Nanocomposite microwave absorbing plate and its preparation method

Abstract

This application discloses a nanocomposite microwave absorbing material and its preparation method, comprising a nano-absorbing wear-resistant layer, a nano-absorbing layer, a first magnetic loss layer, a weight-reducing sound insulation layer, and a second magnetic loss layer stacked sequentially, further comprising a metal fiber shielding layer composited in the second magnetic loss layer, and a reinforcing layer composited at a predetermined position. The nanocomposite microwave absorbing material of this application has advantages such as good microwave absorption effect, can be used alone, thin thickness, light weight, low cost, high shape flexibility, resistance to corrosion from various media, and high practicality.

Description

Technical Field

[0001] This application relates to the field of microwave absorbing materials technology, and in particular to a nanocomposite microwave absorbing material and its preparation method. Background Technology

[0002] With the development of modern science and technology, the impact of electromagnetic radiation on the environment is increasing. Airport flights are delayed due to electromagnetic interference, and mobile phones often interfere with the normal operation of various electronic diagnostic instruments in hospitals. Therefore, controlling electromagnetic pollution and finding a material that can resist and weaken electromagnetic radiation—absorbing materials—has become a major topic in materials science.

[0003] So-called microwave absorbing materials refer to a class of materials that can absorb or significantly reduce the electromagnetic wave energy received on their surface, thereby reducing electromagnetic interference. In engineering applications, in addition to requiring microwave absorbing materials to have a high absorption rate of electromagnetic waves over a wide frequency band, the requirements for microwave absorbing materials also vary depending on the environment. At the same time, microwave absorbing materials must also have the advantage of being lightweight.

[0004] In the existing technology, most commonly used absorbing materials can only work in a certain frequency band, and they have problems such as high surface density and poor corrosion resistance. This not only increases the difficulty of later maintenance and reduces the performance, but also increases their own weight. In particular, aviation equipment has very strict requirements on its own weight, making it difficult to be widely used.

[0005] Therefore, there is an urgent need to design a microwave absorbing material that has high absorption performance, is lightweight and thin, has high strength, and is resistant to corrosion from various media. Summary of the Invention

[0006] To address at least one of the problems mentioned in the background art, embodiments of this application provide a nanocomposite microwave absorbing plate and its preparation method. The nanocomposite microwave absorbing plate has the advantages of high microwave absorption performance, light weight and thinness, high strength, and resistance to corrosion from various media.

[0007] To achieve the above objectives, the first aspect of this application provides a nanocomposite microwave absorbing material, comprising sequentially stacked and connected...

[0008] The nano-absorbing and wear-resistant layer is made of the following nano-scale raw materials in parts by weight, which are then bonded and cured: 1-2.5 parts silicon carbide, 0.5-1.5 parts nickel-zinc ferrite, and 0.5-1.5 parts FeCo50 powder.

[0009] The nano-absorbing layer is made by bonding and curing the following nanoscale raw materials in parts by weight: 1-2.5 parts of iron(III) oxide, 0.5-1.5 parts of ferric oxide, 1-2.5 parts of FeCo50 powder, and 0.5-1.5 parts of nickel-zinc ferrite.

[0010] The first magnetic loss layer is formed by bonding and curing the following nanoscale raw materials in parts by weight: 1.5-3.75 parts of iron(III) oxide, 0.75-1.125 parts of ferric oxide, 0.1-1 parts of aluminum powder, 0.1-1 parts of magnesium oxide, 1-2.5 parts of FeCo50 powder, and 1.5-3.75 parts of high-purity iron powder.

[0011] Weight-reducing sound insulation layer, including polyurethane foam, PVC foam or cardboard honeycomb foam;

[0012] The second magnetic loss layer is formed by bonding and curing the following nano-scale raw materials in parts by weight: 1.5-3.75 parts of nano-scale iron(III) oxide, 0.75-1.12 parts of ferric oxide, 0.1-1 parts of aluminum powder, 0.1-1 parts of magnesium oxide, 1-2.5 parts of FeCo50 powder, and 1.5-3.75 parts of high-purity iron powder.

[0013] It also includes a metal fiber shielding layer, which comprises silver fiber or stainless steel fiber, and the metal fiber shielding layer is composited in the second magnetic loss layer;

[0014] The reinforcing layer includes glass fiber or carbon fiber; at least one layer of the reinforcing layer is provided, and the reinforcing layer is composite in a predetermined layer of a nano-absorbing layer, a first magnetic loss layer and / or a second magnetic loss layer.

[0015] In one feasible implementation, the weight-reducing sound insulation layer further includes carbon black;

[0016] The weight-reducing and sound-insulating layer includes polyurethane foam and PVC foam, and the carbon black is embedded in pre-formed through holes or blind holes on the surface of the polyurethane foam and PVC foam.

[0017] Alternatively, the weight-reducing and sound-insulating layer comprises cardboard honeycomb foam, with the carbon black embedded in the recesses on the surface of the cardboard honeycomb foam.

[0018] In one feasible implementation, the reinforcing layer comprises glass fiber;

[0019] The glass fiber is composited in the nano-absorbing layer, and the glass fiber includes chopped glass fiber; or, the glass fiber is composited in the first magnetic loss layer and / or the second magnetic loss layer, and the glass fiber includes composite glass fiber.

[0020] In one feasible implementation, the nano-absorbing layer is composited with two reinforcing layers, and / or, the metal fiber shielding layer is composited with one reinforcing layer on each side.

[0021] In one feasible implementation, a carbon fiber layer is also bonded to the side of the second magnetic loss layer away from the weight-reducing and sound-insulating layer.

[0022] In one feasible implementation, the thickness of the nano-absorbing wear-resistant layer ranges from 0.1 to 1 mm, the thickness of the nano-absorbing layer ranges from 0.3 to 1 mm, and the thickness of the weight-reducing sound insulation layer ranges from 1 to 50 mm.

[0023] In one feasible implementation, a silicon carbide resin layer is sprayed onto the side of the nano-absorbing wear-resistant layer away from the nano-absorbing layer.

[0024] The second aspect of this application provides a method for preparing a nanocomposite microwave absorbing plate, which includes the following steps:

[0025] Preparation of nano-absorbing and wear-resistant layer;

[0026] A nano-absorbing layer is prepared, wherein a reinforcing layer is laid on the surface of the nano-absorbing wear-resistant layer, and the nano-absorbing layer is then prepared.

[0027] A first magnetic loss layer, a weight-reducing and sound-insulating layer, a second magnetic loss layer, and a metal fiber shielding layer are prepared. On the side of the nano-absorbing layer away from the nano-absorbing and wear-resistant layer, the weight-reducing and sound-insulating layer, the metal fiber shielding layer, and the set reinforcement layer are laid in sequence. The first magnetic loss layer and the second magnetic loss layer are prepared by vacuum induction process.

[0028] In one feasible implementation, the step of preparing the nanoscale microwave absorbing and wear-resistant layer includes:

[0029] The grinding wheel is processed by applying wax and a release agent to the surface of the grinding wheel to make the surface smooth.

[0030] Mix 1 part by weight of adhesive and 0.03 parts by weight of curing agent evenly, add 0.3-0.4 parts by weight of nano-wave-absorbing wear-resistant layer raw material and mix evenly again. Apply the mixed material to the mold surface and cure.

[0031] In one feasible implementation, the step of preparing the nano-absorbing layer includes:

[0032] A set number of reinforcing layers are laid on the surface of the prepared nano-absorbing wear-resistant layer;

[0033] Mix 1 part by weight of adhesive and 0.03 parts by weight of curing agent evenly, then add 0.3-0.4 parts by weight of nano-absorbing layer raw material and mix evenly again.

[0034] A vacuum bag is placed on the side away from the nano-absorbing wear-resistant layer. The material, which has been mixed evenly again, is introduced onto the nano-absorbing wear-resistant layer through a vacuum introduction process and then cured.

[0035] Remove the vacuum bag;

[0036] The steps for preparing the first magnetic loss layer, the weight-reducing sound insulation layer, and the metal fiber shielding layer include:

[0037] On the side of the prepared nano-absorbing layer away from the nano-absorbing wear-resistant layer, a weight-reducing sound insulation layer, a metal fiber shielding layer, and a set reinforcement layer are laid in sequence.

[0038] Mix 2 parts by weight of adhesive and 0.06 parts by weight of curing agent evenly, then add 0.3-0.4 parts by weight of first magnetic loss layer material and 0.3-0.4 parts by weight of second magnetic loss layer material and mix evenly again.

[0039] A vacuum bag is placed on the side away from the nano-absorbing and wear-resistant layer. The material, which has been mixed evenly again, is then introduced into both sides of the weight-reducing and sound-insulating layer, the metal fiber shielding layer, and the reinforcing layer using a vacuum introduction process, and then cured.

[0040] Remove the vacuum bag.

[0041] This application provides a nanocomposite microwave absorbing sheet and its preparation method. The nanocomposite microwave absorbing sheet uses various nano-absorbing agents to prepare a nano-absorbing wear-resistant layer and a nano-absorbing layer, exhibiting absorption effects on electromagnetic waves across a wide frequency range of 1-18 GHz. The absorption effect is enhanced by incorporating a first magnetic loss layer, a second magnetic loss layer, and a metal fiber shielding layer. A weight-reducing sound insulation layer reduces weight and manufacturing costs. A reinforcing layer, a nano-absorbing wear-resistant layer, and a carbon fiber layer improve strength, toughness, and wear resistance, and also provide temperature resistance, moisture resistance, and corrosion resistance. This nanocomposite microwave absorbing sheet has advantages such as good absorption effect, can be used alone, thin thickness, light weight, low cost, high shape flexibility, resistance to corrosion from various media, and high practicality. The preparation method of the nanocomposite microwave absorbing sheet is used in this nanocomposite microwave absorbing sheet. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of a nanocomposite microwave absorbing plate provided in an embodiment of this application;

[0044] Figure 2 This is a schematic diagram of another structure of the nanocomposite microwave absorbing plate provided in the embodiments of this application;

[0045] Figure 3This is another structural schematic diagram of the nanocomposite microwave absorbing material provided in the embodiments of this application;

[0046] Figure 4 for Figure 3 The reflectivity curve of the provided nanocomposite microwave absorbing material;

[0047] Figure 5 This is a schematic diagram illustrating the preparation steps of the nanocomposite microwave absorbing material provided in the embodiments of this application. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. It is worth noting that the embodiments described in the accompanying drawings are only some embodiments of this application, and not all embodiments. That is, the embodiments described with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0049] The following will combine Figures 1-3 The nanocomposite microwave absorbing material provided in the embodiments of this application will be described.

[0050] This application provides a nanocomposite microwave absorbing material, comprising a nano-absorbing wear-resistant layer, a nano-absorbing layer, a first magnetic loss layer, a weight-reducing sound insulation layer, and a second magnetic loss layer stacked sequentially, and further comprising a metal fiber shielding layer composited in the second magnetic loss layer, and a reinforcing layer composited at a predetermined position.

[0051] The connection between adjacent layers can be achieved through adhesive bonding. For example, the preparation layer is formed by mixing an adhesive and a curing agent into the raw materials of the preparation layer and then curing it. A new layer to be prepared is further bonded to the already cured layer using the adhesive and curing agent mixture.

[0052] The nano-absorbing and wear-resistant layer is made of the following nano-scale raw materials in parts by weight, which are then bonded and cured: 1-2.5 parts silicon carbide, 0.5-1.5 parts nickel-zinc ferrite, and 0.5-1.5 parts FeCo50 powder.

[0053] Nanoscale silicon carbide possesses a high specific surface area and high thermal stability, effectively converting electromagnetic waves into heat energy. It also exhibits excellent mechanical properties, enhancing the strength and durability of nanocomposite microwave absorbing panels without compromising microwave absorption performance. A properly proportioned mass ratio of nanoscale silicon carbide improves surface wear resistance, preventing insufficient surface hardness due to an excessively low mass ratio, while avoiding difficulties in material curing due to an excessively high mass ratio. Adding the aforementioned mass ratio of nanoscale silicon carbide can increase the Barcol hardness from 30-40 HBa to approximately 50 HBa.

[0054] Nanoscale nickel-zinc ferrite exhibits good absorption of C-band electromagnetic waves (<4-8 GHz). Nanoscale FeCo50 powder, a soft magnetic alloy composed of iron and cobalt, possesses high permeability and demonstrates good absorption of X-band electromagnetic waves (8-12 GHz). A well-balanced mass ratio of nickel-zinc ferrite and FeCo50 provides excellent absorption for both C-band and X-band electromagnetic waves, avoiding the drawback of insufficient absorption due to low mass ratios, while also preventing the reduction of nano-silicon carbide mass ratios and thus affecting overall hardness due to excessive mass ratios.

[0055] The nano-absorbing layer is made by bonding and curing the following nanoscale raw materials in parts by weight: 1-2.5 parts of iron(III) oxide, 0.5-1.5 parts of ferric oxide, 1-2.5 parts of FeCo50 powder, and 0.5-1.5 parts of nickel-zinc ferrite.

[0056] Among them, nano-sized iron(III) oxide exhibits excellent wave absorption properties, demonstrating good absorption of electromagnetic waves across the entire frequency band from 2 to 18 GHz. Nano-sized iron(III) oxide possesses unpaired electrons and exhibits paramagnetism. In electromagnetic wave adsorption, it guides propagation from low magnetic permeability to high magnetic permeability, directing electromagnetic wave transmission. When the anisotropic spin magnetic moment resonates with the frequency of the applied electromagnetic wave radiation, it absorbs the energy of the external electromagnetic wave. Then, through the rotational coupling of the magnetic moment itself, the electromagnetic wave energy is dissipated as heat. Therefore, the paramagnetic wave absorption of nano-sized iron(III) oxide has a more profound electromagnetic wave dissipation and radiation effect.

[0057] A reasonable mass ratio of nano-grade iron(III) oxide and nano-grade iron(II) oxide can avoid the inability to achieve a good microwave absorption effect due to too low a mass ratio, while also avoiding the overall microwave absorption effect being affected by reducing the mass ratio of other microwave absorbing agent raw materials due to too high a mass ratio.

[0058] The first magnetic loss layer is formed by bonding and curing the following nanoscale raw materials in parts by mass: 1.5-3.75 parts of iron(III) oxide, 0.75-1.125 parts of ferric oxide, 0.1-1 parts of aluminum powder, 0.1-1 parts of magnesium oxide, 1-2.5 parts of FeCo50 powder, and 1.5-3.75 parts of high-purity iron powder.

[0059] Among them, nano-grade high-purity iron powder refers to pure iron powder with a purity of over 99.9% that contains no impurities. Nano-grade high-purity iron powder has the advantages of increasing the hardness and toughness of nano-composite microwave absorbing materials, and also has extremely high conductivity, enabling electromagnetic waves to be rapidly converted into heat energy for dissipation.

[0060] Nanoscale aluminum powder can block electromagnetic wave radiation. When a certain proportion of nanoscale aluminum powder is mixed in, it can enable nanoscale high-purity iron powder to better convert electromagnetic waves.

[0061] Nano-sized magnesium oxide has a certain absorption effect as a broadband microwave absorber. At the same time, it is mainly used to block the normal irradiation process of electromagnetic waves, making the electromagnetic waves reflect in a tortuous way, so that the microwave absorbers in other layers of raw materials can achieve better microwave absorption effect.

[0062] The first magnetic loss layer is mainly composed of nano-sized high-purity iron powder, which converts the energy of electromagnetic waves incident on the layer and absorbs and consumes as much of the incident electromagnetic waves as possible.

[0063] Weight-reducing sound insulation layers include polyurethane foam, PVC foam, or cardboard honeycomb foam.

[0064] The weight-reducing sound insulation layer is mainly used to reduce the specific gravity and has a certain sound insulation effect.

[0065] The density of the polyurethane foam mentioned above can be 30-80 kg³ / m. It can not only reduce weight and provide sound insulation, but also reduce weight and provide sound insulation. PVC and cardboard honeycomb foam are themselves wave-transparent materials and do not have wave-absorbing effects. Their main functions are weight reduction and sound insulation. Compared with polyurethane foam, they are easier to manufacture and have lower costs.

[0066] The second magnetic loss layer is formed by bonding and curing the following nanoscale raw materials in parts by weight: 1.5-3.75 parts of iron(III) oxide, 0.75-1.12 parts of ferric oxide, 0.1-1 parts of aluminum powder, 0.1-1 parts of magnesium oxide, 1-2.5 parts of FeCo50 powder, and 1.5-3.75 parts of high-purity iron powder.

[0067] The second magnetic loss layer, combined with the first magnetic loss layer, enhances the effect of electromagnetic wave attenuation.

[0068] The metal fiber shielding layer includes silver fiber or stainless steel fiber, and the metal fiber shielding layer is composited in the second magnetic loss layer.

[0069] Among them, the metal fiber shielding layer is mainly used to shield and reflect electromagnetic waves, so that the reflected electromagnetic waves pass through the second magnetic loss layer, the weight reduction and sound insulation layer, the first magnetic loss layer, the nano wave absorbing layer and the nano wave absorbing wear-resistant layer for secondary consumption and absorption, thereby enhancing the wave absorption effect.

[0070] The reinforcing layer includes glass fiber or carbon fiber. At least one reinforcing layer is provided, and the reinforcing layer is composited with a designated layer among the nano-absorbing layer, the first magnetic loss layer, and / or the second magnetic loss layer. That is, the reinforcing layer can be composited with any one, any two, or all of the nano-absorbing layer, the first magnetic loss layer, and the second magnetic loss layer, and the number of reinforcing layers at the composite location can be arbitrarily selected, thus adjusting the overall thickness, strength, and toughness.

[0071] The reinforcing layer can reinforce the nanocomposite microwave absorbing plate, resulting in higher strength, toughness, and practicality.

[0072] The reinforcing layer may be made of glass fiber, which, for example, may include chopped glass fiber or composite glass fiber. In some embodiments, the reinforcing layer may also be made of carbon fiber, which, compared to using glass fiber as the reinforcing layer, can give the nanocomposite microwave absorbing panel higher strength and toughness.

[0073] This application provides a nanocomposite microwave absorbing material. This nanocomposite microwave absorbing material is prepared by using various nano-absorbing agents to create a nano-absorbing wear-resistant layer and a nano-absorbing layer, exhibiting absorption effects on electromagnetic waves across a wide frequency range of 1-18 GHz. The absorption effect is enhanced by incorporating a first magnetic loss layer, a second magnetic loss layer, and a metal fiber shielding layer. A weight-reducing sound insulation layer reduces weight and manufacturing costs. The addition of a reinforcing layer, a nano-absorbing wear-resistant layer, and a carbon fiber layer improves strength, toughness, and wear resistance, and also provides temperature resistance, moisture resistance, and corrosion resistance. This nanocomposite microwave absorbing material offers advantages such as excellent microwave absorption, the ability to be used alone, thinness, light weight, low cost, high shape flexibility, resistance to corrosion from various media, and high practicality.

[0074] In one feasible implementation, the weight-reducing sound insulation layer also includes carbon black.

[0075] The weight-reducing and sound-insulating layer includes polyurethane foam and PVC foam, with pre-drilled through holes or blind holes on the surface of the polyurethane foam and PVC foam, and carbon black embedded in the through holes or blind holes.

[0076] Alternatively, the weight-reducing sound insulation layer may include cardboard honeycomb foam, with carbon black embedded in the recesses on the surface of the cardboard honeycomb foam.

[0077] The through-hole design not only allows for the embedding of carbon black, but also improves the air permeability of the weight-reducing and sound-insulating layer, facilitating the penetration of adhesive materials, the first magnetic loss layer, and the second magnetic loss layer within the through-hole, thereby enhancing the bonding and wave absorption effects.

[0078] For example, the surfaces of polyurethane foam and PVC foam can be arranged at an average density of 2-3 cm. 2 Machine a through hole or blind hole with a diameter of 3mm within the surface area.

[0079] For example, 1 part by weight of adhesive and 0.3 parts by weight of carbon black can be mixed evenly, and then 0.01 parts by weight of curing agent can be added and mixed evenly again. The perforated polyurethane foam, perforated PVC foam, or cardboard honeycomb foam is then immersed in the remixed material, heated to 70-120°C to improve its adhesion and leveling properties, and then dried and cured, thus laminating the carbon black onto the material. In some embodiments, the remixed material can also be sprayed onto the surface of the material and then dried and cured.

[0080] In one feasible implementation, the reinforcing layer comprises glass fiber.

[0081] Glass fibers are composited in the nano-absorbing layer, and the glass fibers include chopped glass fibers. Alternatively, glass fibers are composited in the first magnetic loss layer and / or the second magnetic loss layer, and the glass fibers include composite glass fibers.

[0082] The specifications of the chopped glass fiber are 200-450 g / m. 2 Composite glass fiber comprises a composite of chopped strand mat and glass cloth; for example, the composite glass fiber may be 200 g / m². 2 Specifications of 600g / m² chopped strand mat composite 2 Standard fiberglass cloth, 300g / m², is also available. 2 Specifications of 600g / m² chopped strand mat composite 2 Standard glass cloth.

[0083] In one feasible implementation, such as Figure 1 As shown, the nano-absorbing layer is composited with two reinforcing layers, such as... Figure 2 As shown, a reinforcing layer is laminated on each side of the metal fiber shielding layer. Figure 3 As shown, the nano-absorbing layer is composited with two reinforcing layers, and a reinforcing layer is composited on each side of the metal fiber shielding layer.

[0084] In one feasible implementation, a carbon fiber layer is also bonded to the side of the second magnetic loss layer away from the weight-reducing and sound-insulating layer.

[0085] Among them, the carbon fiber layer has electromagnetic shielding and antistatic effects, and can improve surface hardness, with a Barcol hardness of up to 46HBa, which greatly improves the appearance. In addition, the nanocomposite microwave absorbing board has better toughness and is not easy to bend or break.

[0086] In one feasible implementation, the thickness of the nano-absorbing wear-resistant layer ranges from 0.1 to 1 mm, the thickness of the nano-absorbing layer ranges from 0.3 to 1 mm, and the thickness of the weight-reducing sound insulation layer ranges from 1 to 50 mm.

[0087] In this way, the thickness of the nanocomposite microwave absorbing plate can be adjusted according to the actual application scenario. In one embodiment, Figure 3 The thickness of the nanocomposite absorbing plate shown is only 6mm.

[0088] In one feasible implementation, a silicon carbide resin layer is sprayed onto the side of the nano-absorbing wear-resistant layer away from the nano-absorbing layer.

[0089] This can further improve the appearance of the nanocomposite microwave absorbing material.

[0090] The following combination Figure 3 and Figure 4 A specific nanocomposite microwave absorbing material according to an embodiment of this application will be described.

[0091] according to Figure 3 The layer distribution shown indicates the fabrication of a nanocomposite microwave absorbing plate, wherein...

[0092] The nano-absorbing and wear-resistant layer is made of nano-scale raw materials in the following mass proportions by adhesive curing: 2 parts silicon carbide, 1 part nickel-zinc ferrite, and 1 part FeCo50 powder.

[0093] The nano-absorbing layer is made of nanoscale raw materials including the following parts by mass, which are bonded and cured together: 2 parts of iron(III) oxide, 1 part of ferric oxide, 2 parts of FeCo50 powder, and 1 part of nickel-zinc ferrite.

[0094] The reinforcing layer composited with the nano-absorbing layer consists of two layers, each containing a specification of 200-450g / m². 2 Short-cut glass fiber.

[0095] The first magnetic loss layer is formed by bonding and curing the following nanoscale raw materials in parts by mass: 3 parts iron(III) oxide, 1.5 parts ferric oxide, 1 part aluminum powder, 1 part magnesium oxide, 2 parts FeCo50 powder, and 3 parts high-purity iron powder.

[0096] The weight-reducing and sound-insulating layer consists of polyurethane foam, 2mm thick.

[0097] The raw materials and mass fractions of the second magnetic loss layer are the same as those of the first magnetic loss layer.

[0098] The metal fiber shielding layer includes silver fibers.

[0099] The reinforcing layers on both sides of the metal fiber shielding layer both include composite glass fiber, including those with a specification of 200g / m². 2 Fiberglass chopped strand mat composite specification 600g / m 2 Fiberglass cloth.

[0100] The prepared nanocomposite microwave absorbing plate is only 6 mm thick. The mass amount of various raw materials is determined according to the prepared thickness and area.

[0101] The prepared nanocomposite microwave absorbing material was subjected to microwave absorption tests, and the reflectivity test results are shown in Table 1. Figure 4 The reflectivity curve of the nanocomposite absorbing plate is shown.

[0102] Reflectivity is the percentage of reflected radiation energy out of the total energy, and the sum of reflectivity and absorptivity is 1. Reflectivity depends on the properties of the object itself, as well as the wavelength and angle of the incident electromagnetic wave; the larger the incident angle, the stronger the reflection. -dB represents a decrease in signal value; for example, -3dB indicates a reflectivity of 50.1%, and -13dB indicates a reflectivity of 5%. It is understood that the embodiments of this application exhibit high absorptivity for electromagnetic waves within a relatively wide frequency band of 1-18GHz.

[0103]

[0104] The mechanical properties of the prepared nanocomposite microwave absorbing material were tested, and the results are shown in Table 2. It can be seen that the axial bending strength and modulus of the prepared nanocomposite microwave absorbing material are both much greater than the standard values, meeting the application requirements.

[0105]

[0106] The following will combine Figure 5 The nanocomposite microwave absorbing material provided in the embodiments of this application will be described.

[0107] This application provides a method for preparing a nanocomposite microwave absorbing plate, used to prepare the aforementioned nanocomposite microwave absorbing plate, such as... Figure 5 As shown, it includes the following steps:

[0108] Prepare a nano-absorbing and wear-resistant layer.

[0109] A nanoscale absorbing layer is prepared. Specifically, a reinforcing layer is deposited on the surface of the nanoscale absorbing wear-resistant layer, and then the nanoscale absorbing layer is prepared.

[0110] It is worth noting that the number of reinforcing layers is selected according to actual needs. When the nano-absorbing layer is combined with a reinforcing layer, the nano-absorbing layer can be prepared by laying the reinforcing layer and using a vacuum induction process. When the nano-absorbing layer is not combined with a reinforcing layer, i.e., the number of reinforcing layers is set to 0, the nano-absorbing layer can be prepared by coating and curing.

[0111] In some embodiments, after preparing the nano-wave-absorbing wear-resistant layer, the surface of the nano-wave-absorbing wear-resistant layer near the nano-wave-absorbing layer can be polished to make it rough, and then a reinforcement layer or a nano-wave-absorbing wear-resistant layer can be laid or coated to improve the adhesion between the nano-wave-absorbing wear-resistant layer and the nano-wave-absorbing layer.

[0112] A first magnetic loss layer, a weight-reducing and sound-insulating layer, a second magnetic loss layer, and a metal fiber shielding layer are prepared. Specifically, on the side of the nano-absorbing layer away from the nano-absorbing and wear-resistant layer, the weight-reducing and sound-insulating layer, the metal fiber shielding layer, and a designated reinforcing layer are sequentially laid. The first and second magnetic loss layers are then prepared using a vacuum induction process.

[0113] Understandably, the location and number of reinforcing layers can be selected according to actual needs, and the reinforcing layers can be laid accordingly.

[0114] In some embodiments, after the nano-absorbing layer is prepared, the surface of the nano-absorbing layer away from the nano-absorbing wear-resistant layer can be polished to make it rough, and then each layer is laid to improve the adhesion between the nano-absorbing layer and the first magnetic loss layer.

[0115] A carbon fiber layer is prepared. Specifically, the carbon fiber layer is prepared on the side of the metal fiber shielding layer away from the second magnetic loss layer.

[0116] In some embodiments, after the metal fiber shielding layer is prepared, the surface of the metal fiber shielding layer away from the second magnetic loss layer can be polished to make it rough, and then the carbon fiber layer can be prepared to improve the adhesion between the metal fiber shielding layer and the carbon fiber layer.

[0117] A silicon carbide resin layer is prepared. The sheet material with the carbon fiber layer is demolded, and a silicon carbide resin layer is sprayed onto the side of the nano-absorbing and wear-resistant layer furthest from the nano-absorbing layer. The thickness of the silicon carbide resin layer is 0.3-1 mm.

[0118] In some embodiments, after the carbon fiber layer is prepared and demolded, the surface of the nano-wave-absorbing wear-resistant layer away from the nano-wave-absorbing layer can be polished to make it rough, so as to improve the adhesion between the nano-wave-absorbing wear-resistant layer and the silicon carbide resin layer.

[0119] The present application describes a method for preparing nanocomposite microwave absorbing materials. The prepared nanocomposite microwave absorbing materials have the advantages of good microwave absorption effect, can be used alone, are thin, lightweight, have high shape flexibility, are resistant to corrosion by various media, and are highly practical.

[0120] In one feasible implementation, the step of preparing the nanoscale absorbing and wear-resistant layer includes:

[0121] The grinding wheel is processed by applying wax and a release agent to the surface of the grinding wheel to make the surface smooth.

[0122] Mix 1 part by weight of adhesive and 0.03 parts by weight of curing agent evenly, add 0.3-0.4 parts by weight of nano-wave-absorbing wear-resistant layer raw material and mix evenly again. Apply the mixed material to the mold surface and cure.

[0123] The adhesive includes resins, specifically unsaturated flame-retardant resins or epoxy resins. Curing agents for unsaturated resins can include peroxides or methyl ethyl ketone peroxide, while curing agents for epoxy resins are mainly amine-based and acid anhydride-based curing agents.

[0124] By rationally proportioning the adhesive, curing agent, and raw materials for the nano-wave-absorbing wear-resistant layer, a nano-wave-absorbing wear-resistant layer was successfully prepared, exhibiting excellent wave absorption performance. The preparation process... Figure 3 The nanocomposite microwave absorbing board shown can be basically cured in about 50 minutes to reach the demolding standard under normal room temperature and 50% humidity, and can be fully cured after standing for 24 hours.

[0125] In one feasible implementation, the steps for fabricating the nano-absorbing layer include:

[0126] A set number of reinforcing layers are laid on the surface of the prepared nano-absorbing wear-resistant layer.

[0127] Mix 1 part by weight of adhesive and 0.03 parts by weight of curing agent evenly, then add 0.3-0.4 parts by weight of nano-absorbing layer raw material and mix evenly again.

[0128] A vacuum bag is placed on the side furthest from the nano-absorbing wear-resistant layer, i.e., the top reinforcing layer. The material, which has been mixed evenly again, is then introduced onto the nano-absorbing wear-resistant layer through a vacuum introduction process and cured.

[0129] Remove the vacuum bag.

[0130] Among them, preparation Figure 3 The nanocomposite microwave absorbing board shown can typically be cured to the demolding standard in about 35 minutes under ambient temperature and 50% humidity.

[0131] In one feasible implementation, the steps of fabricating the first magnetic loss layer, the weight-reducing sound insulation layer, the first magnetic loss layer, and the metal fiber shielding layer include:

[0132] On the side of the prepared nano-absorbing layer away from the nano-absorbing wear-resistant layer, a weight-reducing sound insulation layer, a metal fiber shielding layer, and a set reinforcement layer are laid in sequence.

[0133] Mix 2 parts by weight of adhesive and 0.06 parts by weight of curing agent evenly, then add 0.3-0.4 parts by weight of first magnetic loss layer material and 0.3-0.4 parts by weight of second magnetic loss layer material and mix evenly again.

[0134] A vacuum bag is placed on the side away from the nano-absorbing and wear-resistant layer. The material, which has been mixed evenly again, is then introduced into both sides of the weight-reducing and sound-insulating layer, the metal fiber shielding layer, and the reinforcing layer using a vacuum introduction process, and then cured.

[0135] Remove the vacuum bag.

[0136] The proper ratio of adhesive, curing agent, and raw materials can prevent the curing time from being affected by an excessively high adhesive content, while also preventing the product's toughness from being affected by an excessively low adhesive content.

[0137] The vacuum infusion process can effectively reduce the proportion of adhesives and increase the proportion of fibers such as metal fibers, thereby improving overall strength and reducing weight. Moreover, the entire process is carried out in a vacuum environment at room temperature, without the need for additional pressure, reducing labor intensity and improving production efficiency.

[0138] In one feasible implementation, the step of preparing the carbon fiber layer includes:

[0139] Mix 1 part adhesive and 0.03 parts curing agent by weight until homogeneous.

[0140] Carbon fiber is laid on the side of the second magnetic loss layer away from the breathable and sound-insulating layer. The uniformly mixed material is evenly coated on the surface of the carbon fiber with a coating thickness of 0.3-0.5mm.

[0141] After the mixed materials are dried, the surface is polished to improve its gloss and prevent UV rays from causing product aging.

[0142] Among them, preparation Figure 3 The nanocomposite microwave absorbing plate shown is typically prepared under conditions of room temperature and 50% humidity. Figure 3 The product shown can be basically cured and reach the demolding standard in about 35 minutes.

[0143] It should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" in the description of this application should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0144] The terms “upper,” “lower,” “front,” “back,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0145] The term "multiple" means two or more, unless otherwise specified precisely.

[0146] The terms “first,” “second,” “third,” “fourth,” etc., (if applicable) are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can include implementations in sequences other than those illustrated or described herein.

[0147] The terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0148] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A nanocomposite microwave absorbing material, characterized in that, Including sequentially stacked connections The nano-absorbing and wear-resistant layer is made of the following nano-scale raw materials in parts by weight, which are then bonded and cured: 1-2.5 parts silicon carbide, 0.5-1.5 parts nickel-zinc ferrite, and 0.5-1.5 parts FeCo50 powder. The nano-absorbing layer is made by bonding and curing the following nanoscale raw materials in parts by weight: 1-2.5 parts of iron(III) oxide, 0.5-1.5 parts of ferric oxide, 1-2.5 parts of FeCo50 powder, and 0.5-1.5 parts of nickel-zinc ferrite. The first magnetic loss layer is formed by bonding and curing the following nanoscale raw materials in parts by weight: 1.5-3.75 parts of iron(III) oxide, 0.75-1.125 parts of ferric oxide, 0.1-1 parts of aluminum powder, 0.1-1 parts of magnesium oxide, 1-2.5 parts of FeCo50 powder, and 1.5-3.75 parts of high-purity iron powder. Weight-reducing sound insulation layer, including polyurethane foam, PVC foam or cardboard honeycomb foam; The second magnetic loss layer is formed by bonding and curing the following nanoscale raw materials in parts by weight: 1.5-3.75 parts of iron(III) oxide, 0.75-1.12 parts of ferric oxide, 0.1-1 parts of aluminum powder, 0.1-1 parts of magnesium oxide, 1-2.5 parts of FeCo50 powder, and 1.5-3.75 parts of high-purity iron powder. It also includes a metal fiber shielding layer, which comprises silver fiber or stainless steel fiber, and the metal fiber shielding layer is composited in the second magnetic loss layer; The reinforcing layer includes glass fiber or carbon fiber; at least one layer of the reinforcing layer is provided, and the reinforcing layer is composite in a predetermined layer of a nano-absorbing layer, a first magnetic loss layer and / or a second magnetic loss layer.

2. The nanocomposite microwave absorbing plate according to claim 1, characterized in that, The weight-reducing and sound-insulating layer also includes carbon black; The weight-reducing and sound-insulating layer includes polyurethane foam and PVC foam, and the carbon black is embedded in pre-formed through holes or blind holes on the surface of the polyurethane foam and PVC foam. Alternatively, the weight-reducing and sound-insulating layer comprises cardboard honeycomb foam, with the carbon black embedded in the recesses on the surface of the cardboard honeycomb foam.

3. The nanocomposite microwave absorbing plate according to claim 1, characterized in that, The reinforcing layer includes glass fiber; The glass fiber is composited in the nano-absorbing layer, and the glass fiber includes chopped glass fiber; or, the glass fiber is composited in the first magnetic loss layer and / or the second magnetic loss layer, and the glass fiber includes composite glass fiber.

4. The nanocomposite microwave absorbing plate according to claim 1, characterized in that, The nano-absorbing layer is composited with two reinforcing layers, and / or, the metal fiber shielding layer is composited with one reinforcing layer on each side.

5. The nanocomposite microwave absorbing material according to any one of claims 1-4, characterized in that, A carbon fiber layer is also bonded to the side of the second magnetic loss layer away from the weight reduction and sound insulation layer.

6. The nanocomposite microwave absorbing material according to any one of claims 1-4, characterized in that, The thickness range of the nano-wave-absorbing wear-resistant layer is 0.1-1mm, the thickness range of the nano-wave-absorbing layer is 0.3-1mm, and the thickness range of the weight-reducing sound insulation layer is 1-50mm.

7. The nanocomposite microwave absorbing material according to any one of claims 1-4, characterized in that, The side of the nano-absorbing wear-resistant layer away from the nano-absorbing layer is coated with a silicon carbide resin layer.

8. A method for preparing a nanocomposite microwave absorbing plate, characterized in that, The method for preparing a nanocomposite microwave absorbing plate as described in any one of claims 1-7 comprises the following steps: Preparation of nano-absorbing and wear-resistant layer; A nano-absorbing layer is prepared, wherein a reinforcing layer is laid on the surface of the nano-absorbing wear-resistant layer, and the nano-absorbing layer is then prepared. A first magnetic loss layer, a weight-reducing and sound-insulating layer, a second magnetic loss layer, and a metal fiber shielding layer are prepared. On the side of the nano-absorbing layer away from the nano-absorbing and wear-resistant layer, the weight-reducing and sound-insulating layer, the metal fiber shielding layer, and the set reinforcement layer are laid in sequence. The first magnetic loss layer and the second magnetic loss layer are prepared by vacuum induction process.

9. The method for preparing the nanocomposite microwave absorbing plate according to claim 8, characterized in that, The steps for preparing the nano-absorbing and wear-resistant layer include: The grinding wheel is processed by applying wax and a release agent to the surface of the grinding wheel to make the surface smooth. Mix 1 part by weight of adhesive and 0.03 parts by weight of curing agent evenly, add 0.3-0.4 parts by weight of nano-wave-absorbing wear-resistant layer raw material and mix evenly again. Apply the mixed material to the mold surface and cure.

10. The method for preparing the nanocomposite microwave absorbing plate according to claim 8, characterized in that, The steps for preparing the nano-absorbing layer include: A set number of reinforcing layers are laid on the surface of the prepared nano-absorbing wear-resistant layer; Mix 1 part by weight of adhesive and 0.03 parts by weight of curing agent evenly, then add 0.3-0.4 parts by weight of nano-absorbing layer raw material and mix evenly again. A vacuum bag is placed on the side away from the nano-absorbing wear-resistant layer. The material, which has been mixed evenly again, is introduced onto the nano-absorbing wear-resistant layer through a vacuum introduction process and then cured. Remove the vacuum bag; The steps for preparing the first magnetic loss layer, the weight-reducing sound insulation layer, and the metal fiber shielding layer include: On the side of the prepared nano-absorbing layer away from the nano-absorbing wear-resistant layer, a weight-reducing sound insulation layer, a metal fiber shielding layer, and a set reinforcement layer are laid in sequence. Mix 2 parts by weight of adhesive and 0.06 parts by weight of curing agent evenly, then add 0.3-0.4 parts by weight of first magnetic loss layer material and 0.3-0.4 parts by weight of second magnetic loss layer material and mix evenly again. A vacuum bag is placed on the side away from the nano-absorbing and wear-resistant layer. The material, which has been mixed evenly again, is then introduced into both sides of the weight-reducing and sound-insulating layer, the metal fiber shielding layer, and the reinforcing layer using a vacuum introduction process, and then cured. Remove the vacuum bag.

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