Ternary composite material, method for preparing the same, and microwave absorbing material

Abstract

The application discloses a ternary composite material and a preparation method thereof and a microwave absorbing material. The ternary composite material comprises a sheet-shaped magnetic metal, amorphous titanium dioxide and a non-metallic two-dimensional material attached to the surface of the sheet-shaped magnetic metal; the mass ratio of the non-metallic two-dimensional material to the sheet-shaped magnetic metal is (0.16-0.4):1, and the mass ratio of the amorphous titanium dioxide to the sheet-shaped magnetic metal is (0.14-0.48):1. The microwave absorbing material comprises the ternary composite material, and when the thickness of the microwave absorbing material is less than 1.5 mm, the effective absorption bandwidth of the microwave absorbing material in a 2GHz-18GHz wave band is greater than 5GHz. Therefore, the microwave absorbing material has high electromagnetic wave absorption capacity when the thickness of the microwave absorbing material is less than 1.5 mm.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microwave absorbing materials, in particular to a ternary composite material, a preparation method thereof and a microwave absorbing material. BACKGROUND

[0002] With the development of communication technology, in the field of civil electronic devices, the electromagnetic radiation generated by electronic equipment poses a potential threat to the operation of precision electronic instruments and human health, therefore, the management and protection of electromagnetic radiation have become an increasingly important issue; in the field of military weapons and equipment, with the development of radar detection technology, the penetration capability of aircraft and missiles has gradually become the key to winning on the battlefield. Microwave absorbing materials, as a functional material that can convert electromagnetic wave energy into heat energy, can effectively reduce the reflection of electromagnetic waves. Microwave absorbing materials not only can reduce the degree of invasion of electromagnetic waves on precision electronic instruments and human health, but also can improve the stealth performance of weapons and equipment in the frequency range of 2GHz-18GHz radar, thereby improving the survival rate of weapons on the battlefield. Therefore, the research and development of new microwave absorbing materials have practical significance and strategic value in both civilian and military fields.

[0003] It should be noted that the above statements are only used to provide background technical information related to the present application, and do not necessarily constitute prior art. SUMMARY

[0004] In the first aspect of the present application, the present application provides a ternary composite material, comprising a sheet-shaped magnetic metal, and amorphous titanium dioxide and non-metallic two-dimensional material attached to the surface of the sheet-shaped magnetic metal; the mass ratio of the non-metallic two-dimensional material to the sheet-shaped magnetic metal is (0.16-0.4):1, and the mass ratio of the amorphous titanium dioxide to the sheet-shaped magnetic metal is (0.14-0.48):1. Thus, the ternary composite material with appropriate proportions of sheet-shaped magnetic metal, non-metallic two-dimensional material and amorphous titanium dioxide can improve the synergistic effect of dielectric properties and magnetic properties of the ternary composite material.

[0005] In some embodiments, the sheet-shaped magnetic metal comprises at least one of iron and its alloys, cobalt and its alloys, and nickel and its alloys. Thus, selecting appropriate types of sheet-shaped magnetic metal helps to further improve the magnetic properties of the ternary composite material.

[0006] Preferably, the sheet-shaped magnetic metal comprises iron.

[0007] In some embodiments, the non-metallic two-dimensional material comprises at least one of graphene, two-dimensional transition metal carbide, two-dimensional transition metal nitride, and two-dimensional transition metal carbonitride. Thus, by selecting a suitable type of non-metallic two-dimensional material, the orientation polarization loss of the dipoles of the ternary composite material can be further improved, and thus the dielectric constant of the ternary composite material can be further improved.

[0008] Preferably, the non-metallic two-dimensional material comprises graphene.

[0009] In some embodiments, the flaky magnetic metal has a particle size of 1-10 μm, the amorphous titanium dioxide has a particle size of 0.1-10 μm, and the non-metallic two-dimensional material has a particle size of 0.1-1 μm. Thus, by using ternary composite materials with different particle sizes, the microstructure and interface of the ternary composite material can be enriched, and the specific surface area of the ternary composite material can be increased, so as to increase the contact area between the electromagnetic wave and the ternary composite material, and improve the absorption rate of the electromagnetic wave.

[0010] In the second aspect of the present application, a method for preparing the ternary composite material is provided, which comprises: mixing a non-metallic material and an organic amine, and then performing a grinding treatment to obtain an organic amine intercalated non-metallic material; performing an ultrasonic dispersion treatment on the organic amine intercalated non-metallic material to obtain an organic amine intercalated non-metallic two-dimensional material; mixing the organic amine intercalated non-metallic two-dimensional material, a flaky magnetic metal, and a titanium dioxide precursor, and then performing a stirring treatment to obtain a ternary composite precipitate, wherein the mass ratio of the organic amine intercalated non-metallic two-dimensional material to the flaky magnetic metal is (0.2-1):1, and the mass ratio of the titanium dioxide precursor to the flaky magnetic metal is (0.6-1.6):1; and performing a calcination treatment on the ternary composite precipitate to obtain the ternary composite material.

[0011] Thus, by the grinding treatment, the non-metallic material and the organic amine are fully mixed, the molecular chain of the organic amine is inserted into the interlayer of the non-metallic material by the friction and shear force generated by the grinding treatment, the intercalation structure formed expands the interlayer spacing of the non-metallic material, thereby increasing the specific surface area and the number of active sites of the non-metallic material. At the same time, the thermal effect generated by the mechanical force during the grinding treatment can further improve the surface energy and reactivity of the non-metallic material intercalated with the organic amine, providing a basis for subsequent ultrasonic dispersion treatment of the non-metallic material intercalated with the organic amine. The ultrasonic dispersion treatment can further promote the intercalation effect of the organic amine in the interlayer of the non-metallic material, and then the cavitation effect and mechanical vibration of the ultrasonic wave make the non-metallic material intercalated with the organic amine fully dispersed, so that the non-metallic material forms a non-metallic two-dimensional material with a nanosheet structure. Through stirring treatment, first, the titanium dioxide precursor is hydrolyzed to form Ti(OH)4 during stirring, and then the non-metallic two-dimensional material intercalated with the organic amine, the sheet-shaped magnetic metal, and Ti(OH)4 gradually agglomerate, providing a basis for subsequent calcination treatment of the ternary composite precipitate. By controlling the ratio of the non-metallic two-dimensional material intercalated with the organic amine, the sheet-shaped magnetic metal, and the titanium dioxide precursor, the content of the non-metallic two-dimensional material, the sheet-shaped magnetic metal, and the titanium dioxide in the ternary composite material can be controlled. Through calcination treatment, organic impurities and excess solvent in the ternary composite precipitate can be removed, promoting the fusion and structure recombination of the ternary composite precipitate, forming a ternary composite material with sheet-shaped magnetic metal, amorphous titanium dioxide, and non-metallic two-dimensional material.

[0012] In some embodiments, before mixing the non-metallic two-dimensional material intercalated with the organic amine, the sheet-shaped magnetic metal, and the titanium dioxide precursor, the sheet-shaped magnetic metal is further subjected to an organic modification treatment, and the organic matter includes at least one of a silane coupling agent, a methoxysilane coupling agent, an epoxy silane coupling agent, an amino silane coupling agent, and a methacryloyloxy silane coupling agent. Thus, the functional groups in the organic molecule chemisorb on the surface of the sheet-shaped magnetic metal to make the surface of the sheet-shaped magnetic metal attach more functional groups to increase the active sites on the surface of the sheet-shaped magnetic metal, providing a basis for subsequent attachment of the non-metallic two-dimensional material and the amorphous titanium dioxide.

[0013] In some embodiments, the grinding treatment satisfies at least one of the following conditions: the non-metallic material comprises at least one of graphite oxide, transition metal carbide, transition metal nitride, and transition metal carbonitride; the organic amine comprises at least one of propylamine, n-butylamine, and n-pentylamine; in the grinding treatment, the mass of the non-metallic material is a, in grams, and the volume of the organic amine is b, in milliliters, and a:b is 1:(10-20); the grinding speed of the grinding treatment is 60-100 rpm, and the grinding time of the grinding treatment is 15-30 minutes. In this way, the appropriate non-metallic material type is selected, the organic amine is inserted into the interlayer of the non-metallic material to form a non-metallic material with an intercalation structure. The organic amine has a long carbon chain and an amino group, and the selection of the appropriate organic amine type facilitates the insertion of the organic amine into the interlayer of the non-metallic material to increase the interlayer spacing of the non-metallic material. The selection of the appropriate ratio of the non-metallic material and the organic amine facilitates further improvement of the intercalation efficiency of the organic amine. The selection of the appropriate grinding speed and grinding time facilitates the control of the particle size of the non-metallic material.

[0014] In some embodiments, the ultrasonic dispersion treatment comprises: adding the organic amine intercalated non-metallic material into a first solvent for the ultrasonic dispersion treatment, the first solvent comprising at least one of methanol, ethanol, and propanol; in the ultrasonic dispersion treatment, the mass of the organic amine intercalated non-metallic material is c, in grams, and the volume of the first solvent is d, in milliliters, and c:d is 1:(300-1000). In this way, the selection of the appropriate first solvent type facilitates the improvement of the dispersibility and stability of the organic amine intercalated non-metallic material in the first solvent. The selection of the appropriate ratio of the organic amine intercalated non-metallic material and the first solvent facilitates the formation of a uniform suspension of the organic amine intercalated non-metallic material in the first solvent.

[0015] In some embodiments, the ultrasonic power of the ultrasonic dispersion treatment is 80-100 W, and the ultrasonic time of the ultrasonic dispersion treatment is 15-30 minutes. In this way, the selection of the appropriate ultrasonic power and ultrasonic time facilitates the formation of a non-metallic two-dimensional material with a nanosheet structure.

[0016] In some embodiments, the calcination treatment satisfies at least one of the following conditions: the protective gas of the calcination treatment comprises at least one of nitrogen and argon; the temperature of the calcination treatment is 300-400°C, and the time of the calcination treatment is 2-4 hours. In this way, the selection of the appropriate protective gas, the temperature of the calcination treatment, and the time of the calcination treatment facilitates the formation of a ternary composite material with a uniform and stable internal structure.

[0017] In a third aspect, the present application provides a microwave absorbing material comprising the ternary composite material as described above, or the ternary composite material obtained by the preparation method of the ternary composite material as described above. The microwave absorbing material of the present application has a synergistic effect of dielectric matching at a higher real part of dielectric coefficient and significant magnetic loss. When the thickness of the microwave absorbing material of the present application is less than 1.5 mm, the effective absorption bandwidth of the microwave absorbing material in the wave band of 2-18 GHz is greater than 5 GHz. Therefore, the microwave absorbing material of the present application still has high efficient electromagnetic wave absorption capacity when the thickness of the microwave absorbing material is less than 1.5 mm. BRIEF DESCRIPTION OF DRAWINGS

[0018] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:

[0019] Figure 1 is a process flow diagram of the preparation method of the ternary composite material in an embodiment of the present application.

[0020] Figure 2 is an X-ray diffraction pattern of the product prepared in Examples 1-3 and Comparative Examples 2-5 in the present application; wherein, Figure 2 the (a) graph in is an X-ray diffraction pattern of the product prepared in Examples 1-3 and Comparative Examples 4-5, Figure 2 the (b) graph in is an X-ray diffraction pattern of the product prepared in Comparative Examples 2-3.

[0021] Figure 3 is a Raman spectrum of Examples 1-3 and Comparative Example 5 in the present application.

[0022] Figure 4 is an XPS N 1s fine spectrum of Examples 1-3, Comparative Example 1 and Comparative Example 5 in the present application.

[0023] Figure 5 is a scanning electron microscope image of Example 3 in the present application.

[0024] Figure 6 is a scanning electron microscope energy spectrum of Example 3 in the present application.

[0025] Figure 7 is a distribution map of iron element in the product prepared in Example 3 in the present application.

[0026] Figure 8 is a distribution map of titanium element in the product prepared in Example 3 in the present application.

[0027] Figure 9 is a relative complex dielectric coefficient and complex magnetic permeability spectrum of Examples 1-3 and Comparative Example 5, wherein, Figure 9 the (a) graph in is a real part of dielectric coefficient graph; Figure 9the (b) graph in FIG. 1 is a dielectric coefficient imaginary part graph; Figure 9 the (c) graph in FIG. 1 is a dielectric loss tangent graph; Figure 9 the (d) graph in FIG. 1 is a magnetic permeability real part graph; Figure 9 the (e) graph in FIG. 1 is a magnetic permeability imaginary part graph; Figure 9 the (f) graph in FIG. 1 is a magnetic loss tangent graph.

[0028] Figure 10 is a relative complex dielectric constant spectrogram of Comparative Example 1-3, wherein, Figure 10 the (a) graph in FIG. 2 is a dielectric coefficient real part graph of Comparative Example 1; Figure 10 the (b) graph in FIG. 2 is a dielectric coefficient imaginary part graph of Comparative Example 1; Figure 10 the (c) graph in FIG. 2 is a dielectric loss tangent graph of Comparative Example 1; Figure 10 the (d) graph in FIG. 3 is a dielectric coefficient real part graph of Comparative Example 2-3; Figure 10 the (e) graph in FIG. 3 is a dielectric coefficient imaginary part graph of Comparative Example 2-3; Figure 10 the (f) graph in FIG. 3 is a dielectric loss tangent graph of Comparative Example 2-3.

[0029] Figure 11 is a reflection loss curve graph of the materials of Example 1-3, Comparative Example 5 at different thicknesses, wherein, Figure 11 the (a) graph in FIG. 4 is a reflection loss curve graph of Example 1; Figure 11 the (b) graph in FIG. 4 is a reflection loss curve graph of Example 2; Figure 11 the (c) graph in FIG. 4 is a reflection loss curve graph of Example 3; Figure 11 the (d) graph in FIG. 4 is a reflection loss curve graph of Comparative Example 5.

[0030] Figure 12 is a reflection loss curve graph of the materials of Comparative Example 1-3 at different thicknesses, wherein, Figure 12 the (a) graph in FIG. 5 is a reflection loss curve graph of Comparative Example 1; Figure 12 the (b) graph in FIG. 5 is a reflection loss curve graph of Comparative Example 2; Figure 12 the (c) graph in FIG. 5 is a reflection loss curve graph of Comparative Example 3. DETAILED DESCRIPTION

[0031] Hereinafter, the ternary composite material and the preparation method thereof, and the microwave absorbing material embodiment of the present application are specifically disclosed with appropriate reference to the accompanying drawings. However, there will be cases where unnecessary detailed descriptions are omitted. For example, there will be cases where detailed descriptions of matters well known, repeated descriptions of actually identical structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy, and to facilitate understanding by those skilled in the art. In addition, the accompanying drawings and the following description are provided in order for those skilled in the art to fully understand the present application, and are not intended to limit the subject matter recited in the claims.

[0032] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is also expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0033] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0034] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0035] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit this application; unless otherwise stated, the values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (e.g., they can be tested according to the methods given in the embodiments of this application).

[0036] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. "First feature" and "second feature" may include one or more of the indicated feature.

[0037] In the description of this application, "A and / or B" can include any of the cases of A alone, B alone, or A and B, where A and B are merely examples and can be any technical feature connected by "and / or" in this application.

[0038] The microwave absorbing material needs to have a certain thickness so that the electromagnetic wave is effectively attenuated inside the microwave absorbing material and converted into heat energy. When the thickness of the microwave absorbing material is less than 1.5 mm, its microwave absorption performance decreases significantly, which limits the application of the microwave absorbing material in the field of material lightweight.

[0039] In order to reduce the thickness of the microwave absorbing material, according to Maxwell equations, the thinning strategy of the microwave absorbing material lies in improving its dielectric coefficient or magnetic permeability, wherein the dielectric coefficient is more easily improved than the magnetic permeability and is considered as the key to realize the thinning of the microwave absorbing material. However, with the increase of the dielectric coefficient, the microwave absorbing material wants to show good microwave absorption effect under the condition of ultra-thin thickness, which needs to meet the counter-intuitive relationship between the real part of the dielectric coefficient and the dielectric loss tangent in a wide frequency band, that is, good dielectric matching. Good dielectric matching helps electromagnetic waves effectively enter the material inside. However, for the microwave absorbing material with a thickness of less than 1.5 mm, it is difficult to achieve wide frequency dielectric matching under the condition of high dielectric coefficient real part.

[0040] Therefore, it is an urgent problem to develop a microwave absorbing material that meets the requirements of material lightweight and has high efficient electromagnetic wave absorption performance.

[0041] In the first aspect of the present application, the present application provides a ternary composite material, comprising a sheet-shaped magnetic metal, and amorphous titanium dioxide and a non-metallic two-dimensional material attached to the surface of the sheet-shaped magnetic metal; the mass ratio of the non-metallic two-dimensional material to the sheet-shaped magnetic metal is (0.16-0.4):1, and the mass ratio of the amorphous titanium dioxide to the sheet-shaped magnetic metal is (0.14-0.48):1.

[0042] The ternary composite of the present application takes flaky magnetic metal as the matrix. The flaky magnetic metal has high magnetic permeability and magnetic loss characteristics, and plays a role in enhancing the magnetic response in the ternary composite. Meanwhile, the flaky morphology of the flaky magnetic metal not only increases the specific surface area of the material and enhances the magnetic interaction to produce strong magnetic natural resonance, but also further improves the magnetic permeability and magnetic loss of the ternary composite through the anisotropic characteristics thereof. The non-metallic two-dimensional material attached to the surface of the flaky magnetic metal has high electrical conductivity and large specific surface area, which can provide dipole orientation polarization loss for the ternary composite, thereby improving the dielectric constant of the ternary composite. The amorphous titanium dioxide attached to the surface of the flaky magnetic metal has high polarization characteristics, which helps to adjust the dielectric properties of the ternary composite, and its amorphous form can provide more defect states to increase the dielectric loss of the ternary composite, thereby improving the energy conversion efficiency of the ternary composite. Therefore, the ternary composite with appropriate proportions of flaky magnetic metal, non-metallic two-dimensional material and amorphous titanium dioxide can improve the synergistic effect of the dielectric and magnetic properties of the ternary composite.

[0043] For example, the mass ratio of the non-metallic two-dimensional material to the flaky magnetic metal can be 0.16:1, 0.2:1, 0.24:1, 0.28:1, 0.32:1, 0.36:1 or 0.4:1.

[0044] For example, the mass ratio of the amorphous titanium dioxide to the flaky magnetic metal can be 0.14:1, 0.18:1, 0.22:1, 0.26:1, 0.3:1, 0.34:1, 0.38:1, 0.42:1 or 0.48:1.

[0045] In some embodiments, the flaky magnetic metal includes at least one of iron and its alloys, cobalt and its alloys, nickel and its alloys. In this way, selecting the appropriate type of flaky magnetic metal helps to further improve the magnetic properties of the ternary composite.

[0046] Preferably, the flaky magnetic metal includes iron, and the microstructure of the iron presents a layered morphology.

[0047] In some embodiments, the non-metallic two-dimensional material includes at least one of graphene, two-dimensional transition metal carbide, two-dimensional transition metal nitride, two-dimensional transition metal carbonitride. In this way, selecting the appropriate type of non-metallic two-dimensional material helps to further improve the dipole orientation polarization loss of the ternary composite, thereby further improving the dielectric constant of the ternary composite.

[0048] In some embodiments, the two-dimensional transition metal carbide satisfies the chemical formula M e C fwherein M comprises at least one of Sc, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W, e is 2-4; f is 1-3.

[0049] As an example, e can be 2, 3 or 4.

[0050] As an example, f can be 1, 2 or 3.

[0051] In some embodiments, the two-dimensional transition metal carbide satisfies the chemical formula M g N h wherein M comprises at least one of Sc, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W, g is 2-4; h is 1-3.

[0052] As an example, g can be 2, 3 or 4.

[0053] As an example, h can be 1, 2 or 3.

[0054] Preferably, the non-metallic two-dimensional material comprises graphene.

[0055] In some embodiments, the flaky magnetic metal has a particle size of 1-10 μm, the amorphous titanium dioxide has a particle size of 0.1-10 μm, and the non-metallic two-dimensional material has a particle size of 0.1-1 μm. Thus, the ternary composite material composed of different particle sizes helps to enrich the microstructure and interface of the ternary composite material, increase the specific surface area of the ternary composite material, thereby increasing the contact area of the electromagnetic wave with the ternary composite material and improving the absorption rate of the electromagnetic wave. Meanwhile, the flaky magnetic metal with a larger particle size helps to improve the overall mechanical strength of the ternary composite material, so that the ternary composite material has better mechanical stability and durability.

[0056] As an example, the flaky magnetic metal can have a particle size of 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm.

[0057] As an example, the amorphous titanium dioxide can have a particle size of 0.1 μm, 0.5 μm, 1 μm, 2 μm, 4 μm, 6 μm, 8 μm or 10 μm.

[0058] As an example, the non-metallic two-dimensional material can have a particle size of 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm or 1 μm.

[0059] In the second aspect of the present application, the present application provides a method for preparing the aforementioned ternary composite material, with reference to Figure 1 The method comprises:

[0060] S100. Non-metallic materials and organic amines are mixed and then ground to obtain non-metallic materials with organic amine intercalation.

[0061] Therefore, through grinding, the non-metallic material and organic amine are thoroughly mixed. The friction and shear forces generated during grinding cause the molecular chains of the organic amine to insert into the interlayer space of the non-metallic material. The resulting intercalation structure expands the interlayer spacing of the non-metallic material, thereby increasing its specific surface area and the number of active sites. Simultaneously, the thermal effect generated by the mechanical force during grinding can further enhance the surface energy and reactivity of the organic amine-intercalated non-metallic material, providing a basis for subsequent ultrasonic dispersion treatment of the organic amine-intercalated non-metallic material.

[0062] In some embodiments, the grinding process satisfies at least one of the following conditions: the non-metallic material includes at least one of graphite oxide, transition metal carbides, transition metal nitrides, and transition metal carbonitrides; the organic amine includes at least one of propylamine, n-butylamine, and n-pentylamine; in the grinding process, the mass of the non-metallic material is 'a' (g), the volume of the organic amine is 'b' (mL), and the ratio of a to b is 1:(10-20); the grinding speed is 60 rpm-100 rpm, and the grinding time is 15 min-30 min. Therefore, selecting a suitable type of non-metallic material facilitates the insertion of the organic amine into the interlayer of the non-metallic material to form a non-metallic material with an intercalation structure. Organic amines have long carbon chains and amino groups; selecting a suitable type of organic amine helps the organic amine to insert into the interlayer of the non-metallic material, thereby increasing the interlayer spacing. Selecting a suitable ratio of non-metallic material to organic amine helps to further improve the intercalation efficiency of the organic amine. Selecting a suitable grinding speed and grinding time helps to control the particle size of the non-metallic material.

[0063] As an example, a:b can be 1:10, 1:12, 1:14, 1:16, 1:18, or 1:20.

[0064] As an example, the grinding speed for the grinding process can be 60 rpm, 70 rpm, 80 rpm, 90 rpm, or 100 rpm.

[0065] As an example, the grinding time for the grinding process can be 15 min, 20 min, 25 min, or 30 min.

[0066] As an example, the grinding treatment satisfies the following conditions: the non-metallic material comprises at least one of graphite oxide, transition metal carbide, transition metal nitride, and transition metal carbonitride; the organic amine comprises at least one of propylamine, n-butylamine, and n-pentylamine; in the grinding treatment, the mass of the non-metallic material is a, in g, the volume of the organic amine is b, in mL, and a:b is 1:(10-20); the grinding speed of the grinding treatment is 60 rpm-100 rpm, and the grinding time of the grinding treatment is 15 min-30 min.

[0067] S200, performing ultrasonic dispersion treatment on the organic amine intercalated non-metallic material to obtain an organic amine intercalated non-metallic two-dimensional material.

[0068] Therefore, the ultrasonic dispersion treatment can further promote the intercalation effect of the organic amine between the layers of the non-metallic material, and then the cavitation effect and mechanical vibration of the ultrasonic wave can make the organic amine intercalated non-metallic material fully dispersed, so that the non-metallic material forms a non-metallic two-dimensional material with a nanosheet structure.

[0069] In some embodiments, the ultrasonic dispersion treatment comprises: adding the organic amine intercalated non-metallic material into a first solvent to perform ultrasonic dispersion treatment.

[0070] In some embodiments, the first solvent comprises at least one of methanol, ethanol, and propanol. Therefore, selecting an appropriate type of first solvent helps to improve the dispersibility and stability of the organic amine intercalated non-metallic material in the first solvent.

[0071] In some embodiments, in the ultrasonic dispersion treatment, the mass of the organic amine intercalated non-metallic material is c, in g, the volume of the first solvent is d, in mL, and c:d is 1:(300-1000). Therefore, selecting an appropriate ratio of the organic amine intercalated non-metallic material and the first solvent helps to form a uniform suspension of the organic amine intercalated non-metallic material in the first solvent.

[0072] As an example, c:d can be 1:300, 1:400, 1:500, 1:600, 1:700, 1:800, 1:900, or 1:1000.

[0073] In some embodiments, the ultrasonic power of the ultrasonic dispersion treatment is 80 W-100 W, and the ultrasonic time of the ultrasonic dispersion treatment is 15 min-30 min. Therefore, selecting an appropriate ultrasonic power and ultrasonic time helps to form a non-metallic two-dimensional material with a nanosheet structure.

[0074] As an example, the ultrasonic power of the ultrasonic dispersion treatment can be 80 W, 85 W, 90 W, 95 W, or 100 W.

[0075] As an example, the ultrasonic time of the ultrasonic dispersion treatment can be 15 min, 20 min, 25 min, or 30 min.

[0076] S300, after mixing the organic amine intercalated non-metallic two-dimensional material, the sheet-shaped magnetic metal, and the titanium dioxide precursor, stirring treatment is performed to obtain a ternary composite precipitate, wherein the mass ratio of the organic amine intercalated non-metallic two-dimensional material to the sheet-shaped magnetic metal is (0.2-1):1, and the mass ratio of the titanium dioxide precursor to the sheet-shaped magnetic metal is (0.6-1.6):1.

[0077] First, the titanium dioxide precursor is hydrolyzed to form Ti(OH)4 during the stirring process, and then the organic amine intercalated non-metallic two-dimensional material, the sheet-shaped magnetic metal, and Ti(OH)4 gradually agglomerate, providing a basis for subsequent calcination treatment of the ternary composite precipitate. By controlling the ratio of the organic amine intercalated non-metallic two-dimensional material, the sheet-shaped magnetic metal, and the titanium dioxide precursor, the content of the non-metallic two-dimensional material, the sheet-shaped magnetic metal, and the titanium dioxide in the ternary composite material can be controlled.

[0078] As an example, the mass ratio of the organic amine intercalated non-metallic two-dimensional material to the sheet-shaped magnetic metal can be 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, or 1:1.

[0079] As an example, the mass ratio of the titanium dioxide precursor to the sheet-shaped magnetic metal can be 0.6:1, 0.8:1, 1:1, 1.2:1, 1.4:1, or 1.6:1.

[0080] In some embodiments, before mixing the organic amine intercalated non-metallic two-dimensional material, the sheet-shaped magnetic metal, and the titanium dioxide precursor, further comprising organic modification treatment of the sheet-shaped magnetic metal. Thus, the functional groups in the organic molecules chemically adsorb on the surface of the sheet-shaped magnetic metal, so that more functional groups are attached to the surface of the sheet-shaped magnetic metal, increasing the active sites on the surface of the sheet-shaped magnetic metal, providing a basis for subsequent attachment of non-metallic two-dimensional materials and amorphous titanium dioxide.

[0081] In some embodiments, the organic matter includes at least one of a silane coupling agent, including methoxysilane coupling agent (KH540), epoxy silane coupling agent (KH560), amino silane coupling agent (KH550), and methacryloyloxy silane coupling agent (KH570). Thus, by selecting appropriate types of silane coupling agents, different types of functional groups can be attached to the surface of the sheet-shaped magnetic metal, thereby further increasing the active sites on the surface of the sheet-shaped magnetic metal.

[0082] In some embodiments, the step of modifying the flaky magnetic metal with the organic matter includes: mixing the flaky magnetic metal, the organic matter, and a second solvent, and then performing a first ultrasonic treatment to obtain a first suspension; mixing the first suspension and ammonia water, and then performing a second ultrasonic treatment to obtain a second suspension; and performing a suction filtration treatment on the second suspension to obtain the flaky magnetic metal modified with the organic matter. In this way, in the first ultrasonic treatment, the flaky magnetic metal and the organic matter are uniformly suspended in the second solvent, in the second ultrasonic treatment, the ammonia water helps the functional groups in the organic matter molecules to chemically adsorb to the surface of the flaky magnetic metal, so that the organic matter is grafted to the flaky magnetic metal, and finally the suction filtration treatment is performed on the second suspension to obtain the flaky magnetic metal modified with the organic matter.

[0083] In some embodiments, the mass of the flaky magnetic metal is i, in grams, the volume of the organic matter is j, in milliliters, and i:j is 2:(0.5-1.5).

[0084] For example, i:j can be 2:0.5, 2:1, or 2:1.5.

[0085] In some embodiments, the mass of the flaky magnetic metal is i, in grams, the volume of the second solvent is k, in milliliters, and i:k is 1:(10-30).

[0086] For example, i:k can be 1:10, 1:15, 1:20, 1:25, or 1:30.

[0087] In some embodiments, the mass of the flaky magnetic metal is i, in grams, the volume of the ammonia water is l, in milliliters, and i:l is 1:(0.1-0.3).

[0088] For example, i:l can be 1:0.1, 1:0.15, 1:0.2, 1:0.25, or 1:0.3.

[0089] In some embodiments, the second solvent includes at least one of ethanol and isopropyl alcohol.

[0090] In some embodiments, the ultrasonic power of the first ultrasonic treatment is 80W-100W, and the ultrasonic time of the first ultrasonic treatment is 20min-40min. In this way, the flaky magnetic metal and the organic matter are further uniformly suspended in the second solvent.

[0091] For example, the ultrasonic power of the first ultrasonic treatment can be 80W, 85W, 90W, 95W, or 100W.

[0092] For example, the ultrasonic time of the first ultrasonic treatment can be 20min, 25min, 30min, 35min, or 40min.

[0093] In some embodiments, the second ultrasonic treatment has an ultrasonic power of 80-100 W and an ultrasonic time of 1-3 h. Thereby, the functional groups in the organic molecules are facilitated to chemically adsorb on the surface of the flaky magnetic metal.

[0094] For example, the second ultrasonic treatment has an ultrasonic power of 80 W, 85 W, 90 W, 95 W, or 100 W.

[0095] For example, the second ultrasonic treatment has an ultrasonic time of 1 h, 1.5 h, 2 h, 2.5 h, or 3 h.

[0096] In some embodiments, the flaky magnetic metal modified by the organic matter is subjected to a washing treatment to obtain a flaky magnetic metal modified by the organic matter after washing. Thereby, the flaky magnetic metal modified by the organic matter with higher purity is obtained.

[0097] In some embodiments, the washing solvent of the washing treatment includes anhydrous ethanol.

[0098] In some embodiments, the flaky magnetic metal modified by the organic matter after washing is subjected to a drying treatment in a vacuum environment.

[0099] In some embodiments, the drying treatment has a drying temperature of 30-50 °C and a drying time of 1-3 h.

[0100] For example, the drying treatment has a drying temperature of 30 °C, 35 °C, 40 °C, 45 °C, or 50 °C.

[0101] For example, the drying treatment has a drying time of 1 h, 1.5 h, 2 h, 2.5 h, or 3 h.

[0102] In some embodiments, the vacuum degree of the vacuum environment is less than 1 kPa.

[0103] For example, the vacuum degree of the vacuum environment includes, but is not limited to, 0.1 kPa, 0.3 kPa, 0.5 kPa, 0.7 kPa, or 0.9 kPa.

[0104] In some embodiments, the titanium dioxide precursor includes at least one of tetrabutyl titanate, tetraisopropyl titanate, n-butyl titanate, ethyl titanate, and tetramethyl titanate.

[0105] In some embodiments, the stirring treatment has a stirring speed of 500-1000 rpm and a stirring time of 1-3 h. Thereby, the titanium dioxide precursor is sufficiently hydrolyzed.

[0106] As an example, the stirring speed of the stirring treatment can be 500 rpm, 600 rpm, 700 rpm, 800 rpm, 900 rpm, or 1000 rpm.

[0107] As an example, the stirring time of the stirring treatment can be 1 h, 1.5 h, 2 h, 2.5 h, or 3 h.

[0108] S400, the calcination treatment is performed on the ternary composite precipitate to obtain a ternary composite material. Thus, through the calcination treatment, the organic impurities and excess solvent in the ternary composite precipitate can be removed, and the phase fusion and structural recombination inside the ternary composite precipitate are promoted, so as to form a ternary composite material with a sheet-shaped magnetic metal, amorphous titanium dioxide, and a non-metallic two-dimensional material.

[0109] In some embodiments, the calcination treatment satisfies at least one of the following conditions: the protective gas of the calcination treatment comprises at least one of nitrogen and argon; the temperature of the calcination treatment is 300-400°C, and the time of the calcination treatment is 2-4 h. Thus, by selecting appropriate protective gas, temperature of the calcination treatment, and time of the calcination treatment, it is helpful to form a ternary composite material with uniform and stable internal structure.

[0110] As an example, the temperature of the calcination treatment can be 300°C, 320°C, 340°C, 360°C, 380°C, or 400°C.

[0111] As an example, the time of the calcination treatment can be 2 h, 2.5 h, 3 h, 3.5 h, or 4 h.

[0112] As an example, the calcination treatment satisfies the following conditions: the protective gas of the calcination treatment comprises at least one of nitrogen and argon; the temperature of the calcination treatment is 300-400°C, and the time of the calcination treatment is 2-4 h.

[0113] In the third aspect of the present application, the present application provides a microwave absorbing material comprising the aforementioned ternary composite material, or using the ternary composite material obtained by the preparation method of the aforementioned ternary composite material. The microwave absorbing material of the present application has a synergistic effect of high dielectric matching under the real part of the dielectric coefficient and significant magnetic loss. When the thickness of the microwave absorbing material of the present application is less than 1.5 mm, the effective absorption bandwidth of the microwave absorbing material in the 2-18 GHz wave band is greater than 5 GHz. Therefore, when the thickness of the microwave absorbing material of the present application is less than 1.5 mm, it still has high efficient electromagnetic wave absorption capacity.

[0114] In some embodiments, the microwave absorbing material further comprises an organic binder. Thus, the organic binder can improve the formability of the microwave absorbing material, so that the microwave absorbing material can be processed into the required shape and size to adapt to the actual use requirements.

[0115] In some embodiments, the organic binder comprises at least one of paraffin, resin.

[0116] In some embodiments, the mass fraction of the ternary composite material is 50%-70% based on the total mass of the microwave absorbing material. In this way, the thickness and electromagnetic wave absorption capacity of the microwave absorbing material can be further optimized.

[0117] As an example, the mass fraction of the ternary composite material can be 50%, 55%, 60%, 65%, or 70% based on the total mass of the microwave absorbing material.

[0118] The scheme of the present application is described below through specific examples. It should be noted that the following examples are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. If the specific technology or condition is not specified in the examples, it is carried out according to the technology or condition described in the literature in the art or according to the product manual. If the reagent or instrument is not specified by the manufacturer, it is a conventional product that can be obtained by purchase.

[0119] Example 1

[0120] (1) Preparation of organic-modified flaky iron powder

[0121] S100, 4g of flaky iron powder, 2mL of KH540, and 100mL of isopropyl alcohol were mixed to perform first ultrasonic treatment, the ultrasonic power of the first ultrasonic treatment was 80W, and the ultrasonic time of the first ultrasonic treatment was 30min, to obtain a first suspension;

[0122] S200, after adding 1mL of ammonia and 6mL of deionized water to the first suspension, second ultrasonic treatment was performed, the ultrasonic power of the second ultrasonic treatment was 80W, and the ultrasonic time of the second ultrasonic treatment was 1h, to obtain a second suspension;

[0123] S300, after the second suspension was subjected to suction filtration treatment, a powder was obtained, the powder was washed with anhydrous ethanol three times, and then the powder was placed in a vacuum environment and dried at 45℃ for 1h, the vacuum degree of the vacuum environment was 0.9kPa; after drying, the powder was ground into fine powder, to obtain organic-modified flaky iron powder.

[0124] (2) Preparation of ternary composite material

[0125] S100, 0.1g of graphite oxide was poured into a mortar, 1mL of n-butylamine was added dropwise to the mortar, and grinding treatment was performed, the grinding rotation speed of the grinding treatment was 60rpm, and the grinding time was 20min, to obtain n-butylamine intercalated graphite oxide;

[0126] S200, the n-butylamine intercalated graphite oxide is placed in a glass bottle, 100 mL of anhydrous ethanol is added to the glass bottle, and then ultrasonic dispersion treatment is performed, the ultrasonic power of the ultrasonic dispersion treatment is 80 W, and the ultrasonic time is 15 min, so as to obtain a n-butylamine intercalated graphene oxide nanosheet dispersion liquid;

[0127] S300, 0.5 g of the sheet-shaped iron powder modified by the organic matter is added to the n-butylamine intercalated graphene oxide nanosheet dispersion liquid, and mechanical stirring is performed at a stirring speed of 500 rpm for 1 h; then 0.423 g of tetrabutyl titanate is added dropwise, and mechanical stirring is continuously performed at a stirring speed of 500 rpm for 2 h; after the stirring is completed, natural drying is performed to obtain a ternary composite precipitate;

[0128] The n-butylamine intercalated graphene oxide nanosheet dispersion liquid contains 0.2 g of n-butylamine intercalated graphene oxide nanosheets.

[0129] S400, after the ternary composite precipitate is ground into a powder, calcination treatment is performed under a nitrogen atmosphere, the calcination temperature of the calcination treatment is 300 DEG C, the calcination time is 2 h, and after the calcination is completed, the powder is cooled to room temperature to obtain a product ternary composite material, which is recorded as RTF-1.

[0130] Example 2

[0131] Example 2 differs from Example 1 in that the addition amount of tetrabutyl titanate is 0.468 g, and the product ternary composite material prepared is recorded as RTF-2.

[0132] Example 3

[0133] Example 3 differs from Example 1 in that the addition amount of tetrabutyl titanate is 0.508 g, and the product ternary composite material prepared is recorded as RTF-3.

[0134] Comparative Example 1

[0135] 0.5 g of graphite oxide is taken into a mortar, 5 mL of n-butylamine is added dropwise into the mortar, and then grinding treatment is performed, the grinding speed of the grinding treatment is 60 rpm, and the grinding time is 30 min, so as to obtain n-butylamine intercalated graphite oxide; the n-butylamine intercalated graphite oxide is placed in a glass bottle, 200 mL of anhydrous ethanol is added to the glass bottle, and then ultrasonic dispersion treatment is performed, the ultrasonic power of the ultrasonic dispersion treatment is 80 W, and the ultrasonic time is 15 min, so as to obtain a n-butylamine intercalated graphene oxide nanosheet dispersion liquid; after the n-butylamine intercalated graphene oxide nanosheet dispersion liquid is naturally dried, the powder is ground, calcination treatment is performed under a nitrogen atmosphere, the calcination temperature of the calcination treatment is 300 DEG C, the calcination time is 2 h, and after the calcination is completed, the powder is cooled to room temperature to obtain a product graphene, which is recorded as rGO.

[0136] Comparative Example 2

[0137] 100 mL of anhydrous ethanol was measured, and 1.99 g of tetrabutyl titanate was added dropwise under magnetic stirring. Mechanical stirring was continued at a stirring speed of 500 rpm for 2 h. After stirring, the hydrolysis precipitate was naturally dried to obtain a powder. The powder was calcined under an air atmosphere at a calcination temperature of 300 °C for 2 h. After calcination, the powder was cooled to room temperature to obtain the product titanium dioxide, which was denoted as TiO2-1.

[0138] Comparative Example 3

[0139] Comparative Example 3 differed from Comparative Example 2 in that the calcination was performed under a nitrogen atmosphere. The product titanium dioxide obtained was denoted as TiO2-2.

[0140] Comparative Example 4

[0141] 4 g of flaky iron powder, 2 mL of KH540, and 100 mL of isopropyl alcohol were mixed to obtain a first suspension. The first suspension was subjected to first ultrasonic treatment at an ultrasonic power of 80 W for 30 min.

[0142] After adding 1 mL of ammonia water and 6 mL of deionized water to the first suspension, the first suspension was subjected to second ultrasonic treatment at an ultrasonic power of 80 W for 1 h to obtain a second suspension.

[0143] The second suspension was subjected to suction filtration to obtain a powder. The powder was washed with anhydrous ethanol three times, and then dried in a vacuum environment at 45 °C for 1 h. The vacuum degree of the vacuum environment was 0.9 kPa. After drying, the powder was ground into fine powder to obtain organic matter modified flaky iron powder.

[0144] The organic matter modified flaky iron powder was ground into a powder, and then subjected to calcination under a nitrogen atmosphere at a calcination temperature of 300 °C for 2 h. After calcination, the powder was cooled to room temperature to obtain the product flaky iron powder, which was denoted as FCI.

[0145] Comparative Example 5

[0146] Example 5 differed from Example 1 in that the amount of tetrabutyl titanate added was 0.847 g. The product ternary composite material obtained was denoted as RTF-4.

[0147] The products obtained in Examples 1-3 and Comparative Examples 1-5 were subjected to performance tests. The performance test items were as follows:

[0148] (1) X-ray diffraction (XRD)

[0149] The products prepared in Examples 1-3 and Comparative Examples 2-5 were subjected to XRD test, and the XRD patterns are shown in Figure 2 .

[0150] The products prepared in Examples 1-3 and Comparative Examples 4-5 were subjected to test using an X-ray diffractometer (Bruker D8 Advance) with a cobalt target, and the test results are shown in (a) of Figure 2 . It can be seen that the products prepared in Examples 1-3 and Comparative Examples 4-5 contain a flaky iron powder phase component, i.e. the ternary composite material of the present application contains a flaky iron powder.

[0151] The products prepared in Comparative Examples 2-3 were subjected to test using an X-ray diffractometer (Rigaku D / max 2500) with a copper target, and the test results are shown in (b) of Figure 2 . It can be seen that the diffraction peaks of TiO2-1 of Comparative Example 2 can be well matched with the PDF card (#21-1272) of anatase titanium dioxide, which indicates that crystalline titanium dioxide can be obtained by calcination in an air atmosphere. The diffraction peaks of TiO2-2 of Comparative Example 3 are only steamed bun peaks, which indicates that amorphous titanium dioxide can be obtained by calcination in a nitrogen atmosphere, and at the same time Figure 2 , the test results of Examples 1-3 and Comparative Example 5 in (a) of have no other obvious diffraction peaks except the diffraction peaks of the flaky iron powder, which can indirectly indicate that the products prepared in Examples 1-3 and Comparative Example 5 contain an amorphous titanium dioxide phase component, i.e. the ternary composite material of the present application contains amorphous titanium dioxide.

[0152] (2) Raman spectrum

[0153] The products prepared in Examples 1-3 and Comparative Example 5 were subjected to Raman spectrum test, and the test instrument model was Horiba LabRAM HR Evolution, the excitation light source wavelength was 514 nm, and the Raman spectrum is shown in Figure 3 .

[0154] As can be seen from Figure 3 , the products prepared in Examples 1-3 and Comparative Example 5 have Raman peaks at -1350 cm -1 and -1590 cm -1 , which correspond to the D peak and G peak of graphene respectively, which can indicate that the products prepared in Examples 1-3 and Comparative Example 5 contain a graphene phase component, i.e. the ternary composite material of the present application contains graphene.

[0155] (3) X-ray photoelectron spectroscopy (XPS)

[0156] The products prepared in Examples 1-3, Comparative Example 1, Comparative Example 5 were subjected to XPS N 1s testing, and the testing instrument was a Thermo Fisher ESCALAB 250Xi. The XPS N 1s fine spectrum is shown in Figure 4 .

[0157] As can be seen from Figure 4 , Examples 1-3, Comparative Example 1, Comparative Example 5 have a relatively obvious main peak at about 400 eV, corresponding to pyrrole N, and the main peak shape of Examples 1-3, Comparative Example 5 and Comparative Example 1 is very similar, which can indicate that the product prepared in Examples 1-3, Comparative Example 5 is doped with nitrogen atoms, and the nitrogen atoms are introduced by intercalation of n-butylamine and then thermal reduction.

[0158] (4) Scanning Electron Microscope

[0159] The product prepared in Example 3 was subjected to electron microscope scanning, and the testing instrument was a Hitachi SU8600. The scanning electron microscope (SEM) image is shown in Figure 5 , and the scanning electron microscope energy spectrum (EDS) image is shown in Figure 6 . Further, Figure 7 is the distribution map of iron elements in the product prepared in Example 3 in the present application. Figure 8 is the distribution map of titanium elements in the product prepared in Example 3 in the present application. Figure 7 and Figure 8 are obtained based on the overall element distribution map. Figure 6

[0160] As can be seen from Figure 5 , the surface of the flaky iron powder is distributed with graphene nanosheets, and the particle size of the flaky iron powder is 1-10 μm, and the particle size of the graphene is 0.1-1 μm.

[0161] As can be seen from Figures 6-8 , the surface of the flaky iron powder is distributed with amorphous titanium dioxide, and the particle size of the amorphous titanium dioxide is 0.1-10 μm.

[0162] (5) Dielectric Coefficient and Magnetic Permeability of Microwave Absorbing Material

[0163] The products prepared in Examples 1-3, Comparative Examples 1-3, and Comparative Example 5 were mixed with paraffin, and the mass ratio of the product to paraffin was 3:2. The mixture was subjected to hydraulic pressure to obtain a coaxial ring with an outer diameter of 7 mm, an inner diameter of 3 mm, and a thickness of 1.5 mm. A vector network analyzer (VNA, Agilent PNA-N5244A) was used to test the relative complex dielectric coefficient and complex magnetic permeability of each coaxial ring.

[0164] The relative complex dielectric coefficient and complex magnetic permeability spectrum of Examples 1-3, Comparative Example 5 is shown in Figure 9 . Among them,​Figure 9 the (a) graph in (a) is a real part graph of dielectric coefficient; Figure 9 the (b) graph in (b) is an imaginary part graph of dielectric coefficient; Figure 9 the (c) graph in (c) is a tangent of dielectric loss angle graph; Figure 9 the (d) graph in (d) is a real part graph of magnetic permeability; Figure 9 the (e) graph in (e) is an imaginary part graph of magnetic permeability; Figure 9 the (f) graph in (f) is a tangent of magnetic loss angle graph.

[0165] The relative complex dielectric coefficient and complex magnetic permeability spectrum graphs of Comparative Examples 1-3 are shown in Figure 10 , wherein, Figure 10 the (a) graph in (a) is a real part graph of dielectric coefficient of Comparative Example 1; Figure 10 the (b) graph in (b) is an imaginary part graph of dielectric coefficient of Comparative Example 1; Figure 10 the (c) graph in (c) is a tangent of dielectric loss angle graph of Comparative Example 1; Figure 10 the (d) graph in (d) is a real part graph of dielectric coefficient of Comparative Example 2-3; Figure 10 the (e) graph in (e) is an imaginary part graph of dielectric coefficient of Comparative Example 2-3; Figure 10 the (f) graph in (f) is a tangent of dielectric loss angle graph of Comparative Example 2-3.

[0166] For the dielectric coefficient, it can be known from the (a) graph to the (c) graph in Figure 10 that the high conductivity of Comparative Example 1 leads to large dielectric coefficient and tangent of dielectric loss angle, although this is beneficial to reduce the thickness of microwave absorbing material, but it is easy to cause impedance mismatch leading to poor microwave absorbing performance, so it needs low-loss components to adjust its dielectric performance. It can be known from the (d) graph to the (f) graph in Figure 9 that due to the existence of a large number of defects in amorphous titanium dioxide, this leads to the dielectric coefficient and tangent of dielectric loss angle of Comparative Example 3 being larger than that of Comparative Example 2, therefore, amorphous titanium dioxide is more suitable as a component of microwave absorbing material to adjust the performance of graphene.

[0167] Therefore, as Figure 9As shown, the microwave absorbing materials of Examples 1-3 combine sheet-like iron powder with graphene and amorphous titanium dioxide. The amorphous titanium dioxide significantly reduces the conductivity of the microwave absorbing material, making its conductivity loss negligible, and also significantly reduces the imaginary part of its dielectric constant and the dielectric loss tangent. Simultaneously, the small amount of nitrogen atoms doped in the graphene phase, the small amount of oxygen-containing functional groups remaining after thermal reduction, the defects present in the amorphous titanium dioxide phase, and the low-barrier Schottky heterostructure interface formed at the contact between the graphene and amorphous titanium dioxide phases slightly increase the polarization loss of the microwave absorbing material while maintaining a relatively large real part of the dielectric constant. Therefore, the dielectric matching with a high real part of the dielectric constant required for the thinned microwave absorbing material is achieved. It is worth noting that because Comparative Example 5 has a higher titanium dioxide content, this leads to a significant decrease in both the dielectric constant and the dielectric loss tangent, making it impossible for the microwave absorbing material of Comparative Example 5 to exhibit sufficient microwave absorption effect at an ultrathin thickness of less than 1.5 mm.

[0168] For permeability, such as Figure 11 As shown, the microwave absorbing materials of Examples 1-3 and Comparative Example 5 contain flake iron powder. The strong natural magnetic resonance of the flake iron powder and the anisotropy of the iron composition morphology result in the real part of its permeability being greater than 1 in the 2GHz-18GHz frequency band, the imaginary part of its permeability being greater than 0 in the 2GHz-18GHz frequency band, and the magnetic loss tangent being greater than 0 in the 2GHz-18GHz frequency band. This not only helps to improve the dielectric matching problem of microwave absorbing materials in a wider frequency band, but also helps to further reduce the thickness of microwave absorbing materials.

[0169] (6) Reflection loss of microwave absorbing materials

[0170] The products obtained in Examples 1-3, Comparative Examples 1-3, and Comparative Example 5 were mixed with paraffin wax, with a mass ratio of 3:2 between each product and paraffin wax. The mixture was then hydraulically pressed into a series of coaxial rings of different thicknesses, with an outer diameter of 7 mm and an inner diameter of 3 mm.

[0171] Figure 11 The graphs show the reflection loss curves of the materials in Examples 1-3 and Comparative Example 5 at different thicknesses. Figure 11 Figure (a) in the figure is the reflection loss curve of Example 1; Figure 11 Figure (b) in the figure is the reflection loss curve of Example 2; Figure 11 Figure (c) in the figure is the reflection loss curve of Example 3; Figure 9 Figure (d) in the figure is the reflection loss curve for Comparative Example 5. The reflection loss values ​​for different thicknesses are based on... Figure 12 The VNA test results are calculated using a single-layer absorption transmission line model and can directly reflect the microwave absorption effect of the microwave absorbing material.

[0172] Figure 12 The reflection loss curves of the materials of Comparative Examples 1-3 at different thicknesses, wherein, Figure 12 the (a) graph of FIG. 1 is the reflection loss curve of Comparative Example 1; Figure 12 the (b) graph of FIG. 2 is the reflection loss curve of Comparative Example 2; Figure 10 the (c) graph of FIG. 3 is the reflection loss curve of Comparative Example 3. The reflection loss values at different thicknesses are calculated by the single-layer absorption transmission line model based on the VNA test results, which can directly reflect the microwave absorption effect. Figure 11 The reflection loss values at different thicknesses are calculated by the single-layer absorption transmission line model based on the VNA test results, which can directly reflect the microwave absorption effect.

[0173] As can be seen from Figure 12 and ​ , due to the synergistic effect of dielectric matching under a higher real part of the dielectric constant and significant magnetic loss, the microwave absorption performance of Examples 1-3 is significantly optimized compared to Comparative Examples 1-3 and Comparative Example 5, i.e., in the case where the thickness of the microwave absorption material is less than 1.5 mm, an effective absorption bandwidth (EAB, EAB refers to the frequency range under a specific thickness where the reflection loss RL is less than -10 dB) of more than 5 GHz and / or a minimum reflection loss (RL min ) of less than -40 dB is obtained.

[0174] Specifically, in Example 1, when the thickness of the microwave absorption material is 1.289 mm, the EAB can reach 5.09 GHz; in Example 2, when the thickness of the microwave absorption material is 1.46 mm, the EAB can reach 5.33 GHz, which can basically cover the entire Ku band (12 GHz to 18 GHz); in particular, in Example 3, when the thickness of the microwave absorption material is 1.463 mm, the EAB can reach 5.01 GHz, and the RL min can reach -45.25 dB; in Example 3, when the thickness of the microwave absorption material is 1.496 mm, the RL min can be as low as -79.51 dB, which can indicate that the microwave absorption material of Example 3 has excellent microwave absorption performance.

[0175] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and embodiments having the same technical idea and playing the same role and effect within the scope of the technical solutions of the present application are all included in the technical scope of the present application. In addition, within the scope of the main idea of the present application, various modifications that can be thought of by those skilled in the art, and other ways constructed by combining part of the components of the embodiments are also included in the scope of the present application.

Claims

1. A microwave absorbing material, characterized by, Thickness is less than 1.5mm, and the effective absorption bandwidth in 2GHz-18GHz wave band is greater than 5GHz, The microwave absorbing material comprises a ternary composite material, the ternary composite material comprises a sheet-shaped magnetic metal, and amorphous titanium dioxide and a non-metallic two-dimensional material attached to the surface of the sheet-shaped magnetic metal; the mass ratio of the non-metallic two-dimensional material to the sheet-shaped magnetic metal is (0.16-0.4):1, and the mass ratio of the amorphous titanium dioxide to the sheet-shaped magnetic metal is (0.14-0.48):1, The particle size of the sheet-shaped magnetic metal is 1-10μm, the particle size of the amorphous titanium dioxide is 0.1-10μm, and the particle size of the non-metallic two-dimensional material is 0.1-1μm.

2. The microwave absorbing material according to claim 1, characterized by, The sheet-shaped magnetic metal comprises at least one of iron and its alloy, cobalt and its alloy, and nickel and its alloy.

3. The microwave absorbing material of claim 1, wherein, The non-metallic two-dimensional material comprises at least one of graphene, two-dimensional transition metal carbide, two-dimensional transition metal nitride, and two-dimensional transition metal carbonitride.

4. The microwave absorbing material of claim 1, wherein, The method for preparing the ternary composite material in the microwave absorbing material comprises: The non-metallic material and the organic amine are mixed and then subjected to grinding treatment to obtain the organic amine intercalated non-metallic material; The organic amine intercalated non-metallic material is subjected to ultrasonic dispersion treatment to obtain the organic amine intercalated non-metallic two-dimensional material; The organic amine intercalated non-metallic two-dimensional material, the sheet-shaped magnetic metal, and the titanium dioxide precursor are mixed and then subjected to stirring treatment to obtain ternary composite precipitate, wherein the mass ratio of the organic amine intercalated non-metallic two-dimensional material to the sheet-shaped magnetic metal is (0.2-1):1, and the mass ratio of the titanium dioxide precursor to the sheet-shaped magnetic metal is (0.6-1.6):1; The ternary composite precipitate is subjected to calcination treatment to obtain the ternary composite material.

5. The microwave absorbing material of claim 4, wherein, Before the organic amine intercalated non-metallic two-dimensional material, the sheet-shaped magnetic metal, and the titanium dioxide precursor are mixed, the sheet-shaped magnetic metal is further subjected to organic modification treatment, and the organic substance comprises at least one of silane coupling agent, epoxy silane coupling agent, amino silane coupling agent, and methacryloxy silane coupling agent.

6. The microwave absorbing material according to claim 4 or 5, characterized in that, The grinding treatment satisfies at least one of the following conditions: The non-metallic material comprises at least one of graphite oxide, transition metal carbide, transition metal nitride, and transition metal carbonitride; The organic amine comprises at least one of propylamine, n-butylamine, and n-pentylamine; In the grinding treatment, the mass of the non-metallic material is a, in g, the volume of the organic amine is b, in mL, and a:b is 1:(10-20); The grinding speed of the grinding treatment is 60-100rpm, and the grinding time of the grinding treatment is 15-30min.

7. The microwave absorbing material according to claim 4 or 5, characterized by The ultrasonic dispersion treatment comprises: adding the organic amine intercalated non-metallic material into a first solvent for the ultrasonic dispersion treatment, and the first solvent comprises at least one of methanol, ethanol, and propanol; In the ultrasonic dispersion treatment, the mass of the organic amine intercalated nonmetallic material is c, the unit is g, the volume of the first solvent is d, the unit is mL, and c:d is 1:(300-1000).

8. The microwave absorbing material of claim 7, wherein, The ultrasonic power of the ultrasonic dispersion treatment is 80W-100W, and the ultrasonic time of the ultrasonic dispersion treatment is 15min-30min.

9. The microwave absorbing material according to claim 4 or 5, characterized by, The calcination treatment meets at least one of the following conditions: The protective gas of the calcination treatment includes at least one of nitrogen and argon; The temperature of the calcination treatment is 300℃-400℃, and the time of the calcination treatment is 2h-4h.

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