High-temperature-resistant spliced nested honeycomb pyramid wave-absorbing material as well as preparation method and application thereof

Abstract

The invention discloses a high-temperature-resistant spliced nested honeycomb pyramid wave-absorbing material as well as a preparation method and application thereof. The high-temperature-resistant spliced nested honeycomb pyramid wave-absorbing material is formed by splicing a plurality of hollow honeycomb pyramid unit arrays and a bottom honeycomb plate, the outer part of each hollow honeycomb pyramid unit is formed by splicing four triangular or trapezoidal honeycomb sheets with saw-toothed edges, and a hollow honeycomb pyramid with a smaller size can be nested in each hollow honeycomb pyramid unit and is wholly impregnated with wave-absorbing slurry. A wave-absorbing agent in the wave-absorbing slurry is one or more of conductive carbon black, conductive carbon fiber, conductive graphite, multi-walled carbon nanotubes, graphene, carbonyl polycrystalline iron fiber, cobalt-based amorphous wires or iron-based amorphous powder. The wave-absorbing performance of the material can be improved, high temperature resistance is achieved, heat concentration is reduced, the use amount of raw materials is reduced by adopting the spliced and nested hollow structure, the cost is low, the structural stability is improved, the service life is prolonged, meanwhile, light weight is achieved, high design flexibility is achieved, and the preparation difficulty and the later maintenance difficulty are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of preparing absorbing materials, and in particular relates to a high temperature resistant spliced ​​nested honeycomb pyramid absorbing material and a preparation method and application thereof. Background Art

[0002] In the fields of 5G / 6G communications, aerospace, new energy vehicles, etc., controlling electromagnetic interference (EMI) and electromagnetic compatibility (EMC) is a key issue. To solve this problem, a large number of electromagnetic tests are required. A microwave anechoic chamber is a specially designed closed test environment, which is mainly used for various electromagnetic compatibility tests, antenna performance tests, and radar cross section (RCS) measurements under pure electromagnetic field conditions. With the advancement of science and technology and the deepening of its application, the design and construction of microwave anechoic chambers are facing higher and higher requirements, especially in the fields of high-power radar systems, wireless communication equipment, spacecraft and satellite component testing, high-power resistance testing of materials and components, and electromagnetic pulse (HEMP) protection. Microwave anechoic chambers require higher tolerance and safety, which requires the construction of high-power microwave anechoic chambers.

[0003] Compared with conventional microwave darkrooms, high-power microwave darkrooms need to cope with the challenges brought by high-power testing to ensure the safe, reliable and effective operation of high-power electromagnetic systems, components and materials. As an important component of microwave darkrooms, the performance of pyramidal absorbing materials is directly related to the purity of the test environment and the accuracy of the test results. The biggest challenge is that the pyramidal absorbing materials that provide pure electromagnetic fields not only need to have a full-band electromagnetic wave absorption capacity of up to 99.99%, but also need to have excellent high temperature tolerance and rapid heat dissipation capabilities in high-power microwave darkrooms to ensure the safe and reliable operation of equipment and materials during the test process.

[0004] However, the performance of the pyramidal absorbing materials currently on the market still has some shortcomings. The base materials of traditional pyramidal absorbing materials are usually polyurethane foam and materials impregnated with polyurethane-carbon black. The heat resistance of such materials is insufficient and usually cannot exceed 100°C. Under long-term irradiation of high-power electromagnetic waves, these materials are prone to thermal deformation, aging and even combustion, which seriously affects the safety and accuracy of the test. In order to overcome the shortcomings of traditional materials, researchers began to explore new high-temperature resistant pyramidal absorbing materials. Among them, a honeycomb pyramidal absorbing material with aramid as the base material has become a better choice to replace traditional materials. It can withstand temperatures of 180°C. However, this high-temperature resistant honeycomb pyramidal absorbing material usually adopts the method of cutting a whole honeycomb board during the preparation process, which not only causes a great waste of raw materials and increases material costs, but also such materials are usually solid structures. The design of the solid structure not only limits the rapid dissipation of heat, but also increases the weight of the pyramid, which is not conducive to the lightweight design and installation and maintenance of the microwave darkroom.

[0005] In summary, the existing pyramid absorbing materials still have certain deficiencies in terms of heat resistance, heat dissipation capacity and cost control. How to develop pyramid absorbing materials with better performance, lower cost and better heat dissipation effect has become a key issue that needs to be solved in the current electromagnetic testing field. Summary of the invention

[0006] In view of the above, the purpose of the present invention is to provide a high temperature resistant spliced ​​nested honeycomb pyramid absorbing material and its preparation method and application, which can not only withstand the high temperature environment under high-power electromagnetic wave radiation, but also reduce the difficulty of preparation, and reduce the material usage and cost when the performance is not much different.

[0007] In order to achieve the above-mentioned invention object, the technical solution provided by the present invention is as follows:

[0008] In the first aspect, the embodiment of the present invention provides a high temperature resistant spliced ​​nested honeycomb pyramid absorbing material, which is composed of a plurality of hollow honeycomb pyramid units arranged in an array and spliced ​​with a bottom honeycomb panel. The outside of each hollow honeycomb pyramid unit is spliced ​​with four triangular or trapezoidal honeycomb sheets with serrated edges, and a small-sized hollow honeycomb pyramid is nested inside. The bottom honeycomb panel and the honeycomb sheet are both honeycomb porous structures with double-sided penetration and impregnated with absorbing slurry. The hollow honeycomb pyramid units can form an n×n pyramid array according to actual application requirements and be spliced ​​on the bottom honeycomb panel, making the design more flexible.

[0009] Preferably, a small-sized hollow honeycomb pyramid is nested inside at least one hollow honeycomb pyramid unit, or multiple hollow honeycomb pyramids of different sizes are nested in layers, and the shape and material of the internally nested hollow honeycomb pyramid are the same as those of the hollow honeycomb pyramid unit, and the size is smaller than the hollow honeycomb pyramid unit, and the internally nested hollow honeycomb pyramid is placed forward or reversely. By nesting smaller-sized hollow honeycomb pyramids, the specific surface area can be increased, aiming to improve the wave absorption performance of the hollow honeycomb pyramid while achieving high temperature resistance and reducing heat concentration.

[0010] Preferably, the bottom side length of the hollow honeycomb corner pyramid unit is 100 to 250 mm, and the height is 450 to 700 mm. By adjusting the size of the hollow honeycomb corner pyramid unit, the wave absorbing performance can be flexibly adjusted, further broadening the application scenarios.

[0011] The size and material of the bottom honeycomb panel will affect the material's wave absorption and heat dissipation properties. Preferably, the bottom honeycomb panel has a thickness of 20 to 120 mm, a honeycomb aperture of 1.83 to 5.5 mm, and the material is one of high-strength and high-temperature resistant aramid paper honeycomb, glass fiber cloth honeycomb or carbon fiber honeycomb.

[0012] The size and material of the honeycomb sheet will affect the material's wave absorption and heat dissipation properties, and since the honeycomb sheet is the main heat dissipation unit, the selection of its thickness and honeycomb aperture also directly affects the heat dissipation performance. Preferably, the honeycomb sheet thickness is 10 to 30 mm, the honeycomb aperture is 3.2 to 5.5 mm, and the material is one of high-strength and high-temperature resistant aramid paper honeycomb, glass fiber cloth honeycomb or carbon fiber honeycomb.

[0013] Preferably, the height of the small-sized hollow honeycomb pyramid is half of the height of the hollow honeycomb pyramid unit, or the heights of the stacked and nested hollow honeycomb pyramids of different sizes are gradually reduced by half. The half height is adopted because the heat is mainly concentrated at one-third of the distance from the tip, and the size of the internal nesting can be outside the heat concentration point, which is convenient for the heat dissipation of the outer hollow pyramid, and realizes efficient heat dissipation effect inside and outside.

[0014] Preferably, the honeycomb sheets, and the honeycomb sheets and the bottom honeycomb panels are spliced ​​together by means of a tenon structure, high temperature resistant structural silica gel and a structural adhesive film. This splicing method is more convenient for preparation and later maintenance.

[0015] The material and content of the absorber directly affect the absorbing performance. Preferably, the absorbing slurry includes an absorber, a high temperature resistant resin and a solvent; wherein the absorber is a combination of one or more of conductive carbon black, conductive carbon fiber, conductive graphite, multi-walled carbon nanotubes, graphene, carbonyl polycrystalline iron fiber, cobalt-based amorphous wire or iron-based amorphous powder, and the content of the absorber is 10% to 30%; the high temperature resistant resin is one of phenolic resin, polyimide resin and epoxy phenolic resin, and the high temperature resistant resin has a temperature tolerance of 250 to 300°C.

[0016] In a second aspect, in order to achieve the above-mentioned purpose of the invention, an embodiment of the present invention further provides a method for preparing the above-mentioned high temperature resistant spliced ​​nested honeycomb pyramid absorbing material, comprising the following steps:

[0017] (1) Structural dimension design and sheet cutting: Determine the overall structure and dimensions of the material based on the application scenario and performance requirements. Calculate the optimal structural dimensions of the material, including the thickness, width, and length of the bottom honeycomb panel and honeycomb sheet. Cut the material according to the calculated dimensions and then blow away the debris.

[0018] (2) Structural splicing and bonding curing: Position and align the processed honeycomb sheets, splice them in a tenon-and-mortise structure, and use high-temperature resistant structural silicone to initially bond them together to form a single pyramid. Then, multiple pyramid arrays are arranged and bonded to the bottom honeycomb board using a structural adhesive film, and finally placed in an oven for heating and curing;

[0019] (3) Preparation of impregnation slurry and sheet impregnation curing: The absorber, high temperature resistant resin and solvent are mixed in a certain proportion to obtain an absorbing slurry, and a coupling agent and a dispersant are added to the absorbing slurry to ensure good dispersibility and wettability. The spliced ​​hollow honeycomb corner cones are immersed in the prepared absorbing slurry, fully soaked, and then blown dry. The slurry is cured by heating to form a stable absorbing layer, and finally a high temperature resistant spliced ​​nested honeycomb corner cone absorbing material is obtained.

[0020] On the third aspect, in order to achieve the above-mentioned purpose of the invention, the embodiment of the present invention also provides a high temperature resistant spliced ​​nested honeycomb pyramid absorbing material for use in microwave darkrooms, radar stealth technology, aerospace, communication base stations, large high-power electronic equipment and laboratories, characterized in that the above-mentioned high temperature resistant spliced ​​nested honeycomb pyramid absorbing material is used for electromagnetic wave absorption, high temperature resistant or lightweight structural parts.

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

[0022] (1) The absorbing material of the present invention adopts a structural design of spliced ​​and nested hollow honeycomb corner cones, which increases the structural stability and service life. It is used for high-temperature resistant applications, takes into account heat dissipation and heat resistance, and improves the material's ability to withstand high temperatures.

[0023] (2) The absorbing material of the present invention adopts a spliced ​​structural design, in which smaller hollow honeycomb pyramids can be nested, thereby enhancing the absorbing performance in the low-frequency band and having the ability to absorb electromagnetic waves in a wide band.

[0024] (3) The wave absorbing material of the present invention adopts hollow honeycomb pyramids, which saves a lot of raw materials compared with solid honeycomb pyramids, reduces the production cost of raw materials, and reduces weight. The spliced ​​structural design also reduces the difficulty of preparation and subsequent maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0026] Figure 1 It is a schematic diagram of the structure of a high temperature resistant spliced ​​nested honeycomb pyramid absorbing material provided by an embodiment of the present invention;

[0027] Figure 2 It is an enlarged view of the local structure of the hollow honeycomb pyramid unit provided by an embodiment of the present invention;

[0028] Figure 3It is a schematic flow chart of a method for preparing a high temperature resistant spliced ​​nested honeycomb pyramid absorbing material provided by an embodiment of the present invention;

[0029] Figure 4 It is a reflection loss RL curve diagram of the high temperature resistant spliced ​​nested honeycomb pyramid absorbing material provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0030] To make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific implementation methods described herein are only used to explain the present invention and do not limit the scope of protection of the present invention.

[0031] The inventive concept of the present invention is: in view of the fact that the pyramid absorbing materials in the prior art still have certain deficiencies in terms of heat resistance, heat dissipation capacity and cost control, the embodiment of the present invention provides a high temperature resistant spliced ​​nested honeycomb pyramid absorbing material and its preparation method and application, which adopts the method of cutting and splicing honeycomb panels to make them into a hollow structure, which not only reduces the cost of raw materials but also has more advantages in heat dissipation, and also reduces the difficulty of maintenance and replacement. The structural design also supports making it into a nested structure to reduce the accumulation of heat at the top of the pyramid, and enhances the absorbing performance of the hollow honeycomb pyramid absorbing material in the low frequency band. It is suitable for microwave darkrooms, radar stealth technology, aerospace, communication base stations, large high-power electronic equipment and laboratories.

[0032] Figure 1 Schematic diagram of the structure of the high temperature resistant spliced ​​nested honeycomb pyramid absorbing material provided by the embodiment of the present invention. Figure 1 As shown, in the high temperature resistant spliced ​​and nested honeycomb corner cone absorbing materials provided in Example 1, Example 2 and Example 3, the bottom side length of a single hollow honeycomb corner cone unit is 200mm, the height is 680mm, the thickness of the bottom honeycomb plate is 20mm, the total height is 700mm, and the honeycomb aperture is 2.75mm. In Example 1, each hollow honeycomb corner cone unit is formed by splicing four triangular honeycomb sheets; in Example 2, each hollow honeycomb corner cone unit is formed by splicing four trapezoidal honeycomb sheets (or directly splicing four triangular honeycomb sheets and then cutting off the tip), and the internal nesting is a small-sized hollow honeycomb corner cone with a height of 340mm placed in the forward direction (with the tip facing up); in Example 3, each hollow honeycomb corner cone unit is formed by splicing four trapezoidal honeycomb sheets (or directly splicing four triangular honeycomb sheets and then cutting off the tip), and the internal nesting is a small-sized hollow honeycomb corner cone with a height of 340mm placed in the reverse direction (with the tip facing down). As Figure 2 The figure shows an enlarged view of the local structure of the hollow honeycomb corner pyramid unit. It can be seen that the honeycomb sheet is a honeycomb porous structure that penetrates both sides.

[0033] Figure 31 is a schematic diagram of a method for preparing a high temperature resistant spliced ​​nested honeycomb pyramid absorbing material provided by an embodiment of the present invention. Figure 3 As shown, the embodiment of the present invention also provides a method for preparing a high temperature resistant spliced ​​nested honeycomb pyramid absorbing material, comprising the following steps:

[0034] S1, structural dimension design and sheet cutting: determine the optimal structural dimensions of the material including the thickness, width and length of the bottom honeycomb panel and honeycomb sheet, cut according to the dimensions, and then blow away the debris;

[0035] S2, structural splicing and bonding curing: Position and align the processed honeycomb sheets, splice them in a tenon-and-mortise structure, use high-temperature resistant structural silicone to initially bond them together to form a single pyramid, then arrange multiple pyramid arrays, bond them to the bottom honeycomb board with a structural adhesive film, and finally put them in an oven for heating and curing;

[0036] S3, preparation of impregnation slurry and impregnation and curing of sheets: the absorber, high temperature resistant resin, solvent, coupling agent and dispersant are mixed in a certain proportion to obtain an absorbing slurry, and the hollow honeycomb corner cones after splicing and curing are immersed in the prepared absorbing slurry, fully soaked, blown dry and heated to cure to form a stable absorbing layer, and finally a high temperature resistant spliced ​​nested honeycomb corner cone absorbing material is obtained.

[0037] Figure 4 1 is a reflection loss RL curve of the high temperature resistant spliced ​​nested honeycomb pyramid absorbing material provided by the embodiment of the present invention. Figure 4 The reflection loss RL curve shown further verifies the absorbing performance of the high temperature resistant spliced ​​nested honeycomb pyramid absorbing material provided by the embodiment of the present invention.

[0038] Example 1

[0039] S101, designed high temperature resistant spliced ​​nested honeycomb pyramid absorber Figure 1 As shown. The base length of a single hollow honeycomb pyramid is 200mm, the height is 680mm, the thickness of the bottom honeycomb panel is 20mm, the total height is 700mm, and the honeycomb aperture is 2.75mm. Then, the 20mm thick aramid paper honeycomb sheet is cut into triangular honeycomb sheets and bottom honeycomb panels according to the design size.

[0040] S102, the cut honeycomb sheets are positioned and aligned, spliced ​​in a mortise and tenon structure, and initially bonded together using high-temperature resistant structural silicone to form a single corner pyramid. Multiple corner pyramid units are then arranged in an array and bonded to the bottom honeycomb panel using a structural adhesive film. Finally, the honeycomb sheets are placed in an oven and heated to 120°C, kept warm for 2 hours for curing, to promote the bonding between the honeycomb sheets and the bottom honeycomb panel and the curing of the structural adhesive.

[0041] S103, preparing an absorbing slurry, mixing an absorber with a high temperature resistant resin, a solvent, a coupling agent, and a dispersant in a certain proportion, wherein the absorber is conductive carbon black, the content of the conductive carbon black is 25%, the high temperature resistant resin is phenolic resin, and the solvent is anhydrous ethanol for adjusting the viscosity of the slurry. The slurry is mixed and ground with a sand mill for 6 hours at a rotation speed of 2000 rpm to ensure good dispersibility and wettability of the slurry.

[0042] S104, immerse the entire hollow honeycomb corner pyramid that has been completely cured in S102 into the prepared absorbing slurry in S103 until it is completely immersed for 15 minutes to ensure full penetration, then use a cold air blower to blow away excess slurry to ensure that the honeycomb holes in the hollow honeycomb corner pyramid are through holes, and then put the hollow honeycomb corner pyramid into an oven at 180°C for 2 hours to finally obtain a high temperature resistant spliced ​​nested honeycomb corner pyramid absorbing material. The reflection loss curve is shown in the figure below. Figure 4 shown.

[0043] Example 2

[0044] The difference from Example 1 is:

[0045] S101, designed high temperature resistant spliced ​​nested honeycomb pyramid absorber Figure 1 As shown, the interior adopts a nested structure. The base length of a single hollow honeycomb pyramid is 200mm, the height is 880mm, the thickness of the bottom honeycomb panel is 20mm, the total height is 900mm, and the honeycomb aperture is 2.75mm. There is a positive hollow honeycomb pyramid nested inside, with a height of 340mm. Then, the 20mm thick aramid paper honeycomb sheet is cut into triangular honeycomb sheets and bottom honeycomb panels according to the design size.

[0046] S102, the cut honeycomb sheets are positioned and aligned, spliced ​​in a mortise and tenon structure, and initially bonded together using high temperature resistant structural silicone to form a single pyramid, and then multiple pyramid units are arrayed and bonded to the bottom honeycomb board using a structural adhesive film, and finally placed in an oven and heated to 120°C, kept warm for 2 hours to cure, to promote the bonding of the honeycomb sheet and the bottom honeycomb board and the curing of the structural adhesive. After the curing is complete, the entire hollow honeycomb pyramid is taken out, minus the pyramid tip, so that the overall height of the hollow honeycomb pyramid is 700mm.

[0047] Example 3

[0048] The difference from Example 2 is:

[0049] S101, with inverted hollow honeycomb pyramids nested inside, has a height of 340mm.

[0050] The specific implementation methods described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above is only the most preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high temperature resistant spliced ​​nested honeycomb pyramid absorbing material, characterized in that: It is composed of a number of hollow honeycomb corner pyramid units arranged in an array and spliced ​​with a bottom honeycomb panel. The outside of each hollow honeycomb corner pyramid unit is made up of four triangular honeycomb sheets with serrated edges, and a small-sized hollow honeycomb corner pyramid is nested inside. The bottom honeycomb panel and honeycomb sheet are both honeycomb porous structures with double-sided penetrations and are impregnated with absorbing slurry.

2. The high temperature resistant spliced ​​nested honeycomb pyramid absorbing material according to claim 1, characterized in that: A small-sized hollow honeycomb corner cone is nested inside at least one hollow honeycomb corner cone unit, or a plurality of hollow honeycomb corner cones of different sizes are nested in a stacked manner. The shape and material of the internally nested hollow honeycomb corner cone are the same as those of the external hollow honeycomb corner cone unit, and the size is smaller than the hollow honeycomb corner cone unit. The internally nested hollow honeycomb corner cone is placed in a forward or reverse direction.

3. The high temperature resistant spliced ​​nested honeycomb pyramid absorbing material according to claim 1, characterized in that: The base length of the hollow honeycomb pyramid unit is 100 to 250 mm, and the height is 450 to 700 mm.

4. The high temperature resistant spliced ​​nested honeycomb pyramid absorbing material according to claim 1, characterized in that: The thickness of the bottom honeycomb panel is 20-120 mm, the honeycomb aperture is 1.83-5.5 mm, and the material is one of high-strength and high-temperature-resistant aramid paper honeycomb, glass fiber cloth honeycomb or carbon fiber honeycomb.

5. The high temperature resistant spliced ​​nested honeycomb pyramid absorbing material according to claim 1, characterized in that: The thickness of the honeycomb sheet is 10-30 mm, the honeycomb aperture is 3.2-5.5 mm, and the material is one of high-strength and high-temperature-resistant aramid paper honeycomb, glass fiber cloth honeycomb or carbon fiber honeycomb.

6. The high temperature resistant spliced ​​nested honeycomb pyramid absorbing material according to claim 2, characterized in that: The height of the small-sized hollow honeycomb corner pyramid is half of the height of the hollow honeycomb corner pyramid unit, or the heights of a plurality of stacked and nested hollow honeycomb corner pyramids of different sizes decrease step by step by half.

7. The high temperature resistant spliced ​​nested honeycomb pyramid absorbing material according to claim 1, characterized in that: The honeycomb sheets, as well as the honeycomb sheets and the bottom honeycomb panels, are spliced ​​together by means of mortise and tenon structures, high temperature resistant structural silicone and structural adhesive films.

8. The high temperature resistant spliced ​​nested honeycomb pyramid absorbing material according to claim 1, characterized in that: The absorbing slurry includes an absorber, a high temperature resistant resin and a solvent; wherein the absorber is a combination of one or more of conductive carbon black, conductive carbon fiber, conductive graphite, multi-walled carbon nanotubes, graphene, carbonyl polycrystalline iron fiber, cobalt-based amorphous wire or iron-based amorphous powder, and the content of the absorber is 10% to 30%; the high temperature resistant resin is one of phenolic resin, polyimide resin and epoxy phenolic resin, and the temperature resistance of the high temperature resistant resin is 250 to 300°C.

9. A method for preparing a high temperature resistant spliced ​​nested honeycomb pyramid absorbing material as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: (1) Structural dimension design and sheet cutting: Determine the overall structure and dimensions of the material based on the application scenario and performance requirements. Calculate the optimal structural dimensions of the material, including the thickness, width, and length of the bottom honeycomb panel and honeycomb sheet. Cut the material according to the calculated dimensions and then blow away the debris. (2) Structural splicing and bonding curing: Position and align the processed honeycomb sheets, splice them in a tenon-and-mortise structure, and use high-temperature resistant structural silicone to initially bond them together to form a single pyramid. Then, multiple pyramid arrays are arranged and bonded to the bottom honeycomb board using a structural adhesive film, and finally placed in an oven for heating and curing; (3) Preparation of impregnation slurry and sheet impregnation curing: The absorber, high temperature resistant resin and solvent are mixed in a certain proportion to obtain an absorbing slurry, and the spliced ​​hollow honeycomb corner cones are immersed in the prepared absorbing slurry to fully saturate it, and then blown dry. The slurry is cured by heating to form a stable absorbing layer, and finally a high temperature resistant spliced ​​nested honeycomb corner cone absorbing material is obtained.

10. Application of a high temperature resistant spliced ​​nested honeycomb pyramid absorbing material in microwave darkrooms, radar stealth technology, aerospace, communication base stations, large high-power electronic equipment and laboratories, characterized in that: The high temperature resistant spliced ​​nested honeycomb pyramid absorbing material described in any one of claims 1 to 8 is used for electromagnetic wave absorption, high temperature resistant or lightweight structural parts.

Images