Broadband stealth composite material as well as preparation method and application thereof

Abstract

The invention discloses a broadband stealth composite material and a preparation method and application thereof, and belongs to the technical field of composite material preparation. The preparation method comprises the following steps: weaving an upper-layer structure and a lower-layer structure of a double-layer composite material by adopting a 2.5 D weaving process and a cross weaving process respectively, dipping in a boron nitride nanosheet dispersion liquid and a phenolic resin diluted solution respectively, performing PIP cyclic dipping to prepare a lower-layer Cf / SiC radar stealth gradient layer, burying the lower-layer part by using Al2O3 spherical powder, and performing high-temperature oxidation to obtain the Cf / SiC radar stealth gradient layer. And circularly dipping silica sol to prepare an upper Si3N4f / SiO2 anti-laser and infrared stealth layer, so as to obtain the broadband stealth composite material. The invention aims to provide a broadband stealth composite material as well as a preparation method and application thereof. The composite material can realize efficient coupling in the aspects of broadband radar wave stealth and laser (heat) protection.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite material preparation, and in particular relates to a broadband stealth composite material and a preparation method and application thereof. Background Art

[0002] With the rapid development of laser technology, its application in military and civilian fields is becoming more and more extensive, especially in guidance, detection and weapon systems, making laser threats one of the important challenges in modern warfare. Lasers have high energy density, precision guidance and long-range strike capabilities, and can detect, track and even directly destroy targets. This puts higher demands on traditional stealth and protection technologies, especially in the face of broadband multi-band laser threats. How to achieve effective stealth and damage resistance becomes the key.

[0003] Traditional stealth technology is mainly concentrated in the field of electromagnetic waves, and stealth is achieved by reducing the radar cross section (RCS) or absorbing electromagnetic waves in a specific band. However, facing the optical threat of laser, which has high monochromaticity and high directionality, traditional stealth means are insufficient. In recent years, the research on stealth protection materials for 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 are difficult to apply to high-temperature environments, and it is difficult to achieve the combination of efficient laser protection and radar stealth functions within a wide frequency range; while laser (thermal) protection materials can adapt to different thermal environments by selecting appropriate materials and structural forms, but have not achieved coupling with radar and infrared stealth; at the same time, the raw material cost of its materials is high, the preparation process is complex, and it is not suitable for large-scale production. Summary of the invention

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

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a broadband stealth composite material comprises 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, so as to obtain a double-layer composite material A;

[0008] S2. In a vacuum environment, the upper fiber bundle of the double-layer composite material A obtained in step S1 is impregnated with a boron nitride nanosheet dispersion, and cured at high temperature to form an upper anti-laser and infrared stealth fiber layer structure, and the lower fiber bundle of the double-layer composite material A obtained in step S1 is impregnated with a phenolic resin diluted solution, and cured at high temperature to form a lower radar stealth gradient layer structure, thereby obtaining a double-layer 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 polycarbosilane under a vacuum environment, and heated under a N2 atmosphere for a curing process and a pyrolysis ceramic process, and the cyclic impregnation is repeated 6-7 times until the weight gain is less than 0.5%, thereby forming a lower layer C f / SiC radar stealth gradient layer, to obtain a double-layer composite material C;

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

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

[0012] Preferably, in step S1, the upper layer of the double-layer composite material is Si3N 4f Fiber, lower material is C f fiber.

[0013] Preferably, in step S1, the lower fiber bundle is wound on a quadrangular prism to obtain a lower fiber bundle with trapezoidal holes, wherein the cross-section of the quadrangular prism is 2.5 mm on the upper side and 5 mm on the other 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 a boron nitride nanosheet dispersion and cured at 200°C for 60 minutes to form an upper laser-resistant and infrared stealth fiber layer structure, and the lower fiber bundle is impregnated with a diluted phenolic resin solution and cured at 700°C for 120 minutes to form a lower radar stealth gradient layer structure.

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

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

[0018] Preferably, in step S4, the lower layer C of the double-layer composite material C obtained in step S3 is buried with 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.

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

[0022] The present invention also provides a broadband stealth composite material prepared by the preparation method or the use of the broadband stealth composite material in counteracting laser.

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

[0024] The present invention discloses a broadband stealth composite material and its preparation method and application, which can achieve efficient coupling in broadband radar wave stealth and laser (heat) protection. The present invention significantly improves fiber protection and interface performance through interface regulation of phenolic resin and boron nitride nanosheets, and also forms a high-performance fabric structure with a dense SiC matrix and a SiO2 matrix through cross-weaving and 2.5D weaving technology combined with cyclic impregnation of liquid polycarbosilane and silica sol, thereby improving the material's high temperature resistance, radar wave penetration ability and low infrared emissivity. The design of the composite material's radar stealth gradient layer and anti-laser and infrared stealth layer enables it to have efficient absorption capacity for radar waves in a broadband range while maintaining excellent stealth effect. In addition, the preparation process of the present 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 is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a process flow chart for preparing a broadband stealth composite material according to Example 1 of the present invention;

[0027] Figure 2 The curing and pyrolysis ceramic temperature curve of the broadband stealth composite material provided in Example 1 of the present invention, wherein Figure 2 A in FIG. 2 is a curing temperature curve, and B in FIG. 2 is a pyrolysis ceramic temperature curve;

[0028] Figure 3 This is the reflection loss curve of the broadband stealth composite material prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0030] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

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

[0032] Embodiment 1 This embodiment provides a broadband stealth composite material, and the preparation method includes the following steps:

[0033] S1. Select a double-layer composite material with a size of 60mm×60mm×10mm in length×width×height. The upper layer material is Si3N 4f Fiber, lower material is C f The lower layer material is woven into a lower layer fiber bundle by a cross weaving process, and the lower layer fiber bundle is wound on a quadrangular prism to obtain a lower layer fiber bundle with trapezoidal holes, with a total thickness of 8 mm, wherein the quadrangular prism section is 2.5 mm on the upper side and 5 mm on the other sides. The upper layer material is woven into an upper layer fiber bundle by a 2.5D weaving process, with a total thickness of 2 mm, to obtain a double-layer composite material A.

[0034] S2. In a vacuum environment, the upper fiber bundle of the double-layer composite material A obtained in step S1 is impregnated with a 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 double-layer composite material A obtained in step S1 is impregnated with a phenolic resin dilute solution, and cured at 700° C. for 120 min to form a lower radar stealth gradient layer structure, thereby obtaining a double-layer composite material B.

[0035] S3, adopting 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 polycarbosilane under a vacuum environment, heated to 100°C in a N2 atmosphere, maintained for 25 minutes, heated to 105°C, maintained for 25 minutes, heated to 130°C, maintained for 2 hours for curing, and continued to heat to 400°C, maintained for 1 hour, heated to 600°C, maintained for 1 hour, heated to 800°C, maintained for 1 hour, heated to 1000°C, maintained for 1 hour, heated to 1200°C, maintained for 2 hours for pyrolysis ceramicization process, and cyclically impregnated 8 times, wherein the weight gain of each cyclic impregnation process is 22.9%, 18.5%, 14.2%, 11.3%, 6.6%, 1.2%, 0.3%, and 0.4%, respectively, to form a lower layer C f / SiC radar stealth gradient layer, to obtain a double-layer composite material C;

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

[0037] S5, the upper infrared stealth layer structure of the double-layer composite material D obtained in step S4 is cyclically impregnated with silica sol SiO2·nH2O under vacuum environment, cracked at 200°C for 120min, and cycled 11 times, wherein the weight gain of each cyclic impregnation process is 5.65%, 5.11%, 3.21%, 2.71%, 2.11%, 2.07%, 1.01%, 0.67%, 0.25%, 0.11%, 0.04%, respectively, to form an upper Si3N 4f / SiO2 anti-laser and infrared stealth layer to obtain a broadband stealth composite material.

[0038] The effect of the broadband stealth composite material provided in Example 1 was verified through the following experiments.

[0039] Using a vector network analyzer, the electromagnetic parameters of the composite material were tested by the waveguide method to obtain the dielectric constant and magnetic permeability of the composite material. After calculation, the electromagnetic loss curve of the composite material was obtained as shown in the figure. Figure 3 shown.

[0040] Depend on Figure 3 It can be seen that the material maintains excellent electromagnetic loss performance at 10 mm, and maintains an electromagnetic loss rate of more than 90% in the 2.4-4.3, 9.4-12, and 15.7-17.2 GHz bands, proving 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 solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for preparing a broadband stealth composite material, characterized in that: The method comprises 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, so as to obtain a double-layer composite material A; S2. In a vacuum environment, the upper fiber bundle of the double-layer composite material A obtained in step S1 is impregnated with a boron nitride nanosheet dispersion, and cured at high temperature to form an upper anti-laser and infrared stealth fiber layer structure, and the lower fiber bundle of the double-layer composite material A obtained in step S1 is impregnated with a phenolic resin diluted solution, and cured at high temperature to form a lower radar stealth gradient layer structure, thereby obtaining a double-layer 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 polycarbosilane under a vacuum environment, and heated under a N2 atmosphere for a curing process and a pyrolysis ceramic process, and the cyclic impregnation is repeated 6-7 times until the weight gain is less than 0.5%, thereby forming a lower layer C f / SiC radar stealth gradient layer, to obtain a double-layer composite material C; S4, using Al2O3 spherical powder with an average particle size of 10 μm to bury the lower layer C of the double-layer composite material C obtained in step S3 f / SiC radar stealth gradient layer, high temperature oxidation double-layer composite material C, to obtain double-layer composite material D; S5, the upper layer of the double-layer composite material D obtained in step S4 is cyclically impregnated with silica sol in a vacuum environment, pyrolyzed at 200°C for 120 minutes, and cycled for more than 10 times until the weight gain is less than 0.2%, forming an upper layer of Si3N 4f / SiO2 anti-laser and infrared stealth layer to obtain a broadband stealth composite material.

2. The preparation method according to claim 1, characterized in that: In step S1, the double-layer composite material, the upper layer material is Si3N 4f Fiber, lower material is C f fiber.

3. The preparation method according to claim 1, characterized in that: In step S1, the lower fiber bundle is wound on a quadrangular prism to obtain a lower fiber bundle with trapezoidal holes, wherein the cross section of the quadrangular prism is 2.5 mm on the upper side and 5 mm on the other sides.

4. 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.

5. The preparation method according to claim 1, characterized in that: In step S2, the upper fiber bundle is impregnated with a boron nitride nanosheet dispersion and cured at 200°C for 60 minutes to form an upper laser-resistant and infrared stealth fiber layer structure, and the lower fiber bundle is impregnated with a diluted phenolic resin solution and cured at 700°C for 120 minutes to form a lower radar stealth gradient layer structure.

6. The preparation method according to claim 1, characterized in that: In step S3, the curing process is specifically as follows: heating to 100°C, maintaining for 25 minutes, heating to 105°C, maintaining for 25 minutes, heating to 130°C, maintaining for 2 hours.

7. The preparation method according to claim 1, characterized in that: In step S3, the pyrolysis ceramic process is specifically: heating to 400°C, keeping for 1 hour, heating to 600°C, keeping for 1 hour, heating to 800°C, keeping for 1 hour, heating to 1000°C, keeping for 1 hour, heating to 1200°C, keeping for 2 hours.

8. The preparation method according to claim 1, characterized in that: In step S4, the lower layer C of the double-layer composite material C obtained in step S3 is buried with 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.

9. A broadband stealth composite material prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the broadband stealth composite material obtained by the preparation method according to any one of claims 1 to 8 or the broadband stealth composite material according to claim 9 in counteracting laser.

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