Honeycomb structure microwave-infrared stealth modulation system packaged by liquid metal layer and preparation method of honeycomb structure microwave-infrared stealth modulation system

Abstract

The invention provides a liquid metal layer packaged honeycomb structure microwave-infrared stealth modulation system, and belongs to the technical field of microwave-infrared compatible camouflage, the liquid metal layer packaged honeycomb structure microwave-infrared stealth modulation system comprises a honeycomb structure and a liquid metal layer, the honeycomb structure comprises a honeycomb bottom and periodically arranged honeycomb cores, the honeycomb cores are arranged on the honeycomb bottom, the liquid metal layer covers the honeycomb cores, and the liquid metal layer covers the honeycomb bottom. The honeycomb bottom and the honeycomb core are made of the same material and are both prepared by mixing an elastomer matrix, a wave-absorbing material and a curing agent, and the liquid metal layer is prepared by mixing a liquid metal, an elastomer matrix and a curing agent. The invention further provides a preparation method of the microwave-infrared stealth modulation system. According to the invention, the reflectivity and the infrared emissivity can be adjusted by adjusting electromagnetic parameters, honeycomb structure parameters, liquid metal concentration and morphology changes. The honeycomb structure packaged by the liquid metal also has the advantages of broadband wave absorption, low infrared emissivity, curved surface conformal capability and good flexibility and heat dissipation performance.

Description

Technical field:

[0001] The present invention belongs to the technical field of microwave-infrared compatible camouflage structures, and relates to a broadband wave-absorbing and infrared low-emissivity material, and in particular to a liquid metal layer-encapsulated honeycomb structure microwave-infrared stealth modulation system and a preparation method thereof. Background technology:

[0002] Current military reconnaissance equipment has a wide band and high resolution, and has achieved complete coverage of the electromagnetic wave band from visible light, infrared, laser, to the entire radar band. Multifunctional stealth materials or structures used to effectively hide military targets in complex environments have received widespread attention, especially radar and infrared detection technology, which accounts for 90% of military detection and interception technology. Due to the contradiction between radar and infrared stealth mechanisms, radar stealth requires the characteristics of high absorptivity and low reflectivity, while infrared stealth materials require high reflectivity and low absorptivity. Therefore, it is difficult to effectively integrate multiple functions into the same material, and it is very important to develop compatible stealth technology that can work well in both radar and infrared bands.

[0003] Based on the microwave infrared stealth mechanism, interface engineering, lattice defects, magnetoelectric synergy effects, etc. have been used in the design of microwave absorbing materials. Infrared thermal stealth can be achieved by modulating thermal emissivity or temperature. Researchers have developed thermal insulation materials with microwave absorption properties, such as porous carbon foam, aerogel, etc., to achieve radar infrared stealth effects. There are also multiple materials assembled to enhance stealth compatibility, such as introducing low-emissivity metals or semiconductor oxide materials to control the infrared emissivity and electromagnetic parameters of composite materials. However, the regulation range of these methods is limited, and it is difficult to achieve broadband absorption and infrared stealth at the same time. In addition, many researchers have begun to pay attention to metamaterial stealth devices and design photonic crystals to control infrared emissivity. However, metamaterials are complex in design and have high processing costs. The properties of the material itself cannot achieve a more perfect compatible stealth effect, and it needs to be regulated from the structural design. Therefore, the present invention provides a liquid metal layer encapsulated honeycomb structure microwave-infrared stealth modulation system and a preparation method thereof to solve the above problems. Summary of the invention:

[0004] The purpose of the present invention is to address the deficiencies in the prior art and to provide a liquid metal layer-encapsulated honeycomb structure microwave-infrared stealth modulation system and a preparation method thereof, aiming to break through the singleness of traditional camouflage by combining a honeycomb structure with a liquid metal layer, while solving the technical problems of broadband wave absorption and low infrared emission.

[0005] The present invention adopts the following technical solutions:

[0006] (I) The present invention provides a liquid metal layer-encapsulated honeycomb structure microwave-infrared stealth modulation system, comprising a honeycomb structure and a liquid metal layer; the honeycomb structure comprises a honeycomb bottom and a periodically arranged honeycomb core, the honeycomb core is arranged on the honeycomb bottom, and the liquid metal layer covers the honeycomb core; the honeycomb bottom and the honeycomb core are made of the same material, both of which are prepared by mixing an elastomer matrix, an absorbing material and a curing agent to form a flexible absorbing structure; the liquid metal layer is prepared by mixing liquid metal, an elastomer matrix and a curing agent. The elastomer matrix is ​​used as a mixture of the absorbing material and the liquid metal.

[0007] Furthermore, the absorbing material is a magnetic absorber, preferably an iron-cobalt alloy absorber with high magnetic permeability.

[0008] Furthermore, the elastomer matrix is ​​polydimethylsiloxane.

[0009] Furthermore, the liquid metal is a metal material that remains liquid at room temperature or close to room temperature, has excellent electrical conductivity and thermal conductivity, and is preferably gallium, gallium-indium alloy or gallium-indium-tin alloy.

[0010] Furthermore, the concentration of the liquid metal in the liquid metal layer is variable; and the addition ratio of the absorbing material in the honeycomb structure is adjustable.

[0011] Furthermore, in the honeycomb bottom and honeycomb core materials, the mass ratio of the absorbing material to the elastomer matrix is ​​(2-5):1; and the mass ratio of the elastomer matrix to the curing agent is 10:1.

[0012] Furthermore, in the honeycomb bottom and honeycomb core materials, the mass ratio of the absorbing material to the elastomer matrix is ​​2:1, 3:1, 4:1 or 5:1.

[0013] Furthermore, in the liquid metal layer, the mass ratio of the liquid metal to the elastomer matrix is ​​(1-3):(1-3); and the mass ratio of the elastomer matrix to the curing agent is 10:1.

[0014] Furthermore, in the liquid metal layer, the mass ratio of liquid metal to elastomer matrix is ​​1:3, 1:1 or 3:1.

[0015] Furthermore, the liquid metal layer is encapsulated on the upper surface of the honeycomb structure through an elastomer matrix as an intermediate adhesion layer, and the elastomer matrix is ​​polydimethylsiloxane.

[0016] Furthermore, the honeycomb core is composed of periodically arranged hollow regular hexagonal prisms, and the side length, height and honeycomb wall thickness of the honeycomb core are adjustable.

[0017] Furthermore, in the honeycomb core, the side length of a single hollow regular hexagonal prism is 5-20 mm, the height is 1-7 mm, and the thickness is 0.5-2.5 mm; the thickness of the honeycomb bottom is 1-3 mm; and the thickness of the liquid metal layer is 500 μm.

[0018] (II) The present invention also provides a method for preparing the above-mentioned liquid metal layer encapsulated honeycomb structure microwave-infrared stealth modulation system, comprising the following steps:

[0019] Step 1: Add the absorbing material into the elastomer matrix according to different mass ratios, add the curing agent and mix well, then pour into the pre-made polytetrafluoroethylene honeycomb mold, and demould after drying to obtain a complete honeycomb structure;

[0020] Step 2: drop the liquid metal into the elastomer matrix, add the curing agent and stir evenly, pour it into the acrylic groove to dry, and then tear off the liquid metal layer;

[0021] Step 3: coating an elastomer matrix on the bottom of the liquid metal layer, and attaching the elastomer matrix to the upper surface of the honeycomb structure when the elastomer matrix is ​​not completely solidified, thereby obtaining a liquid metal encapsulated honeycomb structure.

[0022] Beneficial effects of the present invention:

[0023] The present invention provides a liquid metal layer encapsulated honeycomb structure microwave-infrared stealth modulation system and a preparation method thereof, wherein a flexible honeycomb structure is designed by mixing an elastomer matrix with a magnetic absorber, and the reflectivity and absorption bandwidth can be adjusted by changing the size and thickness of the honeycomb unit; an infrared layer is constructed by utilizing the conductivity of the liquid metal to adjust the surface infrared emissivity of the system. At the same time, the microwave-infrared stealth modulation system of the present invention has the characteristics of broadband absorption, low infrared emissivity, and curved surface conformality.

[0024] Specifically, the present invention can adjust the reflectivity in the range of 2-18GHz by adjusting the honeycomb side length, honeycomb wall thickness, and height; changing the liquid metal concentration can effectively reduce the infrared emissivity. When the honeycomb core is 1mm high and the mass ratio of liquid metal to elastomer matrix is ​​1:3, the reflectivity of the microwave-infrared stealth modulation system of the present invention is lower than -10dB in the range of 8-18GHz, and the infrared emissivity reaches 0.6 in the 8-14μm band. In addition, the present invention is a flexible honeycomb structure that can adapt to various target substrates with curved surface features. Description of the drawings:

[0025] Figure 1 It is a schematic diagram of the three-dimensional structure of the liquid metal layer-encapsulated honeycomb structure microwave-infrared stealth modulation system of the present invention;

[0026] Figure 2It is a two-dimensional top view and cross-sectional structural schematic diagram of the honeycomb structure microwave-infrared stealth modulation system encapsulated by the liquid metal layer of the present invention;

[0027] Figure 3 It is a reflectivity test curve diagram of the honeycomb structure encapsulated by the liquid metal layer with different honeycomb core heights prepared in Examples 1 to 4;

[0028] Figure 4 is a reflectivity test curve diagram of a honeycomb structure encapsulated by a liquid metal layer with different liquid metal concentrations prepared in Examples 1, 5 and 6;

[0029] Figure 5 It is a test curve chart of infrared emissivity of the honeycomb structure encapsulated by the liquid metal layer prepared in Example 1 and Examples 5 to 7. Specific implementation method:

[0030] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0031] Example 1

[0032] Reference Figures 1-2 , an embodiment of the present invention provides a liquid metal layer-encapsulated honeycomb structure microwave-infrared stealth modulation system, comprising a honeycomb structure 2 and a liquid metal layer 1, wherein the honeycomb structure 2 comprises a honeycomb bottom and a periodically arranged honeycomb core, the honeycomb core is arranged on the honeycomb bottom, and the liquid metal layer 1 covers the honeycomb core (encapsulated on the upper surface of the honeycomb core through an elastomer matrix as an intermediate adhesion layer). The honeycomb bottom and the honeycomb core are made of the same material, both of which are prepared by mixing an elastomer matrix, an absorbing material and a curing agent to form a flexible absorption structure; the liquid metal layer 1 is prepared by mixing liquid metal, an elastomer matrix and a curing agent. The flexible absorption material is designed as a honeycomb structure and covered with a liquid metal layer.

[0033] For the honeycomb bottom and honeycomb core materials, the mass ratio of the absorbing material to the elastomer matrix is ​​4:1; the mass ratio of the elastomer matrix to the curing agent is 10:1. The absorbing material is a micron-sized spherical iron-cobalt alloy absorber with high magnetic permeability and a bulk density of about 3.0g / cm 3 The elastomer matrix is ​​a polydimethylsiloxane elastomer having adhesive properties.

[0034] For the liquid metal layer 1, the mass ratio of the liquid metal to the elastomer matrix is ​​1:3; the mass ratio of the elastomer matrix to the curing agent is 10:1. Liquid metal is a metal material that remains liquid at room temperature or close to room temperature, and has excellent electrical conductivity and thermal conductivity. This embodiment uses gallium-indium alloy liquid conductive metal material, and the liquid metal is embedded in the elastomer matrix to present a spherical droplet shape. The elastomer matrix is ​​a polydimethylsiloxane elastomer with adhesiveness.

[0035] In this embodiment, Figure 2 As shown, the thickness h0 of the honeycomb bottom is 2 mm; the honeycomb core is composed of periodically arranged hollow regular hexagonal prisms, and the side length a of a single hollow regular hexagonal prism in the honeycomb core is 10 mm, and the height h w The thickness of the honeycomb core is 5 mm, the honeycomb core wall thickness w is 2.0 mm. The thickness of the liquid metal layer 1 is 500 μm.

[0036] The preparation method of the microwave-infrared stealth modulation system of the honeycomb structure 2 encapsulated by the liquid metal layer 1 of this embodiment includes:

[0037] Step 1. Add the absorbing material to the elastomer matrix at a mass ratio of 4:1, stir mechanically for 30 minutes under electric stirring to mix evenly, add the curing agent, and then pour the mixture into a pre-made polytetrafluoroethylene honeycomb mold. After drying, demold the mold to obtain a complete honeycomb structure 2 with an overall length of about 180 mm, a width of about 180 mm, and an overall height of 7 mm.

[0038] Step 2: Drop the liquid metal into the elastomer matrix at a mass ratio of 1:1 and stir evenly. After adding the curing agent, pour it into the acrylic groove and dry it in a 60°C oven. Then tear off the liquid metal layer 1. The liquid metal layer 1 is 180 mm long, 180 mm wide and 500 μm thick.

[0039] Step 3: Coat a layer of elastomer matrix on the bottom of the liquid metal layer 1, put it in an oven to dry for 30 minutes, and stick it on the upper surface of the honeycomb structure 2 when the elastomer matrix is ​​not completely solidified to obtain a liquid metal encapsulated honeycomb structure.

[0040] Example 2

[0041] This embodiment is basically the same as Embodiment 1, except that:

[0042] In this embodiment, the thickness of the honeycomb bottom h0 is 2 mm, and the height of the honeycomb core h w The overall height of the honeycomb structure is 3 mm, and the thickness of the liquid metal layer 1 is 500 μm.

[0043] Example 3

[0044] This embodiment is basically the same as Embodiment 1, except that:

[0045] In this embodiment, the thickness of the honeycomb bottom h0 is 2 mm, and the height of the honeycomb core h w The overall height of the honeycomb structure is 5 mm, and the thickness of the liquid metal layer 1 is 500 μm.

[0046] Example 4

[0047] This embodiment is basically the same as Embodiment 1, except that:

[0048] In this embodiment, the thickness of the honeycomb bottom h0 is 2 mm, and the height of the honeycomb core h w The overall height of the honeycomb structure is 9 mm, and the thickness of the liquid metal layer 1 is 500 μm.

[0049] Example 5

[0050] This embodiment is basically the same as Embodiment 1, except that:

[0051] In this embodiment, the mass ratio of the liquid metal in the liquid metal layer to the elastomer matrix is ​​1:1.

[0052] Example 6

[0053] This embodiment is basically the same as Embodiment 1, except that:

[0054] In this embodiment, the mass ratio of the liquid metal to the elastomer matrix in the liquid metal layer is 3:1.

[0055] Example 7

[0056] This embodiment is basically the same as Embodiment 1, except that:

[0057] In this embodiment, no liquid metal layer is provided, the thickness of the honeycomb bottom h0 is 2 mm, and the height of the honeycomb core h w The overall height of the honeycomb structure is 7mm.

[0058] Performance Test:

[0059] 1. The honeycomb structure encapsulated by the liquid metal layer prepared in Examples 1 to 4 was subjected to dielectric parameter testing. The test results show that when the ratio of the iron-cobalt absorber to the elastomer is 4:1, the real part of the dielectric parameter ε ′ Between 8.0 and 9.0, the imaginary loss ε ″ Between 0.2 and 1.0, the real part of the magnetic permeability μ ′is 0.8-2.0, and the imaginary part μ″ is 0.4-1.0. On this basis, by changing the height of the honeycomb core from 1mm to 7mm, the reflectivity in the range of 2-18GHz can be adjusted. This shows that when the size of the honeycomb core is determined, the absorption frequency and reflectivity can be adjusted by adjusting the height of the honeycomb core. The combination of honeycomb structure and absorbing material realizes the integration of structure and performance, and can increase the multiple reflection and absorption of electromagnetic waves.

[0060] 2. The honeycomb structure encapsulated with the liquid metal layer prepared in Examples 1 to 4 was subjected to a reflectivity test on a bow frame constructed by a vector network analyzer. The reflectivity curves of the honeycomb cores at different heights are shown in FIG. Figure 3 As shown. Figure 3 It can be seen that when the honeycomb height h w When the honeycomb core is 7mm, the absorption bandwidth less than -5dB covers 4-18GHz. And as the height of the honeycomb core increases, the low-frequency absorption is significantly enhanced.

[0061] 3. The honeycomb structure encapsulated with the liquid metal layer prepared in Examples 1, 5 and 6 was tested for reflectivity on a bow frame constructed by a vector network analyzer. The reflectivity curve is as follows: Figure 4 As shown. Figure 4 It can be seen that the mass ratios of liquid metal to elastomer matrix are 1:3, 1:1 and 3:1 respectively, and h w The honeycomb structure with a diameter of 5 mm is encapsulated with liquid metal. When the liquid metal concentration is 1:3, the reflectivity curve does not move up, but when the concentration exceeds 1:1, the curve shows an upward trend, indicating that the liquid metal layer is too conductive and will hinder the incident electromagnetic waves. When the honeycomb structure is encapsulated with a liquid metal layer, the increase in the concentration of gallium indium liquid metal will affect the absorption of electromagnetic waves.

[0062] 4. The materials prepared in Example 1 and Examples 5 to 7 were subjected to infrared surface emissivity test in a black body furnace. The test results are as follows: Figure 5 As shown. Figure 5 It can be seen that compared with the honeycomb structure that is not encapsulated with a liquid metal layer, the conductive gallium indium metal droplets significantly reduce the infrared emissivity of the target. In the range of 8-14μm, the infrared emissivity of the honeycomb structure reaches about 0.72, while the emissivity of the honeycomb structure encapsulated by the liquid metal layer is reduced to about 0.52. The infrared layer of the liquid metal structure effectively adjusts the surface emissivity of the system. In addition, the system has good flexibility and elasticity, wherein the liquid metal layer can change the morphology of the metal droplets by stretching, and the honeycomb structure can change the height by compression. Therefore, the microwave-infrared stealth modulation system of the present invention also has the characteristics of broadband absorption, low infrared emissivity, and surface conformality.

[0063] The present invention can further adjust the broadband absorption and infrared emissivity by adjusting the honeycomb structure parameters and the stress of the stretchable liquid metal layer to meet the requirements of broadband low emission.

[0064] Compared with traditional structural absorbing materials, the present invention introduces elastomers into the honeycomb structure, and adjusts the reflectivity and infrared emissivity through electromagnetic parameters, honeycomb structure parameters, liquid metal concentration and morphology changes. At the same time, the honeycomb structure encapsulated by liquid metal in the present invention also has broadband absorbing, low infrared emissivity, good flexibility and heat dissipation performance.

[0065] In the present invention, unless otherwise specified, the scientific and technical terms used herein have the meanings commonly understood by those skilled in the art. In addition, the reagents, materials and operating procedures used herein are reagents, materials and conventional procedures widely used in the corresponding fields.

[0066] The above are only preferred implementations of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A liquid metal layer encapsulated honeycomb structure microwave-infrared stealth modulation system, characterized in that: including a honeycomb structure and a liquid metal layer; The honeycomb structure comprises a honeycomb bottom and periodically arranged honeycomb cores, the honeycomb cores are arranged on the honeycomb bottom, and the liquid metal layer covers the honeycomb cores; The honeycomb bottom and the honeycomb core are made of the same material, and are both prepared by mixing an elastomer matrix, an absorbing material and a curing agent; The liquid metal layer is prepared by mixing liquid metal, an elastic matrix and a curing agent.

2. The liquid metal layer encapsulated honeycomb structure microwave-infrared stealth modulation system according to claim 1, characterized in that: The wave absorbing material is an iron-cobalt alloy absorber with high magnetic permeability.

3. The liquid metal layer encapsulated honeycomb structure microwave-infrared stealth modulation system according to claim 1, characterized in that: The elastomer matrix is ​​polydimethylsiloxane.

4. The liquid metal layer encapsulated honeycomb structure microwave-infrared stealth modulation system according to claim 1, characterized in that: The liquid metal is gallium, gallium-indium alloy or gallium-indium-tin alloy.

5. The liquid metal layer encapsulated honeycomb structure microwave-infrared stealth modulation system according to claim 1, characterized in that: In the honeycomb bottom and honeycomb core materials, the mass ratio of the absorbing material to the elastomer matrix is ​​(2-5): 1； The mass ratio of elastomer matrix to curing agent is 10:

1.

6. The liquid metal layer encapsulated honeycomb structure microwave-infrared stealth modulation system according to claim 1, characterized in that: In the liquid metal layer, the mass ratio of the liquid metal to the elastomer matrix is ​​(1-3): (1-3); The mass ratio of elastomer matrix to curing agent is 10:

1.

7. The liquid metal layer encapsulated honeycomb structure microwave-infrared stealth modulation system according to claim 1, characterized in that: The liquid metal layer is encapsulated on the upper surface of the honeycomb structure through an elastomer matrix as an intermediate adhesion layer.

8. The liquid metal layer encapsulated honeycomb structure microwave-infrared stealth modulation system according to claim 1, characterized in that: The honeycomb core is composed of periodically arranged hollow regular hexagonal prisms, and the side length, height and honeycomb wall thickness of the honeycomb core are adjustable.

9. The liquid metal layer encapsulated honeycomb structure microwave-infrared stealth modulation system according to claim 9, characterized in that: In the honeycomb core, the side length of a single hollow regular hexagonal prism is 5-20 mm, the height is 1-7 mm, and the thickness is 0.5-2.5 mm; the thickness of the honeycomb bottom is 1-3 mm; and the thickness of the liquid metal layer is 500 μm.

10. The method for preparing the liquid metal layer encapsulated honeycomb structure microwave-infrared stealth modulation system according to claim 1, characterized in that: The following steps are involved: Step 1: Add the absorbing material into the elastomer matrix according to different mass ratios, add the curing agent and mix well, then pour into the pre-made polytetrafluoroethylene honeycomb mold, and demould after drying to obtain a complete honeycomb structure; Step 2: drip the liquid metal into the elastomer matrix, add the curing agent and stir evenly, pour it into the acrylic groove to dry, and then tear off the liquid metal layer; Step 3: coating an elastomer matrix on the bottom of the liquid metal layer, and attaching the elastomer matrix to the upper surface of the honeycomb structure when the elastomer matrix is ​​not completely solidified, thereby obtaining a liquid metal encapsulated honeycomb structure.

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