based wave-transparent composite materials, which suffer from low strength, poor oxidation resistance, and poor high-temperature resistance. Fabricating grid structures from ceramic matrix composites can achieve high-temperature broadband wave absorption; however, the manufacturing process of ceramic matrix composites is complex, and achieving grid structures through fiber weaving is challenging. Summary of the Invention

[0005] To address the shortcomings of the aforementioned background technology, this invention primarily solves the problems of low strength, poor oxidation resistance, and poor high-temperature resistance in existing grid-structure microwave absorbing materials, which are typically composed of conductive carbon fibers and resin-based microwave-transparent composite materials. This invention provides a grid-type ceramic-based microwave absorbing composite material, its preparation method, and its applications. The grid-type ceramic-based microwave absorbing composite material prepared by this method exhibits excellent room-temperature and high-temperature microwave absorption performance. The mechanical properties of the grid structure are enhanced through an interlocking structure and matrix deposition at the joints.

[0006] The first objective of this invention is to provide a grid-type ceramic matrix absorbing composite material, comprising a grid structure formed by multiple ceramic matrix composite plates intersecting each other;

[0007] Each ceramic-based composite plate is a cuboid;

[0008] Each ceramic-based composite plate has multiple grooves equidistantly spaced on one side along its long side.

[0009] When multiple ceramic matrix composite plates are interwoven, the grooves on the longitudinal ceramic matrix composite plates and the grooves on the transverse ceramic matrix composite plates are interlocked to form an interlocking grid structure.

[0010] The spacing between adjacent grooves on each ceramic-based composite plate is 5-15 mm.

[0011] A matrix is ​​deposited at the connection between the longitudinal ceramic matrix composite plate and the transverse ceramic matrix composite plate in the grid structure.

[0012] The ceramic-based composite plate includes a fiber preform, and an interface layer and a matrix sequentially deposited on the fiber preform;

[0013] The fiber preform is a plate made by laminating multiple layers of fiber cloth; the fiber cloth is woven from continuous ceramic fiber bundles.

[0014] The interface layer includes a boron nitride interface layer;

[0015] The substrate includes a silicon carbide substrate and / or a silicon nitride substrate.

[0016] Preferably, the ceramic fiber includes one or more of silicon carbide fiber, alumina fiber, and silicon nitride fiber.

[0017] Preferably, the thickness of the composite plate is 1 to 8 mm.

[0018] Preferably, the thickness of the interface layer is 200~500 nm.

[0019] The second objective of this invention is to provide a method for preparing a grid-type ceramic-based microwave absorbing composite material, comprising the following steps:

[0020] Preparation of ceramic-based composite flat plates;

[0021] Equally spaced slots are made on the long side of the ceramic matrix composite plate to obtain a ceramic matrix composite grid plate;

[0022] Multiple ceramic matrix composite grid plates are cross-assembled to form an interlocking grid structure. Then, they are fixed with a mold and placed in a deposition furnace to deposit the matrix at the joints, thus obtaining a grid-type ceramic matrix microwave absorbing composite material.

[0023] Preferably, the ceramic-based composite plate is prepared according to the following steps:

[0024] Preparation of fiber preforms;

[0025] The fiber preform is placed in a vacuum furnace and hydrogen, argon, ammonia and boron trichloride are introduced to deposit a boron nitride interface layer on the surface of the fiber preform.

[0026] A fiber preform with a boron nitride interface layer deposited on its surface is placed in a deposition furnace, and argon, hydrogen, and the corresponding gas of the substrate are introduced to deposit the substrate on the surface of the boron nitride interface layer, thus obtaining a ceramic-based composite plate.

[0027] Preferably, when depositing the boron nitride interface layer on the surface of the fiber preform, the pressure inside the vacuum furnace is 200~600Pa, the temperature is 500~900℃, and the deposition time is 20~40h.

[0028] Preferably, when depositing the substrate on the surface of the boron nitride interface layer, the pressure inside the deposition furnace is 400~700Pa, the temperature is 600~9000℃, and the deposition time is 80~120h.

[0029] The third objective of this invention is to provide an application of a grid-type ceramic-based absorbing composite material in electromagnetic wave absorption.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] This invention provides a grid-type ceramic-based microwave absorbing composite material, its preparation method, and its applications. The invention employs chemical vapor infiltration combined with slotted interlocking to provide a simple, short-cycle, and highly efficient process for preparing high-temperature resistant grid-type ceramic-based microwave absorbing composite materials. Through material design of fibers, interfaces, and the matrix, as well as grid structure design, the prepared grid-type ceramic-based microwave absorbing composite material exhibits excellent room-temperature and high-temperature microwave absorption performance. The mechanical properties of the grid structure are enhanced through the interlocking structure and matrix deposition at the joints. Attached Figure Description

[0032] Figure 1 Schematic diagram of ceramic matrix composite grating;

[0033] Figure 2 Photograph of a grid-type ceramic matrix microwave absorbing composite material;

[0034] Figure 3 The microwave absorption performance curves of the grid-type ceramic matrix microwave absorbing composite material at room temperature and 1000℃ are shown.

[0035] Figure 4 The room temperature microwave absorption performance of the SiC / Si3N4 flat panel provided for Comparative Example 1. Detailed Implementation

[0036] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention.

[0037] The first aspect of the present invention provides a ceramic-based composite plate, the composite plate comprising a fiber preform, and an interface layer and a substrate sequentially deposited on the fiber preform; wherein the thickness of the interface layer is 200~500 nm; and the substrate accounts for 45~55% of the volume fraction of the composite plate.

[0038] The fiber preform is a plate made by laminating multiple layers of fiber cloth; the fiber cloth is woven from continuous ceramic fiber bundles.

[0039] The interface layer includes a boron nitride interface layer;

[0040] The substrate includes a silicon carbide substrate and / or a silicon nitride substrate.

[0041] This invention solves the problems of poor oxidation resistance and poor high-temperature resistance of existing preforms by depositing an interface layer and a matrix sequentially onto the fiber preform.

[0042] The ceramic fiber includes one or more of silicon carbide fiber, alumina fiber, and silicon nitride fiber.

[0043] The thickness of the composite plate is 1~8 mm.

[0044] A second aspect of this invention provides a method for preparing a ceramic-based composite flat plate, comprising the following steps:

[0045] Prepare fiber preforms; place the fiber preforms in a vacuum furnace and introduce hydrogen, argon, ammonia and boron trichloride to deposit a boron nitride interface layer on the surface of the fiber preforms;

[0046] A fiber preform with a boron nitride interface layer deposited on its surface is placed in a deposition furnace, and argon, hydrogen, and the corresponding gas of the substrate are introduced to deposit the substrate on the surface of the boron nitride interface layer, thus obtaining a ceramic-based composite plate.

[0047] When depositing a boron nitride interface layer on the surface of the fiber preform, the pressure inside the vacuum furnace is 200~600Pa, the temperature is 500~900℃, and the deposition time is 20~40h.

[0048] When depositing the substrate on the surface of the boron nitride interface layer, the pressure in the deposition furnace is 400~700Pa, the temperature is 600~9000℃, and the deposition time is 80~120h.

[0049] The third aspect of this invention provides an application of a ceramic-based composite plate in a grid-type ceramic-based microwave absorbing composite material.

[0050] A fourth aspect of the present invention provides a grid-type ceramic matrix absorbing composite material, comprising a grid structure formed by multiple ceramic matrix composite plates intersecting each other;

[0051] Each ceramic-based composite plate is a cuboid;

[0052] Each ceramic-based composite plate has multiple grooves equidistantly spaced on one side along its long side.

[0053] When multiple ceramic matrix composite plates are interwoven, the grooves on the longitudinal ceramic matrix composite plates and the grooves on the transverse ceramic matrix composite plates are interlocked to form an interlocking grid structure.

[0054] The spacing between adjacent grooves on each ceramic-based composite plate is 5-15 mm.

[0055] A matrix is ​​deposited at the connection between the longitudinal ceramic matrix composite plate and the transverse ceramic matrix composite plate in the grid structure.

[0056] This invention, through the material design of fibers, interfaces, and matrix, as well as the design of the grid structure, produces a grid-type ceramic matrix microwave absorbing composite material with excellent room temperature and high temperature microwave absorption performance. The mechanical properties of the grid structure are enhanced by an interlocking structure and the deposition of matrix at the joints.

[0057] The fifth aspect of this invention provides a method for preparing a grid-type ceramic-based microwave absorbing composite material, comprising the following steps:

[0058] Preparation of ceramic-based composite flat plates;

[0059] Equally spaced slots are made on the long side of the ceramic matrix composite plate to obtain a ceramic matrix composite grid plate;

[0060] Multiple ceramic matrix composite grid plates are cross-assembled to form an interlocking grid structure. Then, they are fixed with a mold and placed in a deposition furnace to deposit the matrix at the joints, thus obtaining a grid-type ceramic matrix microwave absorbing composite material.

[0061] In one embodiment, a grid-type ceramic-based microwave absorbing composite material, see [link to previous embodiment]. Figure 2 As shown, the grid-type ceramic matrix absorbing composite material is composed of multiple flat plates evenly distributed along the longitudinal and transverse directions; the flat plates in the grid structure are referred to as ceramic matrix composite grid plates; see also Figure 1 As shown, the ceramic matrix composite grating plate includes a ceramic matrix composite plate and grooves evenly distributed along the long side of the plate; the plate has a length of 100~500 mm, a height of 5~50 mm, and a thickness of 1~8 mm; the groove depth is half the height of the composite plate, the groove width is the same as the thickness of the composite plate, and the spacing between the grooves is 5~15 mm.

[0062] The flat plate comprises a fiber preform, an interface layer, and a matrix;

[0063] The fiber preform is woven from ceramic fibers by a spinning machine, including silicon carbide fibers, alumina fibers and silicon nitride fibers; the interface layer is prepared by chemical vapor infiltration process and deposited on the surface of the fiber preform, including boron nitride interface; the matrix is ​​prepared by chemical vapor infiltration process and deposited on the surface of the interface layer, including silicon carbide matrix and silicon nitride matrix.

[0064] In one embodiment, a method for preparing a grid-type ceramic-based microwave absorbing composite material includes the following steps:

[0065] Step 1, Preparation of fiber preform: Continuous ceramic fiber bundles are woven into plain weave fiber cloth. The fiber cloth is cut into the appropriate size according to the length and height of the plate. The cut fiber cloth is stacked according to the thickness of the plate to obtain the fiber preform.

[0066] In step 1, the fiber preform has a length of 100-500 mm, a width of 5-50 mm, and a thickness of 1-8 mm.

[0067] Step 2, preparation of boron nitride interface layer by chemical vapor infiltration process: The fiber preform from step 1 is placed in a vacuum furnace and hydrogen, argon, ammonia and boron trichloride are introduced. Under high temperature and high pressure, boron nitride is generated and deposited on the surface of the fiber preform to obtain boron nitride interface layer.

[0068] In step 2, the pressure inside the vacuum furnace is 200~600Pa, the temperature is 500~900℃, the dilution gas is argon, the carrier gas is hydrogen, boron trichloride provides the boron source, ammonia provides the nitrogen source, the argon flow rate is 6~9L / min, the hydrogen flow rate is 5~8L / min, the boron trichloride flow rate is 3~7L / min, the ammonia flow rate is 4~6L / min, and the deposition time is 20~40h.

[0069] Step 3, Chemical vapor infiltration process to prepare the matrix: The fiber preform from step 2 is placed in a deposition furnace, and argon, hydrogen and gases corresponding to different matrices are introduced into the deposition furnace. The gases react under high temperature and high pressure to generate the corresponding matrix. The matrix is ​​deposited on the surface of the boron nitride interface layer to obtain a ceramic matrix composite plate.

[0070] In step 3, the pressure inside the deposition furnace is 400~700Pa, the temperature is 600~1100℃, argon is used as a dilution gas, hydrogen is used as a carrier gas, and the reaction gases are silicon tetrachloride and ammonia (for silicon nitride substrate) or methyltrichlorosilane (for silicon carbide substrate). The argon flow rate is 6~9L / min, the hydrogen flow rate is 5~8L / min, the silicon tetrachloride flow rate is 3~6L / min, the ammonia flow rate is 2~6L / min, the methyltrichlorosilane flow rate is 3~6L / min, and the deposition time is 80~120h.

[0071] Step 4: Make equidistant slots on the long side of the ceramic matrix composite plate obtained in step 3 to obtain a ceramic matrix composite grid plate.

[0072] In step 4, the ceramic matrix composite grating plate has a length of 100~500 mm, a height of 5~50 mm, and a thickness of 1~8 mm; the groove depth is half the height of the composite plate, the groove width is the same as the thickness of the composite plate, and the spacing between the grooves is 5~15 mm.

[0073] Step 5: Multiple ceramic matrix composite grid plates are cross-assembled to form an interlocking grid structure. Then, a mold is used to fix the grid and it is placed in a deposition furnace. The matrix is ​​deposited at the connection point to obtain a grid-type ceramic matrix microwave absorbing composite material.

[0074] In step 5, the grid-type ceramic matrix absorbing composite material has a length of 100~500mm, a width of 100~500mm, a height of 5~50mm, and a thickness of 1~8mm.

[0075] The sixth aspect of this invention provides an application of a grid-type ceramic-based microwave absorbing composite material in electromagnetic wave absorption. The grid-type ceramic-based microwave absorbing composite material prepared by this invention exhibits excellent room temperature and high temperature microwave absorption properties.

[0076] It should be noted that, unless otherwise specified, the experimental methods used in this invention are all conventional methods; and the reagents and materials used, unless otherwise specified, are all commercially available.

[0077] Example 1

[0078] A method for preparing a grid-type ceramic-based microwave absorbing composite material includes the following steps:

[0079] Step 1: Cut the silicon carbide fiber cloth into strips with a length of 180mm and a width of 20mm, and stack them in a flat mold until the thickness is 1mm to obtain the silicon carbide fiber preform.

[0080] Step 2: Place the silicon carbide fiber preform from Step 1 into a vacuum furnace, and introduce hydrogen, argon, ammonia and boron trichloride. The flow rate of argon is 7 L / min, the flow rate of hydrogen is 6 L / min, the flow rate of boron trichloride is 4 L / min, the flow rate of ammonia is 5 L / min, the temperature is 600℃, the pressure is 300Pa, and the deposition time is 30h to deposit a boron nitride interface layer on the surface of the silicon carbide fiber preform.

[0081] Step 3: Place the silicon carbide fiber preform from Step 2 into a deposition furnace, and introduce argon, hydrogen, silicon tetrachloride and ammonia into the deposition furnace. The flow rate of argon is 7 L / min, the flow rate of hydrogen is 6 L / min, the flow rate of silicon tetrachloride is 6 L / min, the flow rate of ammonia is 6 L / min, the temperature is 900℃, the pressure is 500Pa, and the deposition time is 90h. A silicon nitride substrate is deposited on the surface of the boron nitride interface layer to obtain a SiC / Si3N4 plate.

[0082] Step 4: Equidistant grooves are made on the long side of the SiC / Si3N4 flat plate obtained in Step 3. The groove depth is 10mm, the groove width is 1mm, and the spacing between the grooves is 13mm, resulting in a SiC / Si3N4 grid plate. Figure 1 As shown.

[0083] Step 5: Multiple SiC / Si3N4 grid plates are cross-assembled to form an interlocking grid structure. Then, a mold is used to fix the structure, and it is placed in a deposition furnace. Silicon nitride substrate is deposited at the joints under the same deposition conditions as in Step 3, resulting in a grid-structured SiC / Si3N4 microwave absorbing composite material. Figure 2 As shown.

[0084] The microwave absorption performance of the obtained grid-structured SiC / Si3N4 microwave absorbing composite material was tested, and its microwave absorption performance at room temperature and 1000℃ was as follows: Figure 3 As shown, at room temperature, the grid-structured SiC / Si3N4 exhibits an effective absorption bandwidth (less than -10dB, i.e., an absorption rate greater than 90%) of up to 13.4GHz in the 2–18GHz frequency range, demonstrating excellent broadband absorption performance. Furthermore, the grid-structured SiC / Si3N4 achieves an effective absorption bandwidth of 12.8GHz at 1000℃, realizing high-temperature broadband absorption. The grid structure optimizes the impedance matching characteristics of the material, increasing the amount of electromagnetic waves entering the structure. When electromagnetic waves enter the grid structure, the scattering, reflection, and resonance effects of the periodic grid structure dissipate the electromagnetic wave energy, improving the material's ability to absorb electromagnetic waves and thus enhancing the broadband absorption performance of SiC / Si3N4.

[0085] Example 2

[0086] A method for preparing a grid-type ceramic-based microwave absorbing composite material includes the following steps:

[0087] Step 1: Cut the silicon carbide fiber cloth into strips with a length of 180mm and a width of 10mm, and stack them in a flat mold until the thickness is 2mm to obtain the silicon carbide fiber preform.

[0088] Step 2: Place the silicon carbide fiber preform from Step 1 into a vacuum furnace, and introduce hydrogen, argon, ammonia and boron trichloride. The flow rate of argon is 9 L / min, the flow rate of hydrogen is 8 L / min, the flow rate of boron trichloride is 7 L / min, the flow rate of ammonia is 6 L / min, the temperature is 800℃, the pressure is 500 Pa, and the deposition time is 40 h to deposit a boron nitride interface layer on the surface of the silicon carbide fiber preform.

[0089] Step 3: Place the silicon carbide fiber preform from Step 2 into a deposition furnace, and introduce argon, hydrogen, and methyltrichlorosilane into the deposition furnace. The argon flow rate is 9 L / min, the hydrogen flow rate is 8 L / min, the methyltrichlorosilane flow rate is 5 L / min, the temperature is 1000℃, the pressure is 600 Pa, and the deposition time is 120 h. Deposit silicon carbide substrate on the surface of boron nitride interface layer to obtain SiC / SiC plate.

[0090] Step 4: Make equidistant grooves on the long side of the SiC / SiC flat plate obtained in step 3. The groove depth is 5mm, the groove width is 2mm, and the spacing between the grooves is 10mm to obtain the SiC / SiC grid plate.

[0091] Step 5: Assemble multiple SiC / SiC grid plates in a cross configuration to form an interlocking grid structure. Then, fix the grid structure with a mold and place it in a deposition furnace. Deposit silicon carbide substrate at the connection points under the same deposition conditions as in Step 3 to obtain a grid structure SiC / SiC microwave absorbing composite material.

[0092] The obtained grid-structured SiC / SiC was subjected to microwave absorption performance testing. At room temperature, the grid-structured SiC / SiC achieved an effective absorption bandwidth (less than -10dB, i.e., an absorptivity greater than 90%) of 11.7GHz in the 2–18GHz frequency range, demonstrating excellent broadband absorption performance. Furthermore, the grid-structured SiC / SiC achieved an effective absorption bandwidth of 10.5GHz at 1000℃, realizing high-temperature broadband microwave absorption.

[0093] Example 3

[0094] A method for preparing a grid-type ceramic-based microwave absorbing composite material includes the following steps:

[0095] Step 1: Cut the silicon nitride fiber cloth into strips with a length of 300mm and a width of 15mm, and stack them in a flat mold until the thickness is 1.5mm to obtain the silicon nitride fiber preform;

[0096] Step 2: Place the silicon nitride fiber preform from Step 1 into a vacuum furnace, and introduce hydrogen, argon, ammonia and boron trichloride. The flow rate of argon is 6 L / min, the flow rate of hydrogen is 7 L / min, the flow rate of boron trichloride is 6 L / min, the flow rate of ammonia is 4 L / min, the temperature is 700℃, the pressure is 600 Pa, and the deposition time is 35 h to deposit a boron nitride interface layer on the surface of the silicon nitride fiber preform.

[0097] Step 3: Place the silicon nitride fiber preform from Step 2 into a deposition furnace, and introduce argon, hydrogen, and methyltrichlorosilane into the deposition furnace. The argon flow rate is 6 L / min, the hydrogen flow rate is 7 L / min, the methyltrichlorosilane flow rate is 6 L / min, the temperature is 800℃, the pressure is 700Pa, and the deposition time is 100h. Deposit silicon carbide substrate on the surface of boron nitride interface layer to obtain Si3N4 / SiC plate.

[0098] Step 4: Make equidistant grooves on the long side of the Si3N4 / SiC plate obtained in step 3. The groove depth is 7.5mm, the groove width is 1.5mm, and the spacing between the grooves is 8mm to obtain the Si3N4 / SiC grid plate.

[0099] Step 5: Multiple Si3N4 / SiC grid plates are cross-assembled to form an interlocking grid structure. Then, a mold is used to fix it and it is placed in a deposition furnace. Silicon carbide substrate is deposited at the connection. The deposition conditions are the same as in Step 3 to obtain the grid structure Si3N4 / SiC microwave absorbing composite material.

[0100] The obtained Si3N4 / SiC grating structure was subjected to microwave absorption performance testing. At room temperature, the Si3N4 / SiC grating structure achieved an effective absorption bandwidth (less than -10dB, i.e., an absorptivity greater than 90%) of 12.6GHz in the 2–18GHz frequency range, demonstrating excellent broadband absorption performance. Furthermore, the Si3N4 / SiC grating structure achieved an effective absorption bandwidth of 11.2GHz at 1000℃, realizing high-temperature broadband microwave absorption.

[0101] Comparative Example 1

[0102] The difference between this comparative example and Example 1 is that a SiC / Si3N4 flat plate is provided, while Example 1 provides a grid structure SiC / Si3N4.

[0103] The room temperature microwave absorption performance of SiC / Si3N4 flat panels is as follows: Figure 4 As shown. By Figure 4 It can be seen that the minimum reflection loss of the SiC / Si3N4 flat plate is -4.6 dB, and the effective absorption bandwidth is 0 GHz. Its broadband absorption performance is far worse than that of the grid structure SiC / Si3N4 composite material.

[0104] This invention describes preferred embodiments and their effects. However, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to include both the preferred embodiments and all changes and modifications falling within the scope of this invention.

[0105] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A grid type ceramic-based wave-absorbing composite material, characterized in that, The grid structure comprises a plurality of ceramic matrix composite plates arranged in a crisscross manner; Each ceramic matrix composite plate is a cuboid; Each ceramic matrix composite plate is provided with a plurality of grooves at equal intervals on one side thereof along the long side direction; When the plurality of ceramic matrix composite plates are arranged in a crisscross manner, the grooves on the ceramic matrix composite plates in the longitudinal direction and the grooves on the ceramic matrix composite plates in the transverse direction are embedded in each other to form an interlocking grid structure; The distance between adjacent grooves on each ceramic matrix composite plate is 5-15 mm; The connection between the ceramic matrix composite plates in the longitudinal direction and the ceramic matrix composite plates in the transverse direction in the grid structure is provided with a matrix; The ceramic matrix composite plate comprises a fiber preform, an interface layer and a matrix deposited on the fiber preform in sequence; The fiber preform is a plate body prepared by stacking a plurality of fiber cloths; the fiber cloth is woven by continuous ceramic fiber bundles; The interface layer comprises a boron nitride interface layer; The matrix comprises a silicon carbide matrix and / or a silicon nitride matrix; The ceramic fiber comprises one or more of silicon carbide fiber, aluminum oxide fiber and silicon nitride fiber; The thickness of the composite plate is 1-8 mm; The thickness of the interface layer is 200-500 nm.

2. The method for preparing the grid type ceramic matrix wave absorbing composite material of claim 1, characterized in that, The method comprises the following steps: Preparation of a ceramic matrix composite plate; Equal-interval grooving on the long side of the ceramic matrix composite plate to obtain a ceramic matrix composite grid plate; Cross-assembly of a plurality of ceramic matrix composite grid plates to form an interlocking grid structure, followed by fixation using a mold and placement in a deposition furnace to deposit a matrix at the connection to obtain a grid-type ceramic matrix wave-absorbing composite material.

3. The method of claim 2, wherein the ceramic matrix wave-absorbing composite is prepared by the steps of: preparing a ceramic matrix composite by mixing a ceramic matrix material and a wave-absorbing material; and coating the ceramic matrix composite with a metal mesh. The ceramic matrix composite plate is prepared according to the following steps: Preparation of a fiber preform; Placing the fiber preform in a vacuum furnace, and introducing hydrogen, argon, ammonia and boron trichloride to deposit a boron nitride interface layer on the surface of the fiber preform; Placing the fiber preform with the boron nitride interface layer deposited on the surface thereof in a deposition furnace, and introducing argon, hydrogen and a gas corresponding to the matrix to deposit the matrix on the surface of the boron nitride interface layer to obtain the ceramic matrix composite plate.

4. The method of claim 3, wherein the ceramic matrix wave-absorbing composite is prepared by the steps of: preparing a ceramic matrix composite by mixing a ceramic matrix material and a reinforcing material; and coating the ceramic matrix composite with a wave-absorbing material. When the boron nitride interface layer is deposited on the surface of the fiber preform, the pressure in the vacuum furnace is 200-600 Pa, the temperature is 500-900℃, and the deposition time is 20-40 h.

5. The method of claim 3, wherein the ceramic matrix wave-absorbing composite is prepared by the steps of: preparing a ceramic matrix composite by mixing a ceramic matrix material and a reinforcing material; and coating the ceramic matrix composite with a wave-absorbing material. When the matrix is deposited on the surface of the boron nitride interface layer, the pressure in the deposition furnace is 400-700 Pa, the temperature is 600-9000℃, and the deposition time is 80-120 h.

6. Use of the grid-type ceramic matrix wave-absorbing composite material of claim 1 in electromagnetic wave absorption.

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