Fe2.25Te2 (at) graphene electromagnetic wave-absorbing material as well as preparation method and application thereof

Abstract

The invention provides a Fe2. 25Te2 at graphene electromagnetic wave-absorbing material and a preparation method and application thereof.The preparation method comprises the steps that S1, a quartz boat filled with Te blocks is placed on the upstream of a tubular furnace hot area, and the temperature of the hot area is kept at the temperature sufficient to enable Te to be smelted slowly; s2, mixing Fe2O3 powder, fused salt and graphene oxide powder according to a certain mass part ratio, uniformly grinding, thinly paving the mixture in another quartz boat, and placing the quartz boat in the central position of the hot area of the tube furnace; s3, heating the quartz boat in the S1 and the other quartz boat in the S2 at the same time, and carrying out sufficient reaction by using a molten salt assisted chemical vapor deposition technology; and S4, after the reaction in the S3 is completed, naturally cooling to obtain the tetragonal-phase Fe < 2.25 > Te2 (at) graphene broadband electromagnetic wave-absorbing material. The preparation method is simple, convenient and efficient, the product achieves broadband wave absorption through the synergistic effect of the two-dimensional Fe2. 25Te2 nanosheets and graphene, the quality is stable, and performance evaluation is high.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic wave absorbing materials and relates to Fe 2.25 Te2@graphene broadband electromagnetic absorbing material and its preparation method and application. Background Art

[0002] With the rapid development of 5G technology, many electronic devices that use electromagnetic waves as information carriers have been widely used in various fields. Although these devices and devices have made significant contributions to global communications, they have also brought serious radiation pollution. Therefore, "thin, light, wide, and strong" high-performance absorbing materials have become a research hotspot and have broad development prospects in the civil and military fields.

[0003] When designing and synthesizing such high-performance absorbing materials, selecting appropriate component units and controlling the interface contact between the units, enhancing polarization, etc. are the keys to achieving high-performance absorbing materials. However, most of the current research on high-performance absorbing materials focuses on improving the absorption intensity, that is, blindly pursuing high reflection loss values. There is insufficient research on how to increase the effective use range of absorbers, that is, broaden the effective absorbing bandwidth. For example, Chinese patent CN202311658723.6 discloses a carbon-cobalt-nickel alloy composite absorbing material with an effective absorbing bandwidth of 4.0 GHz; Chinese patent CN202311151311.3 discloses a Cr5Te8@expanded graphite electromagnetic absorbing material with an effective absorbing bandwidth of 4.6 GHz. Based on this situation, how to develop electromagnetic absorbing materials with a wider effective absorbing bandwidth has become an important improvement goal in this field, which is of great significance for better coping with complex and changeable electromagnetic interference environments. Summary of the invention

[0004] In view of this, the present invention provides an electromagnetic wave absorbing material and a preparation method and application thereof. The output obtained by the preparation method benefits from Fe 2.25 The strong interface polarization loss caused by the heterogeneous interface of Te2 and graphene and the synergistic effect of rich interlayer scattering optimize the impedance matching of the absorbing material, making the absorbing material have excellent electromagnetic absorbing performance and a broadened effective absorbing bandwidth.

[0005] Specifically, on one hand, the present invention provides a method for preparing an electromagnetic absorbing material, which comprises the following steps: S1: placing a quartz boat filled with Te blocks upstream of a hot zone of a tube furnace, and maintaining the temperature of the hot zone at a temperature sufficient to melt Te slowly; S2: mixing Fe2O3 powder, molten salt and graphene oxide powder in a certain mass ratio and grinding them evenly, thinly spreading them in another quartz boat and placing it in the center of the hot zone of the tube furnace; S3: simultaneously heating the quartz boat described in S1 and the other quartz boat described in S2, and performing a sufficient reaction using molten salt assisted chemical vapor deposition technology; S4: after the reaction in S3 is completed, naturally cooling to obtain a tetragonal Fe 2.25 Te2@graphene broadband electromagnetic absorbing material.

[0006] Optionally, the temperature in S1 sufficient to cause Te to melt slowly is 450-480°C.

[0007] Optionally, the Fe2O3 powder, molten salt and graphene oxide powder are mixed in S2 according to a certain mass ratio, specifically including: in the mixture, the mass ratio of Fe2O3 powder and molten salt is 1:1 / 100-1:1, and the mass ratio of Fe2O3 powder and graphene oxide powder is 1:1 / 10-1:10.

[0008] Preferably, the molten salt is one of NaCl, KCl and KI.

[0009] Optionally, the heating treatment in S3 specifically includes: before starting the heating, using a high-purity argon gas at a certain flow rate to purge the reaction chamber for 10 minutes; mixing Ar and H2 at a certain flow rate ratio and using them as carrier gases throughout the heating process; starting the heating process from room temperature at a rate of 10-30°C min -1 The heating rate is adjusted until the growth temperature reaches 500-580°C and the growth temperature is maintained for a certain period of time.

[0010] Preferably, the flow rate of the high-purity argon gas is 700 sccm.

[0011] Optionally, the flow ratio of Ar to H2 is 20:1-5:1.

[0012] Optionally, the growth temperature is maintained for 10-30 minutes.

[0013] The second aspect of the present invention provides a tetragonal Fe prepared according to the preparation method 2.25 Te2@graphene broadband electromagnetic absorbing material.

[0014] The third aspect of the present invention provides a tetragonal Fe 2.25 Application of Te2@graphene broadband electromagnetic absorbing materials in the field of electromagnetic protection.

[0015] The beneficial effects of the present invention are:

[0016] (1) Preparation of tetragonal two-dimensional Fe 2.25 The combination of atomic spin magnetism of Te2 nanosheets and lightweight graphene exerts a magneto-electric synergistic effect, improving the impedance matching of the material.

[0017] (2)Fe 2.25 The close contact between Te2 and graphene can trigger the transfer of interfacial charges, which is conducive to the polarization loss at the interface, thereby increasing the Fe 2.25 Reflection loss and absorption bandwidth of Te2@graphene absorber.

[0018] (3) The molten salt-assisted chemical vapor deposition technology is used to ensure that the reaction raw materials Fe2O3 and Te react fully. On the other hand, the presence of molten salt can induce the formation of porous graphene carbon, which is beneficial to the multiple scattering attenuation of electromagnetic waves.

[0019] In addition, additional advantages, objects, and features of the present invention will be described in part in the following description, and will become apparent to those skilled in the art after studying the following, or may be learned from the practice of the present invention. The objects and other advantages of the present invention may be realized and obtained by the structures and method steps specifically pointed out in the written description and claims and the accompanying drawings.

[0020] Those skilled in the art will appreciate that the objectives and advantages that can be achieved with the present invention are not limited to the above specific description, and the above and other objectives that can be achieved by the present invention will be more clearly understood from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of this application, and do not constitute a limitation of the present invention.

[0022] Figure 1 In the embodiment of the present invention, Fe 2.25 Schematic diagram of the preparation method steps of Te2@graphene broadband absorbing material;

[0023] Figure 2 is Fe in Example 1 of the present invention 2.25 SEM image of Te2@graphene broadband absorbing material;

[0024] Figure 3 is Fe in Example 2 of the present invention 2.25 XRD spectrum of Te2@graphene broadband absorbing material;

[0025] Figure 4The Fe content in Example 4 is 20% when the loading amount of the present invention is 20%. 2.25 3D reflection loss results of Te2@graphene broadband absorber in the 2-18GHz frequency range;

[0026] Figure 5 The Fe content in Example 4 is 20% when the loading amount of the present invention is 20%. 2.25 2D reflection loss results of Te2@graphene broadband absorber in the 2-18GHz frequency range;

[0027] Figure 6 This is a 3D reflection loss result diagram of Comparative Example 1 when the loading amount of the present invention is 20%;

[0028] Figure 7 This is a 3D reflection loss result diagram of Comparative Example 2 when the loading amount of the present invention is 20%. DETAILED DESCRIPTION

[0029] In order 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 embodiments and the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0030] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the solutions according to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0031] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, elements, steps or components, but does not exclude the presence or addition of one or more other features, elements, steps or components.

[0032] Combined with Figure 1 As shown, an embodiment of the present invention provides a method for preparing an electromagnetic absorbing material, which comprises the following steps: S1: placing a quartz boat filled with Te blocks upstream of a hot zone of a tube furnace, and maintaining the temperature of the hot zone at a temperature sufficient to melt Te slowly; S2: mixing Fe2O3 powder, molten salt and graphene oxide powder in a certain mass ratio and grinding them evenly, thinly spreading them in another quartz boat and placing it in the center of the hot zone of the tube furnace; S3: heating the quartz boat in S1 and the other quartz boat in S2 at the same time, and using molten salt assisted chemical vapor deposition technology to fully react; S4: after the reaction in S3 is completed, naturally cooling to obtain tetragonal Fe 2.25 Te2@graphene broadband electromagnetic absorbing material.

[0033] Optionally, the temperature in S1 sufficient to cause slow melting of Te is 450-480°C.

[0034] Optionally, in S2, Fe2O3 powder, molten salt and graphene oxide powder are mixed in a certain mass ratio, specifically including: in the mixture, the mass ratio of Fe2O3 powder and molten salt is 1:1 / 100-1:1, and the mass ratio of Fe2O3 powder and graphene oxide powder is 1:1 / 10-1:10.

[0035] Preferably, the molten salt is one of NaCl, KCl and KI.

[0036] Optionally, the heating treatment in S3 specifically includes: before starting the heating, using a high-purity argon gas at a certain flow rate to purge the reaction chamber for 10 minutes; mixing Ar and H2 at a certain flow rate ratio and using them as carrier gases throughout the heating process; starting the heating process from room temperature at a rate of 10-30°C min -1 The heating rate is adjusted until the growth temperature reaches 500-580°C and the growth temperature is maintained for a certain period of time.

[0037] Preferably, the flow rate of high-purity argon gas is 700 sccm.

[0038] Optionally, the flow ratio of Ar to H2 is 20:1-5:1.

[0039] Optionally, the growth temperature is maintained for 10-30 minutes.

[0040] The present invention is further described in detail below through specific examples. The following examples are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0041] A second aspect of an embodiment of the present invention provides a tetragonal Fe prepared according to a preparation method. 2.25 Te2@graphene broadband electromagnetic absorbing material.

[0042] A third aspect of the embodiment of the present invention provides a tetragonal Fe 2.25 Application of Te2@graphene broadband electromagnetic absorbing materials in the field of electromagnetic protection.

[0043] The present invention is further described in detail below through specific implementation methods and related comparative examples. The following examples are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0044] Example 1

[0045] Place the quartz boat filled with Te blocks upstream of the hot zone of the tube furnace, and the hot zone temperature is about 450°C. Take 1 part by mass of Fe2O3 powder, 1 / 100 part by mass of NaCl, and 1 / 10 part by mass of graphene oxide powder of Fe2O3, grind and mix them evenly, and spread them thinly in the quartz boat, then put the quartz boat in a quartz tube with a diameter of one inch and place it in the center of the hot zone of the tube furnace. Use high-purity argon (Ar, 700sccm) to purge the reaction chamber for 10 minutes before starting heating; a mixture of Ar and H2 is used as the carrier gas throughout the heating process, and the ratio of Ar flow to H2 flow is 20:1, where the Ar flow is 100sccm and the H2 flow is 5sccm; the growth temperature is set to 580°C, and the heating rate is 30°C min -1 After the reaction is completed, the tetragonal Fe 2.25 Te2@graphene broadband absorbing material, its SEM image is as follows Figure 2 shown.

[0046] Example 2.

[0047] Place the quartz boat filled with Te blocks upstream of the hot zone of the tube furnace, and the hot zone temperature is about 450°C. Take 1 part by mass of Fe2O3 powder, 1 / 10 part by mass of NaCl, and 1 part by mass of graphene oxide powder of Fe2O3, grind and mix them evenly, and spread them thinly in the quartz boat, then put the quartz boat in a quartz tube with a diameter of one inch and place it in the center of the hot zone of the tube furnace. Before starting heating, use high-purity argon (Ar, 700sccm) to purge the reaction chamber for 10 minutes. During the heating process, a mixture of Ar and H2 is used as the carrier gas. The ratio of Ar flow rate to H2 flow rate is 5:1, where the Ar flow rate is 50sccm and the H2 flow rate is 10sccm; the growth temperature is set to 500°C, and the heating rate is 10°C min -1 After the reaction is completed, the tetragonal Fe 2.25 Te2@graphene broadband absorbing material, its XRD spectrum is as follows Figure 3 shown.

[0048] Example 3.

[0049] Place the quartz boat filled with Te blocks upstream of the hot zone of the tube furnace, and the hot zone temperature is about 450°C. Take 1 part by mass of Fe2O3 powder, 1 part by mass of NaCl of Fe2O3, and 10 parts by mass of graphene oxide powder of Fe2O3, grind and mix them evenly, and spread them thinly in the quartz boat, then put the quartz boat in a quartz tube with a diameter of one inch and place it in the center of the hot zone of the tube furnace. Before starting heating, use high-purity argon (Ar, 700sccm) to purge the reaction chamber for 10 minutes. During the entire heating process, a mixture of Ar and H2 is used as the carrier gas. The ratio of Ar flow rate to H2 flow rate is 10:1, where the Ar flow rate is 80sccm and the H2 flow rate is 8sccm; the growth temperature is set to 550°C, and the heating rate is 20°C min -1 After the reaction is completed, the tetragonal Fe 2.25 Te2@graphene broadband absorbing material.

[0050] Example 4.

[0051] Place the quartz boat filled with Te blocks upstream of the hot zone of the tube furnace, and the hot zone temperature is about 450°C. Take 1 part by mass of Fe2O3 powder, 1 / 50 part by mass of NaCl, and 1 / 2 part by mass of graphene oxide powder of Fe2O3, grind and mix them evenly, and spread them thinly in the quartz boat, then put the quartz boat in a quartz tube with a diameter of one inch and place it in the center of the hot zone of the tube furnace. Before starting heating, use high-purity argon (Ar, 700sccm) to purge the reaction chamber for 10 minutes. During the entire heating process, a mixture of Ar and H2 is used as the carrier gas. The ratio of Ar flow rate to H2 flow rate is 20:1, of which the Ar flow rate is 40sccm and the H2 flow rate is 2sccm; the growth temperature is set to 570°C, and the heating rate is 30°C min -1 After the reaction is completed, the tetragonal Fe 2.25 Te2@graphene broadband absorbing material, its reflection loss and effective absorbing bandwidth are as follows Figure 4 and Figure 5 shown.

[0052] Comparative Example 1

[0053] Place the quartz boat filled with Te blocks upstream of the hot zone of the tube furnace, and the hot zone temperature is about 500°C. Take 1 part by mass of Fe2O3 powder and 1 / 20 part by mass of NaCl and spread them in another quartz boat, then put the quartz boat on a quartz tube with a diameter of one inch and place it in the center of the hot zone of the tube furnace. Before starting heating, use high-purity argon (Ar, 700sccm) to purge the reaction chamber for 10 minutes. During the heating process, a mixture of Ar and H2 is used as the carrier gas. The ratio of Ar flow to H2 flow is 20:1, where the Ar flow can be set to 60sccm and the H2 flow can be set to 3sccm; Fe2.25 The growth temperature of Te2 was set at 580 °C and the heating rate was 30 °C min -1 After the reaction is completed, it is cooled naturally to obtain Fe 2.25 Te2, its microwave absorption performance is as follows Figure 6 shown.

[0054] Comparative Example 2

[0055] Take 1 part by mass of graphene oxide powder and spread it in a quartz boat, then place the quartz boat in a quartz tube with a diameter of one inch and place it in the center of the hot zone of the tube furnace. Use high-purity argon (Ar, 700sccm) to purge the reaction chamber for 10 minutes before starting heating. A mixture of Ar and H2 is used as the carrier gas throughout the heating process. The ratio of Ar flow to H2 flow is 20:1, where the Ar flow can be set to 60sccm and the H2 flow can be set to 3sccm. The reaction temperature is set to 580℃, and the heating rate is 30℃min -1 After the reaction is completed, the partially reduced graphene oxide is obtained by natural cooling. Its microwave absorption performance is as follows Figure 7 shown.

[0056] Table 1. Fe content in different embodiments / comparative examples 2.25 Comparison of performance parameters of Te2@graphene broadband absorbing materials

[0057]

[0058] The smaller the reflection loss (RL), the better the absorbing effect. When the reflection loss is less than -10dB, 90% of the incident electromagnetic waves can be absorbed and converted into heat energy. The frequency range where the reflection loss is less than -10dB is the effective absorption bandwidth. The effective absorption bandwidth determines the effective working performance range of the absorbing material. The wider the bandwidth, the larger the effective use range. Figure 4 and Figure 5 As shown, the Fe 2.25 Te2@graphene broadband absorbing material has excellent absorbing performance and wide effective absorbing bandwidth. Combined with the data in Table 1, it can be seen that when the loading amount with paraffin is 20wt% and the thickness is 2.0mm, the minimum reflection loss can reach -45.8dB; when the thickness is 2.3mm, the effective absorbing bandwidth can reach 6.9GHz. Compared with the comparative example ( Figure 6 and Figure 7 ), Fe 2.25 Te2@graphene broadband absorbing material has more outstanding absorbing performance, which is the result of the composite structure giving full play to the physical advantages of the unit components and improving the matching of material and space impedance.

[0059] In addition, the Fe prepared by the present invention 2.25Te2@graphene broadband absorbing material not only has the characteristics of low loading, excellent electromagnetic absorbing performance, and wide effective absorbing bandwidth, but also has a simple preparation method, easy operation, and low production cost, which meets the requirements of actual production and is expected to play an application value in the fields of equipment electromagnetic interference protection.

[0060] It should be clear that the present invention is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present invention.

[0061] In the present invention, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with features of other embodiments or replace features of other embodiments.

[0062] The specific description above further illustrates the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A kind of Fe 2.25 The method for preparing Te2@graphene electromagnetic absorbing material is characterized in that: The method comprises the following steps: S1: Place a quartz boat filled with Te blocks upstream of the hot zone of a tube furnace, and maintain the hot zone temperature at a temperature sufficient to melt Te slowly; S2: Fe2O3 powder, molten salt and graphene oxide powder are mixed and ground evenly according to a certain mass ratio, and thinly spread in another quartz boat and placed in the center of the hot zone of the tube furnace; S3: heating the quartz boat described in S1 and the other quartz boat described in S2 simultaneously, and performing a full reaction by using a molten salt assisted chemical vapor deposition technology; S4: After the reaction of S3 is completed, it is cooled naturally to obtain tetragonal Fe 2.25 Te2@graphene broadband electromagnetic absorbing material.

2. The method according to claim 1, characterized in that: The temperature in the S1 sufficient to cause Te to melt slowly is 450-480°C.

3. The method according to claim 1, characterized in that: The step of mixing Fe2O3 powder, molten salt and graphene oxide powder in S2 according to a certain mass ratio specifically includes: In the mixture, the mass ratio of Fe2O3 powder to molten salt is 1:1 / 100-1:1, and the mass ratio of Fe2O3 powder to graphene oxide powder is 1:1 / 10-1:

10.

4. The method according to claim 3, characterized in that: The molten salt is one of NaCl, KCl and KI.

5. The method according to claim 1, characterized in that The heating treatment in S3 specifically includes: Before starting heating, the reaction chamber was purged with high-purity argon gas at a certain flow rate for 10 min; Ar and H2 are mixed at a certain flow ratio and used as carrier gas throughout the heating process; The heating process starts from room temperature and is carried out at a rate of 10-30°C min -1 The heating rate is adjusted until the growth temperature reaches 500-580°C and the growth temperature is maintained for a certain period of time.

6. The method according to claim 5, characterized in that: The flow rate of the high-purity argon gas is 700 sccm.

7. The method according to claim 5, characterized in that: The flow ratio of Ar and H2 is 20:1-5:

1.

8. The method according to claim 5, characterized in that: The growth temperature is maintained for 10-30 minutes.

9. A tetragonal Fe prepared by the preparation method according to any one of claims 1 to 8 2.25 Te2@graphene broadband electromagnetic absorbing material.

10. A tetragonal Fe according to claim 9 2.25 Application of Te2@graphene broadband electromagnetic absorbing materials in the field of electromagnetic protection.

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