A broadband stealth composite material, its preparation method and application

Abstract

This invention discloses a broadband stealth composite material, its preparation method, and its application, belonging to the field of composite material preparation technology. The preparation method includes the following steps: the upper and lower layers of the bilayer composite material are woven using 2.5D weaving and cross-weaving processes, respectively; the lower layer is prepared by impregnating boron nitride nanosheet dispersion and phenolic resin dilution solution, respectively, using PIP cyclic impregnation. f The upper Si3N layer is prepared by using a SiC radar stealth gradient layer, embedding a portion of the lower layer with Al2O3 spherical powder under high-temperature oxidation, and cyclic impregnation with silica sol. 4f A broadband stealth composite material is obtained by using a SiO2 anti-laser and infrared stealth layer. This invention aims to provide a broadband stealth composite material, its preparation method, and its applications. This composite material can achieve efficient coupling in terms of broadband radar wave stealth and laser (thermal) protection.

Description

Technical Field

[0001] This invention belongs to the field of composite material preparation technology, specifically relating to a broadband stealth composite material, its preparation method, and its application. Background Technology

[0002] With the rapid development of laser technology, its applications in military and civilian fields are becoming increasingly widespread, especially in guidance, detection, and weapon systems, making laser threats one of the major challenges in modern warfare. Lasers possess high energy density, precision guidance, and long-range strike capabilities, enabling them to detect, track, and even directly destroy targets. This places higher demands on traditional stealth and protection technologies, particularly in the face of broadband, multi-band laser threats, where achieving effective stealth and damage resistance becomes crucial.

[0003] Traditional stealth technology primarily focuses on the electromagnetic wave domain, achieving stealth by reducing the radar cross-section (RCS) or absorbing specific bands of electromagnetic waves. However, traditional stealth methods are insufficient against lasers, an optical threat characterized by high monochromaticity and high directionality. In recent years, research on stealth protection materials targeting laser threats has mainly focused on material systems such as coatings, heat sink structures, lattice structures, and honeycomb structures. However, among the existing materials, radar stealth materials and infrared stealth materials achieve impedance matching, broadband absorption, and low emissivity through structural design, but they are difficult to apply to high-temperature environments and cannot achieve a combination of efficient laser protection and radar stealth functions over a wide frequency range. While laser (thermal) protection materials can adapt to different thermal environments by selecting appropriate materials and structural forms, they have not achieved coupling with radar and infrared stealth. At the same time, their raw material costs are high, and their manufacturing processes are complex, making them unsuitable for large-scale production. Summary of the Invention

[0004] The present invention aims to provide a broadband stealth composite material, its preparation method and application, which can achieve efficient coupling in terms of broadband radar wave stealth and laser (thermal) protection.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A method for preparing a broadband stealth composite material includes the following steps;

[0007] S1. Select a double-layer composite material, use a cross-weaving process to weave the lower layer material into a lower fiber bundle, and use a 2.5D weaving process to weave the upper layer material into an upper fiber bundle to obtain a double-layer composite material A.

[0008] S2. In a vacuum environment, the upper fiber bundle of the bilayer composite material A obtained in step S1 is impregnated with boron nitride nanosheet dispersion and cured at high temperature to form an upper anti-laser and infrared stealth fiber layer structure. The lower fiber bundle of the bilayer composite material A obtained in step S1 is impregnated with phenolic resin dilution solution and cured at high temperature to form a lower radar stealth gradient layer structure, thus obtaining the bilayer composite material B.

[0009] S3. Using the PIP cyclic impregnation process, the lower radar stealth gradient layer structure of the double-layer composite material B obtained in step S2 is cyclically impregnated with liquid polycarbonylsilane in a vacuum environment. Under N2 atmosphere, the mixture is heated to undergo a curing and pyrolysis vitrification process. This cyclic impregnation is repeated 6-7 times until the weight gain is less than 0.5%, forming the lower layer C. f / SiC radar stealth gradient layer, to obtain a two-layer composite material C;

[0010] S4. The lower layer C of the bilayer composite material C obtained in step S3 is buried using Al2O3 spherical powder with an average particle size of 10 μm. f / SiC radar stealth gradient layer, high-temperature oxidation of double-layer composite material C, to obtain double-layer composite material D;

[0011] S5. The upper laser-resistant and infrared stealth layer structure of the double-layer composite material D obtained in step S4 is cyclically impregnated with silica sol in a vacuum environment, pyrolyzed at 200℃ for 120 min, and repeated more than 10 times until the weight gain is less than 0.2%, forming the upper Si3N layer. 4f / SiO2 anti-laser and infrared stealth layer, to obtain broadband stealth composite material.

[0012] Preferably, in step S1, the upper layer of the double-layer composite material is Si3N. 4f The fiber and the underlying material are C f fiber.

[0013] Preferably, in step S1, the lower fiber bundle is wound around a quadrangular prism to obtain a lower fiber bundle with trapezoidal holes, wherein the quadrangular prism has a cross-section of 2.5 mm on the top side and 5 mm on the remaining sides.

[0014] Preferably, in step S1, the total thickness of the lower fiber bundle is 8 mm, and the total thickness of the upper fiber bundle is 1.5-2 mm.

[0015] Preferably, in step S2, the upper fiber bundle is impregnated with boron nitride nanosheet dispersion and cured at 200°C for 60 min to form an upper anti-laser and infrared stealth fiber layer structure, and the lower fiber bundle is impregnated with phenolic resin dilution solution and cured at 700°C for 120 min to form a lower radar stealth gradient layer structure.

[0016] Preferably, in step S3, the curing process specifically includes: heating to 100°C and holding for 25 minutes, heating to 105°C and holding for 25 minutes, and heating to 130°C and holding for 2 hours.

[0017] Preferably, in step S3, the pyrolysis vitrification process specifically involves: heating to 400°C and holding for 1 hour, heating to 600°C and holding for 1 hour, heating to 800°C and holding for 1 hour, heating to 1000°C and holding for 1 hour, and heating to 1200°C and holding for 2 hours.

[0018] Preferably, in step S4, the lower layer C of the bilayer composite material C obtained in step S3 is buried using Al2O3 spherical powder with an average particle size of 10 μm. f / SiC radar stealth gradient layer, double-layer composite material C, oxidized at 700℃ for 300min.

[0019] Preferably, the silica sol in step S5 is SiO2·nH2O.

[0020] The present invention also provides a broadband stealth composite material prepared by the preparation method described above.

[0021] Preferably, the broadband stealth composite material has a double-layer structure, with the upper layer being Si3N. 4f / SiO2 anti-laser and infrared stealth layer, with C as the lower layer. f / SiC radar stealth gradient layer.

[0022] The present invention also provides a broadband stealth composite material prepared by the preparation method described above, or the application of the broadband stealth composite material in countering lasers.

[0023] Compared with the prior art, the present invention has the following advantages and technical effects:

[0024] This invention discloses a broadband stealth composite material, its preparation method, and its applications. This material achieves efficient coupling in broadband radar stealth and laser (thermal) protection. Through interface modulation of phenolic resin and boron nitride nanosheets, this invention significantly improves fiber protection and interface properties. Furthermore, by combining cross-weaving and 2.5D weaving techniques with cyclic impregnation of liquid polycarbosilane and silica sol, a high-performance fabric structure with a dense SiC matrix and SiO2 matrix is ​​formed, improving the material's high-temperature resistance, radar wave transmission capability, and low infrared emissivity. The design of the radar stealth gradient layer and the anti-laser and infrared stealth layer of the composite material enables it to have efficient radar wave absorption capability over a wide frequency range while maintaining excellent stealth performance. In addition, the preparation process of this invention optimizes cost and production efficiency, making this high-performance composite material more suitable for large-scale production.

[0025] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0026] Figure 1 A process flow diagram for preparing broadband stealth composite materials in Example 1 of the present invention;

[0027] Figure 2 The curing and pyrolysis ceramization temperature curves of the broadband stealth composite material provided in Embodiment 1 of the present invention are shown below. Figure 2 In Figure 2, A represents the curing temperature curve, and B in Figure 2 represents the pyrolysis veneer temperature curve.

[0028] Figure 3 The reflection loss curve of the broadband stealth composite material prepared in Example 1 of the present invention. Detailed Implementation

[0029] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0031] In this invention, unless otherwise specified, all other test materials and instruments are conventional test materials in the field and can be purchased through commercial channels.

[0032] Example 1 This example provides a broadband stealth composite material, the preparation method of which includes the following steps:

[0033] S1. Select a double-layer composite material with dimensions of 60mm × 60mm × 10mm (length × width × height), with the upper layer material being Si3N. 4f The fiber and the underlying material are C f The fibers are woven using a cross-braiding process to form a lower layer fiber bundle. This lower layer fiber bundle is then wound around a quadrangular prism to obtain a lower layer fiber bundle with trapezoidal holes, with a total thickness of 8mm. The quadrangular prism has a cross-section of 2.5mm on the top side and 5mm on the remaining sides. Using a 2.5D braiding process, the upper layer material is woven into an upper layer fiber bundle, with a total thickness of 2mm, resulting in a double-layer composite material A.

[0034] S2. In a vacuum environment, the upper fiber bundle of the bilayer composite material A obtained in step S1 is impregnated with boron nitride nanosheet dispersion and cured at 200°C for 60 min to form an upper anti-laser and infrared stealth fiber layer structure. The lower fiber bundle of the bilayer composite material A obtained in step S1 is impregnated with phenolic resin dilution solution and cured at 700°C for 120 min to form a lower radar stealth gradient layer structure, thus obtaining the bilayer composite material B.

[0035] S3. Using the PIP cyclic impregnation process, the lower radar stealth gradient layer structure of the double-layer composite material B obtained in step S2 is cyclically impregnated with liquid polycarbonylsilane in a vacuum environment. Under N2 atmosphere, it is heated to 100℃ and held for 25 min, then heated to 105℃ and held for 25 min, then heated to 130℃ and held for 2 h for curing. The temperature is then further increased to 400℃ and held for 1 h, then to 600℃ and held for 1 h, then to 800℃ and held for 1 h, then to 1000℃ and held for 1 h, and finally heated to 1200℃ and held for 2 h for pyrolysis and vitrification. This cyclic impregnation is repeated 8 times. The weight gain during each cyclic impregnation is 22.9%, 18.5%, 14.2%, 11.3%, 6.6%, 1.2%, 0.3%, and 0.4%, respectively, forming the lower layer C. f / SiC radar stealth gradient layer, to obtain a two-layer composite material C;

[0036] S4. The lower layer C of the bilayer composite material C obtained in step S3 is buried using Al2O3 spherical powder with an average particle size of 10 μm. f / SiC radar stealth gradient layer, high temperature oxidation at 700℃ for 300min, double-layer composite material C, to obtain double-layer composite material D;

[0037] S5. The upper infrared stealth layer structure of the bilayer composite material D obtained in step S4 is cyclically impregnated with silica sol SiO2·nH2O in a vacuum environment, pyrolyzed at 200℃ for 120 min, and repeated 11 times. The weight gain of each impregnation cycle is 5.65%, 5.11%, 3.21%, 2.71%, 2.11%, 2.07%, 1.01%, 0.67%, 0.25%, 0.11%, and 0.04%, respectively, forming the upper Si3N layer. 4f / SiO2 anti-laser and infrared stealth layer, to obtain broadband stealth composite material.

[0038] The following experiments were conducted to verify the effectiveness of the broadband stealth composite material provided in Example 1.

[0039] Using a vector network analyzer and the waveguide method, the electromagnetic parameters of the composite material were tested to obtain its dielectric constant and permeability. The electromagnetic loss curve of the composite material was then calculated as follows: Figure 3 As shown.

[0040] Depend on Figure 3 It can be seen that the material maintains excellent electromagnetic loss performance at 10 mm, and its electromagnetic loss rate remains above 90% in the 2.4–4.3, 9.4–12, and 15.7–17.2 GHz bands. This proves the excellent electromagnetic loss performance of the overall composite material.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a broadband stealth composite material, characterized in that, Includes the following steps; S1. Select a double-layer composite material, use a cross-weaving process to weave the lower layer material into a lower fiber bundle, and use a 2.5D weaving process to weave the upper layer material into an upper fiber bundle to obtain a double-layer composite material A. S2. In a vacuum environment, the upper fiber bundle of the bilayer composite material A obtained in step S1 is impregnated with boron nitride nanosheet dispersion and cured at 200°C for 60 min to form an upper anti-laser and infrared stealth fiber layer structure. The lower fiber bundle of the bilayer composite material A obtained in step S1 is impregnated with phenolic resin dilution solution and cured at 700°C for 120 min to form a lower radar stealth gradient layer structure, thus obtaining the bilayer composite material B. S3. Using the PIP cyclic impregnation process, the lower radar stealth gradient layer structure of the double-layer composite material B obtained in step S2 is cyclically impregnated with liquid polycarbonylsilane in a vacuum environment. Under N2 atmosphere, the mixture is heated to undergo a curing and pyrolysis vitrification process. This cyclic impregnation is repeated 6-7 times until the weight gain is less than 0.5%, forming the lower layer C. f / SiC radar stealth gradient layer, to obtain a two-layer composite material C; S4. The lower layer C of the bilayer composite material C obtained in step S3 is buried using Al2O3 spherical powder with an average particle size of 10 μm. f / SiC radar stealth gradient layer, high temperature oxidation at 700℃ for 300min, double-layer composite material C, to obtain double-layer composite material D; S5. The upper laser-resistant and infrared stealth fiber layer structure of the double-layer composite material D obtained in step S4 is cyclically impregnated with silica sol in a vacuum environment, pyrolyzed at 200℃ for 120 min, and repeated more than 10 times until the weight gain is less than 0.2%, forming the upper Si3N layer. 4f A / SiO2 laser-resistant and infrared stealth fiber layer structure was used to obtain a broadband stealth composite material; In step S1, the upper layer of the double-layer composite material is Si3N. 4f The fiber and the underlying material are C f fiber; In step S3, the curing process specifically includes: heating to 100°C and holding for 25 minutes, heating to 105°C and holding for 25 minutes, and heating to 130°C and holding for 2 hours. In step S3, the pyrolysis vitrification process specifically involves: heating to 400°C and holding for 1 hour, heating to 600°C and holding for 1 hour, heating to 800°C and holding for 1 hour, heating to 1000°C and holding for 1 hour, and heating to 1200°C and holding for 2 hours.

2. The preparation method according to claim 1, characterized in that, In step S1, the lower fiber bundle is wound around a quadrangular prism to obtain a lower fiber bundle with trapezoidal holes, wherein the quadrangular prism has a cross-section of 2.5 mm on the top side and 5 mm on the remaining sides.

3. The preparation method according to claim 1, characterized in that, In step S1, the total thickness of the lower fiber bundle is 8 mm, and the total thickness of the upper fiber bundle is 1.5-2 mm.

4. The broadband stealth composite material prepared by the preparation method according to any one of claims 1-3.

5. The application of the broadband stealth composite material as described in claim 4 in countering lasers.

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