Multifunctional composite material for photoelectric fairing

Abstract

The invention relates to the field of photoelectric fairing materials, in particular to a multifunctional composite material for a photoelectric fairing. The multifunctional composite material for the photoelectric fairing comprises a substrate, and a microwave shielding layer, an anti-reflection layer, an infrared low-emission layer and a high-temperature protection layer which are sequentially stacked on the substrate. The multifunctional composite material for the photoelectric fairing is an advanced composite material with wide spectrum, high transmittance, low infrared emissivity and strong electromagnetic shielding performance, and can meet the requirements of photoelectric detection and electromagnetic protection of a high-speed aircraft in an extreme environment.

Description

Technical Field

[0001] The invention relates to the field of photoelectric fairing materials, in particular to a multifunctional composite material for photoelectric fairings. Background Art

[0002] Optoelectronic detection system windows for modern high-speed aircraft face three major technical challenges: first, thermal barriers. High-speed flight causes fairing surface temperatures to exceed 300°C, drastically degrading the performance of traditional optical materials. Second, infrared stealth. The fairing's own infrared radiation can easily expose it to enemy infrared detection methods. Given the temperature range, target infrared radiation is primarily concentrated in the 8-14μm band. Third, electromagnetic threats. Strong electromagnetic attacks can penetrate aircraft electronic systems through optoelectronic windows. To meet these challenges, materials must remain stable in high-temperature environments (≥300°C), possess high transmittance across a wide band (visible to infrared), low infrared emissivity (ε <0.20 in the 8-14μm band), and exhibit excellent microwave shielding performance (shielding effectiveness ≥20dB in the 2-18GHz band).

[0003] Existing technologies typically employ multilayer composite structures, but these suffer from issues such as interlayer thermal stress mismatch and interface failure at high temperatures. Furthermore, there's a trade-off between broadband anti-reflection and microwave shielding performance. Single-crystal materials like sapphire and spinel are heat-resistant, but have high infrared emissivity (>0.8) and lack electromagnetic shielding capabilities. ITO transparent conductive film offers electromagnetic shielding properties, but its temperature resistance is insufficient (<200°C) and affects optical transmittance. Metal mesh structures impair optical imaging quality and struggle to meet broadband electromagnetic shielding requirements.

[0004] Therefore, there is an urgent need to develop a new type of multifunctional composite material that can simultaneously meet the above-mentioned multiple performance requirements and is suitable for optoelectronic windows of high-speed aircraft to cope with the extreme working environment they face. Summary of the Invention

[0005] Based on the above content, the present invention provides a multifunctional composite material for an optoelectronic fairing.

[0006] To achieve the above object, the present invention provides the following solutions: The invention provides a multifunctional composite material for an optoelectronic fairing, comprising a substrate and a microwave shielding layer, a transmittance-enhancing layer, an infrared low-emission layer and a high-temperature protection layer sequentially stacked on the substrate.

[0007] In a preferred embodiment of the present invention, the substrate is yttrium aluminum garnet (Y3A l5 O 12 , YAG) single crystal; the thickness of the substrate is 1.5-2 mm. In the present invention, the function of the substrate is to achieve mechanical support and high temperature stability.

[0008] In a preferred embodiment of the present invention, the microwave shielding layer adopts an embedded metal grid-conductive oxide composite layer, wherein the metal grid is a Cu grid or an Ag grid, and the conductive oxide is ITO or ZnO; the thickness of the conductive oxide is 10~18μm, the line width of the metal grid is 1.5~4μm, and the period is 40~55μm; the thickness of the microwave shielding layer is 10-20μm.

[0009] In the present invention, the function of the microwave shielding layer is to achieve 2-18 GHz electromagnetic shielding.

[0010] In a preferred embodiment of the present invention, the anti-reflection layer adopts 3-6 layers of MgF2 / Al2O3 gradient film; the MgF2 / Al2O3 gradient film is a multilayer structure of alternating Al2O3 layers and MgF2 layers, wherein the thickness of the Al2O3 layer is 110~140nm, and the thickness of the MgF2 layer is 60~120nm; the Al2O3 layer at the bottom of the MgF2 / Al2O3 gradient film is directly bonded to the surface of the microwave shielding layer.

[0011] In a preferred embodiment of the present invention, the thickness of the anti-reflection layer is 150-250 nm. In the present invention, the function of the anti-reflection layer is to improve the visible light-infrared transmittance.

[0012] In a preferred embodiment of the present invention, the infrared low-emission layer adopts Ag / TiN or Au / TiO2 nano-composite coating; wherein the volume fraction of Ag in the Ag / TiN nano-composite coating is 15%~17%, and the volume fraction of Au in the Au / TiO2 nano-composite coating is 10%~13%; the thickness of the infrared low-emission layer is 100-200nm.

[0013] In the present invention, the infrared low-emission layer is used to suppress infrared radiation in the 8-14 μm band.

[0014] In a preferred embodiment of the present invention, the high-temperature protection layer is made of yttria-doped stabilized zirconia (Y2O3-ZrO2, YSZ) or AlON ceramics; the thickness of the high-temperature protection layer is 50-100 μm.

[0015] In the present invention, the high temperature protection layer has the function of achieving the effects of anti-scouring, anti-oxidation and high temperature resistance.

[0016] The present invention achieves the synergistic effect of each functional layer through the following innovative designs: Thermal-optical-electrical coupling design: The material parameters of each layer are optimized to avoid mutual cancellation of functions; Interlayer energy transfer control: The infrared suppression layer and microwave shielding layer work together to reduce heat accumulation; Gradient interface engineering: solving the thermal stress mismatch problem of different CTE materials at high temperatures; Optical-electromagnetic collaborative design: Metal mesh parameters are jointly optimized with the anti-reflection film system to balance optical transmittance and electromagnetic shielding effectiveness.

[0017] The present invention does not impose any particular limitation on the preparation method of the multifunctional composite material of the optoelectronic fairing, and adopts preparation methods familiar to those skilled in the art, such as nanoimprinting + electroplating to prepare a microwave shielding layer, ion beam assisted deposition of an anti-reflection layer, magnetron sputtering to deposit an infrared low-emission layer, and atmospheric plasma spraying of a high-temperature protective layer.

[0018] The present invention discloses the following technical effects: The multifunctional composite material of the optoelectronic fairing of the present invention is an advanced composite material with a wide spectrum, high transmittance, low infrared emissivity and strong electromagnetic shielding performance, which can meet the optoelectronic detection and electromagnetic protection needs of high-speed aircraft in extreme environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 It is a schematic structural diagram of the multifunctional composite material of the photoelectric fairing of the present invention.

[0021] Figure 2 This is a schematic diagram of the process flow for preparing the multifunctional composite material for the optoelectronic fairing according to Example 1 of the present invention. DETAILED DESCRIPTION

[0022] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0023] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0024] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0025] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0026] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0027] Unless otherwise specified, the technical solutions described in the present invention are all conventional solutions in the field, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or have been disclosed.

[0028] The chemical formula of the inorganic silicate resin used in the embodiments of the present invention is Na2O·51SiO2, where 51 represents the molar ratio of silicon dioxide to sodium oxide.

[0029] The thermal expansion coefficient CTE of the YAG single crystal used in the embodiment of the present invention is 8.2×10 -6 / K <100> .

[0030] The test method involved in the present invention is: The infrared emissivity test refers to "ASTM C1371-04 Standard Test Method for Determination of Radiation of Materials at Near Room Temperature Using a Portable Emissometer". Based on the reflection method (indirect method), a portable emissivity meter is used to measure the hemispherical directional reflectivity ρ(λ, θ) of the sample at a specific wavelength (usually the 8-14μm atmospheric window). The normal emissivity is then calculated based on Kirchhoff's law and energy conservation (for opaque materials): ε(λ, θ) = 1 - ρ(λ, θ).

[0031] The test of visible transmittance refers to "GB / T 2680 Determination of Visible Light Transmittance and Direct Sunlight Transmittance of Architectural Glass". A monochromator or grating spectrometer is used to measure the sample's transmitted light intensity (I) and the reference light intensity (I0) wavelength by wavelength. The transmittance is Tλ=I / I0. The test of infrared transmittance refers to "GJB / J 3417 Measurement Method of Infrared Transmittance of Military Optical Materials". The interference pattern of the infrared band is obtained by Fourier transform infrared spectrometer, and the spectrum is obtained by Fourier transform to calculate the transmittance.

[0032] The microwave shielding effectiveness test refers to "GB / T 12190 Measurement method of shielding effectiveness of electromagnetic shielding rooms". Using the antenna radiation method, the transmitting antenna and the receiving antenna are placed inside and outside the shielding room tooling respectively. The change in the receiving antenna's received power is tested with and without composite materials blocking the tooling window. The frequency band covered is 2-18GHz.

[0033] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0034] The structural diagram of the multifunctional composite material of the photoelectric rectifier of the present invention is as follows: Figure 1 shown.

[0035] The process flow diagram of preparing the multifunctional composite material of the photoelectric rectifier according to Example 1 of the present invention is as follows: Figure 2 shown.

[0036] Example 1 A multifunctional composite material for an optoelectronic rectifier consists of a substrate and, stacked sequentially on the substrate, a microwave shielding layer, an anti-reflection layer, an infrared low-emission layer, and a high-temperature protection layer. The high-temperature protection layer is 80μm thick, made of yttria-doped stabilized zirconia (Y2O3-ZrO2, YSZ); the infrared low-emission layer is 150nm thick, made of Ag / TiN (Ag volume fraction 15%); the anti-reflection layer comprises a five-layer MgF2 / Al2O3 gradient film with a total thickness of 200nm; the microwave shielding layer is a 15μm-thick ITO nanowire coating with an additional Cu grid with a line width of 3μm and a period of 50μm; and the substrate is a YAG single crystal, 1.8mm thick.

[0037] The preparation method of the multifunctional composite material of the photoelectric fairing comprises the following steps: (1) Double-sided optical polishing of YAG single crystal substrate (Ra < 0.5nm); (2) Spin coating of ITO nanowire dispersion (solid content 3%, inorganic silicate resin as solvent) with a thickness of 15 μm and vacuum curing at 300 °C; (3) Nanoimprinting was used to produce microgrooves on the PI surface, and Cu was electroplated to form a grid with a line width of 3 μm and a period of 50 μm; (4) Ion beam assisted deposition of 5 layers of gradient MgF2 / Al2O3 antireflection coating; (5) A Ag / TiN low-emission layer was deposited on the surface of the antireflection film by magnetron sputtering, where the Ag volume fraction was 15%, and annealed at 400 °C for 1 hour under Ar gas protection; (6) Atmospheric plasma spraying of YSZ protective layer (power 40kW, powder feeding rate 30g / min); (7) Vacuum annealing to strengthen the interface (using Ar gas protection, 600℃ / 2h).

[0038] This preparation process can achieve uniform preparation of large-area (≥Φ200mm) materials, with thickness control accuracy of each layer of ±5% and interface bonding strength ≥30MPa.

[0039] The performance indicators of the multifunctional composite material for the optoelectronic fairing prepared in Example 1 are shown in Table 1: Table 1 Material performance indicators of Example 1 ,

[0040] The multifunctional composite material for the optoelectronic fairing prepared in Example 1 was subjected to an aging test for 100 hours at 350°C. The changes in the material's related properties are shown in Table 2. Table 2 Aging test results of materials in Example 1 ,

[0041] It can be seen from Table 2 that the multifunctional composite material for the optoelectronic fairing prepared in Example 1 has little performance degradation in a high temperature environment and meets the requirements for long-term use.

[0042] The gradient MgF2 / Al2O3 antireflection coating in step (3) is a gradient refractive index design. By alternately stacking low-refractive-index MgF2 (n=1.38) and high-refractive-index Al2O3 (n=1.76), a smooth transition of the refractive index from the substrate side (n≈1.82) to the infrared low-emission layer is achieved, thereby reducing reflection loss over a wide spectral range. Its specific structural parameters are shown in Table 3: Table 3 MgF2 / Al2O3 multilayer film structure .

[0043] Example 2 A multifunctional composite material for an optoelectronic rectifier consists of a substrate and, stacked sequentially on the substrate, a microwave shielding layer, an anti-reflection layer, an infrared low-emission layer, and a high-temperature protection layer. The high-temperature protection layer is 100μm thick, made of YSZ (Y2O3-ZrO2); the infrared low-emission layer is 200nm thick, made of Ag / TiN (Ag volume fraction 17%); the anti-reflection layer comprises five layers of MgF2 / Al2O3 gradient film, with a total thickness of 225.5nm; the microwave shielding layer comprises an 18μm-thick coating containing ITO nanowires (3% solid content, using an inorganic silicate resin as the solvent), supplemented by a Cu grid with a line width of 4μm and a period of 55μm; and the substrate is a 2.0mm-thick YAG single crystal.

[0044] The preparation method of the multifunctional composite material for the optoelectronic fairing in this embodiment refers to that in Example 1.

[0045] The performance indicators of the multifunctional composite material for the optoelectronic fairing prepared in this embodiment are shown in Table 4: Table 4 Material performance indicators of Example 2 ,

[0046] The multifunctional composite material for the optoelectronic fairing prepared in Example 2 was subjected to an aging test for 100 hours at 350°C. The changes in the material's related properties are shown in Table 5. Table 5 Aging test results of materials in Example 2 ,

[0047] In this embodiment, the specific structural parameters of the 5-layer MgF2 / Al2O3 gradient film are shown in Table 6: Table 6 MgF2 / Al2O3 multilayer film structure .

[0048] Example 3 A multifunctional composite material for an optoelectronic fairing, which differs from Example 1 only in that the high-temperature protection layer adopts 80 μm thick AlON ceramics.

[0049] The performance indicators of the multifunctional composite material for the optoelectronic fairing prepared in this example are shown in Table 7: Table 7 Material performance indicators of Example 3 ,

[0050] As can be seen from Table 7, AlON ceramics can achieve similar performance to YSZ protective layer, while at a lower cost, and are suitable for large-scale applications.

[0051] Example 4 A multifunctional composite material for an optoelectronic fairing consists of a substrate and, stacked sequentially on the substrate, a microwave shielding layer, an anti-reflection layer, an infrared low-emission layer, and a high-temperature protection layer. The high-temperature protection layer is 50μm thick, made of AlON ceramic; the infrared low-emission layer is 100nm thick, a composite Au / TiO2 (Au volume fraction 10%) coating; the anti-reflection layer comprises three layers of MgF2 / Al2O3 gradient film, with a total thickness of 177nm; the microwave shielding layer comprises a 10μm-thick coating containing ZnO nanowires (5% solid content, using an inorganic silicate resin as the solvent), supplemented by an Ag grid with a line width of 1.5μm and a period of 40μm. The substrate is a 1.5mm thick YAG single crystal.

[0052] The preparation method of the multifunctional composite material for the optoelectronic fairing in this embodiment refers to that in Example 1.

[0053] The performance indicators of the multifunctional composite material for the optoelectronic fairing prepared in this example are shown in Table 8: Table 8 Material performance indicators of Example 4 ,

[0054] The multifunctional composite material for the optoelectronic fairing prepared in Example 4 was subjected to an aging test at 350° C. for 100 hours. The changes in the material's related properties are shown in Table 9. Table 9 Aging test results of materials in Example 4 ,

[0055] In this embodiment, the specific structural parameters of the three-layer MgF2 / Al2O3 gradient film are shown in Table 10: Table 10 MgF2 / Al2O3 multilayer film structure .

[0056] Example 5 A multifunctional composite material for an optoelectronic fairing, which differs from Example 1 only in that the thickness of the infrared low-emission layer is 80 nm, and other parameters are the same as those of Example 1.

[0057] The performance indicators of the multifunctional composite material for the optoelectronic fairing prepared in this example are shown in Table 11: Table 11 Material performance indicators of Example 5 ,

[0058] It can be seen from Table 11 that due to the reduction in the thickness of the infrared low-emission layer, the emissivity of 8-14μm increases and does not meet the requirements.

[0059] Example 6 A multifunctional composite material for an optoelectronic fairing, which differs from Example 1 only in that a microwave shielding layer comprises a 15 μm thick ITO nanowire coating (solid content 3%, solvent: inorganic silicate resin) and an additional Cu grid with a line width of 3 μm and a period of 80 μm; other parameters are the same as those in Example 1.

[0060] The performance indicators of the multifunctional composite material for the optoelectronic fairing prepared in this example are shown in Table 12: Table 12 Material performance indicators of Example 6 ,

[0061] It can be seen from Table 12 that when the Cu grid period increases to 80 μm, the period is too large, resulting in a decrease in microwave shielding effectiveness.

[0062] Example 7 A multifunctional composite material for an optoelectronic fairing, which differs from Example 1 only in that the infrared low-emission layer adopts a 150 nm thick Au / TiO2 nanocomposite coating (Au particle size 30 nm, solid content 4%; TiO2 particle size 100 nm, solid content 5%; solvent is inorganic silicate resin), and the infrared low-emission layer is prepared by brushing; other parameters are the same as those in Example 1.

[0063] The performance indicators of the multifunctional composite material for the optoelectronic fairing prepared in this example are shown in Table 13: Table 13 Material performance indicators of Example 7 ,

[0064] As can be seen from Table 13, the use of Au / TiO2 nanocomposite coating can achieve similar performance to Ag / TiN nanocomposite film, with a simpler preparation process and is suitable for large-scale applications.

[0065] Example 8 A multifunctional composite material for an optoelectronic fairing is different from Example 1 only in that an antireflection layer is omitted, and other parameters are the same as those of Example 1.

[0066] The performance indicators of the multifunctional composite material for the optoelectronic fairing prepared in this example are shown in Table 14: Table 14 Material performance indicators of Example 8 ,

[0067] Table 14 shows that the absence of the antireflection layer increases interfacial reflection losses (especially in the mid-infrared band), directly impairing light transmittance. The visible-infrared transmittance decreased from 78.2% to 65.4% (a 12.8% decrease). A 100-hour high-temperature aging test at 350°C revealed that the visible-infrared transmittance further decreased to 61.8% after aging, failing to meet the >75% target. Infrared emissivity stability decreased, with the initial emissivity rising to 0.19 (still meeting the standard) but increasing to 0.21 after aging (exceeding the <0.20 requirement). The antireflection layer, which originally served as a protective barrier for the low-infrared emissivity layer, increased the Ag / TiN film's susceptibility to high-temperature oxidation after removal. The bonding strength also decreased by 10.0% after aging (compared to a 6.3% decrease in Example 1) due to the lack of the antireflection layer to buffer interfacial stress. However, the shielding effectiveness (22.5 dB) and temperature resistance (≥350°C) still met the standards, as both rely on the metal mesh and YSZ / YAG substrate.

[0068] Example 9 A multifunctional composite material for an optoelectronic fairing, which differs from Example 1 only in that the high-temperature protection layer adopts a SiC ceramic layer with a thickness of 80 μm (thermal expansion coefficient CTE = 4.4×10 -6 / K), prepared by plasma spraying; other parameters are the same as those in Example 1.

[0069] The performance indicators of the multifunctional composite material for the optoelectronic fairing prepared in this example are shown in Table 15: Table 15 High temperature test results of Example 9 materials ,

[0070] It can be seen from Table 15 that due to the large difference in thermal expansion coefficients between the high-temperature protective layer and the substrate, the overall high-temperature resistance of the composite material is seriously deteriorated. At the same time, the far-infrared emissivity increases significantly after the high-temperature test.

[0071] Comparative Example 1 A multifunctional composite material for an optoelectronic rectifier is provided. The only difference from Example 1 is that the anti-reflection layer uses a single layer of MgF2 with a thickness of 200 nm. Other parameters are the same as those of Example 1.

[0072] The performance indicators of the multifunctional composite material for the optoelectronic fairing prepared in this comparative example are shown in Table 16: Table 16 Material performance indicators of comparative example 1 .

[0073] Comparative Example 2 The only difference from Example 1 is that the antireflection layer is replaced with a two-layer structure: the first layer (near the substrate): Al2O3, thickness 100nm (n=1.76); the second layer (outer layer): MgF2, thickness 100nm (n=1.38). The total thickness is 200nm (the same as Example 1), and the gradient refractive index design is eliminated. Performance comparison results are shown in Table 17.

[0074] Table 17 Material performance indicators of Comparative Example 2 ,

[0075] Example 1 uses the five-layer gradient film shown in Table 3 to achieve wide-spectrum anti-reflection (>78%) through a gradual change in refractive index (1.82→1.76→1.38). However, the double-layer structure has a transmittance reduction of nearly 10% due to sudden interface reflection, and the interface bonding strength is significantly degraded at high temperatures.

[0076] Comparative Example 3 The only difference from Example 1 is that the coating sequence has been adjusted to: substrate → infrared low-emissivity layer (Ag / TiN) → microwave shielding layer (ITO + Cu grid) → anti-reflection layer → high-temperature protection layer. The parameters for each layer are the same as in Example 1. The performance comparison results are shown in Table 18.

[0077] Table 18 Material performance indicators of Comparative Example 3 ,

[0078] Example 1 uses the following sequence: substrate → microwave shielding layer → antireflection layer → infrared low-emission layer → high-temperature protective layer. This ensures that the Cu mesh is exposed to the outermost layer (step 3) for optimal shielding. Ag / TiN is placed above the antireflection layer to prevent optical loss. The YSZ protective layer provides protection against high-temperature oxidation. Table 18 shows that reversing this sequence results in core functional failure.

[0079] Comparative Example 4 The only difference from Example 1 is that the volume fraction of Ag in the infrared low-emission layer Ag / TiN is reduced to 8% (15% in Example 1). The performance comparison results are shown in Table 19.

[0080] Table 19 Material performance indicators of Comparative Example 4 ,

[0081] In Example 1, the Ag volume fraction is 15%, which better ensures low emissivity (<0.20) at high temperatures. The performance deteriorates significantly after the parameters deviate.

[0082] Comparative Example 5 The only difference from Example 1 is that the microwave shielding layer retains only the 15 μm thick ITO nanowire coating and the Cu grid structure is omitted. The performance comparison results are shown in Table 20.

[0083] Table 20 Material performance indicators of Comparative Example 5 ,

[0084] Example 1 uses a composite structure of "15 μm ITO nanowire coating + 3 μm line width / 50 μm period Cu grid", with a shielding effectiveness of >22 dB over the entire frequency range of 2-18 GHz. Table 20 shows that the high-frequency shielding performance of the ITO layer alone is insufficient.

[0085] The above embodiments demonstrate that the present invention achieves excellent performance of the multifunctional composite material for the optoelectronic fairing through the coordinated design of the functional layers: The synergy of the optical parameters of the infrared low-emissivity layer and the anti-reflection layer is the key to achieving low far-infrared emissivity (ε < 0.20) and high visible-infrared transmittance (> 75%). At the same time, the presence of the anti-reflection layer is beneficial to the anti-aging performance of the entire material. The combined optimization of the geometric parameters of the metal grid (line width ≤ 5 μm, period ≤ 50 μm) and the anti-reflection film resolves the inherent contradiction between optical and electromagnetic performance. The difference in the thermal expansion coefficient of each layer of material needs to be controlled within ± 1.5 × 10 -6 / K, and thermal matching is achieved through gradient interface design; the composite structure of the metal grid and transparent conductive oxide (ITO / ZnO) in the microwave shielding layer simultaneously meets the requirements of high-temperature stability and shielding effectiveness. In this invention, optimizing each parameter in isolation cannot achieve the overall performance target, and the multi-physics field collaborative design method of the present invention must be adopted.

[0086] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A multifunctional composite material for a photoelectric fairing, characterized in that: It includes a substrate and a microwave shielding layer, an anti-reflection layer, an infrared low-emission layer and a high-temperature protection layer sequentially stacked on the substrate; The microwave shielding layer adopts an embedded metal grid-conductive oxide composite layer, wherein the metal grid is a Cu grid or an Ag grid, and the conductive oxide is ITO or ZnO; The anti-reflection layer adopts 3-5 layers of MgF2 / Al2O3 gradient film; The infrared low-emission layer adopts Ag / TiN or Au / TiO2 nanocomposite coating.

2. The multifunctional composite material for photoelectric fairing according to claim 1, characterized in that: The substrate is yttrium aluminum garnet single crystal; the thickness of the substrate is 1.5-2 mm.

3. The multifunctional composite material for photoelectric fairing according to claim 1, characterized in that: The thickness of the conductive oxide is 10-18 μm, the line width of the metal grid is 1.5-4 μm, and the period is 40-55 μm; the thickness of the microwave shielding layer is 10-20 μm.

4. The multifunctional composite material for photoelectric fairing according to claim 1, characterized in that: The MgF2 / Al2O3 gradient film is a multilayer structure in which Al2O3 layers and MgF2 layers are alternately stacked, wherein the thickness of the Al2O3 layer is 110~140nm, and the thickness of the MgF2 layer is 60~120nm; the Al2O3 layer at the bottom of the MgF2 / Al2O3 gradient film is directly bonded to the surface of the microwave shielding layer.

5. The multifunctional composite material for photoelectric fairing according to claim 1 or 4, characterized in that: The thickness of the antireflection layer is 150-250 nm.

6. The multifunctional composite material for photoelectric fairing according to claim 1, characterized in that: The volume fraction of Ag in the Ag / TiN nanocomposite coating is 15%-17%, and the volume fraction of Au in the Au / TiO2 nanocomposite coating is 10%-13%; the thickness of the infrared low-emission layer is 100-200nm.

7. The multifunctional composite material for photoelectric fairing according to claim 1, characterized in that: The high-temperature protection layer is made of yttria-doped stabilized zirconia or AlON ceramics; the thickness of the high-temperature protection layer is 50-100 μm.

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