Preparation method of composite wave-absorbing material, composite wave-absorbing material and communication equipment

Abstract

The application discloses a preparation method of a composite wave-absorbing material, the composite wave-absorbing material and communication equipment. The preparation method comprises the following steps: performing copper plating treatment on graphene oxide to obtain copper-plated graphene oxide; and performing composite treatment on the copper-plated graphene oxide and carbonyl iron powder to obtain the composite wave-absorbing material.

Description

Technical Field

[0001] This application belongs to the field of microwave absorbing materials technology, specifically relating to a method for preparing a composite microwave absorbing material, the composite microwave absorbing material, and a communication device. Background Technology

[0002] 2.4 GHz wireless technology boasts advantages such as bidirectional propagation, strong anti-interference capabilities, long transmission distance, and low power consumption. However, the 2.4 GHz frequency band is congested, with many different types of wireless devices, such as Wi-Fi, Bluetooth, and microwave ovens, operating in this band. Too many devices operating on the same 2.4 GHz band can lead to signal interference or conflicts. Therefore, Bluetooth frequency hopping technology, selecting different Bluetooth frequency bands, and choosing more advanced Wi-Fi technology standards can be used to combat interference and attenuation. Furthermore, absorbing materials can be configured to shield non-channel electromagnetic waves in the corresponding frequency band, improving the signal-to-noise ratio and reducing interference. However, the impedance matching and thermal conductivity performance of absorbing materials in these technologies still need improvement. Summary of the Invention

[0003] The purpose of this application is to provide a method for preparing composite absorbing materials, composite absorbing materials, and communication equipment, which can improve the impedance performance and thermal conductivity of absorbing materials.

[0004] In a first aspect, embodiments of this application provide a method for preparing a composite material, which includes: treating graphene oxide with copper to obtain copper-plated graphene oxide; and combining the copper-plated graphene oxide with carbonyl iron powder to obtain a composite microwave absorbing material.

[0005] Secondly, embodiments of this application provide a composite absorbing material, which is prepared according to the preparation method of the composite absorbing material as described in the first aspect.

[0006] Thirdly, embodiments of this application provide a communication device that employs the composite absorbing material described in the second aspect.

[0007] In the preparation method of the composite microwave absorbing material provided in this application embodiment, graphene oxide is modified by copper plating to obtain copper-plated graphene oxide. Then, the copper-plated graphene oxide is composited with carbonyl iron powder to obtain the composite microwave absorbing material. This composite microwave absorbing material not only has excellent impedance matching performance, but also excellent thermal conductivity. That is, the composite microwave absorbing material prepared by the above preparation method can improve the impedance matching performance and thermal conductivity of the composite microwave absorbing material. Attached Figure Description

[0008] Figure 1A schematic flowchart of a method for preparing a composite microwave absorbing material according to an embodiment of this application is shown; Figure 2 A schematic flowchart of another method for preparing a composite microwave absorbing material provided in an embodiment of this application is shown; Figure 3 The X-ray diffraction pattern of graphene oxide provided in an embodiment of this application is shown. Figure 4a A scanning electron microscope image of copper-plated graphene oxide provided in an embodiment of this application is shown. Figure 4b , Figure 4c , Figure 4d , Figure 4e and Figure 4f Scanning electron microscope images of a composite absorbing material provided in an embodiment of this application are shown respectively; Figure 5a This illustration shows a schematic diagram illustrating the variation of the real part of the dielectric constant of copper-plated graphene oxide provided in an embodiment of this application; Figure 5b This illustration shows a schematic diagram illustrating the variation of the imaginary part of the dielectric constant of a copper-plated graphene oxide according to an embodiment of this application. Figure 5c This illustration shows a schematic diagram illustrating the variation of the real part of the dielectric constant of a composite absorbing material provided in an embodiment of this application; Figure 5d This diagram illustrates the variation of the imaginary part of the dielectric constant of a composite absorbing material provided in an embodiment of this application. Figure 6a This paper illustrates a schematic diagram showing the variation of reflection loss in a composite absorbing material provided in an embodiment of this application. Figure 6b This illustration shows a schematic diagram illustrating the variation in reflection loss of another composite absorbing material provided in an embodiment of this application; Figure 7a This paper presents a 3D reflection loss diagram of carbonyl iron powder (CIP) as a function of thickness and frequency, according to an embodiment of this application. Figure 7b , Figure 7c , Figure 7d , Figure 7e and Figure 7f The following are 3D reflection loss diagrams showing the band mapping of a composite absorbing material as a function of thickness and frequency, according to embodiments of this application. Figure 8 This illustration shows a comparative diagram of the thermal conductivity of a composite microwave absorbing material prepared based on different concentrations of graphene oxide, as provided in an embodiment of this application. Detailed Implementation

[0009] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0010] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0011] The preparation method of the composite absorbing material, the composite absorbing material, and the communication equipment provided in this application will be described in detail below with reference to the accompanying drawings and through specific embodiments and application scenarios.

[0012] Figure 1 This document illustrates a flowchart of a method for preparing a composite microwave absorbing material according to an embodiment of this application. (See attached diagram.) Figure 1 The method may include the following steps.

[0013] Step 102: Copper plating is performed on the graphene oxide to obtain copper-plated graphene oxide.

[0014] In some embodiments, step 102 is implemented through the following steps.

[0015] Step 1021: The graphene oxide is placed in a sensitization solution for sensitization treatment; wherein, metal cations are attached to the surface of the sensitized graphene oxide.

[0016] In this process, graphene oxide (GO) is sensitized to attach metal cations to its surface, which then act as reducing agents for subsequent activation treatment.

[0017] Step 1022: The sensitized graphene oxide is placed in an activation solution for activation treatment; wherein, a metal layer is attached to the surface of the activated graphene oxide, and the metal layer has catalytic activity.

[0018] In this process, the sensitized graphene oxide is reactivated to attach a catalytically active metal to its surface, which is then used to initiate the subsequent electroless copper plating reaction.

[0019] Step 1023: The activated graphene oxide is placed in a copper plating solution for copper plating to obtain copper-plated graphene oxide.

[0020] In this method, copper-plated graphene oxide is obtained by placing sensitized and activated graphene oxide in a copper plating solution and performing copper plating through chemical copper plating. This copper-plated graphene oxide is then used to prepare composite microwave absorbing materials by combining it with carbonyl iron powder.

[0021] Step 104: The copper-plated graphene oxide is composited with carbonyl iron powder to obtain a composite microwave absorbing material.

[0022] Among them, carbonyl iron powder (CIP) is a high-performance wireless carbonyl iron absorbing material.

[0023] In this embodiment, graphene oxide is modified by copper plating to obtain copper-plated graphene oxide. The copper-plated graphene oxide is then composited with carbonyl iron powder to obtain a composite microwave absorbing material. This composite microwave absorbing material not only has excellent impedance matching performance but also excellent thermal conductivity. That is, the composite microwave absorbing material prepared by the above preparation method can improve the impedance matching performance and thermal conductivity of the composite microwave absorbing material.

[0024] In one implementation, the graphene oxide is flocculent graphene oxide; step 1021 above, which involves sensitizing the graphene oxide in a sensitizing solution, may include the following steps.

[0025] Step a1: The flocculent graphene oxide is placed in distilled water and ultrasonically dispersed. Step a2: The ultrasonically dispersed flocculent graphene oxide is placed in the sensitization solution and heated in a water bath, magnetically stirred and centrifuged to obtain the sensitized flocculent graphene oxide.

[0026] In some embodiments, the sensitizing solution comprises a mixed solution of hydrochloric acid and stannous chloride, and the metal cation comprises stannous ions.

[0027] In some embodiments, the mass fraction of graphene oxide can be 0.2-0.4 g / L. The concentration of hydrochloric acid (HCl) solution can be 30-50 mL / L, and the concentration of stannous chloride (SnCl2) solution can be 10-30 g / L. The water bath heating temperature can be 80-90℃, and the stirring time can be 20-40 min.

[0028] In this embodiment, flocculent graphene oxide is ultrasonically dispersed in distilled water to ensure uniform distribution. The ultrasonically dispersed flocculent graphene oxide is then placed in a sensitizing solution and subjected to water bath heating, magnetic stirring, and centrifugal washing to obtain sensitized flocculent graphene oxide. The surface of the sensitized flocculent graphene oxide is coated with metal cations, which serve as reducing agents for subsequent activation treatment.

[0029] In one implementation, step 1022 above, which involves placing the sensitized graphene oxide in an activation solution for activation, may include the following steps.

[0030] Step b1: The sensitized graphene oxide is subjected to ultrasonic dispersion treatment. Step b2: The ultrasonically dispersed graphene oxide is placed in the activation solution and heated in a water bath, magnetically stirred and centrifuged to obtain the activated graphene oxide.

[0031] In some embodiments, the activation solution comprises a mixed solution of hydrochloric acid and palladium chloride, and the metal layer comprises palladium.

[0032] In some embodiments, the concentration of hydrochloric acid solution can be 30-50 mL / L. The concentration of palladium chloride (PbCl2) solution can be 0.4-0.6 g / L. The water bath heating temperature can be 80-90℃, and the stirring time can be 20-40 min.

[0033] In this embodiment, the sensitized graphene oxide is ultrasonically dispersed to ensure uniform distribution. The ultrasonically dispersed graphene oxide is then placed in an activation solution and heated in a water bath, magnetically stirred, and centrifuged to obtain activated graphene oxide. The surface of the activated graphene oxide is coated with a catalytically active metal, which is used to initiate the subsequent electroless copper plating reaction and serves as a substrate for electroless copper plating.

[0034] In one implementation, step 1023 above, which involves placing the activated graphene oxide in a copper plating solution for copper plating to obtain the copper-plated graphene oxide, may include the following steps.

[0035] Step c1: The activated graphene oxide is subjected to ultrasonic dispersion treatment. Step c2 involves placing the ultrasonically dispersed graphene oxide into the copper plating solution and heating it in a water bath, stirring, adding sodium hydroxide solution and formaldehyde solution, washing and drying to obtain the copper-plated graphene oxide.

[0036] In some embodiments, the copper plating solution comprises a mixed solution of copper sulfate pentahydrate, disodium ethylenediaminetetraacetate, and potassium sodium tartrate. Copper sulfate pentahydrate is the main salt, while disodium ethylenediaminetetraacetate and potassium sodium tartrate are reducing agents.

[0037] In some embodiments, the concentration of copper sulfate pentahydrate (CuSO4·5H2O) solution can be 8-12 g / L. The concentration of disodium ethylenediaminetetraacetate (EDTA-2Na) solution can be 12-18 g / L. The concentration of potassium sodium tartrate (NaKC4H4O6) solution can be 12-18 g / L.

[0038] The sodium hydroxide solution is used to adjust the pH of the mixed solution to achieve a pH of 12.0-12.5.

[0039] In some embodiments, the formaldehyde (HCHO) solution concentration can be 8-12 mL / L. The water bath heating temperature can be 75-85℃. The electroless plating time can be 10-15 min. The number of cleaning cycles can be 3-4. The drying temperature can be 50-55℃. The drying time can be 2-4 h.

[0040] In this embodiment, the sensitized and activated graphene oxide is first subjected to ultrasonic dispersion to ensure uniform distribution. Then, the ultrasonically dispersed graphene oxide is placed in a copper plating solution and heated in a water bath, stirred, and subjected to the addition of sodium hydroxide solution and formaldehyde solution, followed by washing and drying to obtain copper-plated graphene oxide. This copper-plated graphene oxide is modified by chemical copper plating and then used to composite with carbonyl iron powder to prepare a composite microwave absorbing material.

[0041] In one implementation, step 104 above, which involves composite treatment of the copper-plated graphene oxide and carbonyl iron powder to obtain a composite microwave absorbing material, may include: placing the copper-plated graphene oxide and the carbonyl iron powder in anhydrous ethanol and mixing, dispersing, and vacuum drying them to obtain the composite microwave absorbing material.

[0042] In this embodiment, graphene oxide is modified by copper plating to obtain copper-plated graphene oxide. The copper-plated graphene oxide is then placed in anhydrous ethanol and mixed, dispersed, and vacuum dried by ultrasonication to achieve composite treatment, resulting in a composite microwave absorbing material. This composite microwave absorbing material not only has excellent impedance matching performance but also excellent thermal conductivity.

[0043] Figure 2 This paper illustrates a flowchart of another method for preparing a composite microwave absorbing material according to an embodiment of this application. See also... Figure 2 The method may include the following steps.

[0044] Step 201: Select flocculent graphene oxide and place it in distilled water for ultrasonic dispersion treatment. Place the ultrasonically dispersed graphene oxide in a mixed solution of hydrochloric acid and stannous chloride and wash it by water bath heating, magnetic stirring and centrifugation to obtain sensitized graphene oxide.

[0045] Among them, the surface of the sensitized graphene oxide is coated with easily oxidized stannous ions (Sn). 2+ ).

[0046] The selected flocculent graphene oxide had a mass fraction of 0.2-0.4 g / L, the hydrochloric acid solution concentration was 30-50 mL / L, the stannous chloride solution concentration was 10-30 g / L, the water bath heating temperature was 80-90℃, and the stirring time was 20-40 min.

[0047] Step 202: The sensitized graphene oxide is subjected to ultrasonic dispersion treatment. The ultrasonically dispersed graphene oxide is placed in a mixed solution of hydrochloric acid and palladium chloride and heated in a water bath, magnetically stirred and centrifuged to obtain activated graphene oxide.

[0048] In this process, the surface of the activated graphene oxide is coated with palladium particles with catalytic activity.

[0049] The concentration of hydrochloric acid solution is 30-50 mL / L. The concentration of palladium chloride solution is 0.4-0.6 g / L. The water bath heating temperature is 80-90℃, and the stirring time is 20-40 min.

[0050] Step 203: The activated graphene oxide is subjected to ultrasonic dispersion treatment. The ultrasonically dispersed graphene oxide is placed in a mixed solution of copper sulfate pentahydrate, disodium ethylenediaminetetraacetate and potassium sodium tartrate, and is heated in a water bath, stirred, and subjected to the addition of sodium hydroxide solution and formaldehyde solution, followed by washing and drying to obtain copper-plated graphene oxide.

[0051] The concentrations of copper sulfate pentahydrate solution, disodium ethylenediaminetetraacetate solution, and potassium sodium tartrate solution are all specified. The ratio of these three components can be adjusted based on the amount of raw materials. Sodium hydroxide solution and formaldehyde solution are added dropwise, with a formaldehyde solution concentration of 8-12 mL / L. The pH of the mixed solution is adjusted to 12.0-12.5. The water bath heating temperature is 75-85℃. The electroless plating time is 10-15 minutes. The solution is cleaned 3-4 times with anhydrous alcohol. The drying temperature is 50-55℃. The drying time is 2-4 hours.

[0052] See Figure 3 , Figure 3The illustration shows X-ray diffraction patterns of graphene oxide provided in this application, including X-ray diffraction patterns of graphene oxide solutions with concentrations of 1%, 0.8%, 0.5%, 0.3%, and 0.1%, as well as X-ray diffraction patterns of copper-plated graphene oxide obtained after sensitization, activation, and copper plating. The horizontal axis represents the diffraction angle 2θ, and the vertical axis represents the diffraction intensity, in arbitrary units (au).

[0053] pass Figure 3 It can be seen that the diffraction peaks of copper-plated graphene oxide obtained after sensitization, activation and copper plating are different from those of untreated graphene oxide, that is, the properties of copper-plated graphene oxide are changed.

[0054] Step 204: Copper-plated graphene oxide and carbonyl iron powder are placed in anhydrous ethanol and then ultrasonically mixed, dispersed, and vacuum dried to obtain a composite microwave absorbing material.

[0055] The ultrasonic mixing and stirring power is 110-130W, the ultrasonic time is 10-15min, the drying temperature is 50-55℃, and the drying time is 2-4h.

[0056] See Figure 4a , Figure 4b , Figure 4c , Figure 4d , Figure 4e and Figure 4f , Figure 4a This image shows a scanning electron microscope image of copper-plated graphene oxide provided in an embodiment of this application. Figure 4b , Figure 4c , Figure 4d , Figure 4e and Figure 4f The image shows a scanning electron microscope image of a composite microwave absorbing material provided in an embodiment of this application, which includes a composite microwave absorbing material obtained by combining copper-plated graphene obtained by copper plating with graphene oxide solutions of concentrations of 0.1%, 0.3%, 0.5%, 0.8%, and 1.0% with carbonyl iron powder.

[0057] pass Figure 4a , Figure 4b , Figure 4c , Figure 4d , Figure 4e and Figure 4f As can be seen, the composite absorbing material prepared by the method provided in this application presents a fine sheet-like and uniformly distributed morphology, which can enhance conductivity loss and multiple reflection loss, thereby more efficiently converting electromagnetic wave energy into heat energy, optimizing impedance matching, and improving absorption performance and thermal conductivity.

[0058] See Figure 5a , Figure 5b , Figure 5c and Figure 5d , Figure 5a This diagram illustrates the variation of the real part of the dielectric constant of copper-plated graphene oxide according to an embodiment of this application. Figure 5b The illustration shows a schematic diagram of the change of the imaginary part of the dielectric constant of copper-plated graphene oxide provided in an embodiment of this application, including copper plating treatment of graphene oxide solutions with concentrations of 0.1%, 0.3%, 0.5%, 0.8%, and 1.0% to obtain copper-plated graphene oxide. Figure 5c This diagram illustrates the variation of the real part of the dielectric constant of a composite absorbing material provided in an embodiment of this application. Figure 5d This illustration shows a schematic diagram illustrating the variation of the imaginary part of the dielectric constant of a composite absorbing material provided in an embodiment of this application. It includes a composite absorbing material obtained by combining copper-plated graphene oxide (obtained by copper plating with graphene oxide solutions at concentrations of 0.1%, 0.3%, 0.5%, 0.8%, and 1.0%) with carbonyl iron powder. The horizontal axis represents frequency in GHz, and the vertical axis represents the dielectric constant, including both the real and imaginary parts, in units of [missing information - likely a unit of measurement]. .

[0059] pass Figure 5a , Figure 5b , Figure 5c and Figure 5d It is understood that the composite absorbing material prepared by the method provided in the embodiments of this application has an absorption peak located near the 2.4 GHz wireless frequency band of the S-band. It can be applied to the 2.4 GHz wireless frequency band to absorb signals from the 1.14 to 2.4 GHz wireless frequency band, thereby reducing signal interference near the 2.4 GHz wireless frequency band.

[0060] See Figure 6a and Figure 6b , Figure 6a The illustration shows a schematic diagram of the reflection loss variation of a composite absorbing material provided in an embodiment of this application. The composite absorbing material is obtained by combining copper-plated graphene oxide (Cu plated GO) with a thickness of 1.5 mm, obtained by copper plating with graphene oxide solutions with concentrations of 0.1%, 0.3%, 0.5%, 0.8%, and 1.0%, with carbonyl iron powder. Figure 6bThis illustration shows a schematic diagram illustrating the variation in reflection loss of another composite absorbing material provided in this application embodiment. It includes a composite absorbing material obtained by combining copper-plated graphene oxide (2 mm thick) obtained by copper plating with graphene oxide solutions at concentrations of 0.1%, 0.3%, 0.5%, 0.8%, and 1.0% with carbonyl iron powder. The horizontal axis represents frequency in GHz, and the vertical axis represents reflection loss in dB.

[0061] pass Figure 6a and Figure 6b It is understood that the composite absorbing material prepared by the method provided in this application has a reflection valley located near the 2.4 GHz wireless frequency band in the S-band, and can be applied to the 2.4 GHz wireless frequency band to absorb signals from the 1.14 to 2.4 GHz wireless frequency band, thereby reducing signal interference near the 2.4 GHz wireless frequency band. Furthermore, the composite absorbing material obtained by combining copper-plated graphene oxide with a thickness greater than or equal to 1.5 mm and less than or equal to 2 mm with carbonyl iron powder exhibits good characteristics for application near the 2.4 GHz wireless frequency band.

[0062] See Figure 7a , Figure 7b , Figure 7c , Figure 7d , Figure 7e and Figure 7f , Figure 7a This paper presents a 3D reflection loss map of carbonyl iron powder (CIP) as a function of thickness and frequency, according to an embodiment of this application. Figure 7b , Figure 7c , Figure 7d , Figure 7e and Figure 7f This paper illustrates a 3D reflection loss diagram of a composite absorbing material as a function of thickness and frequency, according to an embodiment of this application. Figure 7b Corresponding to a 0.1% concentration of graphene oxide solution, Figure 7c Corresponding to a 0.3% concentration of graphene oxide solution, Figure 7d Corresponding to a 0.5% concentration of graphene oxide solution, Figure 7e Corresponding to a 0.8% concentration of graphene oxide solution, Figure 7f This corresponds to a 1.0% concentration of graphene oxide solution. The coordinate dimensions include frequency (GHz), thickness (mm), and reflection loss (dB).

[0063] pass Figure 7a , Figure 7b , Figure 7c , Figure 7d , Figure 7e and Figure 7f It is known that by selecting copper-plated graphene oxide of appropriate thickness and using the composite absorbing material prepared by the method provided in the embodiments of this application, the composite absorbing material can absorb signals in the 1.14 to 2.4 GHz wireless frequency band, thereby reducing signal interference near the 2.4 GHz wireless frequency band and improving the signal-to-noise ratio.

[0064] See Figure 8 , Figure 8 This illustration shows a comparative diagram of the thermal conductivity of a composite microwave absorbing material prepared based on graphene oxide of different concentrations, provided in an embodiment of this application. The unit of thermal conductivity is W / m*K.

[0065] pass Figure 8 It is known that, compared with the thermal conductivity of carbonyl iron powder, the composite microwave absorbing material prepared by the method provided in the embodiments of this application has better thermal conductivity, which is beneficial for heat dissipation in narrow device spaces, reducing the operating temperature of the device, and improving the environmental adaptability of the device.

[0066] Furthermore, this application also provides a communication device that uses a composite absorbing material prepared by the method described in the above embodiments of this application. This communication device can reduce signal interference caused by busy wireless frequency bands, such as the 2.4 GHz wireless frequency band, and improve the signal-to-noise ratio.

[0067] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0068] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A method for preparing a composite microwave absorbing material, characterized in that, include: Copper plating was performed on graphene oxide to obtain copper-plated graphene oxide. The copper-plated graphene oxide is combined with carbonyl iron powder to obtain a composite microwave absorbing material.

2. The preparation method according to claim 1, characterized in that, The process of plating copper onto graphene oxide to obtain copper-plated graphene oxide includes: The graphene oxide is placed in a sensitization solution for sensitization treatment; wherein, metal cations are attached to the surface of the sensitized graphene oxide. The sensitized graphene oxide is placed in an activation solution for activation treatment; wherein, a metal layer is attached to the surface of the activated graphene oxide, and the metal layer has catalytic activity. The activated graphene oxide was placed in a copper plating solution for copper plating to obtain copper-plated graphene oxide.

3. The preparation method according to claim 2, characterized in that, The graphene oxide is flocculent graphene oxide; the sensitization treatment of the graphene oxide in a sensitizing solution includes: The flocculent graphene oxide was placed in distilled water and ultrasonically dispersed. The ultrasonically dispersed flocculent graphene oxide was placed in the sensitization solution and then heated in a water bath, magnetically stirred, and centrifuged to obtain the sensitized flocculent graphene oxide.

4. The preparation method according to claim 2 or 3, characterized in that, The sensitizing solution comprises a mixed solution of hydrochloric acid and stannous chloride, and the metal cation comprises stannous ions.

5. The preparation method according to claim 2, characterized in that, The step of activating the sensitized graphene oxide in an activation solution includes: The sensitized graphene oxide was then subjected to ultrasonic dispersion. The ultrasonically dispersed graphene oxide was placed in the activation solution and heated in a water bath, magnetically stirred and centrifuged to obtain the activated graphene oxide.

6. The preparation method according to claim 2 or 5, characterized in that, The activation solution comprises a mixed solution of hydrochloric acid and palladium chloride, and the metal layer comprises palladium.

7. The preparation method according to claim 2, characterized in that, The step of placing the activated graphene oxide in a copper plating solution for copper plating to obtain copper-plated graphene oxide includes: The activated graphene oxide was then subjected to ultrasonic dispersion. The ultrasonically dispersed graphene oxide was placed in the copper plating solution and subjected to water bath heating, stirring, dropwise addition of sodium hydroxide solution and formaldehyde solution, washing and drying to obtain the copper-plated graphene oxide.

8. The preparation method according to claim 2 or 7, characterized in that, The copper plating solution comprises a mixed solution of copper sulfate pentahydrate, disodium ethylenediaminetetraacetate, and potassium sodium tartrate.

9. The preparation method according to claim 1, characterized in that, The composite microwave absorbing material obtained by combining the copper-plated graphene oxide with carbonyl iron powder includes: The copper-plated graphene oxide and the carbonyl iron powder were placed in anhydrous ethanol and then ultrasonically mixed, dispersed, and vacuum dried to obtain the composite microwave absorbing material.

10. A composite microwave absorbing material, characterized in that, The composite absorbing material is prepared according to the preparation method of the composite absorbing material as described in any one of claims 1 to 9.

11. The composite absorbing material according to claim 10, characterized in that, The composite absorbing material is used to absorb signals in the 1.14 to 2.4 GHz wireless frequency band.

12. A communication device, characterized in that, The communication device uses the composite absorbing material as described in claim 10 or 11.

Images