Rare earth magnetic far infrared dual functional material and preparation method and application thereof

Abstract

The application provides a rare earth magnetic far-infrared dual-functional material and a preparation method and application thereof. The rare earth magnetic far-infrared dual-functional material is of a core-shell structure, wherein the core is a high-entropy alloy, the structural formula of the high-entropy alloy is Gd x Tb x Dy (1‑2x） / 3 Ho (1‑2x） / 3Y (1‑2x） / 3 Fe 14 B, wherein the value range of x is 0.1-0.3, and the shell layer is a rare earth citrate connected with the core through Si-O-RE covalent bonds. The rare earth magnetic far-infrared dual-functional material has a high-entropy effect, and the structural stability and intrinsic magneto-caloric effect and far-infrared radiation characteristics are significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of composite functional materials technology, and in particular relates to a rare earth magnetic far-infrared dual-functional material, its preparation method and application. Background Technology

[0002] Neodymium iron boron (NdFeB) permanent magnets are widely used due to their excellent magnetic properties, but their function is mainly limited to providing a magnetic field. However, in fields such as physiotherapy and energy conservation, materials often need to possess both magnetic and far-infrared functions. Current technologies typically employ physical composite methods, simply mixing magnetic powder with far-infrared ceramic powder. This approach has significant drawbacks: first, the interfacial bonding between the two phases is weak, leading to component separation during long-term use; second, the addition of far-infrared ceramic powder significantly dilutes the magnetic phase concentration, resulting in a substantial decrease in magnetic properties; and third, physical mixing makes it difficult to achieve a synergistic enhancement effect. Single NdFeB magnetic alloys or rare-earth far-infrared materials each have their limitations. The far-infrared emission performance of magnetic alloys is usually determined by their lattice vibrations, with an upper limit to improvement; while physically mixing rare-earth salts and magnetic powders suffers from poor interfacial compatibility and performance degradation. The challenge currently facing technology is how to construct a robust and efficient functionalized layer on the surface of a magnetic alloy without compromising its magnetic properties, thereby generating a synergistic effect of "1+1>2". Summary of the Invention

[0003] In view of this, the present invention aims to overcome the defects in the prior art and propose a rare earth magnetic far-infrared bifunctional material, its preparation method and application.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0005] In a first aspect, the present invention provides a rare-earth magnetic far-infrared dual-functional material, wherein the rare-earth magnetic far-infrared dual-functional material has a core-shell structure, wherein the core is a high-entropy alloy, and the high-entropy alloy has the structural formula Gd. x Tb x Dy (1-2x） / 3Ho (1-2x） / 3 Y (1-2x） / 3 Fe 14 B, where x ranges from 0.1 to 0.3, and the shell is a rare earth citrate bond connected to the core via Si-O-Ce covalent bonds.

[0006] In a first aspect, the present invention provides a method for preparing the above-mentioned rare-earth magnetic far-infrared bifunctional material, comprising the following steps:

[0007] S1. Weigh metals Gd, Tb, Dy, Ho, Y and Fe-B alloy and melt them to obtain alloy ingots after the metals and alloys are completely melted. Heat the alloy ingots to a molten state and use a single-roll rapid quenching method to prepare amorphous thin strips. Ball mill the amorphous thin strips to obtain high-entropy alloy powder for later use.

[0008] S2. After surface activation of high-entropy alloy powder, it is reacted with a silane coupling agent to obtain silanized alloy powder;

[0009] S3. Dissolve the silanized alloy powder in water to obtain an alloy suspension. Dissolve the rare earth salt and citric acid in deionized water to obtain a rare earth salt-citric acid complex solution. Add the rare earth salt-citric acid complex solution dropwise to the alloy suspension and then carry out a hydrothermal reaction.

[0010] S4. After the reaction is completed and the material is naturally cooled, centrifugation, washing, and vacuum drying are performed to obtain a core-shell structured rare-earth magnetic far-infrared bifunctional material.

[0011] Preferably, the Fe-B alloy in step S1 contains 19.5% B.

[0012] Preferably, the mass ratio of the high-entropy alloy powder, silane coupling agent, rare earth salt and citric acid is (90-110):(8-12):(20-25):(38-45).

[0013] Preferably, the specific steps of the smelting operation in step S1 are as follows: placing the raw material into a vacuum arc melting furnace and evacuating it to a vacuum level of 4.0-6.0 × 10⁻⁶. -3 After Pa, inert gas is introduced for protection, and the mixture is repeatedly melted 4-6 times at a melting current of 1400-1600 A.

[0014] Preferably, the process parameters for the single-roll rapid quenching method in step S1 are: linear speed controlled at 30-40 m / s, and crystallization treatment at 670-690℃ under inert gas protection for 8-12 minutes.

[0015] Preferably, the specific steps of ball milling in step S1 are as follows: the amorphous ribbon is placed in a planetary ball mill for crushing, the ball milling speed is 300-400 rpm, the ball-to-material ratio is (8-12):1, the time is 1.5-2.5 h, and the average particle size D50 is 2.5-3.5 μm.

[0016] Preferably, step S2 includes the following steps:

[0017] S21. Disperse high-entropy alloy powder in dilute nitric acid solution, sonicate for 4-6 minutes, stir at room temperature for 0.5-1.5 minutes, then wash with deionized water and anhydrous ethanol alternately by centrifugation 2-4 times, and finally disperse in anhydrous toluene to obtain a toluene suspension.

[0018] S22. Add silane coupling agent to toluene suspension, and reflux at 105-115℃ for 5-7 hours under inert gas protection. After the reaction, wash with toluene and acetone alternately by centrifugation 2-4 times, and dry under vacuum at 55-65℃ for 3-5 hours to obtain silanized alloy powder.

[0019] Preferably, the concentration of the dilute nitric acid solution in step S21 is 0.08-0.12 M.

[0020] Preferably, the silane coupling agent in step S22 is one or a mixture of two or more of 3-aminopropyltriethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, vinyltriethoxysilane, and bis(3-triethoxysilylpropyl)tetrasulfide.

[0021] Preferably, the rare earth salt-citric acid complex solution in step S3 is a cerium nitrate-citric acid complex solution and / or a cerium chloride-citric acid complex solution.

[0022] Preferably, the specific steps of the hydrothermal reaction in step S3 are as follows:

[0023] The silanized alloy powder was dispersed in deionized water and sonicated for 25-35 minutes to form a uniform alloy suspension. The rare earth salt-citric acid complex solution was added dropwise to the alloy suspension and transferred to a hydrothermal reactor. The reaction was carried out at 115-125℃ for 3.5-4.5 hours.

[0024] Preferably, in step S4, the material is washed alternately by centrifugation with deionized water and anhydrous ethanol, and then vacuum dried at 75-85°C for 10-14 hours to obtain a core-shell structured rare-earth magnetic far-infrared bifunctional material.

[0025] Thirdly, the present invention also provides the application of the above-mentioned rare earth magnetic far-infrared dual-functional materials in the preparation of high-performance magnetothermal-far-infrared synergistic therapy devices, intelligent sensing or high-efficiency energy conversion devices.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] The rare-earth magnetic far-infrared bifunctional material of this invention exhibits a high-entropy effect, significantly enhancing its structural stability and intrinsic magnetocaloric effect and far-infrared radiation characteristics. The Si-O-Ce covalent bonds constructed through a silane coupling agent serve as a robust bridge connecting the core and the outer shell. This differs from the weak interactions of physical adsorption, ensuring the stability of the outer shell and preventing the functional layer from peeling off during long-term use or under harsh environments. The five rare-earth elements in the high-entropy alloy are randomly distributed at lattice sites, resulting in lattice distortion. This distortion drastically alters the material's phonon spectrum (lattice vibration modes), significantly enhancing its lattice vibrations in the mid- and far-infrared bands (especially 8-14 μm), thus providing excellent far-infrared emission capabilities with a far-infrared emissivity as high as 0.95. Furthermore, the remanence of the rare-earth magnetic far-infrared bifunctional material of this invention is >1.13T, achieving dual synergy between magnetism and far-infrared radiation. Attached Figure Description

[0028] Figure 1 This is a TEM image of the rare-earth magnetic far-infrared bifunctional material prepared in Example 1 of the present invention. Detailed Implementation

[0029] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0030] In this document, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0031] In this document, when values ​​are described as ranges, it should be understood that such disclosure includes disclosure of all possible subranges within that range, as well as the specific numerical values ​​that fall within that range, regardless of whether the specific numerical value or specific subrange is explicitly specified.

[0032] In this article, the terms "multiple" or "more than" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0033] In this document, the terms "preferred" and "more preferred" are used only to describe implementation methods or embodiments with better effects, and should be understood as not constituting a limitation on the scope of protection of this invention.

[0034] In this document, terms such as "further" are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of this invention.

[0035] In this article, the term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0036] In this document, the term "about" means a specified value of + / - 10%, preferably + / - 5%, and more preferably + / - 1%.

[0037] In this article, the terms “include,” “including,” “have,” “contain,” etc., are all open-ended terms, meaning that they include but are not limited to.

[0038] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention.

[0039] The preparation method of the rare-earth magnetic far-infrared bifunctional material of the present invention includes the following steps:

[0040] S1. High-entropy alloy core (Gd x Tb x Dy (1-2x） / 3 Ho (1-2x） / 3 Y (1-2x） / 3 Fe 14 Preparation of B):

[0041] S11. Batching and Melting

[0042] Weigh out the various high-purity metals (Gd, Tb, Dy, Ho, Y purity ≥ 99.9%) and Fe-B alloy (B content 19.5%), place the prepared material blocks into a vacuum electric arc melting furnace, and evacuate to 4.0-6.0 × 10⁻⁶. -3 After Pa, high-purity argon gas is introduced for protection, and the metal is completely melted under a melting current of 1400-1600 A. The melting is repeated 4-6 times to ensure uniform composition.

[0043] S12. Rapid quenching and crystallization

[0044] The alloy ingot is induction heated to a molten state and then rapidly cooled under argon protection using a single-roller rapid quenching device to form an amorphous ribbon. The rapid quenching speed is controlled at 30-40 m / s. The ribbon is then crystallized at 670-690℃ under argon protection for 8-12 minutes. The crystallized ribbon is then crushed in a planetary ball mill at a speed of 300-400 rpm, a ball-to-material ratio of 8-12:1, and a time of 1.5-2.5 h. Powder with a D50 of 2.5-3.5 μm is sieved for later use.

[0045] S2. Core surface silanization modification:

[0046] S21. Surface activation

[0047] Take 90-110 parts by weight of high-entropy alloy powder and disperse it in 0.08-0.12 M dilute nitric acid. Sonicate for 4-6 minutes, stir slowly at room temperature for 0.5-1.5 minutes, and immediately wash with deionized water and anhydrous ethanol alternately by centrifugation 2-4 times. Finally, disperse it in anhydrous toluene.

[0048] S22. Silane modification

[0049] Add 8-12 parts by weight of silane coupling agent to toluene suspension, and reflux at 105-115℃ for 5-7 hours under nitrogen protection. After the reaction, wash with toluene and acetone alternately by centrifugation 2-4 times, and dry under vacuum at 55-65℃ for 3-5 hours to obtain silanized alloy powder.

[0050] S3. Chemical grafting of rare earth salt shells:

[0051] S31. Preparation of rare earth salt-citric acid complex solution

[0052] Weigh 20-25 parts by weight of rare earth salt and 38-45 parts by weight of citric acid, dissolve them in deionized water, and stir magnetically for 25-35 minutes to form a stable [Ce(Cit)3]3. 3- Complexed anion solution.

[0053] S32. Hydrothermal bonding reaction

[0054] The silanized alloy powder was redispersed in deionized water and sonicated for 25-35 minutes to form a uniform suspension. The rare earth salt-citric acid complex solution was added dropwise to the alloy suspension and transferred to a hydrothermal reactor. The reaction was carried out at 115-125℃ for 3.5-4.5 hours to promote the formation of stable Si-O-Ce covalent bonds at the interface.

[0055] S4. Post-processing

[0056] After the reaction is completed and the material is naturally cooled, it is washed alternately by centrifugation with deionized water and anhydrous ethanol, and then vacuum dried at 75-85℃ for 10-14 hours to obtain a core-shell structured rare earth magnetic far-infrared bifunctional material.

[0057] The present invention will be described in detail below with reference to the embodiments.

[0058] Example 1

[0059] S1. High-entropy alloy core (Gd 0.2 Tb 0.2 Dy 0.2 Ho 0.2 Y 0.2 Fe 14 Preparation of B)

[0060] S11. Batching and Melting

[0061] Press Gd 0.2 Tb 0.2 Dy 0.2 Ho 0.2 Y 0.2 Fe 14 B. Calculate and weigh out 100g of each high-purity metal (Gd, Tb, Dy, Ho, Y purity ≥ 99.9%) and Fe-B alloy (B content 19.5%). Place the prepared material into a copper crucible in a vacuum arc melting furnace. Repeatedly evacuate the furnace to 5.0 × 10⁻⁶. -3 After reaching Pa, high-purity argon gas is introduced to -0.05 MPa. Arc melting is initiated, with the melting current controlled at 1500 A to ensure complete melting of the metal. To ensure uniform composition, the melting process is repeated at least 5 times.

[0062] S12. Rapid quenching and crystallization

[0063] The molten alloy ingot was placed in a quartz tube and induction heated to a molten state. Using a single-roll rapid quenching device, under argon protection, the molten alloy was sprayed onto a copper roller rotating at a linear velocity of 35 m / s, rapidly cooling to form an amorphous ribbon. The ribbon was collected and crystallized in a tube furnace at 680°C under argon protection for 10 minutes, followed by water quenching. The crystallized ribbon was then crushed in a planetary ball mill (argon protection, speed 350 rpm, ball-to-material ratio 10:1, time 2 h), and powder with a D50 of approximately 3.0 μm was sieved for later use.

[0064] S2. Core surface silanization modification

[0065] S21. Surface activation

[0066] Take 10 g of the above high-entropy alloy powder, disperse it in 200 mL of 0.1 M dilute nitric acid, sonicate for 5 minutes, and then stir slowly at room temperature for 1 minute. Immediately wash it three times by alternating centrifugation with deionized water and anhydrous ethanol, and finally disperse it in 50 mL of anhydrous toluene. This step generates abundant hydroxyl groups (-OH) on the surface of the alloy powder.

[0067] S22. Silane modification

[0068] 1.0 g of 3-aminopropyltriethoxysilane (KH-550) was added to the above toluene suspension. The mixture was refluxed at 110 °C for 6 hours under nitrogen protection. The ethoxy group of the silane underwent hydrolytic condensation with the hydroxyl group on the alloy surface, forming a Si-OM covalent bond (M being the metal on the alloy surface). After the reaction was complete, the mixture was washed three times alternately by centrifugation with toluene and acetone, and then vacuum dried at 60 °C for 4 hours to obtain a silanized alloy powder with amino (-NH2) groups on its surface.

[0069] S3. Chemical grafting of rare earth salt shells

[0070] S31. Preparation of rare earth salt-citric acid complex solution

[0071] Weigh 2.2 g of cerium nitrate (Ce(NO3)3•6H2O) and 4.2 g of citric acid, dissolve them in 80 mL of deionized water, and stir magnetically for 30 minutes to form a stable [Ce(Cit)3]3. 3- Complexed anion solution.

[0072] S32. Hydrothermal bonding reaction

[0073] All the silanized alloy powder obtained in step S2 was redispersed in 100 mL of deionized water and sonicated for 30 minutes to form a homogeneous suspension. Under vigorous stirring, a rare earth salt-citric acid complex solution was added dropwise to the alloy suspension. The mixed suspension was transferred to a 200 mL polytetrafluoroethylene-lined stainless steel hydrothermal reactor. The reactor was placed in an oven and reacted at 120°C for 4 hours. During this process, [Ce(Cit)3]... 3- With the -NH3 on the core surface + Adsorption occurs through electrostatic interaction, and stable Si-O-Ce covalent bonds are formed at the interface under high temperature and pressure.

[0074] S4. Post-processing

[0075] After the reaction was completed and the mixture was allowed to cool naturally, the product was washed alternately by centrifugation with deionized water and anhydrous ethanol until the supernatant was clear. The product was then dried in a vacuum drying oven at 80°C for 12 hours to finally obtain a core-shell structured rare-earth magnetic far-infrared bifunctional material.

[0076] TEM image of the core-shell structured rare-earth magnetic far-infrared bifunctional material prepared in Example 1 is shown below. Figure 1 As shown, the material has a complete "core-shell" structure, with a dark-colored high-entropy alloy particle core and a light-colored, uniformly thick rare earth salt layer on the outer shell.

[0077] Example 2

[0078] S1. High-entropy alloy core (Gd 0.1 Tb 0.1 Dy 0.27 Ho 0.27 Y 0.27 Fe 14 Preparation of B)

[0079] S11. Batching and Melting

[0080] Press Gd 0.1 Tb 0.1 Dy 0.27 Ho 0.27 Y 0.27 Fe14 B. Calculate and weigh out 100g of each high-purity metal (Gd, Tb, Dy, Ho, Y purity ≥ 99.9%) and Fe-B alloy (B content 19.5%). Place the prepared material into a copper crucible in a vacuum arc melting furnace. Repeatedly evacuate to 4.0 × 10⁻⁶. -3 After reaching Pa, high-purity argon gas is introduced to -0.04 MPa. Arc melting is initiated, with the melting current controlled at 1400 A to ensure complete melting of the metal. To ensure uniform composition, the melting process is repeated at least 6 times.

[0081] S12. Rapid quenching and crystallization

[0082] The molten alloy ingot was placed in a quartz tube and induction heated to a molten state. Using a single-roll rapid quenching device, under argon protection, the molten alloy was sprayed onto a copper roller rotating at a linear velocity of 30 m / s, rapidly cooling to form an amorphous ribbon. The ribbon was collected and crystallized in a tube furnace at 670°C under argon protection for 12 minutes, followed by water quenching. The crystallized ribbon was then crushed in a planetary ball mill under argon protection at a speed of 300 rpm, a ball-to-material ratio of 8:1, and a time of 1.5 hours. Powder with a D50 of approximately 2.5 μm was sieved for later use.

[0083] S2. Core surface silanization modification

[0084] S21. Surface activation

[0085] Take 0.9 g of the above high-entropy alloy powder, disperse it in 200 mL of 0.08 M dilute nitric acid, sonicate for 4 minutes, and then stir slowly at room temperature for 0.5 minutes. Immediately wash the powder four times with alternating centrifugation using deionized water and anhydrous ethanol, and finally disperse it in 50 mL of anhydrous toluene. This step generates abundant hydroxyl groups (-OH) on the surface of the alloy powder.

[0086] S22. Silane modification

[0087] 0.8 g of 3-methacryloxypropyltrimethoxysilane (MPS) was added to the above toluene suspension. The mixture was refluxed at 110 °C for 6 hours under nitrogen protection. The ethoxy group of the silane underwent hydrolytic condensation with the hydroxyl group on the alloy surface, forming a Si-OM covalent bond (M being the metal on the alloy surface). After the reaction was complete, the mixture was washed four times alternately by centrifugation with toluene and acetone, and then vacuum dried at 55 °C for 3 hours to obtain a silanized alloy powder with amino (-NH2) groups on its surface.

[0088] S3. Chemical grafting of rare earth salt shells

[0089] S31. Preparation of rare earth salt-citric acid complex solution

[0090] Weigh 2.0 g of cerium nitrate (Ce(NO3)3•6H2O) and 3.8 g of citric acid, dissolve them in 80 mL of deionized water, and stir magnetically for 25 minutes to form a stable [Ce(Cit)3]3. 3- Complexed anion solution.

[0091] S32. Hydrothermal bonding reaction

[0092] All the silanized alloy powder obtained in step S2 was redispersed in 100 mL of deionized water and sonicated for 25 minutes to form a homogeneous suspension. Under vigorous stirring, a rare earth salt-citric acid complex solution was added dropwise to the alloy suspension. The mixed suspension was transferred to a 200 mL polytetrafluoroethylene-lined stainless steel hydrothermal reactor. The reactor was placed in an oven and reacted at 115°C for 3.5 hours. During this process, [Ce(Cit)3]... 3- With the -NH on the core surface 3+ Adsorption occurs through electrostatic interaction, and stable Si-O-Ce covalent bonds are formed at the interface under high temperature and pressure.

[0093] S4. Post-processing

[0094] After the reaction was completed and the mixture was allowed to cool naturally, the product was washed alternately by centrifugation with deionized water and anhydrous ethanol until the supernatant was clear. The product was then dried in a vacuum drying oven at 75°C for 14 hours to finally obtain a core-shell structured rare-earth magnetic far-infrared bifunctional material.

[0095] Example 3

[0096] S1. High-entropy alloy core (Gd 0.3 Tb 0.3 Dy 0.13 Ho 0.13 Y 0.13 Fe 14 Preparation of B)

[0097] S11. Batching and Melting

[0098] Press Gd 0.3 Tb 0.3 Dy 0.13 Ho 0.13 Y 0.13 Fe 14 B. Calculate and weigh out 100g of each high-purity metal (Gd, Tb, Dy, Ho, Y purity ≥ 99.9%) and Fe-B alloy (B content 19.5%). Place the prepared material into a copper crucible in a vacuum arc melting furnace. Repeatedly evacuate to 6.0 × 10⁻⁶. -3 After reaching Pa, high-purity argon gas is introduced to -0.06 MPa. Arc melting is initiated, with the melting current controlled at 1600 A to ensure complete melting of the metal. To ensure uniform composition, the melting process is repeated at least 6 times.

[0099] S12. Rapid quenching and crystallization

[0100] The molten alloy ingot was placed in a quartz tube and induction heated to a molten state. Using a single-roll rapid quenching device, under argon protection, the molten alloy was sprayed onto a copper roller rotating at a linear velocity of 40 m / s, rapidly cooling to form an amorphous ribbon. The ribbon was collected and crystallized in a tube furnace at 690°C under argon protection for 8 minutes, followed by water quenching. The crystallized ribbon was then crushed in a planetary ball mill under argon protection at a speed of 300 rpm, a ball-to-material ratio of 12:1, and a time of 2.5 hours. Powder with a D50 of approximately 3.5 μm was sieved for later use.

[0101] S2. Core surface silanization modification

[0102] S21. Surface activation

[0103] Take 1.1 g of the above high-entropy alloy powder, disperse it in 200 mL of 0.12 M dilute nitric acid, sonicate for 6 minutes, and then stir slowly at room temperature for 1.5 minutes. Immediately wash twice with deionized water and anhydrous ethanol alternately by centrifugation, and finally disperse it in 50 mL of anhydrous toluene. This step generates abundant hydroxyl groups (-OH) on the surface of the alloy powder.

[0104] S22. Silane modification

[0105] 1.2 g of bis(3-triethoxysilylpropyl)tetrasulfide (Si-69) was added to the above toluene suspension. The mixture was refluxed at 115 °C for 7 hours under nitrogen protection. The ethoxy group of the silane underwent hydrolytic condensation with the hydroxyl group on the alloy surface, forming a Si-OM covalent bond (M being the metal on the alloy surface). After the reaction was complete, the mixture was washed twice by alternating centrifugation with toluene and acetone, and then vacuum dried at 65 °C for 5 hours to obtain a silanized alloy powder with amino (-NH2) groups on its surface.

[0106] S3. Chemical grafting of rare earth salt shells

[0107] S31. Preparation of rare earth salt-citric acid complex solution

[0108] Weigh 2.5g of cerium chloride (CeCl3•6H2O) and 4.5g of citric acid, dissolve them in 80 mL of deionized water, and stir magnetically for 35 minutes to form a stable [Ce(Cit)3]3. 3- Complexed anion solution.

[0109] S32. Hydrothermal bonding reaction

[0110] All the silanized alloy powder obtained in step S2 was redispersed in 100 mL of deionized water and sonicated for 35 minutes to form a homogeneous suspension. Under vigorous stirring, a rare earth salt-citric acid complex solution was added dropwise to the alloy suspension. The mixed suspension was transferred to a 200 mL polytetrafluoroethylene-lined stainless steel hydrothermal reactor. The reactor was placed in an oven and reacted at 125°C for 4.5 hours. During this process, [Ce(Cit)3]... 3- With the -NH3 on the core surface + Adsorption occurs through electrostatic interaction, and stable Si-O-Ce covalent bonds are formed at the interface under high temperature and pressure.

[0111] S4. Post-processing

[0112] After the reaction was completed and the mixture was allowed to cool naturally, the product was washed alternately by centrifugation with deionized water and anhydrous ethanol until the supernatant was clear. The product was then dried in a vacuum drying oven at 75°C for 10 hours to finally obtain a core-shell structured rare-earth magnetic far-infrared bifunctional material.

[0113] Example 4

[0114] Preparation of high-entropy alloy core in S1: The alloy powder preparation method is the same as in Example 1, and 10.5 g of alloy powder is taken.

[0115] S2 core surface silanization modification: Add 0.95 g of vinyltriethoxysilane (A-151) and reflux at 108 °C for 6.3 hours.

[0116] Chemical grafting of rare earth salt shell in S3: Weigh 2.1 g of cerium chloride heptahydrate (CeCl3·7H2O) and 4.1 g of citric acid, and follow the same steps as in Example 1.

[0117] Comparative Example 1

[0118] Compared with Example 1, this comparative example uses a physical mixing method in the preparation of the composite material, directly mechanically mixing the high-entropy alloy powder and cerium citrate powder without surface silanization modification and hydrothermal bonding reaction. All other methods and steps are the same.

[0119] Comparative Example 2

[0120] Compared with Example 1, this comparative example uses a high-entropy alloy core of Gd. 0.25 Tb 0.25 Dy 0.25 Ho 0.25 Fe 14 B, except for the other steps, are all the same.

[0121] Comparative Example 3

[0122] Compared with Example 1, this comparative example uses a high-entropy alloy core of Gd.0.25 Tb 0.25 Ho 0.25 Y 0.25 Fe 14 B, except for the other steps, are all the same.

[0123] Comparative Example 4

[0124] Compared with Example 1, this comparative example uses a traditional neodymium iron boron alloy (N38) instead of a high-entropy alloy in the preparation of the high-entropy alloy core. All other methods and steps are the same.

[0125] The rare-earth magnetic far-infrared bifunctional materials prepared in the examples and comparative examples were subjected to far-infrared emissivity and remanence measurements, wherein:

[0126] The powder material to be tested is pressed into a flat, uniformly thick sheet sample at 15 MPa. The prepared sample and a standard blackbody source are placed in the measurement optical path of the instrument. At room temperature, the infrared spectra of the sample and the blackbody source in a specific wavelength band are measured. By comparing the spectral radiation signal of the sample with that of an ideal blackbody at the same temperature, the far-infrared emissivity (8-14 μm) of the sample in the normal direction is calculated.

[0127] Remanence measurement was performed in accordance with GB / T 43750-2024 "Method for measuring the magnetic properties of isotropic rare earth bonded permanent magnet powder".

[0128] The measurement results are shown in the table below:

[0129]

[0130] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rare-earth magnetic far-infrared dual-functional material, characterized in that: The rare-earth magnetic far-infrared dual-functional material has a core-shell structure, wherein the core is a high-entropy alloy with the structural formula Gd. x Tb x Dy (1-2x） / 3 Ho (1-2x） / 3 Y (1-2x） / 3Fe 14 B, where x ranges from 0.1 to 0.3, and the shell is a rare earth citrate bond connected to the core via Si-O-RE covalent bonds.

2. The preparation method of the rare earth magnetic far-infrared dual-functional material according to claim 1, characterized in that: Includes the following steps: S1. Weigh metals Gd, Tb, Dy, Ho, Y and Fe-B alloy and melt them to obtain alloy ingots after the metals and alloys are completely melted. Heat the alloy ingots to a molten state and use a single-roll rapid quenching method to prepare amorphous thin strips. Ball mill the amorphous thin strips to obtain high-entropy alloy powder for later use. S2. After surface activation of high-entropy alloy powder, it is reacted with a silane coupling agent to obtain silanized alloy powder; S3. Dissolve the silanized alloy powder in water to obtain an alloy suspension. Dissolve the rare earth salt and citric acid in deionized water to obtain a rare earth salt-citric acid complex solution. Add the rare earth-citric acid complex solution dropwise to the alloy suspension and then carry out a hydrothermal reaction. S4. After the reaction is completed and the material is naturally cooled, centrifugation, washing, and vacuum drying are performed to obtain a core-shell structured rare-earth magnetic far-infrared bifunctional material.

3. The preparation method of the rare-earth magnetic far-infrared dual-functional material according to claim 2, characterized in that: The mass ratio of the high-entropy alloy powder, silane coupling agent, rare earth salt and citric acid is (90-110): (8-12): (20-25): (38-45).

4. The preparation method of the rare-earth magnetic far-infrared dual-functional material according to claim 2, characterized in that: The specific steps of the S1 smelting operation are as follows: Place the raw material into a vacuum arc melting furnace and evacuate to a vacuum level of 4.0-6.0 × 10⁻⁶. -3 After Pa, inert gas is introduced for protection, and the mixture is repeatedly melted 4-6 times at a melting current of 1400-1600 A. The process parameters for the single-roll rapid quenching method of S1 are: linear speed controlled at 30-40 m / s, crystallization treatment at 670-690℃ under inert gas protection for 8-12 minutes; The specific steps of ball milling S1 are as follows: the amorphous ribbon is placed in a planetary ball mill for crushing, the ball milling speed is 300-400 rpm, the ball-to-material ratio is (8-12):1, the time is 1.5-2.5 h, and the average particle size D50 is 2.5-3.5 μm.

5. The preparation method of the rare-earth magnetic far-infrared dual-functional material according to claim 2, characterized in that: The specific steps of S2 include: S21. Disperse high-entropy alloy powder in dilute nitric acid solution, sonicate for 4-6 minutes, stir at room temperature for 0.5-1.5 minutes, then wash with deionized water and anhydrous ethanol alternately by centrifugation 2-4 times, and finally disperse in anhydrous toluene to obtain a toluene suspension. S22. Add silane coupling agent to toluene suspension, and reflux at 105-115℃ for 5-7 hours under inert gas protection. After the reaction, wash with toluene and acetone alternately by centrifugation 2-4 times, and dry under vacuum at 55-65℃ for 3-5 hours to obtain silanized alloy powder.

6. The method for preparing rare-earth magnetic far-infrared dual-functional materials according to claim 5, characterized in that: The concentration of the dilute nitric acid solution in S21 is 0.08-0.12 M; the silane coupling agent in S22 is one or a mixture of two or more of 3-aminopropyltriethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, vinyltriethoxysilane, and bis(3-triethoxysilylpropyl)tetrasulfide.

7. The method for preparing rare-earth magnetic far-infrared dual-functional materials according to claim 2, characterized in that: The rare earth salt-citric acid complex solution in S3 is a cerium nitrate-citric acid complex solution and / or a cerium chloride-citric acid complex solution.

8. The method for preparing rare-earth magnetic far-infrared dual-functional materials according to claim 2, characterized in that: The specific steps of the hydrothermal reaction in S3 are as follows: The silanized alloy powder was dispersed in deionized water and sonicated for 25-35 minutes to form a uniform alloy suspension. The rare earth salt-citric acid complex solution was added dropwise to the alloy suspension and transferred to a hydrothermal reactor. The reaction was carried out at 115-125℃ for 3.5-4.5 hours.

9. The method for preparing rare-earth magnetic far-infrared dual-functional materials according to claim 2, characterized in that: S4 was washed alternately by centrifugation with deionized water and anhydrous ethanol, and then vacuum dried at 75-85℃ for 10-14 hours to obtain a core-shell structured rare earth magnetic far-infrared bifunctional material.

10. The application of the rare-earth magnetic far-infrared dual-functional material according to claim 1, characterized in that: The application involves using the rare-earth magnetic far-infrared dual-functional material to prepare high-performance magnetothermal-far-infrared synergistic therapy devices, intelligent sensing devices, or high-efficiency energy conversion devices.

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