2:17 type rare earth cobalt / graphite nanocomposite electromagnetic wave absorbing material and preparation method thereof

Abstract

The application discloses a series of 2:17 type rare earth cobalt / graphene nanocomposites with high-frequency electromagnetic wave absorption and a preparation method thereof in the field of rare earth functional materials. 3+ The application discloses a series of 2:17 type rare earth cobalt / graphene nanocrystalline composite materials with high-frequency electromagnetic wave absorption and a preparation method thereof in the field of rare earth functional materials 2+ The application discloses a series of 2:17 type rare earth cobalt / graphene composite materials with high-frequency electromagnetic wave absorption and a preparation method thereof in the field of rare earth function materials. 17 The application discloses a series of 2:17 type rare earth cobalt / graphene nano composite materials with high-frequency electromagnetic wave absorption and a preparation method thereof in the field of rare earth functions materials. 17 The application discloses a series of 2:17 type rare earth cobalt / graphene complex materials with high-frequency electromagnetic wave absorption and a preparation method thereof in the field of rare earth function material. 17 The application discloses a series of 2:17 type rare earth cobalt / graphene materials with high-frequency electromagnetic wave absorption and a preparation method thereof in the field of rare earth function. 17 The application discloses a series of 2:17 type rare earth cobalt / graphene material with high-frequency electromagnetic wave absorption and a preparation method thereof in the field of rare earth function. The application discloses a series of 2:17 type rare earth cobalt / graphene nanometer composite structure with high-frequency electromagnetic wave absorption and a preparation method thereof in the field of rare earth function material.

Description

Technical Field

[0001] This invention relates to a 2:17 type rare earth cobalt / graphite nanocomposite material with high-frequency electromagnetic wave absorption and its preparation method in the field of rare earth functional materials. Background Technology

[0002] The preparation of high-purity and single-phase rare earth-transition metal alloys and compounds, along with the control of their phase and microstructure, are key factors determining the performance and applications of high-performance rare earth-based metal materials. Currently, rare earth-based metal materials are mainly prepared using physical metallurgical methods such as smelting and mechanical alloying. However, the impurities, separated phases, or second phases formed during the preparation process restrict the improvement of material properties and, to some extent, limit their practical applications. Because metallic rare earths are highly chemically reactive and extremely prone to oxidation in air, and because the atomic radii of rare earth metals are much larger than those of most other metal elements, the formation of rare earth-based metal alloys or compounds under conventional conditions is more difficult. Therefore, developing new preparation techniques to obtain single-phase rare earth metal alloys or compounds has always been an important scientific and technological issue that urgently needs to be addressed in the fields of materials science, physics, and chemistry.

[0003] A wide variety of easily magnetic anisotropic rare-earth-transition metal compounds (e.g., Ce2Fe) 17 and Pr2Co 17 Rare earth-based metals (such as 3d metals) possess high saturation magnetization and low coercivity, exhibiting soft magnetic properties. Furthermore, they possess high-frequency permeability and cutoff frequencies distinct from conventional 3d metal-based soft magnetic alloys. Both theoretical and experimental studies demonstrate that single-phase, anisotropic rare earth-transition metal compounds and their composites with ideal microstructures exhibit excellent high-frequency soft magnetic properties in the X-band and Ku-band, holding promise as a novel class of high-frequency soft magnetic materials applicable in the gigahertz frequency range. Currently, for anisotropic rare earth-based metal materials prepared using conventional physical metallurgical methods, the limitations of the preparation methods make it difficult to obtain ideal phase and microstructures, resulting in suboptimal high-frequency soft magnetic properties. Therefore, it is necessary to develop new preparation methods to obtain structurally ideal anisotropic rare earth-transition metal compounds and their composites, thereby improving their high-frequency soft magnetic properties and developing practical high-performance high-frequency soft magnetic materials.

[0004] This invention provides a technique for controlling the reduction of rare earth-cobalt amorphous hydroxide precursors by calcium, precisely controlling the reduction process of rare earth ions and cobalt ions, and is used to prepare a series of high-purity and single-phase easily surface magnetically anisotropic 2:17 type rare earth cobalt (RE2Co). 17 RE (Y, Ce, Pr, Nd, and Gd) / graphitic carbon (C) nanocomposites. RE ions and Co ions are reduced to form RE₂Co. 17In the nanoparticle process, introducing an appropriate amount of graphite nanosheets for surface modification improves RE2Co 17 The antioxidant properties of the nanoparticles improved their dispersibility, while the electromagnetic parameters were adjusted to achieve five easy-surface magnetic anisotropy RE2Co. 17 / C nanocomposites exhibit consistent high-frequency electromagnetic wave absorption properties. As a novel electromagnetic wave absorbing material with stable structure and performance, they can be used to prepare electromagnetic absorbing coatings or devices in the frequency range of 8–18 GHz. Summary of the Invention

[0005] The purpose of this invention is to provide a series of RE2Co materials with high-frequency electromagnetic wave absorption. 17 / C nanocomposites and their preparation methods. The structural characteristics of this type of rare-earth alloy-carbon nanocomposite electromagnetic absorbing material are that fragmented graphite nanosheets are dispersedly coated on a flower-like single-phase RE2Co. 17 A stable and dispersed RE2Co structure with an average particle size of 200–350 nm is formed on the surface of the nanoparticles. 17 / C nanocomposite particles, wherein the mass fraction of C is 3-9%, and the remainder is RE2Co. 17 Its material properties are as follows: RE2Co 17 The saturation magnetization of the / C nanocomposite particles is slightly less than the theoretical value of the 2:17 phase ratio of their respective single phases, and their coercivity ( i H c The numerical range of RE2Co is 152–310 Oe; within the range of 2–18 GHz, the frequency range of electromagnetic wave absorption is 8–18 GHz, the maximum absorption intensity range is -20–-70 dB, and the maximum effective absorption bandwidth range is 2.5–5.7 GHz. Due to the five RE2Co... 17 / C nanocomposites exhibit consistent high-frequency electromagnetic wave absorption performance. As a diverse and structurally and structurally stable electromagnetic wave absorbing material, they have broad application prospects in aerospace, medical devices, and communication equipment.

[0006] To achieve the above objectives, the technical solution of the present invention includes the following steps:

[0007] (1) Amorphous RE-Co hydroxide / GO composite precursor powder was prepared by rapid co-precipitation: GO was dissolved in deionized water and ultrasonically dispersed for 1-3 hours to prepare an aqueous solution with a concentration of 0.2-2 mg / mL; then, hydrated rare earth chloride and cobalt chloride hexahydrate (CoCl2·6H2O) with a molar ratio of 2:10-2:23 were fully dissolved in the above aqueous solution containing GO; then, a mixed alkaline aqueous solution with a concentration of 0.3-0.4 mol / L sodium hydroxide and a concentration of 0.1-0.2 mol / L sodium carbonate was rapidly poured into the above mixed aqueous solution containing rare earth ions, Co ions and GO as a precipitant. The mixed aqueous solution was stirred while pouring in the precipitant. The concentration of the mixed alkaline aqueous solution should be such that the pH of the reaction solution is high. With an H value of 9–11, continue stirring for 10–30 minutes to ensure complete precipitation of metal ions. Centrifuge the solution containing the flocculent precipitate to obtain a surface-wet solid precipitate. The centrifugation speed is 2000–5000 rpm, the centrifugation time is 2–5 minutes, and the centrifugation liquid is deionized water. Repeat the centrifugation 5–10 times. Place the precipitate in a drying oven at 40–80℃ and dry it until completely dry. Then grind the dried solid material to obtain a brown amorphous RE-Co hydroxide / GO composite precursor powder.

[0008] (2) RE2Co was prepared by controlled calcium reduction method 17 / C Nanocomposite Material: The composite precursor powder prepared in step one is thoroughly mixed with appropriate amounts of potassium chloride and calcium granules to form a reaction mixture, wherein the mass ratio of composite precursor powder, potassium chloride, and calcium granules is 1:(1~6):(0.5~5); the reaction mixture is then placed in a controlled atmosphere heat treatment furnace and heated at 850~1100℃ for 1~4 hours under the protective atmosphere of argon, and then naturally cooled to room temperature to obtain the reaction product; the reaction product is washed multiple times with deionized water to remove unreacted Ca and CaO formed after calcium reduction reaction, and then washed multiple times with anhydrous ethanol to remove water from the product, obtaining a gray-black substance, which is then placed in a vacuum drying oven at 25~80℃ to obtain RE2Co. 17 / C nanocomposite materials.

[0009] This invention not only develops a new method for preparing single-phase rare earth compounds, but also expands the application range of high-performance rare earth functional materials; the raw materials involved are abundant and inexpensive, the preparation process is simple and easy to implement and suitable for large-scale production, and the preparation process is environmentally friendly. Attached Figure Description

[0010] Figure 1 Five RE2Co species in five embodiments 17 X-ray diffraction (XRD) spectra of / C nanocomposites, wherein:

[0011] Figure 1 (a) is Y2Co 17 XRD patterns of / C nanocomposites;

[0012] Figure 1 (b) is Ce2Co 17 XRD patterns of / C nanocomposites;

[0013] Figure 1 (c) is Pr2Co 17 XRD patterns of / C nanocomposites;

[0014] Figure 1 (d) is Nd2Co 17 XRD patterns of / C nanocomposites;

[0015] Figure 1 (e) is Gd2Co 17 XRD patterns of / C nanocomposites;

[0016] Figure 2 The amorphous Y-Co composite precursor and Y2Co in Example 1 17 Raman spectrum of / C nanocomposite material

[0017] Figure 3 Five RE2Co species in five embodiments 17 Scanning electron microscopy (SEM) morphology of / C nanocomposite material, including:

[0018] Figure 3 (a) is Y2Co 17 SEM morphology of / C nanocomposite material;

[0019] Figure 3 (b) is Ce2Co 17 SEM morphology of / C nanocomposite material;

[0020] Figure 3 (c) is Pr2Co 17 SEM morphology of / C nanocomposite material;

[0021] Figure 3 (d) is Nd2Co 17 SEM morphology of / C nanocomposite material;

[0022] Figure 3 (e) is Gd2Co 17 SEM morphology of / C nanocomposite material;

[0023] Figure 4 Five RE2Co species in five embodiments 17The reflection loss curve of / C nanocomposite material, where

[0024] Figure 4 (a) is Y2Co 17 / C nanocomposite material reflection loss curve;

[0025] Figure 4 (b) is Ce2Co 17 / C nanocomposite material reflection loss curve;

[0026] Figure 4 (c) is Pr2Co 17 / C nanocomposite material reflection loss curve;

[0027] Figure 4 (d) is Nd2Co 17 / C nanocomposite material reflection loss curve;

[0028] Figure 4 (e) is Gd2Co 17 / C nanocomposite material reflection loss curve; Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings:

[0030] Example 1

[0031] Y₂Co with high-frequency electromagnetic wave absorption properties 17 / C nanocomposite materials, in which Y2Co 17 The average particle size is 200 nm, Y2Co 17 The mass fraction of is 95%, and the mass fraction of C is 5%. The preparation steps are as follows:

[0032] (1) Dissolve GO in deionized water and disperse it by ultrasonication for 1 hour to prepare an aqueous solution with a concentration of 1 mg / mL; dissolve YCl3·6H2O and CoCl2·6H2O in 18 mL of the above aqueous solution containing GO by uniform stirring; then use a mixed aqueous solution of 0.35 mol / L sodium hydroxide and 0.15 mol / L sodium carbonate as a precipitant, and quickly pour it into the above aqueous solution containing Y ions, Co ions and GO to make the pH of the reaction solution reach 10, and then continue stirring for 20 minutes to make the metal ions completely precipitate; centrifuge the solution containing flocculent precipitate to obtain a surface-wet solid precipitate at a centrifugation rate of 3500 rpm for 3 minutes, using deionized water as the centrifugation liquid, and repeat the centrifugation 9 times; put the precipitate into a drying oven at 60℃ and dry it completely, and then grind the dried solid material to obtain a brown amorphous Y-Co hydroxide / GO composite precursor powder;

[0033] (2) The composite precursor powder prepared in (1) is thoroughly mixed with appropriate amounts of potassium chloride and calcium granules to form a reaction mixture, wherein the mass ratio of the composite precursor powder, potassium chloride and calcium granules is 1:3:1.5; the reaction mixture is then placed in a controlled atmosphere heat treatment furnace, heated at 850°C for 2 hours under the protective atmosphere of argon, and then naturally cooled to room temperature to obtain the reaction product; the reaction product is washed multiple times with deionized water to remove unreacted Ca and CaO formed after calcium reduction reaction, and then washed multiple times with anhydrous ethanol to remove water from the product, and then dried in a vacuum dryer at 45°C to obtain Y2Co. 17 / C nanocomposite materials.

[0034] from Figure 1 (a) It can be seen that the XRD pattern of the product obtained after controlled calcium reduction of the amorphous Y-Co hydroxide / GO composite precursor shows Y2Co. 17 The diffraction peaks of the amorphous precursor were observed, but no XRD diffraction peaks were found for elemental Co, oxides, or other Y-Co alloys. Therefore, high-purity single-phase Y₂Co can be prepared by controlled calcium reduction of the amorphous precursor. 17 Furthermore, amorphous diffuse inclusions appeared in the XRD pattern of the product. (Comparison) Figure 2 Raman spectra of GO in the precursor and carbon in the product reveal that GO, after thermal reduction and calcium reduction, forms incompletely crystallized graphite. Therefore, the amorphous diffuse inclusions originate from amorphous graphite. Figure 1 (b)- Figure 1 (e) It can be seen that other RE2Co can be prepared using similar preparation methods. 17 / C(RE=Ce, Pr, Nd and Gd)) nanocomposites.

[0035] from Figure 3 (a) It can be seen that fragmented graphite nanosheets are dispersedly coated on flower-like Y2Co 17 Y₂Co particles with an average particle size of approximately 200 nm are formed on the surface of the nanoparticles. 17 / C nanocomposite particles. From Figure 3 (b)- Figure 3 (e) It can be seen that the other RE2Co types 17 / C (RE = Ce, Pr, Nd and Gd) nanocomposites also exhibit similar flower-like particle morphology.

[0036] from Figure 4 It can be seen that the five RE2Co 17 / C (RE = Y, Ce, Pr, Nd and Gd) nanocomposites exhibit consistent and excellent high-frequency electromagnetic wave absorption properties, effectively absorbing electromagnetic waves in the range of 8-18 GHz.

[0037] In this embodiment, Y2Co 17 The electromagnetic wave absorption performance characteristics of / C nanocomposite materials are as follows: the maximum absorption intensity of electromagnetic waves is -66.49dB in the range of 2 to 18GHz, the maximum effective absorption bandwidth is 5.55GHz, and the frequency range of electromagnetic wave absorption is 11.71 to 17.26GHz.

[0038] Example 2

[0039] Ce2Co with high-frequency electromagnetic wave absorption properties 17 / C nanocomposite materials, in which Ce2Co 17 The average particle size is 194 nm, Ce2Co 17 The mass fraction of is 96%, and the mass fraction of C is 4%. The preparation steps are as follows:

[0040] (1) Dissolve GO in deionized water and disperse it by ultrasonication for 2 hours to prepare an aqueous solution with a concentration of 0.8 mg / mL; mix CeCl3·7H2O and CoCl2·6H2O with a molar ratio of 2:10 and stir thoroughly to dissolve in 18 mL of the above aqueous solution containing GO; then use a mixed aqueous solution of 0.3 mol / L sodium hydroxide and 0.1 mol / L sodium carbonate as a precipitant and quickly pour it into the above aqueous solution containing Ce ions, Co ions and GO to make the pH of the reaction solution reach 9, and then continue stirring for 10 minutes to make the metal ions completely precipitate; centrifuge the solution containing flocculent precipitate to obtain a surface-wet solid precipitate at a centrifugation rate of 2000 rpm for 5 minutes, using deionized water as the centrifugation liquid, and repeat the centrifugation 5 times; put the precipitate into a drying oven at 40℃ and dry it completely, and then grind the dried solid material to obtain a brown amorphous Ce-Co composite hydroxide / GO composite precursor powder;

[0041] (2) The composite precursor powder prepared in (1) is thoroughly mixed with appropriate amounts of potassium chloride and calcium granules to form a reaction mixture, wherein the mass ratio of the composite precursor powder, potassium chloride and calcium granules is 1:1:0.5; the reaction mixture is then placed in a controlled atmosphere heat treatment furnace and heated at 900°C for 4 hours under the protective atmosphere of argon, and then naturally cooled to room temperature to obtain the reaction product; the reaction product is washed multiple times with deionized water to remove unreacted Ca and CaO formed after calcium reduction reaction, and then washed multiple times with anhydrous ethanol to remove water from the product, and then dried in a vacuum dryer at 25°C to obtain Ce2Co.17 / C nanocomposite materials.

[0042] In this embodiment, Ce2Co 17 The electromagnetic wave absorption performance characteristics of / C nanocomposite materials are as follows: in the range of 2 to 18 GHz, the maximum absorption intensity of electromagnetic waves is -33.50 dB, the maximum effective absorption bandwidth is 5.63 GHz, and the frequency range of electromagnetic wave absorption is 11.87 to 17.50 GHz.

[0043] Example 3

[0044] Pr2Co with high-frequency electromagnetic wave absorption properties 17 / C nanocomposite materials, in which Pr2Co 17 The average particle size is 350 nm, Pr2Co 17 The mass fraction of is 97%, and the mass fraction of C is 3%. The preparation steps are as follows:

[0045] (1) Dissolve GO in deionized water and disperse it by ultrasonication for 3 hours to prepare an aqueous solution with a concentration of 0.2 mg / mL; PrCl3·6H2O and CoCl2·6H2O with a molar ratio of 2:23 are uniformly and thoroughly dissolved in 18 mL of the above aqueous solution containing GO; then, a mixed aqueous solution of 0.4 mol / L sodium hydroxide and 0.2 mol / L sodium carbonate is used as a precipitant and quickly poured into the above aqueous solution containing Pr ions, Co ions and GO to make the pH of the reaction solution reach 11, and then continue to stir for 30 minutes to make the metal ions completely precipitate; the solution containing flocculent precipitate is centrifuged to obtain a surface-wet solid precipitate at a centrifugation rate of 5000 rpm for 2 minutes, and deionized water is used as the centrifugation liquid, and the centrifugation is repeated 10 times; the precipitate is placed in a drying oven at 80℃ and dried until completely dry, and then the dried solid material is ground to obtain a brown amorphous Pr-Co composite hydroxide / GO composite precursor powder;

[0046] (2) The composite precursor powder prepared in (1) is thoroughly mixed with appropriate amounts of potassium chloride and calcium granules to form a reaction mixture, wherein the mass ratio of the composite precursor powder, potassium chloride and calcium granules is 1:6:5; the reaction mixture is then placed in a controlled atmosphere heat treatment furnace, heated at 1100℃ for 1 hour under the protective atmosphere of argon, and then naturally cooled to room temperature to obtain the reaction product; the reaction product is washed multiple times with deionized water to remove unreacted Ca and CaO formed after calcium reduction reaction, and then washed multiple times with anhydrous ethanol to remove water from the product, and then dried in a vacuum dryer at 35℃ to obtain Pr2Co. 17 / C nanocomposite materials.

[0047] In this embodiment, Pr2Co 17 The electromagnetic wave absorption performance characteristics of / C nanocomposite materials are as follows: the maximum absorption intensity of electromagnetic waves is -20.30dB in the range of 2 to 18GHz, the maximum effective absorption bandwidth is 2.71GHz, and the frequency range of electromagnetic wave absorption is 14.18 to 16.89GHz.

[0048] Example 4

[0049] Nd2Co with high-frequency electromagnetic wave absorption properties 17 / C nanocomposite materials. Among them, Nd2Co 17 The average particle size is 267 nm, Nd2Co 17 The mass fraction of is 93%, and the mass fraction of C is 7%. The preparation steps are as follows:

[0050] (1) Dissolve GO in deionized water and disperse it by ultrasonication for 2 hours to prepare an aqueous solution with a concentration of 1.4 mg / mL; Dissolve NdCl3·6H2O and CoCl2·6H2O in 18 mL of the above aqueous solution containing GO by uniform stirring and thorough stirring; Then use a mixed aqueous solution of 0.30 mol / L sodium hydroxide and 0.10 mol / L sodium carbonate as a precipitant, and quickly pour it into the above aqueous solution containing Nd ions, Co ions and GO to make the pH of the reaction solution reach 9, and then continue stirring for 20 minutes to make the metal ions completely precipitate; Centrifuge the solution containing flocculent precipitate to obtain a surface-wet solid precipitate at a centrifugation rate of 4500 rpm for 4 minutes, using deionized water as the centrifugation liquid, and repeat centrifugation 8 times; Place the precipitate in a drying oven at 50℃ and dry it completely, and then grind the dried solid material to obtain a brown amorphous Nd-Co composite hydroxide / GO composite precursor powder;

[0051] (2) The composite precursor powder prepared in (1) is thoroughly mixed with appropriate amounts of potassium chloride and calcium granules to form a reaction mixture, wherein the mass ratio of the composite precursor powder, potassium chloride and calcium granules is 1:3:3; the reaction mixture is then placed in a controlled atmosphere heat treatment furnace and heated at 900°C for 2 hours under the protective atmosphere of argon, and then naturally cooled to room temperature to obtain the reaction product; the reaction product is washed multiple times with deionized water to remove unreacted Ca and CaO formed after calcium reduction reaction, and then washed multiple times with anhydrous ethanol to remove water from the product, and then dried in a vacuum dryer at 60°C to obtain Nd2Co. 17 / C nanocomposite materials.

[0052] In this embodiment, Nd2Co 17The electromagnetic wave absorption performance characteristics of / C nanocomposite materials are as follows: the maximum absorption intensity of electromagnetic waves is -25.19dB in the range of 2 to 18GHz, the maximum effective absorption bandwidth is 2.5GHz, and the frequency range of electromagnetic wave absorption is 15.25 to 17.75GHz.

[0053] Example 5

[0054] Gd2Co with high-frequency electromagnetic wave absorption properties 17 / C nanocomposite materials. Among them, Gd2Co 17 The average particle size is 300 nm, Gd2Co 17 The mass fraction of is 91%, and the mass fraction of C is 9%. The preparation steps are as follows:

[0055] (1) Dissolve GO in deionized water and disperse it by ultrasonication for 1 hour to prepare an aqueous solution with a concentration of 2 mg / mL; GdCl3·6H2O and CoCl2·6H2O with a molar ratio of 2:17 are uniformly stirred and dissolved in 18 mL of the above aqueous solution containing GO; then, a mixed aqueous solution of 0.38 mol / L sodium hydroxide and 0.15 mol / L sodium carbonate is used as a precipitant and quickly poured into the above aqueous solution containing Gd ions, Co ions and GO to make the pH of the reaction solution reach 10, and then continue stirring for 25 minutes to make the metal ions completely precipitate; the solution containing flocculent precipitate is centrifuged to obtain a surface-wet solid precipitate at a centrifugation rate of 3500 rpm for 4 minutes, and deionized water is used as the centrifugation liquid, and the centrifugation is repeated 6 times; the precipitate is placed in a drying oven at 60℃ and dried until completely dry, and then the dried solid material is ground to obtain a brown amorphous Gd-Co composite hydroxide / GO composite precursor powder;

[0056] (2) The composite precursor powder prepared in (1) is thoroughly mixed with appropriate amounts of potassium chloride and calcium granules to form a reaction mixture, wherein the mass ratio of the composite precursor powder, potassium chloride and calcium granules is 1:4:2; the reaction mixture is then placed in a controlled atmosphere heat treatment furnace, heated at 1000℃ for 3 hours under the protective atmosphere of argon, and then naturally cooled to room temperature to obtain the reaction product; the reaction product is washed multiple times with deionized water to remove unreacted Ca and CaO formed after calcium reduction reaction, and then washed multiple times with anhydrous ethanol to remove water from the product, and then dried in a vacuum dryer at 80℃ to obtain Gd2Co. 17 / C nanocomposite materials.

[0057] In this embodiment, Gd2Co 17The electromagnetic wave absorption performance characteristics of / C nanocomposite materials are as follows: the maximum absorption intensity of electromagnetic waves is -69.58dB in the range of 2 to 18GHz, the maximum effective absorption bandwidth is 4.9GHz, and the frequency range of electromagnetic wave absorption is 9.78 to 14.68GHz.

Claims

1. RE2Co with high-frequency electromagnetic wave absorption 17 / Graphite nanocomposite material, wherein the RE is selected from one of Y, Ce, Pr, Nd or Gd, characterized in that: The material has a structure in which fragmented graphite nanosheets are dispersedly coated on flower-like RE2Co. 17 A novel RE2Co with stable structure and dispersed particle size, exhibiting high-frequency electromagnetic wave absorption, is formed on the surface of nanoparticles. 17 / Graphite nanocomposite particles; in which Five types of single-phase RE2Co flowers 17 Nanoparticles are generated by co-reduction of RE and Co ions in an amorphous RE-Co hydroxide / monolayer graphene oxide composite precursor via a controllable calcium thermal reduction method. Graphite nanosheets are generated from the monolayer graphene oxide in the aforementioned precursor through thermal reduction and calcium reduction; RE2Co 17 The average particle size of the graphite nanocomposite particles is 200–350 nm, the mass fraction of graphite is 3–9%, and the remainder is RE2Co. 17 .

2. The RE2Co with high-frequency electromagnetic wave absorption according to claim 1 17 / Graphite nanocomposite material, characterized in that RE2Co 17 Graphite nanocomposites all possess intrinsic magnetic properties such as high saturation magnetization and high coercivity, due to RE2Co 17 RE2Co in graphite nanocomposites 17 The particles possess high purity, and due to the magnetic dilution effect of a small amount of graphitic carbon, the saturation magnetization of the various composite particles is slightly less than the theoretical value of the 2:17 phase ratio of their respective single phases; due to RE2Co 17 The surface of the particles is weakly oxidized, and the flower-like microstructure and graphitic carbon surface modification effect contribute to RE2Co. 17 Graphite nanocomposites exhibit high coercivity. i H c The numerical range is 152–310 Oe.

3. The RE2Co with high-frequency electromagnetic wave absorption according to claims 1–2 17 / Graphite nanocomposite material, characterized in that Within the range of 2–18 GHz, the frequency range of electromagnetic wave absorption is 8–18 GHz, the maximum absorption intensity range is -20 to -70 dB, and the maximum effective absorption bandwidth range is 2.5–5.7 GHz.

4. RE2Co with high-frequency electromagnetic wave absorption 17 The preparation method of graphite nanocomposite materials includes the following steps: Step 1: Amorphous RE-Co hydroxide / monolayer graphene oxide composite precursor powder is prepared using a rapid co-precipitation method: Monolayer graphene oxide is dissolved in deionized water and ultrasonically dispersed for 1–3 hours to prepare a monolayer graphene oxide aqueous solution with a concentration of 0.2–2 mg / mL; then, hydrated rare earth chlorides and cobalt chloride hexahydrate (CoCl2·6H2O) with a molar ratio of 2:10–2:23 are fully dissolved in the above aqueous solution containing monolayer graphene oxide. The hydrated rare earth chlorides used are commercially available yttrium chloride hexahydrate (YCl3·6H2O), praseodymium chloride hexahydrate (PrCl3·6H2O), gadolinium chloride hexahydrate (GdCl3·6H2O), neodymium chloride hexahydrate (NdCl3·6H2O), and cerium chloride heptahydrate (CeCl3·7H2O); subsequently, sodium hydroxide with a concentration of 0.3–0.4 mol / L and cobalt chloride with a concentration of 0.1–0.2 mol / L are added. A mol / L sodium carbonate mixed alkaline solution is rapidly poured into the above-mentioned mixed aqueous solution containing rare earth ions, Co ions, and monolayer graphene oxide as a precipitant. The mixed aqueous solution is stirred simultaneously with the addition of the precipitant. The amount of mixed alkaline solution used is determined by titration. The pH of the reaction solution should be adjusted to 9–11. Stirring continues for 10–30 minutes to ensure complete precipitation of the metal ions. The solution containing the flocculent precipitate is then centrifuged to obtain a surface-wet solid precipitate. The centrifugation speed is 2000–5000 rpm, and the centrifugation time is 2–5 minutes. Deionized water is used as the centrifugation solution. The centrifugation is repeated 5–10 times. The precipitate is then placed in a 40–80 mL container. o The material was dried in a drying oven at C until completely dry. The dried solid was then ground to obtain a brown amorphous RE-Co hydroxide / monolayer graphene oxide composite precursor powder. Step 2: Prepare RE2Co using a controlled calcium reduction method. 17 / Graphite nanocomposite material: The composite precursor powder prepared in step one is thoroughly mixed with appropriate amounts of potassium chloride and calcium granules to form a reaction mixture, wherein the mass ratio of the composite precursor powder, potassium chloride, and calcium granules is 1:(1-6):(0.5-5); the reaction mixture is then placed in a controlled atmosphere heat treatment furnace and heated at 850-1100°C under the protective atmosphere of argon. o Heating at C for 1–4 hours followed by natural cooling to room temperature yields the reaction product. The product is then washed multiple times with deionized water to remove unreacted calcium and CaO formed during calcium reduction. Next, the product is washed multiple times with anhydrous ethanol to remove water, resulting in a grayish-black substance, which is then placed at 25–80 °C. o RE2Co was obtained after drying in a vacuum drying oven of C. 17 / Graphite nanocomposite materials.

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