CN114643365A

CN114643365A - Interface induction synthesis ordered L10Method for structuring permanent-magnet nanoparticles

Info

Publication number: CN114643365A
Application number: CN202210309658.5A
Authority: CN
Inventors: 裴文利; 赵东; 白羽丰
Original assignee: Northeastern University China
Current assignee: Northeastern University China
Priority date: 2022-03-28
Filing date: 2022-03-28
Publication date: 2022-06-21
Anticipated expiration: 2042-03-28
Also published as: CN114643365B

Abstract

The invention belongs to the technical field of magnetic nano materials, and particularly relates to interface-induced synthesis of ordered L1₀A method of structuring permanent magnetic nanoparticles. Firstly, adding a certain proportion of a seed crystal core metal precursor, a surfactant and a reducing agent into a solvent, heating the mixed solution to a certain temperature, preserving the temperature, then cooling to room temperature, and reducing the seed crystal core metal precursor to form a seed crystal core. Then adding a certain proportion of shell metal precursor, slowly heating to a certain temperature, then cooling to room temperature after heat preservation, reducing the shell metal precursor by a reducing agent, and growing under the induction of the interface of the seed crystal core to form L1₀Structural casings, finallyCentrifugal washing is carried out to obtain ordered L1₀The structure of the black powder of the permanent magnetic nano particles. Monodisperse high coercivity ordered L1 synthesis by ordered metal seed interface induction₀The structure nano material has lower synthesis temperature and simple operation.

Description

Interface induction synthesis ordered L10Method for structuring permanent-magnet nanoparticles

The technical field is as follows:

the invention belongs to the technical field of magnetic nano materials, and particularly relates to interface-induced synthesis of ordered L1₀Structure of the productA method of permanent magnetic nanoparticles.

Background art:

some transition group intermetallic compounds have abundant phase structure and various intrinsic magnetism, such as: FeCo and FeNi generally have structures of A2 and B2, show high saturation magnetization and low coercive force and are good soft magnetic materials; common MnAl and MnGa have a tau-phase structure and exhibit ferrimagnetism. If these intermetallic compounds can be made into chemically ordered L1₀Tetragonal phase, L1₀-FeCo、L1₀-FeNi、L1₀-MnAl、L1₀MnGa, the crystal structure of which has high symmetry, presents large magnetocrystalline anisotropy, high Curie temperature and high coercivity, is an excellent permanent magnetic material, the intermetallic compound does not contain rare earth elements, has low cost and wide application prospect, and the alloy is made into nano particles and has important application value in the aspects of high-density magnetic storage, electrochemical catalysis, micro-nano devices, biomedicine and the like.

However, it is difficult to obtain ordered tetragonal phases with high magnetocrystalline anisotropy with the usual direct preparation of FeCo, FeNi, MnAl, MnGa nanoparticles, because the process window for obtaining this structural alloy is narrow, for example: l1₀MnAl is a metastable phase formed by quenching and subsequent annealing (usually at 500 ℃ C.) of a Mn-rich epsilon phase, which readily decomposes into a non-magnetic phase. L1₀Slow diffusion of-FeNi phase at an order-disorder transition temperature of 593K, L1₀FeNi is only present in meteorites that have cooled at very low cooling rates over billions of years. L1₀FeCo has a ratio L1₀FeNi more desirable magnetic properties, but due to limited knowledge of the thermodynamics of phase formation, L1₀The preparation method of FeCo is still to be studied, and L1 has not been successfully synthesized in any laboratory so far₀-a FeCo phase. The existing chemical synthesis method generally directly reduces a metal precursor, and atoms form FeCo, FeNi, MnAl or MnGa alloy cores in a certain reaction environment and then grow into FeCo, FeNi, MnAl or MnGa nano particlesIs prepared from L1₀FeCo, FeNi, MnAl and MnGa nano materials with the structure. How to induce atoms to grow orderly in the nucleation growth process, and the L1 with good controllability and high order degree₀FeCo, FeNi, MnAl and MnGa nano particles are the bottleneck problem in the field.

The invention content is as follows:

the invention aims to provide an interface-induced synthetic ordered L1₀The method for structuring permanent magnetic nano particles is ordered L1₀The structural permanent magnetic nano particles refer to the nano particles of the transition group intermetallic compound, and particularly the ordered L1 is difficult to form by the conventional method₀The intermetallic compound of the structure specifically includes an intermetallic compound permanent magnetic nanoparticle such as FeCo, FeNi, MnAl, MnGa, and the like.

The idea of the invention patent is as follows:

L1₀the structural nano particles of FeCo, FeNi, MnAl, MnGa and the like are difficult to obtain by direct synthesis, so that the structural nano particles need to be induced to form an ordered structure in the synthesis process. Chemically synthesized nanoparticles are generally carried out in a nucleation growth mode, in which a nucleus is first formed and then grown into large-sized particles or various nanomaterials. During the growth process, different atoms are generally stacked along the surface of the crystal nucleus, and epitaxial growth along the interface is the main growth mode, so that the structure of the crystal nucleus has inheritance to the synthesized nano particle. If it will have L1₀Putting seed crystal of the structure into a reaction system, taking the seed crystal as a mass point of heterogeneous nucleation, stacking the reduced atoms along the surface of the seed crystal core, and when the lattice constant of the seed crystal is close to that of the particle to be synthesized, the lattice matching degree of the seed crystal is higher, the atoms can grow along the original crystal plane in an epitaxial way, thereby continuing to grow into ordered L1₀Structured nanoparticles.

Intermetallic compounds such as AuCu, MnNi, FePt and the like exist stably at lower temperature, are easy to obtain by chemical synthesis, and have lattice lattices and order L1₀The lattice lattices of FeCo, FeNi, MnAl and MnGa have higher matching degree and are easy to form epitaxial growth. Therefore, L1 can be synthesized first₀AuCu, MnNi, FePt of structure asSeeds, which are then centered and induced by the interface of their lattices, can give ordered L1₀Permanent magnetic nanoparticles of these transition group intermetallics of structure (e.g., FeCo, FeNi, MnAl, MnGa, etc., as described above).

The permanent magnetic nanoparticles thus formed are designated L1₀The crystal seed of intermetallic compound of AuCu, MnNi, FePt, etc. with structure is used as core and L1₀Transition intermetallic compounds such as FeCo, FeNi, MnAl, MnGa and the like with the structure are taken as shells, and the shape, the degree of order and the magnetic property of the product can be controlled by adjusting the proportion of the precursor, controlling the chemical components of the product, changing the reaction temperature, the reaction time and the like.

In order to achieve the purpose, the invention adopts an interface to induce and synthesize the ordered L1₀A method of structuring permanent magnetic nanoparticles. Firstly, adding a seed crystal core metal precursor, a surfactant and a reducing agent in a certain proportion into a solvent, heating the mixed solution to a certain temperature, preserving the temperature, then cooling to room temperature, and reducing the seed crystal core metal precursor to form L1₀The crystal seed core of intermetallic compound of AuCu, MnNi, FePt, etc. Then adding FeCo, FeNi, MnAl or MnGa shell metal precursor in a certain proportion, slowly heating to a certain temperature, then removing a heating source after heat preservation, cooling to room temperature, reducing the shell metal precursor by a reducing agent, and growing under the induction of an interface of a seed crystal core to form L1₀FeCo, FeNi, MnAl or MnGa shell with a structure, and finally carrying out centrifugal cleaning to obtain ordered L1₀The structure of the black powder of the permanent magnetic nano particles.

The method specifically comprises the following steps:

s1: the seed core metal precursor and the reducing agent are weighed.

The seed crystal core metal precursor is L1 capable of forming a high-order structure₀The metal source mixture of two metals of the metal alloy can be reduced to produce L1₀Seed core of the structure. Specifically, the intermetallic compound or metal alloy used as the seed core may be AuCu, MnNi, FePt, and thus the seed core metal precursor may be a gold source and a copper source, manganeseThe source and a nickel source or a mixture of an iron source and a platinum source, wherein the molar ratio of metal ions in the two metal sources is preferably (0.1-1): (0.1 to 1).

Specifically, in the seed core metal precursor: the gold source is chloroauric acid HAuCl₄Potassium tetrachloroaurate KAuCl₄One or more of (a); the copper source is acetylacetone copper Cu (acac)₂Copper acetate Cu (Ac)₂Copper chloride CuCl₂One or more of (a); the manganese source is manganese acetate Mn (Ac)₂MnCl, manganese chloride₂Manganese acetylacetonate Mn (acac)₂One or more of (a); the nickel source is nickel acetate Ni (Ac)₂Nickel nitrate Fe (NO)₃)₃Nickel sulfate Fe₂(SO₄)₃Nickel chloride NiCl₂Nickel acetylacetonate Ni (acac)₂One or more of (a); the iron source is ferric chloride FeCl₃FeNO, iron nitrate₃Iron (Fe) sulfate₂(SO₄)₃Fe (acac) acetylacetonate₃One or more of (a); the platinum source is chloroplatinic acid H₂PtCl₆Platinum acetylacetonate Pt (acac)₂Chloroplatinic acid K₂PtCl₆One or more of (a).

The reducing agent is potassium borohydride KBH₄Sodium borohydride NaBH₄1, 2-hexadecanediol C₁₆H₃₄O₂Lithium aluminum hydride LiAlH, sodium cyanoborohydride CH₃One or more BNNa. The actual total addition amount of the reducing agent is not less than the theoretical addition amount, and the theoretical addition amount of the reducing agent is the amount which can completely reduce metal ions in the seed crystal core metal precursor and the shell metal precursor into 0-valent metal. Specifically, the ratio of the actual addition amount of the reducing agent to the theoretical addition amount may be (1-10): 1.

s2: adding the crystal seed core metal precursor into a solvent, carrying out dehydration treatment under the action of a protective atmosphere, and adding a surfactant after the dehydration treatment to form a mixed solution.

Preferably, the solvent is hexadecylamine C₁₆H₃₅N, trioctylamine C₂₄H₅₁N, octadecylamine C₁₈H₃₉N, icosanamine C₂₀H₄₃N, oleylamine C₁₈H₃₇One or more of N, and the surfactant is decaalkyl quaternary ammonium bromide C₁₆H₃₈Br₂N₂Lecithin C₄₂H₈₀NO₈P, glyceryl monostearate C₂₁H₄₂O₄Oleylamine C₁₈H₃₇N and oleic acid C₁₈H₃₄O₂Mixing the two substances, wherein the two substances of the surfactant are mixed according to the volume ratio (0.1-1): (0.1-1) mixing and adding. The above-mentioned solvent and surfactant can promote more favorable growth of the metal atoms generated after the seed core metal precursor is reduced to L1₀The structure also promotes the metal atoms of the shell metal precursor after being reduced to grow into L1 better under the induction of the crystal lattice interface of the seed crystal core₀And (5) structure. The solvent provides a good platform for the growth of the two, and the surfactant can retain the synthetic L1 to the maximum extent₀The surface activity of the structure and various groups on the surface of the structure provide guarantee for subsequent various applications.

The molar ratio of metal ions to solvent in the seed crystal core metal precursor is 1: (10-30), wherein the molar ratio of the solvent to the surfactant (the surfactant is the total amount of two substances) is 10: (1.0-5.0).

Preferably, the protective atmosphere is 93% Ar + 7% H₂、95％Ar+5％H₂High purity argon Ar or high purity nitrogen N₂One of (1) and (b). The method for water removal treatment comprises the following steps: under the action of protective atmosphere, heating to 100-120 ℃ at a heating rate of 1-10 ℃/min, and preserving heat for 30-120 min. The water removal treatment is more beneficial to the function of the surfactant.

S3: and heating the mixed solution to a first reaction temperature, preserving the temperature, carrying out a reaction for generating a seed crystal core, cooling, weighing and adding a shell metal precursor.

In the process of temperature rise and heat preservation, the seed crystal core metal precursor is reduced into 0-valent metal atoms and assembled into an intermetallic compound to form L1₀Seed core of the structure. Therefore, before this process, i.e., before the reaction for forming the seed core, it is necessary to ensure that the solution is dissolvedThe liquid contains sufficient reducing agent.

Preferably, the first reaction temperature is 280-360 ℃, the heat preservation time is 30-300 min, and the mixed solution is cooled to 60-120 ℃ after the reaction.

The shell metal precursor is ordered L1 formed to be prepared₀A metal source mixture of two metals of the structured permanent magnetic nanoparticles, such as FeCo, FeNi, MnAl or MnGa, and thus in particular the shell metal precursor may be a mixture of an iron and cobalt, iron and nickel, manganese and aluminium or manganese and gallium source.

As previously mentioned, these metals are generally difficult to form into ordered L1₀The intermetallic compound or the gold nanoparticle with the structure, and the difficulty of forming the intermetallic compound with the structure is greatly reduced on the premise that the seed crystal core exists and interface induction is carried out.

Preferably, the molar ratio of two metal ions in the shell metal precursor metal source is (0.2-1): (0.2-1). In the shell metal precursor, the iron source is ferric chloride FeCl₃Carbonyl iron Fe (CO)₅Fe (acac) acetylacetonate₃C, iron oleate₅₄H₉₉FeO₆One or more of the above; the cobalt source is cobalt acetylacetonate Co (acac)₂Octacarbonyldicobalt Co₂(CO)₈Cobalt acetate Co (Ac)₂One or more of the above; the nickel source is nickel acetate Ni (Ac)₂Nickel nitrate Fe (NO)₃)₃Nickel sulfate Fe₂(SO₄)₃Nickel chloride NiCl₂Nickel acetylacetonate Ni (acac)₂One or more of (a); the manganese source is manganese acetate Mn (Ac)₂MnCl, manganese chloride₂Manganese acetylacetonate Mn (acac)₂One or more of (a); the aluminum source is aluminum chloride AlCl₃Aluminum acetylacetonate Al (acac)₃One or more of (a); the gallium source is gallium acetate Ga (Ac)₂Gallium chloride GaCl₂Ga (acac) acetylacetonate₂One or more of (a).

When a shell metal precursor is added into the mixed solution, the molar ratio of the total amount of metal ions in the shell metal precursor to the total amount of metal ions in the seed crystal core metal precursor is (0.4-1): (0.2 to 1).

S4: heating the mixed solution to a second reaction temperature, preserving heat, carrying out a shell generation reaction, cooling to room temperature, and carrying out centrifugal cleaning on the mixed solution to obtain black powder, namely the ordered L1₀Structural permanent magnetic nanoparticles.

During the heating and heat preservation, the shell metal precursor is reduced into 0-valent metal atoms, and ordered L1 is formed under the induction of the interface of the seed crystal core₀Structural intermetallic compounds. It is therefore necessary to ensure that the mixed solution contains a sufficient amount of reducing agent before the process, i.e. the reaction to produce the shell.

Preferably, the second reaction temperature is 200-300 ℃, and the heat preservation time is 10-60 min.

Preferably, in both the step S3 and the step S4, the temperature of the mixed solution is raised to the reaction temperature by a slow temperature raising method with a temperature raising rate of 1 to 10 ℃/min, so as to ensure sufficient reduction of the precursor and to allow sufficient growth time of the intermetallic compound.

A method for obtaining black powder by centrifugal cleaning of the mixed solution is described as follows:

carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to a volume ratio of (1-5): (5-1), wherein the mixed solvent B is deionized water and absolute ethyl alcohol in a volume ratio of (1-5): (5-1) a mixed solvent.

The mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is (1-5): 1, then carrying out centrifugal separation, and pouring out upper-layer liquid after the centrifugal separation to obtain black powder;

then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 3-5 times;

cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, wherein the process of centrifugally separating after cleaning the mixed solvent B and after cleaning the mixed solvent A is called as 1 time, and the process is repeated for 3-5 times;

finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol.

In the method, the rotating speed of a centrifugal machine for centrifugal separation is 6000-12000 rpm, and the time for each centrifugation is 3-10 min.

In the above method, it is described that in the reaction of producing the seed crystal core and producing the shell in step S3 and step S4, it is necessary to ensure a sufficient amount of the reducing agent in the mixed solution. Specifically, the reducing agent is added in one of two ways:

the method A comprises the following steps: all reducing agents are added prior to the seed core generation reaction of step S3, for example, all reducing agents may be added to the solvent at step S2 along with the seed core metal precursor.

The method B comprises the following steps: a first portion of reducing agent, such as a solvent, may be added with the seed core metal precursor prior to the seed core generation reaction of step S3, the first portion being added in an amount no less than the amount capable of fully reducing the seed core metal precursor, and a second portion of the remaining reducing agent, such as a solvent, may be added with the shell metal precursor prior to the shell generation reaction of step S4, to ensure full reduction of the shell metal precursor.

By the method, ordered L1 can be successfully synthesized by utilizing interface induction₀The degree of order of the structure nano particles is 0.85-0.95. The coercive force Hc reaches 850.5-1500.8 Oe, and the saturation magnetization Ms reaches 61.2-185.8 emu/g.

The invention has the beneficial effects that:

(1) synthesis of monodisperse high coercivity ordered L1 by interfacial induction of ordered metal seeds₀The structural nano material has lower synthesis temperature and simple operation;

(2) by optimizing the synthesis process, the ordered L1 with excellent dispersibility, high order degree and excellent magnetic property can be obtained₀A structural nanomaterial;

(3) the invention aims to prepare high-order L1 by adopting interface induction₀The structure nano particle avoids the phenomena of aggregation and abnormal growth caused in the heat treatment process, and is used for preparing high-order L1₀Structure of the productThe nano material provides theoretical support and promotes the practical process.

Description of the drawings:

FIG. 1 is an XRD pattern of the product synthesized in example 1 of the process of the present invention;

FIG. 2 is a hysteresis loop of the product synthesized in example 1 of the process of the present invention;

FIG. 3 is a TEM image of a synthesized product of example 1 of the method of the present invention;

FIG. 4 is an XRD pattern of the product synthesized in example 2 of the process of the present invention;

FIG. 5 is a hysteresis loop of the synthesized product in example 2 of the present invention;

FIG. 6 is a TEM image of a synthesized product of example 2 of the method of the present invention;

FIG. 7 is an XRD pattern of the product synthesized by method example 3 of the present invention;

FIG. 8 is a hysteresis loop of a synthesized product in example 3 of the present invention;

FIG. 9 is a TEM image of a synthesized product of example 3 of the method of the present invention.

The specific implementation mode is as follows:

the present invention will be described in further detail with reference to examples.

In the following examples:

the experimental equipment, instruments and experimental reagents are all purchased commercially.

The experimental equipment and instruments include: a three-neck flask, a condenser tube, an electronic balance, a mechanical stirring heating sleeve, a centrifuge and the like;

the experimental reagent comprises: chloroauric acid, potassium tetrachloroaurate, copper acetylacetonate, copper acetate, copper chloride, manganese acetate, manganese chloride, manganese acetylacetonate, nickel acetate, nickel nitrate, nickel sulfate, nickel chloride, nickel acetylacetonate, ferric chloride, ferric nitrate, ferric sulfate, ferric acetylacetonate, chloroplatinic acid, platinum acetylacetonate, potassium chloroplatinate, carbonyl iron, ferric oleate, cobalt acetylacetonate, octacarbonyl cobaltic acetate, cobalt acetate, nickel nitrate, nickel sulfate, nickel chloride, nickel acetylacetonate, manganese acetate, manganese chloride, manganese acetylacetonate, manganese chloride, aluminum acetylacetonate, gallium acetate, gallium chloride, gallium acetylacetonate, potassium borohydride, sodium borohydride, 1, 2-hexadecaneDiol, lithium aluminum hydride, sodium cyanoborohydride, hexadecylamine, trioctylamine, octadecylamine, eicosylamine, oleylamine, oleic acid, 93% Ar + 7% H₂、95％Ar+5％H₂High purity argon Ar, high purity nitrogen N₂Chloroform, absolute ethyl alcohol and deionized water, all purchased from the market.

The magnetic properties of the product were determined using a Vibrating Sample Magnetometer (VSM), the morphology of the product was observed using a field emission Transmission Electron Microscope (TEM), and the phase of the product was analyzed by x-ray diffraction (XRD).

In the following examples, the reducing agent was added in one of two ways:

the method A comprises the following steps: all reducing agents are added prior to the seed core generation reaction, for example, all reducing agents may be added to the solvent at step S2 along with the seed core metal precursor.

The method B comprises the following steps: the first portion of reducing agent is added prior to the seed core generation reaction, for example, a solvent may be added with the seed core metal precursor, the first portion being added in an amount not less than the amount capable of fully reducing the seed core metal precursor, and the second portion of remaining reducing agent is added prior to the shell generation reaction of step S4, ensuring full reduction of the shell metal precursor.

The reducing agent is not particularly described in the following examples, and only the kind and amount of the reducing agent are described, as long as the reducing agent can ensure that all of the metal sources in the seed core metal precursor and the shell metal precursor can be reduced in two reactions of the seed core formation and the shell formation.

Example 1:

(1) firstly, weighing a seed crystal core metal precursor copper source acetylacetone copper and gold source chloroauric acid by using an electronic balance, wherein the molar ratio of the two is 0.3: 0.2, weighing a reducing agent 1, 2-hexadecanediol, wherein the proportional relation between the theoretical value and the actual value of the using amount of the reducing agent is 1: 1.

(2) adding weighed crystal seed core metal precursor powder (a copper source and a gold source) and a reducing agent 1, 2-hexadecanediol into a three-neck flask filled with a solvent hexadecylamine, wherein the molar ratio of the crystal seed core metal precursor to the solvent is 1: 10. In a protective atmosphere of 93% Ar + 7% H₂Under the action of the temperature, the temperature is raised to 120 ℃ at the temperature rise rate of 10 ℃/min and is kept for 120min, the water removal treatment is carried out, and then the surfactant (oleylamine + oleic acid) is added into the mixed solution according to the volume ratio, the oleylamine: oleic acid 1: 1; in terms of molar ratio, solvent: surfactant 10: 1.0.

(3) slowly heating the mixed solution to 280 ℃ at a heating rate of 1 ℃/min, preserving the temperature for 300min to obtain a black mixed solution, then cooling to 60 ℃, adding shell metal precursor powder iron source ferric chloride and cobalt source cobalt acetylacetonate into the mixed solution, wherein the molar ratio of the shell metal precursor powder to the metal in the seed crystal core metal precursor powder is 1:0.5, the molar ratio of two metal ions in the shell metal precursor is 0.5: 0.5.

(4) and (3) heating the mixed solution to 300 ℃ at the heating rate of 1 ℃/min, then preserving the heat for 60min, and cooling to room temperature to obtain a black mixed solution.

And (2) carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to a volume ratio of 5: 1, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 1: 5 in a mixed solvent; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 1:1, then carrying out centrifugal separation, and pouring out upper liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 3 times; then cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 3 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotating speed of the centrifugal machine for centrifugal separation is 12000rpm, and the time of each centrifugation is 10 min.

Characterization of the product phase by X-ray diffractometry to L1₀FeCo, which contains ordered phase characteristic peaks (001), (110) and (002), the degree of order is 0.92, and the XRD pattern is shown in figure 1. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_c1175.6Oe, the saturation magnetization Ms is 89.9emu/g, and the hysteresis loop is shown in FIG. 2. The product shape was observed by field emission transmission electron microscopyThe appearance is a uniformly dispersed core-shell appearance, and a TEM image is shown in an attached figure 3. The coercive force of the core-shell Nano-particle obtained by heat treatment at 380 ℃ is 846Oe, which is similar to the result in the embodiment.

Example 2:

(1) firstly, weighing seed crystal core metal precursors of copper source copper acetate and gold source potassium tetrachloroaurate by using an electronic balance, wherein the molar ratio of the copper source copper acetate to the gold source potassium tetrachloroaurate is 0.5: 0.2, weighing a certain amount of reducing agent potassium borohydride, wherein the proportion relation between the theoretical value and the actual value of the reducing agent is 1: 1.

(2) adding weighed seed crystal core metal precursor powder (a copper source and a gold source) and a reducing agent potassium borohydride into a three-neck flask filled with a solvent trioctylamine, wherein the molar ratio of the seed crystal core metal precursor to the solvent is 1: 15. in a protective atmosphere of 95% Ar + 5% H₂Under the action of the temperature, the temperature is raised to 100 ℃ at the rate of 1 ℃/min and is kept for 120min, the water removal treatment is carried out, then, the surfactant (brominated decahydrocarbon quaternary amine + oleic acid) is added into the mixed solution, and the volume ratio of the brominated decahydrocarbon quaternary amine: oleic acid 1: 0.5; in terms of molar ratio, solvent: surfactant 10: 2.0.

(3) slowly heating the mixed solution to 290 ℃ at a heating rate of 2 ℃/min, preserving the temperature for 200min to obtain a black mixed solution, then cooling to 120 ℃, adding shell metal precursor powder iron carbonyl iron and cobalt source octacarbonyl dicobalt into the mixed solution, wherein the molar ratio of metal in the shell metal precursor powder to metal in the seed crystal core metal precursor powder is 1:0.2, and the molar ratio of two metal ions in the shell metal precursor is 1: 0.2.

(4) and (3) heating the mixed solution to 270 ℃ at the heating rate of 2 ℃/min, then preserving the heat for 10min, and cooling to room temperature to obtain a black mixed solution.

Carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to the volume ratio of 5: 2, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 3: 5 in a mixed solvent; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 2: 1, then carrying out centrifugal separation, and pouring out upper-layer liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 3 times; then cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 3 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotating speed of the centrifugal machine for centrifugal separation is 8000-12000 rpm, and the time for each centrifugation is 3 min.

Characterization of the product phase by X-ray diffractometry to L1₀FeCo, which contains ordered phase characteristic peaks (001), (110) and (002), the degree of order is 0.90, and an XRD pattern is shown in figure 4. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_cThe saturation magnetization Ms was 1028.9Oe, 91.0emu/g, and the hysteresis loop is shown in FIG. 5. The morphology of the product is observed to be a uniformly dispersed core-shell morphology by a field emission transmission electron microscope, and a TEM image is shown in figure 6. The coercive force of the core-shell Nano-particle obtained by heat treatment at 380 ℃ is 846Oe, which is similar to the result in the embodiment.

Example 3:

(1) firstly, weighing seed crystal core metal precursor copper source chloride and gold source chloroauric acid by adopting an electronic balance, wherein the molar ratio of the copper source chloride to the gold source chloroauric acid is 0.1: 1, weighing a certain amount of reducing agent sodium borohydride, wherein the ratio of the theoretical value to the actual value of the using amount of the reducing agent is 1: 2.

(2) adding weighed seed crystal core metal precursor powder (a copper source and a gold source) and a reducing agent sodium borohydride into a three-neck flask filled with a solvent trioctylamine, wherein the molar ratio of the seed crystal core metal precursor to the solvent is 1: 20. under the action of high-purity argon Ar in protective atmosphere, heating to 105 ℃ at the heating rate of 2 ℃/min, preserving the temperature for 100min, removing water, then adding a surfactant (decahydroquaternary ammonium bromide + oleic acid) into the mixed solution, and according to the volume ratio, brominating the decahydroquaternary ammonium: oleic acid 0.4: 1; in terms of molar ratio, solvent: surfactant 10: 3.0.

(3) slowly heating the mixed solution to 300 ℃ at a heating rate of 3 ℃/min, preserving heat for 250min to obtain a black mixed solution, then cooling to 100 ℃, adding shell metal precursor powder iron source ferric acetylacetonate and cobalt source cobalt acetate into the mixed solution, wherein the molar ratio of metal in the shell metal precursor powder to metal in the seed crystal core metal precursor powder is 1:0.7, and the molar ratio of two metal ions in the shell metal precursor is 1: 0.5.

(4) and (3) heating the mixed solution to 260 ℃ at a heating rate of 5 ℃/min, then preserving the heat for 20min, and cooling to room temperature to obtain a black mixed solution.

Carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to the volume ratio of 5: 4, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 5: 5 in a mixed solvent; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 3: 1, then carrying out centrifugal separation, and pouring out upper-layer liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 4 times; then, cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 4 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotating speed of the centrifugal machine for centrifugal separation is 8000-10000 rpm, and the time for each centrifugation is 4-8 min.

Characterization of the product phase by X-ray diffractometry to L1₀FeCo, which contains ordered phase characteristic peaks (001), (110) and (002), the degree of order is 0.91, and the XRD pattern is shown in figure 7. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_c1093.1Oe, the saturation magnetization Ms is 76.4emu/g, and the hysteresis loop is shown in FIG. 8. The morphology of the product is observed to be a uniformly dispersed core-shell morphology by a field emission transmission electron microscope, and a TEM image is shown in figure 9. The coercive force of the core-shell Nano-particle obtained by heat treatment at 380 ℃ is 846Oe, which is similar to the result in the embodiment.

Example 4:

(1) firstly, weighing seed crystal core metal precursor copper source acetylacetone copper and gold source potassium tetrachloroaurate by using an electronic balance, wherein the molar ratio of the copper source acetylacetone copper to the gold source potassium tetrachloroaurate is 0.5: 1, weighing a certain amount of reducing agent 1, 2-hexadecanediol, wherein the proportion relation between the theoretical value and the actual value of the using amount of the reducing agent is 1: 2.

(2) adding weighed crystal seed core metal precursor powder (a copper source and a gold source) and a reducing agent 1, 2-hexadecanediol into a three-neck flask filled with a solvent octadecylamine, wherein the molar ratio of the crystal seed core metal precursor to the solvent is 1: 25. high purity nitrogen N in protective atmosphere₂Under the action of the temperature, the temperature is raised to 110 ℃ at the temperature rise rate of 10 ℃/min and is kept for 80min, the water removal treatment is carried out, and then the surfactant (oleylamine + lecithin) is added into the mixed solution according to the volume ratio, the ratio of oleylamine: lecithin ═ 0.3: 1; in terms of molar ratio, solvent: surfactant 10: 4.0.

(3) slowly heating the mixed solution to 320 ℃ at a heating rate of 5 ℃/min, preserving the temperature for 150min to obtain a black mixed solution, then cooling to 90 ℃, adding shell metal precursor powder iron source ferric oleate and cobalt source cobalt acetylacetonate into the mixed solution, wherein the molar ratio of the shell metal precursor powder to the metal in the seed crystal core metal precursor powder is 1:0.5, and the molar ratio of two metal ions in the shell metal precursor is 1: 1.

(4) and (3) heating the mixed solution to 200 ℃ at the heating rate of 1 ℃/min, then preserving the heat for 30min, and cooling to room temperature to obtain a black mixed solution.

Carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to a volume ratio of 4: 5, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 5: 4 in a mixed solvent; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 4:1, then carrying out centrifugal separation, and pouring out upper-layer liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 4 times; then cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 4 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotating speed of the centrifugal machine for centrifugal separation is 8000-10000 rpm, and the time for each centrifugation is 6-8 min.

Using x-ray diffraction instrumentsThe phase of the product was characterized as L1₀FeCo, containing ordered phase characteristic peaks (001), (110) and (002), with an order degree of 0.95. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_cThe saturation magnetization Ms was 1405.5Oe and 92.5 emu/g. The morphology of the product is observed to be uniformly dispersed core-shell morphology by a field emission transmission electron microscope.

Example 5:

(1) firstly, weighing seed crystal core metal precursors of manganese source manganese acetate and nickel source nickel acetate by using an electronic balance, wherein the molar ratio of the manganese source acetate to the nickel source nickel acetate is 0.3: 1, weighing a certain amount of reducing agent lithium aluminum hydride, wherein the proportion relation between the theoretical value and the actual value of the reducing agent is 1: 3.

(2) adding weighed crystal seed core metal precursor powder (a manganese source and a nickel source) and a reducing agent lithium aluminum hydride into a three-neck flask filled with a solvent icosane, wherein the molar ratio of the crystal seed core metal precursor to the solvent is 1: 30. under the action of protective atmosphere high-purity argon Ar, heating to 115 ℃ at a heating rate of 5 ℃/min, preserving heat for 50min, removing water, and then adding a surfactant (oleylamine + glyceryl monostearate) into the mixed solution, wherein the ratio by volume of oleylamine: glycerol monostearate ═ 1: 0.3; in terms of molar ratio, solvent: surfactant 10: 5.0.

(3) slowly heating the mixed solution to 340 ℃ at a heating rate of 8 ℃/min, preserving heat for 100min to obtain a black mixed solution, then cooling to 80 ℃, adding shell metal precursor powder nickel acetate and iron oleate into the mixed solution, wherein the molar ratio of the shell metal precursor powder to the metal in the seed crystal core metal precursor powder is 1:0.4, and the molar ratio of two metal ions in the shell metal precursor is 0.5: 1.

(4) heating the mixed solution to 245 ℃ at a heating rate of 8 ℃/min, then preserving the heat for 40min, and cooling to room temperature to obtain a black mixed solution.

Carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to a volume ratio of 2: 5, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 5: 2 in a mixed solvent; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 5: 1, then carrying out centrifugal separation, and pouring out upper-layer liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 5 times; then, cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 3 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotating speed of the centrifugal machine for centrifugal separation is 8000-10000 rpm, and the time for each centrifugation is 3-10 min.

Characterization of the product phase by x-ray diffractometry was L1₀FeNi, containing ordered phase characteristic peaks (001), (110) and (002), with an order degree of 0.95. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_cThe saturation magnetization Ms was 1405.5Oe and 92.5 emu/g. The morphology of the product is observed to be uniformly dispersed core-shell morphology by a field emission transmission electron microscope.

Example 6:

(1) firstly, weighing a seed crystal core metal precursor manganese source manganese chloride and nickel source nickel nitrate by using an electronic balance, wherein the molar ratio of the manganese source manganese chloride to the nickel source nickel nitrate is 1:0.5, weighing a certain amount of reducing agent sodium cyanoborohydride, wherein the proportion relation between the theoretical value and the actual value of the reducing agent is 1: 4.

(2) adding weighed seed crystal core metal precursor powder (a manganese source and a nickel source) and a reducing agent sodium cyanoborohydride into a three-neck flask filled with oleylamine, wherein the molar ratio of the seed crystal core metal precursor to the solvent is 1: 25. in a protective atmosphere of 95% Ar + 5% H₂Under the action of the temperature, the temperature is raised to 120 ℃ at the temperature raising rate of 8 ℃/min and is kept for 30min, the water removing treatment is carried out, then, the surfactant (decahydroquaternary ammonium bromide + lecithin) is added into the mixed solution, and the decahydroquaternary ammonium bromide is prepared by the following steps: lecithin ═ 1: 1; in terms of molar ratio, solvent: surfactant 10: 2.0.

(3) slowly heating the mixed solution to 360 ℃ at a heating rate of 10 ℃/min, preserving heat for 30min to obtain a black mixed solution, then cooling to 60 ℃, adding shell metal precursor powder iron source ferric acetylacetonate and nickel source nickel nitrate into the mixed solution, wherein the molar ratio of the shell metal precursor powder to the metal in the seed crystal core metal precursor powder is 1:1, and the molar ratio of two metal ions in the shell metal precursor is 0.2: 1.

(4) heating the mixed solution to 240 ℃ at a heating rate of 10 ℃/min, then preserving the heat for 50min, and cooling to room temperature to obtain a black mixed solution.

Carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to a volume ratio of 1: 5, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 5: 1, a mixed solvent; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 5: 1, then carrying out centrifugal separation, and pouring out upper-layer liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 5 times; then, cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 5 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotating speed of the centrifugal machine for centrifugal separation is 6000-12000 rpm, and the time of each centrifugation is 3-10 min.

Characterization of the product phase by X-ray diffractometry to L1₀FeNi, containing ordered phase characteristic peaks (001), (110) and (002), with an order degree of 0.95. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_c1500.8Oe, the saturation magnetization Ms is 85.6 emu/g. The morphology of the product is observed to be uniformly dispersed core-shell morphology by a field emission transmission electron microscope.

Example 7:

(1) firstly, weighing seed crystal core metal precursors of manganese source acetylacetone manganese and nickel source nickel sulfate by using an electronic balance, wherein the molar ratio of the manganese source acetylacetone manganese to the nickel source nickel sulfate is 1:0.2, weighing a certain amount of reducing agent 1, 2-hexadecanediol, wherein the proportion relation between the theoretical value and the actual value of the using amount of the reducing agent is 1: 3.

(2) adding weighed crystal seed core metal precursor powder (manganese source + nickel source) and reducing agent 1, 2-hexadecanediol into a three-neck flask filled with solvent hexadecylamine, wherein the molar ratio of the crystal seed core metal precursor to the solvent is1: 10. in a protective atmosphere of 93% Ar + 7% H₂Under the action of the temperature, heating to 100 ℃ at the heating rate of 1 ℃/min, preserving the temperature for 30min, removing water, and then adding a surfactant (oleylamine + oleic acid) into the mixed solution, wherein the volume ratio of oleylamine: oleic acid 1: 1; in terms of molar ratio, solvent: surfactant 10: 1.0.

(3) slowly heating the mixed solution to 280 ℃ at the heating rate of 1 ℃/min, preserving the temperature for 30min to obtain a black mixed solution, then cooling to 60 ℃, adding shell metal precursor powder iron carbonyl iron and nickel sulfate, wherein the molar ratio of metal in the shell metal precursor powder to metal in the seed crystal core metal precursor powder is 0.8:1, and the molar ratio of two metal ions in the shell metal precursor is 0.5: 0.5.

(4) and heating the mixed solution to 280 ℃ at a heating rate of 1 ℃/min, then preserving the heat for 60min, and cooling to room temperature to obtain a black mixed solution.

And (2) carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to a volume ratio of 1: 5, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 1: 5 in a mixed solvent; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 1:1, then carrying out centrifugal separation, and pouring out upper-layer liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 3 times; then cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 3 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotation speed of the centrifugal machine for centrifugal separation is 6000rpm, and the centrifugation time is 3min each time.

Characterization of the product phase by X-ray diffractometry to L1₀FeNi, which contains ordered phase characteristic peaks (001), (110) and (002), and has an order degree of 0.86. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_c896.8Oe, the saturation magnetization Ms is 163.8 emu/g. The morphology of the product is observed to be uniformly dispersed core-shell morphology by a field emission transmission electron microscope.

Example 8:

(1) firstly, weighing seed crystal core metal precursors including manganese source manganese chloride and nickel source nickel chloride by using an electronic balance, wherein the molar ratio of the manganese source manganese chloride to the nickel source nickel chloride is 0.5: 1, weighing a certain amount of reducing agent potassium borohydride, wherein the ratio of the theoretical value to the actual value of the using amount of the reducing agent is 1: 7.

(2) adding weighed seed crystal core metal precursor powder (a manganese source and a nickel source) and a reducing agent potassium borohydride into a three-neck flask filled with a solvent octadecylamine, wherein the molar ratio of the seed crystal core metal precursor to the solvent is 1: 30. heating to 120 ℃ at a heating rate of 10 ℃/min under the action of high-purity argon in a protective atmosphere, preserving heat for 120min, removing water, adding a surfactant (oleylamine + lecithin) into the mixed solution, and mixing the oleylamine: lecithin ═ 0.1: 1; in terms of molar ratio, solvent: surfactant 10: 5.0.

(3) slowly heating the mixed solution to 360 ℃ at a heating rate of 10 ℃/min, preserving heat for 300min to obtain a black mixed solution, then cooling to 120 ℃, adding shell metal precursor powder iron source ferric chloride and nickel source nickel chloride into the mixed solution, wherein the molar ratio of the shell metal precursor powder to the metal in the seed crystal core metal precursor powder is 1:1, and the molar ratio of two metal ions in the shell metal precursor is 0.2: 1.

(4) heating the mixed solution to 340 ℃ at a heating rate of 10 ℃/min, then preserving the heat for 60min, and cooling to room temperature to obtain a black mixed solution.

Carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to a volume ratio of 1:1, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 1:1, a mixed solvent; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 5: 1, then carrying out centrifugal separation, and pouring out upper-layer liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 5 times; then, cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 4 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotating speed of the centrifugal machine for centrifugal separation is 12000rpm, and the time for each centrifugation is 10 min.

Characterization of the product phase by X-ray diffractometry to L1₀FeNi, containing ordered phase characteristic peaks (001), (110) and (002), with an order degree of 0.89. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_c1096.8Oe, the saturation magnetization Ms is 185.8 emu/g. The morphology of the product is observed to be uniformly dispersed core-shell morphology by a field emission transmission electron microscope.

Example 9:

(1) firstly, weighing seed crystal core metal precursors of manganese source acetylacetone manganese and nickel source acetylacetone nickel by an electronic balance, wherein the molar ratio of the manganese source acetylacetone manganese to the nickel source acetylacetone nickel is 0.8:1, weighing a certain amount of reducing agent sodium borohydride, wherein the ratio of the theoretical value to the actual value of the using amount of the reducing agent is 1: 2.

(2) adding weighed seed crystal core metal precursor powder (a manganese source and a nickel source) and a reducing agent sodium borohydride into a three-neck flask filled with a solvent trioctylamine, wherein the molar ratio of the seed crystal core metal precursor to the solvent is 1: 20. under the action of high-purity nitrogen in protective atmosphere, heating to 110 ℃ at a heating rate of 5 ℃/min, keeping the temperature for 75min, removing water, adding a surfactant (brominated decahydrocarbon quaternary amine + oleic acid) into the mixed solution, and mixing the brominated decahydrocarbon quaternary amine: oleic acid 1: 0.1; in terms of molar ratio, solvent: surfactant 10: 3.0.

(3) slowly heating the mixed solution to 320 ℃ at a heating rate of 5 ℃/min, preserving the temperature for 150min to obtain a black mixed solution, then cooling to 90 ℃, adding shell metal precursor powder iron source ferric oleate and nickel source nickel acetylacetonate into the mixed solution, wherein the molar ratio of metal in the shell metal precursor powder to metal in the seed crystal core metal precursor powder is 1:0.7, and the molar ratio of two metal ions in the shell metal precursor is 1: 0.2.

(4) and (3) heating the mixed solution to 300 ℃ at the heating rate of 5 ℃/min, then preserving the heat for 30min, and cooling to room temperature to obtain a black mixed solution.

Carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to the volume ratio of 5: 1, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 5: 1, a mixed solvent; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 1:1, then carrying out centrifugal separation, and pouring out upper-layer liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 4 times; then cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 4 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotation speed of the centrifugal machine for centrifugal separation is 9000rpm, and each time of centrifugation is 6 min.

Characterization of the product phase by X-ray diffractometry to L1₀FeNi, which contains ordered phase characteristic peaks (001), (110) and (002), and has an order degree of 0.90. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_cThe saturation magnetization Ms was 1206.7Oe and 61.2 emu/g. The morphology of the product is observed to be uniformly dispersed core-shell morphology by a field emission transmission electron microscope.

Example 10:

(1) firstly, weighing seed crystal core metal precursors of manganese source manganese acetate and nickel source nickel chloride by using an electronic balance, wherein the molar ratio of the manganese source manganese acetate to the nickel source nickel chloride is 0.7: 1, weighing a certain amount of reducing agent sodium cyanoborohydride, wherein the ratio of the theoretical value to the actual value of the amount of the reducing agent is 1: 1.

(2) adding weighed seed crystal core metal precursor powder (a manganese source and a nickel source) and a reducing agent sodium cyanoborohydride into a three-neck flask filled with a solvent eicosylamine, wherein the molar ratio of the seed crystal core metal precursor to the solvent is 1: 10. in a protective atmosphere of 93% Ar + 7% H₂Under the action of the temperature, heating to 120 ℃ at a heating rate of 10 ℃/min, preserving the temperature for 120min, removing water, and then adding a surfactant (oleylamine + glyceryl monostearate) into the mixed solution, wherein the volume ratio of oleylamine: glycerol monostearate ═ 1: 1; in terms of molar ratio, solvent: surfactant 10: 1.0.

(3) slowly heating the mixed solution to 280 ℃ at the heating rate of 1 ℃/min, preserving the temperature for 300min to obtain a black mixed solution, then cooling to 60 ℃, adding shell metal precursor powder, namely manganese acetate and aluminum chloride, into the mixed solution, wherein the molar ratio of metal in the shell metal precursor powder to metal in the seed crystal core precursor powder is 0.4:1, and the molar ratio of two metal ions in the shell metal precursor is 0.5: 0.5.

Carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to the volume ratio of 5: 1, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 1: 5 in a mixed solvent; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 1:1, then carrying out centrifugal separation, and pouring out upper-layer liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, performing centrifugal separation, and repeating for 3 times; then cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 5 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotating speed of the centrifugal machine for centrifugal separation is 6000-12000 rpm, and the time of each centrifugation is 10 min.

Characterization of the product phase by X-ray diffractometry to L1₀MnAl, which contains ordered phase characteristic peaks (001), (110) and (002), and has an order degree of 0.92. Measuring the magnetic hysteresis loop of the product at room temperature by a vibrating sample magnetometer, and the coercive force H of the product_cIt was 1231.8Oe and the saturation magnetization Ms was 75.8 emu/g. The morphology of the product is observed to be uniformly dispersed core-shell morphology by a field emission transmission electron microscope.

Example 11:

(1) firstly, weighing a seed crystal core metal precursor gold source chloroauric acid and a copper source copper chloride by using an electronic balance, wherein the molar ratio of the gold source chloroauric acid to the copper source copper chloride is 1:0.7, weighing a certain amount of reducing agent 1, 2-hexadecanediol, wherein the proportion relation between the theoretical value and the actual value of the using amount of the reducing agent is 1: 6.

(2) weighing seed crystal core metal precursor powderAdding powder (a gold source and a copper source) and a reducing agent 1, 2-hexadecanediol into a three-neck flask filled with a solvent hexadecylamine, wherein the molar ratio of the seed crystal core metal precursor to the solvent is 1: 10. in a protective atmosphere of 93% Ar + 7% H₂Under the action of the temperature, heating to 120 ℃ at the heating rate of 8 ℃/min, preserving the temperature for 120min, removing water, and then adding a surfactant (oleylamine + oleic acid) into the mixed solution according to the volume ratio, wherein the ratio of oleylamine: oleic acid 1: 1; in terms of molar ratio, solvent: surfactant 10: 1.0.

(3) slowly heating the mixed solution to 280 ℃ at the heating rate of 1 ℃/min, preserving the temperature for 300min to obtain a black mixed solution, then cooling to 60 ℃, adding shell metal precursor powder, namely manganese source manganese chloride and aluminum source aluminum chloride, into the mixed solution, wherein the molar ratio of metal in the shell metal precursor powder to metal in the seed crystal core metal precursor powder is 1:0.6, and the molar ratio of two metal ions in the shell metal precursor is 1: 0.2.

Carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to the volume ratio of 5: 1, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 1: 5, a mixed solvent; first, the mixed solution is washed by a mixed solvent a: the volume ratio of the mixed solution is 1:1, then carrying out centrifugal separation, and pouring out upper-layer liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 3 times; then cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 3 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotating speed of the centrifugal machine for centrifugal separation is 9000rpm, and the time of each centrifugation is 10 min.

Characterization of the product phase by X-ray diffractometry to L1₀MnAl, which contains ordered phase characteristic peaks (001), (110) and (002), and has an order degree of 0.93. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_cIt was 1332.7Oe, and the saturation magnetization Ms was 71.5 emu/g. The morphology of the product is observed to be uniformly dispersed core-shell morphology by a field emission transmission electron microscope.

Example 12:

(1) firstly, weighing a seed crystal core metal precursor gold source potassium tetrachloroaurate and a copper source copper acetylacetonate by using an electronic balance, wherein the molar ratio of the gold source potassium tetrachloroaurate to the copper source copper acetylacetonate is 1:0.2, weighing a certain amount of reducing agent 1, 2-hexadecanediol, wherein the proportion relation between the theoretical value and the actual value of the using amount of the reducing agent is 1: 9.

(2) adding weighed crystal seed core metal precursor powder (a gold source and a copper source) and a reducing agent 1, 2-hexadecanediol into a three-neck flask filled with a solvent hexadecylamine, wherein the molar ratio of the crystal seed core metal precursor to the solvent is 1: 10. in a protective atmosphere of 93% Ar + 7% H₂Under the action of the temperature, the temperature is raised to 100 ℃ at the rate of 1 ℃/min and is kept for 30min, the water removal treatment is carried out, and then the surfactant (oleylamine + oleic acid) is added into the mixed solution according to the volume ratio, the ratio of oleylamine: oleic acid 1: 1; in terms of molar ratio, solvent: surfactant 10: 1.0.

(3) slowly heating the mixed solution to 280 ℃ at a heating rate of 1 ℃/min, preserving the temperature for 30min to obtain a black mixed solution, then cooling to 60 ℃, adding shell metal precursor powder manganese acetylacetonate and aluminum source aluminum acetylacetonate into the mixed solution, wherein the molar ratio of metal in the shell metal precursor powder to metal in the seed crystal core metal precursor powder is 0.8:1, and the molar ratio of two metal ions in the shell metal precursor is 0.5: 0.5.

Carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to a volume ratio of 1: 5, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 1: 5 in a mixed solvent; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 1:1, then carrying out centrifugal separation, and pouring out upper liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 3 times; then cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 3 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotation speed of the centrifugal machine for centrifugal separation is 6000rpm, and the centrifugation time is 3min each time.

Characterization of the product phase by X-ray diffractometry to L1₀MnAl, which contains ordered phase characteristic peaks (001), (110) and (002), and has an order degree of 0.94. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_cIt was 1231.8Oe, and the saturation magnetization Ms was 75.8 emu/g. The morphology of the product is observed to be uniformly dispersed core-shell morphology by a field emission transmission electron microscope.

Example 13:

(1) firstly, weighing iron source ferric chloride and platinum source platinum acetylacetonate which are core metal precursors of the seed crystal by an electronic balance, wherein the molar ratio of the iron source ferric chloride to the platinum source platinum acetylacetonate is 0.5: 1, weighing a certain amount of reducing agent potassium borohydride, wherein the ratio of the theoretical value to the actual value of the amount of the reducing agent is 1: 2.

(2) adding weighed seed crystal core metal precursor powder (an iron source and a platinum source) and a reducing agent potassium borohydride into a three-neck flask filled with a solvent octadecylamine, wherein the molar ratio of the seed crystal core metal precursor to the solvent is 1: 30. under the action of high-purity argon in protective atmosphere, heating to 120 ℃ at a heating rate of 10 ℃/min, preserving heat for 120min, removing water, and then adding a surfactant (oleylamine + lecithin) into the mixed solution, wherein the ratio by volume of oleylamine: lecithin ═ 0.1: 1; in terms of molar ratio, solvent: surfactant 10: 5.0.

(3) slowly heating the mixed solution to 360 ℃ at a heating rate of 10 ℃/min, preserving heat for 300min to obtain a black mixed solution, then cooling to 120 ℃, adding shell metal precursor powder manganese source manganese acetylacetonate and gallium source gallium acetate into the mixed solution, wherein the molar ratio of metal in the shell metal precursor powder to metal in the seed crystal core metal precursor powder is 1:1, and the molar ratio of two metal ions in the shell metal precursor is 0.2: 1.

(4) and (3) heating the mixed solution to 340 ℃ at a heating rate of 10 ℃/min, then preserving the heat for 60min, and cooling to room temperature to obtain a black mixed solution.

And (2) carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to a volume ratio of 1:1, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 1:1, a mixed solvent; first, the mixed solution is washed by a mixed solvent a: the volume ratio of the mixed solution is 5: 1, then carrying out centrifugal separation, and pouring out upper-layer liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 5 times; then cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 5 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotating speed of the centrifugal machine for centrifugal separation is 12000rpm, and the time of each centrifugation is 10 min.

Characterization of the product phase by X-ray diffractometry to L1₀MnGa containing ordered phase characteristic peaks (001), (110) and (002) and having an order degree of 0.95. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_cIt was 1450.5Oe, and the saturation magnetization Ms was 85.9 emu/g. The morphology of the product is observed to be uniformly dispersed core-shell morphology by a field emission transmission electron microscope.

Example 14:

(1) firstly, weighing iron source ferric nitrate and platinum source chloroplatinic acid serving as seed crystal core metal precursors by using an electronic balance, wherein the molar ratio of the iron source ferric nitrate to the platinum source chloroplatinic acid is 0.8:1, weighing a certain amount of reducing agent sodium borohydride, wherein the ratio of the theoretical value to the actual value of the using amount of the reducing agent is 1: 2.

(2) adding weighed seed crystal core metal precursor powder (an iron source and a platinum source) and a reducing agent sodium borohydride into a three-neck flask filled with a solvent trioctylamine, wherein the molar ratio of the seed crystal core metal precursor to the solvent is 1: 20. under the action of high-purity nitrogen in protective atmosphere, heating to 110 ℃ at a heating rate of 5 ℃/min, keeping the temperature for 75min, removing water, adding a surfactant (brominated decahydrocarbon quaternary amine + oleic acid) into the mixed solution, and mixing the brominated decahydrocarbon quaternary amine: oleic acid 1: 0.1; in terms of molar ratio, solvent: surfactant 10: 3.0.

(3) slowly heating the mixed solution to 320 ℃ at a heating rate of 5 ℃/min, preserving the temperature for 150min to obtain a black mixed solution, then cooling to 90 ℃, adding shell metal precursor powder, namely manganese acetate and gallium chloride, into the mixed solution, wherein the molar ratio of metal in the shell metal precursor powder to metal in the seed crystal core metal precursor powder is 1:0.7, and the molar ratio of two metal ions in the shell metal precursor is 1: 0.2.

(4) heating the mixed solution to 300 ℃ at a heating rate of 5 ℃/min, then preserving the heat for 30min, and cooling to room temperature to obtain a black mixed solution.

Carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to the volume ratio of 5: 1, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 5: 1; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 1:1, then carrying out centrifugal separation, and pouring out upper liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 4 times; then cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 4 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotating speed of the centrifugal machine for centrifugal separation is 9000rpm, and the time of each centrifugation is 6 min.

Characterization of the product phase by X-ray diffractometry to L1₀MnGa containing ordered phase characteristic peaks (001), (110) and (002) and having an order degree of 0.90. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_cIt was 1460.8Oe, and the saturation magnetization Ms was 160.5 emu/g. The morphology of the product is observed to be uniformly dispersed core-shell morphology by a field emission transmission electron microscope.

Example 15:

(1) firstly, weighing iron source ferric sulfate and platinum source potassium chloroplatinate serving as core metal precursors of the seed crystal by using an electronic balance, wherein the molar ratio of the iron source ferric sulfate to the platinum source potassium chloroplatinate is 0.7: 1, weighing a certain amount of reducing agent sodium cyanoborohydride, wherein the ratio of the theoretical value to the actual value of the reducing agent is 1: 6.

(2) adding weighed seed crystal core metal precursor powder (an iron source and a platinum source) and reducing agent sodium cyanoborohydride into a three-neck flask filled with solvent icosamine, wherein the molar ratio of the seed crystal core metal precursor to the solvent is 1: 10. in a protective atmosphere of 93% Ar + 7% H₂Under the action of the temperature, heating to 120 ℃ at a heating rate of 10 ℃/min, preserving the temperature for 120min, removing water, and then adding a surfactant (oleylamine + glyceryl monostearate) into the mixed solution, wherein the volume ratio of oleylamine: glycerol monostearate ═ 1: 1; in terms of molar ratio, solvent: surfactant 10: 1.0.

(3) slowly heating the mixed solution to 280 ℃ at the heating rate of 1 ℃/min, preserving the temperature for 300min to obtain a black mixed solution, then cooling to 60 ℃, adding shell metal precursor powder manganese source manganese chloride and gallium source gallium acetylacetonate into the mixed solution, wherein the molar ratio of metal in the shell metal precursor powder to metal in the seed crystal core metal precursor powder is 0.4:1, the molar ratio of two metal ions in the shell metal precursor is 0.5: 0.5.

(4) and (3) heating the mixed solution to 200 ℃ at the heating rate of 1 ℃/min, then preserving the heat for 60min, and cooling to room temperature to obtain a black mixed solution.

Carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to the volume ratio of 5: 1, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 1: 5 in a mixed solvent; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 1:1, then carrying out centrifugal separation, and pouring out upper liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 3 times; then cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 5 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotating speed of the centrifugal machine for centrifugal separation is 6000-12000 rpm, and the time of each centrifugation is 10 min.

Characterization of the product phase by X-ray diffractometry to L1₀MnGa containing ordered phase characteristic peaks (001), (110) and (002) and having an order degree of 0.92. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_cIt was 1492.4Oe, and the saturation magnetization Ms was 126.8 emu/g. The morphology of the product is observed to be uniformly dispersed core-shell morphology through a field emission transmission electron microscope.

Example 16:

(1) firstly, weighing iron source acetylacetone iron and platinum source chloroplatinic acid serving as seed crystal core metal precursors by an electronic balance, wherein the molar ratio of the iron source acetylacetone iron to the platinum source chloroplatinic acid is 0.2: 0.3, weighing a certain amount of reducing agent 1, 2-hexadecanediol, wherein the proportion relation between the theoretical value and the actual value of the using amount of the reducing agent is 1: 4.

(2) adding weighed crystal seed core metal precursor powder (an iron source and a platinum source) and a reducing agent 1, 2-hexadecanediol into a three-neck flask filled with a solvent hexadecylamine, wherein the molar ratio of the crystal seed core metal precursor to the solvent is 1: 10. in a protective atmosphere of 93% Ar + 7% H₂Under the action of the temperature, the temperature is raised to 100 ℃ at the temperature rise rate of 1 ℃/min and is kept for 120min, the water removal treatment is carried out, and then the surfactant (oleylamine + oleic acid) is added into the mixed solution according to the volume ratio, the ratio of oleylamine: oleic acid 0.2: 1; in terms of molar ratio, solvent: surfactant 10: 1.0.

(3) slowly heating the mixed solution to 280 ℃ at a heating rate of 10 ℃/min, preserving the temperature for 200min to obtain a black mixed solution, then cooling to 60 ℃, adding shell metal precursor powder manganese source manganese acetate and gallium source gallium acetylacetonate into the mixed solution, wherein the metal molar ratio of the shell metal precursor powder to the seed crystal core metal precursor powder is 1:0.5, the molar ratio of two metal ions in the shell metal precursor is 0.5: 0.5.

(4) heating the mixed solution to 280 ℃ at a heating rate of 10 ℃/min, then preserving the heat for 15min, and cooling to room temperature to obtain a black mixed solution.

And (2) carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to a volume ratio of 5: 1, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 1: 5 in a mixed solvent; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 1:1, then carrying out centrifugal separation, and pouring out upper-layer liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 3 times; then cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 3 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotating speed of the centrifugal machine for centrifugal separation is 6000-12000 rpm, and the time of each centrifugation is 10 min.

Characterization of the product phase by X-ray diffractometry to L1₀MnGa containing ordered phase characteristic peaks (001), (110) and (002) and having an order degree of 0.91. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_c1358.6Oe, and the saturation magnetization Ms is 143.8 emu/g. The morphology of the product is observed to be uniformly dispersed core-shell morphology by a field emission transmission electron microscope.

Example 17:

(1) firstly, weighing iron source ferric sulfate and platinum source potassium chloroplatinate serving as core metal precursors of a seed crystal by using an electronic balance, wherein the molar ratio of the iron source ferric sulfate to the platinum source potassium chloroplatinate is 0.2: 1, weighing a certain amount of reducing agent potassium borohydride, wherein the ratio of the theoretical value to the actual value of the using amount of the reducing agent is 1: 1.

(2) adding weighed seed crystal core metal precursor powder (an iron source and a platinum source) and a reducing agent potassium borohydride into a three-neck flask filled with a solvent trioctylamine, wherein the molar ratio of the seed crystal core metal precursor to the solvent is 1: 10. in a protective atmosphere of 95% Ar + 5% H₂Under the action of the temperature, the temperature is raised to 120 ℃ at the temperature rise rate of 3 ℃/min and is kept for 100min, the water removal treatment is carried out, then, the surfactant (brominated decahydrocarbon quaternary amine + oleic acid) is added into the mixed solution, and the volume ratio of the brominated decahydrocarbon quaternary amine: oleic acid 0.8: 1; in terms of molar ratio, solvent: surfactant 10: 4.1.

(3) slowly heating the mixed solution to 320 ℃ at a heating rate of 7 ℃/min, preserving the temperature for 300min to obtain a black mixed solution, then cooling to 120 ℃, adding shell metal precursor powder iron source ferric chloride and cobalt source cobalt acetylacetonate into the mixed solution, wherein the molar ratio of metal in the shell metal precursor powder to metal in the seed crystal core metal precursor powder is 1: 0.8, the molar ratio of two metal ions in the shell metal precursor is 0.2: 1.

(4) and (3) heating the mixed solution to 220 ℃ at the heating rate of 1 ℃/min, then preserving the heat for 60min, and cooling to room temperature to obtain a black mixed solution.

Carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to a volume ratio of 1: 5, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 5: 1, a mixed solvent; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 5: 1, then carrying out centrifugal separation, and pouring out upper-layer liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, performing centrifugal separation, and repeating for 5 times; then cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 5 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotating speed of the centrifugal machine for centrifugal separation is 6000-12000 rpm, and the time of each centrifugation is 3-4 min.

Characterization of the product phase by X-ray diffractometry to L1₀FeCo, containing ordered phase characteristic peaks (001), (110) and (002), with an order degree of 0.93. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_cIt was 1434.5Oe, and the saturation magnetization Ms was 120.7 emu/g. The morphology of the product is observed to be uniformly dispersed core-shell morphology through a field emission transmission electron microscope.

Example 18:

(1) firstly, weighing a seed crystal core metal precursor gold source chloroauric acid and a copper source copper acetylacetonate by using an electronic balance, wherein the molar ratio of the gold source chloroauric acid to the copper source copper acetylacetonate is 1:0.4, weighing a certain amount of reducing agent sodium borohydride, wherein the ratio of the theoretical value to the actual value of the using amount of the reducing agent is 1: 3.

(2) adding weighed seed crystal core metal precursor powder (a gold source and a copper source) and a reducing agent sodium borohydride into a three-neck flask filled with a solvent octadecylamine, wherein the molar ratio of the seed crystal core metal precursor to the solvent is 1: 10. under the action of high-purity argon Ar in protective atmosphere, heating to 110 ℃ at a heating rate of 5 ℃/min, preserving heat for 30min, removing water, and then adding a surfactant (oleylamine + lecithin) into the mixed solution, wherein the volume ratio of oleylamine: lecithin ═ 1: 0.1; in terms of molar ratio, solvent: surfactant 10: 3.8.

(3) slowly heating the mixed solution to 360 ℃ at a heating rate of 9 ℃/min, preserving heat for 100min to obtain a black mixed solution, then cooling to 110 ℃, adding shell metal precursor powder iron source ferric chloride and cobalt source cobalt acetylacetonate into the mixed solution, wherein the molar ratio of the shell metal precursor powder to the metal in the seed crystal core metal precursor powder is 1: 0.8, the molar ratio of two metal ions in the shell metal precursor is 1: 0.9.

(4) and (3) heating the mixed solution to 240 ℃ at a heating rate of 7 ℃/min, preserving the heat for 10min, and cooling to room temperature to obtain a black mixed solution.

Carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to a volume ratio of 3: 4, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 1: 4, a mixed solvent; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 2: 1, then carrying out centrifugal separation, and pouring out upper liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 3 times; then cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 4 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotating speed of the centrifugal machine for centrifugal separation is 7000-10000 rpm, and the time for each centrifugation is 3-7 min.

Characterization of the product phase by x-ray diffractometry was L1₀FeCo, which contains ordered phase characteristic peaks (001), (110) and (002), and has an order degree of 0.86. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_cIt was 952.8Oe, and the saturation magnetization Ms was 85.2 emu/g. The morphology of the product is observed to be uniformly dispersed core-shell morphology through a field emission transmission electron microscope.

Example 19:

(1) firstly, weighing a seed crystal core metal precursor manganese source manganese acetate and a nickel source nickel acetylacetonate by using an electronic balance, wherein the molar ratio of the manganese source manganese acetate to the nickel source nickel acetylacetonate is 1: 0.1, weighing a certain amount of reducing agent 1, 2-hexadecanediol, wherein the proportion relation between the theoretical value and the actual value of the using amount of the reducing agent is 1: 5.

(2) adding weighed seed crystal core metal precursor powder (a manganese source and a nickel source) and a reducing agent 1, 2-hexadecanediol into a three-neck flask filled with a solvent icosamine, wherein the molar ratio of the seed crystal core metal precursor to the solvent is 1: 10. high purity nitrogen N in protective atmosphere₂Under the action of the temperature, the temperature is raised to 117 ℃ at the temperature rise rate of 7 ℃/min and is kept for 70min, the water removal treatment is carried out, and then a surfactant (oleylamine + glyceryl monostearate) is added into the mixed solution according to the volume ratio, oleylamine: glycerol monostearate ═ 1: 0.5; in terms of molar ratio, solvent: surfactant 10: 1.9.

(3) slowly heating the mixed solution to 300 ℃ at the heating rate of 1 ℃/min, preserving the temperature for 20min to obtain a black mixed solution, then cooling to 90 ℃, adding shell metal precursor powder iron source ferric chloride and cobalt source cobalt acetylacetonate into the mixed solution, wherein the molar ratio of metal in the shell metal precursor powder to metal in the seed crystal core metal precursor powder is 1: 0.8, the molar ratio of two metal ions in the shell metal precursor is 1: 0.2.

(4) and (3) heating the mixed solution to 260 ℃ at a heating rate of 5 ℃/min, then preserving the heat for 40min, and cooling to room temperature to obtain a black mixed solution.

Carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to the volume ratio of 5: 2, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 4: 1; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 3: 1, then carrying out centrifugal separation, and pouring out upper-layer liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 4 times; then, cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 5 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotating speed of the centrifugal machine for centrifugal separation is 7000-8000 rpm, and the time of each centrifugation is 5-7 min.

Characterization of the product phase by x-ray diffractometry was L1₀FeCo, containing ordered phase characteristic peaks (001), (110) and (002), with an order degree of 0.93. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_cThe saturation magnetization Ms was 1168.4Oe and 106.8 emu/g. The morphology of the product is observed to be uniformly dispersed core-shell morphology by a field emission transmission electron microscope.

Example 20:

(1) firstly, weighing iron source ferric chloride and platinum source chloroplatinic acid serving as seed crystal core metal precursors by using an electronic balance, wherein the molar ratio of the iron source ferric chloride to the platinum source chloroplatinic acid is 0.9: 1, weighing a certain amount of reducing agent lithium aluminum hydride, wherein the proportional relation between a theoretical value and an actual value of the amount of the reducing agent is 1: 3.

(2) adding weighed crystal seed core metal precursor powder (an iron source and a platinum source) and a reducing agent lithium aluminum hydride into a three-neck flask filled with oleylamine, wherein the molar ratio of the crystal seed core metal precursor to the solvent is 1: 10. in a protective atmosphere of 93% Ar + 7% H₂Under the action of the temperature, the temperature is raised to 105 ℃ at the temperature raising rate of 10 ℃/min and is kept for 50min, the water removing treatment is carried out, then, the surfactant (decahydroquaternary ammonium bromide + lecithin) is added into the mixed solution, and the volume ratio of the decahydroquaternary ammonium bromide: lecithin ═ 1: 0.1; in terms of molar ratio, solvent: surfactant 10: 5.0.

(3) slowly heating the mixed solution to 340 ℃ at a heating rate of 3 ℃/min, preserving heat for 30min to obtain a black mixed solution, then cooling to 70 ℃, adding shell metal precursor powder iron source ferric chloride and nickel source nickel nitrate into the mixed solution, wherein the molar ratio of metal in the shell metal precursor powder to metal in the seed crystal core metal precursor powder is 1: 0.8, the molar ratio of two metal ions in the shell metal precursor is 0.9: 1.

(4) and (3) heating the mixed solution to 265 ℃ at the heating rate of 4 ℃/min, preserving the heat for 60min, and cooling to room temperature to obtain a black mixed solution.

And (2) carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to a volume ratio of 3: 5, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 2: 5 in a mixed solvent; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 4:1, then carrying out centrifugal separation, and pouring out upper-layer liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, carrying out centrifugal separation, and repeating for 5 times; then, cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 3 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotating speed of the centrifugal machine for centrifugal separation is 9000rpm, and the time for each centrifugation is 5-9 min.

Characterization of the product phase by X-ray diffractometry to L1₀FeNi, containing ordered phase characteristic peaks (001), (110) and (002), with an order degree of 0.93. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_cThe saturation magnetization Ms was 1069.5Oe and 86.5 emu/g. The morphology of the product is observed to be uniformly dispersed core-shell morphology by a field emission transmission electron microscope.

Example 21:

(1) firstly, weighing a seed crystal core metal precursor gold source potassium tetrachloroaurate and a copper source copper acetylacetonate by using an electronic balance, wherein the molar ratio of the two precursors is 0.3: 0.8, weighing a certain amount of reducing agent sodium cyanoborohydride, wherein the proportion relation between the theoretical value and the actual value of the reducing agent is 1: 1.

(2) adding weighed seed crystal core metal precursor powder (a gold source and a copper source) and a reducing agent sodium cyanoborohydride into a three-neck flask filled with a solvent hexadecylamine, wherein the molar ratio of the seed crystal core metal precursor to the solvent is 1: 10. in a protective atmosphere of 95% Ar + 5% H₂Under the action of the temperature, heating to 113 ℃ at the heating rate of 8 ℃/min, preserving the temperature for 60min, removing water, and then adding a surfactant (oleylamine + oleic acid) into the mixed solution, wherein the volume ratio of oleylamine: oleic acid 0.8: 1; in terms of molar ratio, solvent: surfactant 10: 2.2.

(3) slowly heating the mixed solution to 350 ℃ at a heating rate of 4 ℃/min, keeping the temperature for 120min to obtain a black mixed solution, then cooling to 80 ℃, adding shell metal precursor powder manganese source manganese acetylacetonate and gallium source gallium chloride into the mixed solution, wherein the metal molar ratio of the shell metal precursor powder to the seed crystal core metal precursor powder is 1:0.4, the molar ratio of two metal ions in the shell metal precursor is 0.5: 1.

(4) and heating the mixed solution to 235 ℃ at a heating rate of 9 ℃/min, preserving the heat for 50min, and cooling to room temperature to obtain a black mixed solution.

And (2) carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to a volume ratio of 2: 3, wherein the mixed solvent B is deionized water and absolute ethyl alcohol according to a volume ratio of 3: 2 in a mixed solvent; the mixed solution is first washed by a mixed solvent a: the volume ratio of the mixed solution is 3.2: 1, then carrying out centrifugal separation, and pouring out upper-layer liquid after the centrifugal separation to obtain black powder; then cleaning the black powder by using a mixed solvent A, performing centrifugal separation, and repeating for 3 times; then, cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 5 times; finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol; the rotating speed of the centrifugal machine for centrifugal separation is 7500-10000 rpm, and the time for each centrifugation is 6-9 min.

Characterization of the product phase by X-ray diffractometry to L1₀MnGa containing ordered phase characteristic peaks (001), (110) and (002) and having an order degree of 0.92. Measuring the magnetic hysteresis loop of the product at room temperature by using a vibrating sample strong magnetometer, and the coercive force H of the product_cIt was 1086.7Oe, and the saturation magnetization Ms was 96.5 emu/g. The morphology of the product is observed to be uniformly dispersed core-shell morphology by a field emission transmission electron microscope.

As can be seen from the above examples, L1 was successfully synthesized by using ordered nanoparticle interfacial induction₀-FeCo、L1₀-FeNi、L1₀-MnAl、L1₀-MnGa nanomaterial, which has excellent dispersibility, high degree of order and excellent magnetic properties.

Claims

1. Interface induction synthesis ordered L1₀A method of structuring permanent magnetic nanoparticles, comprising the steps of:

s1: weighing a seed crystal core metal precursor and a reducing agent;

s2: adding the crystal seed core metal precursor into a solvent, carrying out dehydration treatment under the action of a protective atmosphere, and adding a surfactant after the dehydration treatment to form a mixed solution;

s3: heating the mixed solution to a first reaction temperature, preserving heat, carrying out a reaction for generating a seed crystal core, then cooling, weighing and adding a shell metal precursor;

s4: heating the mixed solution to a second reaction temperature, preserving heat, carrying out a shell generation reaction, cooling to room temperature, and carrying out centrifugal cleaning on the mixed solution to obtain black powder, namely the ordered L1₀Structural permanent magnetic nanoparticles;

the seed crystal core metal precursor is L1 capable of forming a high-order structure₀A metal source mixture of two metals of a metal alloy; the shell metal precursor is ordered L1 formed to be prepared₀A metal source mixture of two metals of a structured permanent magnetic nanoparticle;

the total addition amount of the reducing agent is not less than the theoretical addition amount, and the theoretical addition amount of the reducing agent is the addition amount of the reducing agent capable of completely reducing the seed crystal core metal precursor and the shell metal precursor.

2. The interface-induced synthetic ordered L1 of claim 1₀Method for structuring permanent-magnet nanoparticles, characterized in that said particles are capable of forming highly ordered structures L1₀The two metals of the metal alloy are AuCu, MnNi or FePt, which constitute ordered L1 to be produced₀Two metals of the structural permanent magnetic nano particle are FeCo, FeNi, MnAl or MnGa;

the molar ratio of two metal ions in the seed crystal core metal precursor is (0.1-1): (0.1 to 1);

the molar ratio of two metal ions in the shell metal precursor is (0.2-1): (0.2 to 1).

3. The interface-induced synthetic ordered L1 of claim 2₀A method of structuring permanent magnetic nanoparticles, characterized by:

in the seed core metal precursor: the gold source is chloroauric acid HAuCl₄Potassium tetrachloroaurate KAuCl₄The copper source is copper acetylacetonate Cu (acac)₂Copper acetate Cu (Ac)₂Copper chloride CuCl₂The manganese source is manganese acetate Mn (Ac)₂MnCl, manganese chloride₂Manganese acetylacetonate Mn (acac)₂The nickel source is nickel acetate Ni (Ac)₂Nickel nitrate Fe (NO)₃)₃Nickel sulfate Fe₂(SO₄)₃Nickel chloride NiCl₂Nickel acetylacetonate Ni (acac)₂The iron source is one or more of ferric chloride FeCl₃FeNO, iron nitrate₃Iron (Fe) sulfate₂(SO₄)₃Fe (acac) acetylacetonate₃One or more of (1), the platinum source is chloroplatinic acid H₂PtCl₆Platinum acetylacetonate Pt (acac)₂Chloroplatinic acid K₂PtCl₆One or more of (a);

in the shell metal precursor: the iron source is ferric chloride FeCl₃Carbonyl iron Fe (CO)₅Fe (acac) acetylacetonate₃C, iron oleate₅₄H₉₉FeO₆One or more of the above; the cobalt source is cobalt acetylacetonate Co (acac)₂Octacarbonyldicobalt Co₂(CO)₈Cobalt acetate Co (Ac)₂One or more of the above; the nickel source is nickel acetate Ni (Ac)₂Nickel nitrate Fe (NO)₃)₃Nickel sulfate Fe₂(SO₄)₃Nickel chloride NiCl₂Nickel acetylacetonate Ni (acac)₂One or more of (a); the manganese source is manganese acetate Mn (Ac)₂MnCl, manganese chloride₂Manganese acetylacetonate Mn (acac)₂One or more of (a); the aluminum source is aluminum chloride AlCl₃Aluminum acetylacetonate Al (acac)₃One or more of (a); the gallium source is gallium acetate Ga (Ac)₂Gallium chloride GaCl₂Ga (acac) acetylacetonate₂One or more of (a).

4. The interface-induced synthetic ordered L1 of claim 1₀The method for preparing the structural permanent magnetic nanoparticles is characterized in that the molar ratio of the total amount of metal ions in the shell metal precursor to the total amount of metal ions in the seed crystal core metal precursor is (0.4-1): (0.2 to 1).

5. The interface-induced synthetic ordered L1 of claim 1₀The method for structuring permanent magnetic nanoparticles is characterized in that in the step S2, the solvent is hexadecylamine C₁₆H₃₅N, trioctylamine C₂₄H₅₁N, octadecylamine C₁₈H₃₉N, icosanamine C₂₀H₄₃N, oleylamine C₁₈H₃₇One or more of N;

the surfactant is decahydrocarbon quaternary ammonium bromide C₁₆H₃₈Br₂N₂Lecithin C₄₂H₈₀NO₈P, glyceryl monostearate C₂₁H₄₂O₄Oleylamine C₁₈H₃₇N and oleic acid C₁₈H₃₄O₂Mixing the two substances, wherein the two substances of the surfactant are mixed according to a volume ratio (0.1-1): (0.1-1) mixing and adding;

the molar ratio of metal ions to solvent in the seed crystal core metal precursor is 1: (10-30), wherein the molar ratio of the solvent to the surfactant is 10: (1.0-5.0).

6. The interface-induced synthetic ordered L1 of claim 1₀The method for preparing the structural permanent magnetic nano particle is characterized in that the reducing agent is potassium borohydride KBH₄Sodium borohydride NaBH₄1, 2-hexadecanediol C₁₆H₃₄O₂Lithium aluminum hydride LiAlH, sodium cyanoborohydride CH₃One or more of BNNa; the reducing agent is added by one of the following two methods:

the method A comprises the following steps: adding all reducing agents prior to the seed core generation reaction of step S3;

the method B comprises the following steps: a first portion of the reducing agent is added prior to the seed core generation reaction of step S3, the first portion being added in an amount not less than the amount of the reducing agent capable of reducing the seed core metal precursor in its entirety, and a second portion of the remaining reducing agent is added prior to the shell generation reaction of step S4.

7. The interface-induced synthetic ordered L1 of claim 1₀The method for preparing structural permanent magnetic nanoparticles is characterized in that in the step S2, the protective atmosphere is 93% Ar + 7% H₂、95％Ar+5％H₂High purity argon Ar or high purity nitrogen N₂One kind of (1);

the method for water removal treatment is to heat up to 100-120 ℃ at a heating rate of 1-10 ℃/min for 30-120 min under the action of protective atmosphere.

8. The interface-induced synthetic ordered L1 of claim 1₀The method for structuring the permanent magnetic nanoparticles is characterized in that in the step S3, the first reaction temperature is 280-360 ℃, the heat preservation time is 30-300 min, and the cooling temperature is 60-120 ℃; in the step S4, the second reaction temperature is 200-300 ℃, and the heat preservation time is 10-60 min.

9. The interface-induced synthetic ordered L1 of claim 1₀The method for preparing the structural permanent magnetic nanoparticles is characterized in that in the step S3 and the step S4, the heating rate of heating the mixed solution to the reaction temperature is 1-10 ℃/min.

10. The interface-induced synthetic ordered L1 of claim 1₀The method for preparing the structural permanent magnetic nanoparticles is characterized in that the method for obtaining the black powder by centrifugally cleaning the mixed solution in the step S4 comprises the following steps:

carrying out centrifugal cleaning by adopting two mixed solvents, wherein the mixed solvent A is absolute ethyl alcohol and chloroform according to a volume ratio of (1-5): (5-1), wherein the mixed solvent B is deionized water and absolute ethyl alcohol in a volume ratio of (1-5): (5-1) a mixed solvent;

cleaning and centrifugally separating the black powder by adopting a mixed solvent B and a mixed solvent A in turn, and repeating for 3-5 times;

finally, storing the black powder after the last cleaning and centrifugal separation in absolute ethyl alcohol;

the rotating speed of the centrifugal machine for centrifugal separation is 6000-12000 rpm, and the time of each centrifugation is 3-10 min.