Honeycomb electromagnetic wave composite material with internal wave absorber structure and preparation method thereof

Abstract

The invention provides a honeycomb electromagnetic wave composite material with an internal wave absorber structure and a preparation method, and belongs to the technical field of electromagnetic functional materials. The method comprises a honeycomb internal structure design part, the interior of a honeycomb structure is designed in a dip-coating, spray-coating or 3D printing mode, a wave-absorbing body structure with a shape is formed in the interior, and the wave-absorbing honeycomb achieves structural impedance matching in space so that the absorbing effect of the honeycomb on electromagnetic wave energy can be improved; and the honeycomb appearance structure is not damaged, so that the mechanical structure is not influenced. Through the preparation processes of filling, dip-coating, drying and the like, a radar cross section (RCS) can be greatly reduced, and the composite material has the characteristics of high loss and high absorption on electromagnetic waves.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic functional materials, and particularly to a honeycomb electromagnetic wave composite material with an internal absorber structure and a preparation method thereof. Background Art

[0002] Currently, with the rapid development of wireless communication and electronic devices, a large amount of electromagnetic interference and electromagnetic pollution will inevitably be generated, which may even pose a potential threat to the immune and central nervous systems of the human body. Moreover, with the continuous development of anti-radar stealth technology, the survivability of various military weapons and military bases in combat has been greatly reduced. Absorbing materials can absorb and dissipate electromagnetic waves and convert them into other forms of energy, effectively reducing the probability of military systems being detected by radar. Therefore, the design and application of electromagnetic wave absorbing materials have become one of the important research directions in the military field.

[0003] The radar stealth technology of aircraft is mainly achieved through shape optimization and the application of absorbing materials. Among them, the shape design reduces the corner reflection effect by eliminating sharp geometric features and cavity structures, and adopts a streamlined profile to reduce the surface protrusion density, thereby suppressing the radar cross-section (RCS); the material stealth technology relies on absorbing materials to convert the incident electromagnetic wave energy into heat energy, and its loss mechanism is divided into electrical loss type (such as conductive carbon black) and magnetic loss type (such as ferrite), weakening the echo intensity through Ohmic loss or hysteresis effect. Among them, absorbing materials can be further divided into coating type and structural type according to their functions. The former is only used for surface coverage, while the latter, such as honeycomb structures, has both mechanical properties and broadband absorbing characteristics. By means of periodic porous design, multiple reflections and impedance matching are enhanced, and it is widely used in load-bearing components such as aircraft wings and air inlets, becoming the main research direction of current stealth materials.

[0004] When the honeycomb material is perpendicular to the panel direction of the entire honeycomb structure, a large specular reflection phenomenon will occur, resulting in a sharp increase in the radar cross-section (RCS) in the direction of normal incidence of electromagnetic waves. The present invention adopts an effective method to arrange the absorbing coating in a certain pattern to form a specific absorber shape inside, so as to enhance the absorption of electromagnetic waves by the honeycomb, reduce the amount of absorbing material used, and without cutting the honeycomb substrate, effectively maintaining the mechanical structure of the original aramid paper honeycomb and not affecting the overall mechanical properties. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation method for a honeycomb electromagnetic wave composite material with an internal absorber structure, so as to solve the problem of high RCS when electromagnetic waves are incident perpendicular to the panel of the honeycomb.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A honeycomb electromagnetic composite material with an absorber structure formed inside, which includes three parts: stuffing, dip coating, and air drying processes. The honeycomb structure forms an absorber structure with a specific shape inside, and the rest is a white honeycomb, belonging to a wave-transparent structure.

[0008] Preferably, when using foam to stuff the honeycomb holes, the real parts of the complex permittivity and complex permeability of the foam are between 1 and 4, and the loss tangent is between 0 and 0.1 at 0.3 - 18 GHz.

[0009] Preferably, when the wave-transparent foam is filled inside each honeycomb hole, a sloped surface is formed in the same direction, and the slope of these surfaces is between 20° and 40°.

[0010] Preferably, the main absorber material in the dip coating is a carbon-based micron-sized particulate material with controlled carbon content.

[0011] Preferably, the honeycomb paper is a Nomex honeycomb structure, which is an ordered porous framework.

[0012] Preferably, the aperture of the honeycomb paper is 2.75 mm and 3.75 mm.

[0013] Preferably, the carbon powder solid content of the absorber dip coating is 10%.

[0014] A preparation method of a honeycomb electromagnetic wave composite material with an internal absorber structure, including the following steps:

[0015] Step 1: Use aramid paper honeycomb as the absorber honeycomb substrate and cut it into the required shape according to the requirements.

[0016] Step 2: Use wave-transparent foam in the honeycomb holes, and the height of the foam in each honeycomb hole is manually controlled to make its macroscopic shape a sharp-corner structure, and the slope of the inclined plane formed at the top of the foam is 20° - 60°.

[0017] Step 3: Immerse the honeycomb panel in the soaking pool for 15 s, and then lift it up and use a blower to dry the dip coating liquid on the honeycomb wall.

[0018] Step 4: Repeat Step 3 three times to make the honeycomb thickness reach the ideal absorber thickness.

[0019] Step 5: Put it into an oven, set the temperature to 50 °C, and dry it.

[0020] Step 6: Fill all the places in the honeycomb holes without wave-transparent foam with wave-transparent foam to form a closed foam board, which is the honeycomb electromagnetic composite material with an absorber structure formed inside.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. The honeycomb material prepared by the present invention has a very small RCS under normal incidence and good electromagnetic wave transmissivity, enabling electromagnetic waves to more easily enter the material interior and be further absorbed and dissipated.

[0023] 2. The honeycomb material prepared by the present invention has stronger absorption of the reflected energy from the bottom PEC, making it more difficult for electromagnetic wave energy to be reflected back to the radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be described in more detail below based on embodiments with reference to the drawings. Among them:

[0025] Figure 1 Shows a schematic diagram of the preparation process of a honeycomb electromagnetic wave composite material with an internal wave-absorbing structure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The following will further describe the present invention in detail in conjunction with the Figure 1 drawings and embodiments. The present invention is not limited to this embodiment.

[0027] Embodiment 1

[0028] As Figure 1 shown, a preparation method of a honeycomb electromagnetic wave composite material with an internal wave-absorbing structure includes the following steps:

[0029] Step 1: Use aramid paper honeycomb as the wave-absorbing honeycomb substrate and cut it into the required shape according to requirements.

[0030] Step 2: Use wave-transparent foam in the honeycomb holes. The height of the foam in each honeycomb hole is manually controlled to make its macroscopic shape a sharp-corner structure, and the slope of the inclined plane formed at the top of the foam is 30°.

[0031] Step 3: Immerse the honeycomb panel in the immersion pool for 15 s, then lift it and use a blower to dry the dipping liquid on the honeycomb wall.

[0032] Step 4: Repeat Step 3 three times to make the honeycomb thickness reach the ideal wave-absorbing thickness.

[0033] Step 5: Place it in an oven, set the temperature to 50 °C, and dry it.

[0034] Step 6: Fill all the places in the honeycomb holes without wave-transparent foam with wave-transparent foam to form a closed foam board, which is the honeycomb electromagnetic composite material with an internal wave-absorbing structure formed.

[0035] Embodiment 2

[0036] As Figure 1 shown, a preparation method of a honeycomb electromagnetic wave composite material with an internal wave-absorbing structure includes the following steps:

[0037] Step 1: Use aramid paper honeycomb as the wave-absorbing honeycomb substrate and cut it into the required shape according to the requirements.

[0038] Step 2: Use wave-transparent foam in the honeycomb holes. The height of the foam in each honeycomb hole is manually controlled to make its macroscopic shape a sharp-corner structure, and the slope of the inclined plane formed at the top of the foam is 45°.

[0039] Step 3: Immerse the honeycomb panel in the immersion pool for 15 s, then lift it and use a blower to dry the dipping liquid on the honeycomb wall.

[0040] Step 4: Repeat Step 3 three times to make the honeycomb thickness reach the ideal wave-absorbing thickness.

[0041] Step 5: Put it into an oven, set the temperature to 50 °C, and dry it.

[0042] Step 6: Fill all the places in the honeycomb holes without wave-transparent foam with wave-transparent foam to form a closed foam board, which is the honeycomb electromagnetic composite material with a wave-absorbing body structure formed inside.

[0043] Example 3

[0044] As Figure 1 shown, a preparation method of a honeycomb electromagnetic wave composite material with an internal wave-absorbing body structure includes the following steps:

[0045] Step 1: Use aramid paper honeycomb as the wave-absorbing honeycomb substrate and cut it into the required shape according to the requirements.

[0046] Step 2: Use wave-transparent foam in the honeycomb holes. The height of the foam in each honeycomb hole is manually controlled to make its macroscopic shape a sharp-corner structure, and the slope of the inclined plane formed at the top of the foam is 60°.

[0047] Step 3: Immerse the honeycomb panel in the immersion pool for 15 s, then lift it and use a blower to dry the dipping liquid on the honeycomb wall.

[0048] Step 4: Repeat Step 3 three times to make the honeycomb thickness reach the ideal wave-absorbing thickness.

[0049] Step 5: Put it into an oven, set the temperature to 50 °C, and dry it.

[0050] Step 6: Fill all the places in the honeycomb holes without wave-transparent foam with wave-transparent foam to form a closed foam board, which is the honeycomb electromagnetic composite material with a wave-absorbing body structure formed inside.

[0051] The above is only used to understand the method and core idea of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the rights of the present invention.

Claims

1. A honeycomb electromagnetic wave composite material with an internal absorber structure, characterized in that: The honeycomb electromagnetic wave composite material includes an absorber structure with a specific shape formed inside, and the rest is a white honeycomb, which belongs to a wave-transmitting structure.

2. The honeycomb electromagnetic wave composite material with an internal absorber structure according to claim 1, wherein: The honeycomb holes are filled with foam. The complex permittivity of the foam is 0.3 - 18 GHz, the real part of the complex permeability of the foam is between 1 and 4, and the tangent of the loss angle of the foam is between 0 and 0.

1.

3. The honeycomb electromagnetic wave composite material with an internal absorber structure according to claim 1, characterized in that: The wave-transmitting foam filled in each honeycomb hole forms a sloped surface in the same direction, and the slope of these surfaces is between 20° and 40°.

4. The honeycomb electromagnetic wave composite material with an internal absorber structure according to claim 1, characterized in that: The honeycomb electromagnetic wave composite material adopts a dip-coating process. The main absorber material in the dip-coating solution is a carbon-based micron-sized particulate material with controlled carbon content.

5. The honeycomb electromagnetic wave composite material with an internal absorber structure according to claim 1, characterized in that: The honeycomb paper is of Nomex honeycomb structure, which is an ordered porous framework.

6. The honeycomb electromagnetic wave composite material with an internal absorber structure according to claim 1, characterized in that: The aperture of the honeycomb paper is 2.75 mm - 3.75 mm.

7. The honeycomb electromagnetic wave composite material with an internal absorber structure according to claim 1, characterized in that: The internal absorber structure is a hexagonal pyramid type or a wedge-shaped structure.

8. The honeycomb electromagnetic wave composite material with an internal absorber structure according to claim 4, characterized in that: The carbon powder solid content of the absorber coating for dip-coating is 10%.

9. The preparation method of the honeycomb electromagnetic wave composite material with an internal absorber structure according to any one of claims 1 to 8, characterized in that It includes the following steps: Step 1: Use aramid paper honeycomb as the absorber honeycomb substrate and cut it into shape. Step 2: Use wave-transmitting foam in the honeycomb holes, and the height of the foam in each honeycomb hole is artificially controlled to make its macroscopic shape a sharp-corner structure. Step 3: Immerse the honeycomb panel in the soaking pool for 15 s, then lift it up and use a blower to dry the dip-coating liquid on the honeycomb walls. Step 4: Repeat Step 3 multiple times to make the thickness of the honeycomb reach the predetermined absorption thickness. Step 5: Put it into an oven for drying. Step 6: Inject wave-transmitting foam into all the places in the honeycomb holes where there is no wave-transmitting foam, so as to form a closed foam board, which is the honeycomb electromagnetic composite material with an absorber structure formed inside.

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