CN117070794A - Preparation method of morphology-controllable magnetic nano alloy and application of morphology-controllable magnetic nano alloy in microwave absorption - Google Patents

Preparation method of morphology-controllable magnetic nano alloy and application of morphology-controllable magnetic nano alloy in microwave absorption Download PDF

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CN117070794A
CN117070794A CN202311072439.0A CN202311072439A CN117070794A CN 117070794 A CN117070794 A CN 117070794A CN 202311072439 A CN202311072439 A CN 202311072439A CN 117070794 A CN117070794 A CN 117070794A
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magnetic nano
organic
acetylacetonate
transition metal
alloy
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汪宏
胡仁超
潘德胜
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Southern University of Science and Technology
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/10—Alloys containing non-metals
    • C22C1/1026—Alloys containing non-metals starting from a solution or a suspension of (a) compound(s) of at least one of the alloy constituents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K9/00—Screening of apparatus or components against electric or magnetic fields
    • H05K9/0073—Shielding materials
    • H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K9/00—Screening of apparatus or components against electric or magnetic fields
    • H05K9/0073—Shielding materials
    • H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
    • H05K9/009—Electromagnetic shielding materials, e.g. EMI, RFI shielding comprising electro-conductive fibres, e.g. metal fibres, carbon fibres, metallised textile fibres, electro-conductive mesh, woven, non-woven mat, fleece, cross-linked
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures

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Abstract

A preparation method of magnetic nano alloy with controllable morphology and application in microwave absorption belong to the technical field of microwave absorption. The preparation method of the magnetic nano alloy comprises the following steps: preparing a precursor: mixing a transition metal source, a sulfur source and an organic amine solvent, heating to a preset temperature under the protection of inert gas for reaction, carrying out solid-liquid separation, and drying to obtain a precursor containing metal sulfide; the transition metal source comprises organic iron and organic transition metal, and the transition element in the organic transition metal is not iron element; the preset temperature is not higher than the boiling point of the organic amine solvent; preparing a magnetic nano alloy: under the protection of inert gas, the precursor reacts with the tri-coordination phosphorus compound to carry out desulfurization, and organic matters in the precursor are removed, so that the magnetic nano alloy is prepared in situ. The magnetic nano alloy prepared by the method has higher saturation magnetization and good electromagnetic wave absorption efficiency in a wide frequency band and a low frequency band.

Description

Preparation method of morphology-controllable magnetic nano alloy and application of morphology-controllable magnetic nano alloy in microwave absorption
Technical Field
The application relates to the technical field of microwave absorbing materials, in particular to a preparation method of a magnetic nano alloy with controllable morphology and application of the magnetic nano alloy in microwave absorption.
Background
The microwave absorber is mainly used for stealth coatings of airplanes, tanks or missiles and the like and anti-electromagnetic interference packaging layers in electronic devices, and has the action mechanism that a large amount of loss is generated on incident electromagnetic waves, and electromagnetic wave reflection is reduced. Inside the electronic device, complex circuits and signal generators create complex electromagnetic environments, so electromagnetic wave sensitive accessories need to be protected. The microwave absorber can consume electromagnetic waves in the environment, protect electromagnetic wave sensitive parts from being interfered by the electromagnetic waves in the environment, and ensure the normal operation of electronic devices.
The conventional commercial microwave absorber is usually filled with ferrite powder, solves the problem of electromagnetic compatibility when an electronic device works, protects the normal work of the electronic device, is mainly applied to the technologies of RFID, wireless charging and the like, and is widely used in consumer products such as mobile phones, digital cameras and the like.
However, with the development and maturation of 5G technology (Sub-6 GHz), the electric frequency electrons are not easily attenuated by the existing electromagnetic wave absorber due to the longer wavelength of the low frequency electromagnetic wave, and the microwave absorber is required to have higher complex permeability and complex permittivity. The magnetic permeability of the current ferrite material tends to be 1 along with the increase of frequency, and in order to realize impedance matching, the dielectric constant is low, and the absorption performance at low frequency is poor. In addition, due to the limitation of the performance of the existing wave-absorbing material, the thickness of the existing microwave absorber is large, which is not beneficial to many practical application scenes. Therefore, development of a high-efficiency microwave absorber for low frequency band and wide frequency band is a problem to be solved.
Disclosure of Invention
Based on the defects, the application provides a preparation method of a magnetic nano alloy with controllable morphology and application of the magnetic nano alloy in microwave absorption, so as to partially or completely solve the problem of low absorption efficiency of microwave absorption materials to electromagnetic waves in low frequency band and wide frequency band in the related technology.
The application is realized in the following way:
in a first aspect, examples of the present application provide a method for preparing a shape-controllable magnetic nanoalloy, comprising:
preparing a precursor: mixing a transition metal source, a sulfur source and an organic amine solvent, heating to a preset temperature under the protection of inert gas for reaction, carrying out solid-liquid separation, and drying to obtain a precursor containing metal sulfide; the transition metal source comprises organic iron and organic transition metal, and the transition element in the organic transition metal is not iron element; the preset temperature is not higher than the boiling point of the organic amine solvent;
preparing a magnetic nano alloy: under the protection of inert gas, the precursor reacts with the tri-coordination phosphorus compound to carry out desulfurization, and organic matters in the precursor are removed, so that the magnetic nano alloy is prepared in situ.
In the implementation process, after heating under the protection of inert gas, the transition metal source and the sulfur source in the mixed solution can form a precursor containing metal sulfide with a certain morphology structure under the action of an organic amine solvent. And then removing sulfur element and organic matters in the precursor in the subsequent desulfurization reaction, so that the magnetic nano alloy basically maintaining the precursor morphological structure can be prepared in situ. The magnetic nano alloy prepared by the method has high saturation magnetization and good electromagnetic wave absorption efficiency in a wide frequency band and a low frequency band.
With reference to the first aspect, in an alternative example of the present application, the transition element in the organic transition metal is selected from at least one of Co, ni, ag, cu, pt, cr, nb, nd, ti or Mn.
In the implementation process, the magnetic nano alloy formed by the transition metal and the iron has higher saturation magnetization intensity and good electromagnetic wave absorption efficiency in a wide frequency band and a low frequency band.
With reference to the first aspect, in an alternative example of the present application, the organic iron is selected from at least one of ferric acetylacetonate or ferrous acetylacetonate; the organic transition metal is at least one selected from cobalt acetylacetonate, nickel acetylacetonate, silver acetylacetonate, copper acetylacetonate, platinum acetylacetonate, chromium acetylacetonate, niobium acetylacetonate, neodymium acetylacetonate, titanium acetylacetonate and manganese acetylacetonate.
With reference to the first aspect, in an alternative example of the present application, the sulfur source is selected from at least one of thiourea, thiosemicarbazide, sodium thiosulfate, thioacetamide or L-cysteine.
In combination with the first aspect, in an alternative example of the present application, the organic amine solvent is selected from at least one of diethylenetriamine, triethylenetetramine, hexamethylenediamine or propylenediamine.
In the implementation process, the organic ligand in the organic metal source is selected from acetylacetone, and can be uniformly dispersed with sulfur sources such as thiourea, sodium thiosulfate or thioacetamide in an organic amine solvent. The temperature at which acetylacetone as an organic metal source of an organic ligand decomposes and precipitates metal ions in an organic amine solvent is not greatly different from the precipitation temperature at which sulfur ions are precipitated in an organic amine solvent from a sulfur source such as thiourea, sodium thiosulfate or thioacetamide, and metal ions and sulfur ions can be precipitated almost simultaneously at a temperature lower than the boiling point of the organic amine solvent, and a metal sulfide is formed by the reaction. In addition, the organic amine solvent such as diethylenetriamine, triethylenetetramine, hexamethylenediamine or propylenediamine can be used as a support of metal sulfide in the process of forming a precursor by reaction, and can form a complex to restrict the crystal morphology of the metal sulfide, so that the precursor with a certain morphology structure can be obtained.
In combination with the first aspect, in an alternative example of the present application, the tri-coordinated phosphorus compound is selected from at least one of tri-n-octylphosphine, tricyclohexylphosphine, trialkylphosphine, tris (4-trifluorotolyl) phosphine, or tri-t-butylphosphine.
Optionally, the precursor is reacted with a tri-dentate phosphorus compound to effect desulfurization, and the temperature at which organics are removed is 270-290 ℃ for 2-4 hours.
In the implementation process, tri-coordination phosphorus compounds such as tri-n-octyl phosphine, tricyclohexyl phosphine, trialkyl phosphine, tri (4-trifluoro-tolyl) phosphine or tri-tert-butyl phosphine can react with metal sulfide in the precursor at 270-290 ℃ to desulfurize the metal sulfide, and simultaneously remove organic matters in the precursor to obtain the magnetic nano alloy basically free of sulfide and organic matters, and the morphology and structure of the magnetic nano alloy are basically consistent with those of the precursor.
In combination with the first aspect, in an alternative example of the present application, in the transition metal source, a molar ratio of the iron element to the transition element is 1:0.01-0.4; the molar ratio of the metal element in the transition metal source to the sulfur element in the sulfur source is 1:0.5-2.
Alternatively, the preset temperature is not lower than 180 ℃.
Optionally, the preset temperature is 180-200 ℃.
In the implementation process, in the transition metal source, the molar ratio of the iron element to the transition element is 1:0.01-0.4, and can obtain the iron-based transition metal magnetic nano alloy. The molar ratio of the metal element in the transition metal source to the sulfur element in the sulfur source is 1:0.5-2, metal sulfides with different components can be obtained to obtain iron-based magnetic nano alloys with different morphologies and components.
And the raw materials in the mixed solution are reacted at 180-200 ℃, so that metal ions and sulfur ions can be separated out basically at the same time, small seed crystals of metal sulfide can be formed by reaction, and the organic amine solvent can be kept relatively stable to be matched with the organic amine solvent to regulate the growth of metal sulfide crystals and regulate the structural morphology of the precursor.
In combination with the first aspect, in an alternative example of the present application, the structure of the magnetic nano alloy is a one-dimensional structure, the sulfur source is selected from thioacetamide, and the organic amine solvent is selected from at least one of diethylenetriamine or hexamethylenediamine. The magnetic nano alloy has a two-dimensional structure, the sulfur source is selected from thiourea, and the organic amine solvent is selected from triethylene tetramine; alternatively, the sulfur source is selected from sodium thiosulfate and the organic amine solvent is selected from diethylenetriamine. The magnetic nano alloy has a three-dimensional structure, the sulfur source is selected from sodium thiosulfate, and the organic amine solvent is selected from triethylene tetramine.
In the implementation process, the application provides a method for regulating the morphology and structure of the magnetic nano alloy, wherein a sulfur source is selected from thioacetamide, an organic amine solvent is selected from diethylenetriamine, or the sulfur source is selected from thioacetamide, the organic amine solvent is selected from hexamethylenediamine, and the magnetic nano alloy with a one-dimensional nano fiber structure can be prepared. The sulfur source is selected from thiourea, the organic amine solvent is selected from triethylene tetramine, or the sulfur source is selected from sodium thiosulfate, and the organic amine solvent is selected from diethylenetriamine, so that the magnetic nano alloy with the two-dimensional nano sheet structure can be prepared. The sulfur source is selected from sodium thiosulfate, and the organic amine solvent is selected from triethylene tetramine, so as to prepare the magnetic nano alloy with the three-dimensional block structure.
The structural morphology of the precursor can be regulated and controlled by regulating and controlling the types of the reactant sulfur sources and selecting different solvents, so that the magnetic nano alloy with the specific morphology can be prepared in situ after the subsequent high-temperature desulfurization. Compared with the existing ferrite magnetic powder, the magnetic nano alloy with the one-dimensional, two-dimensional or three-dimensional structure has higher efficient low-frequency microwave absorption performance and wider microwave absorption bandwidth.
In a second aspect, examples of the present application provide a magnetic nanoalloy whose chemical composition includes at least one of an iron element and a transition metal element other than iron, and whose structure includes one-dimensional and/or two-dimensional structures.
In a third aspect, the present application provides the use of a magnetic nanoalloy as provided according to the second aspect for the preparation of a microwave absorber.
In the implementation process, the magnetic nano alloy is used for preparing the microwave absorber, and has high saturation magnetization, so that the magnetic nano alloy has good electromagnetic wave absorption efficiency in a wide frequency band and a low frequency band, and the wave absorption effect of the microwave absorber can be improved.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.
FIG. 1 is a schematic diagram of a process for preparing a nano magnetic alloy according to an example of the present application;
fig. 2 is an SEM image of a two-dimensional FeNb nanoplatelet provided in example 1 of the present application;
fig. 3 is an SEM image of a one-dimensional FeNb nanofiber provided in example 2 of the present application;
FIG. 4 is an SEM image of three-dimensional FeNb particles according to example 3 of the present application;
FIG. 5 is a graph showing the magnetization curve provided by the test example of the present application;
FIG. 6 is a graph showing the frequency versus microwave absorption intensity provided by the test example of the present application.
Detailed Description
Embodiments of the present application will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only for illustrating the present application and should not be construed as limiting the scope of the present application. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
At present, a microwave absorber is generally prepared by filling neoprene with a wave absorbing material such as ferrite powder. However, the conventional microwave absorber based on the wave absorbing material such as ferrite powder cannot be applied to the absorption of electromagnetic waves in a low frequency band, and the conventional microwave absorber has a narrow absorption frequency range.
Based on the above, the application provides a magnetic nano alloy and a preparation method thereof, so as to solve the problem that the microwave absorbing material has poor wave absorbing capability in low frequency range and wide frequency range.
The following describes in detail the preparation method of the magnetic nano alloy provided by the example of the application with reference to the accompanying drawings.
Referring to fig. 1, the method for preparing the magnetic nano alloy with controllable morphology provided by the example of the application includes:
s1, preparing a precursor
Mixing a transition metal source, a sulfur source and an organic amine solvent, heating to a preset temperature under the protection of inert gas for reaction, carrying out solid-liquid separation, and drying to obtain a precursor containing metal sulfide; the transition metal source comprises organic iron and organic transition metal, and the transition element in the organic transition metal is not iron element; the preset temperature is not higher than the boiling point of the organic amine solvent.
Dispersing a transition metal source and a sulfur source in an organic amine solvent, so that after the subsequent temperature rise, the transition metal source can decompose and separate out metal ions, and the transition metal source reacts with ions of sulfur elements separated out from the sulfur source to form metal sulfides. The organic amine is used as a solvent, the temperature during the reaction is not higher than the boiling point of the organic amine solvent, the organic amine can be used as an organic support of the metal sulfide, and the organic amine is matched with a sulfur source to regulate and limit the growth of the metal sulfide seed crystal, so that the precursor with a certain morphology structure is obtained.
In one possible embodiment, the organic amine solvent is selected from at least one of diethylenetriamine, triethylenetetramine, hexamethylenediamine or propylenediamine.
Further, the present application is not limited to the specific type of transition metal source, and the relevant person may make a corresponding choice as required.
In one possible embodiment, the transition element in the organic transition metal may be selected from at least one of Co, ni, ag, cu, pt, cr, nb, nd, ti or Mn.
Illustratively, the transition element may be selected from Nb.
In one possible embodiment, the organic iron may be selected from at least one of iron acetylacetonate or ferrous acetylacetonate.
The organic iron may be selected from iron acetylacetonate, for example.
The organic iron may be selected from ferrous acetylacetonate, for example.
In one possible embodiment, the organic transition metal may be selected from at least one of cobalt acetylacetonate, nickel acetylacetonate, silver acetylacetonate, copper acetylacetonate, platinum acetylacetonate, chromium acetylacetonate, niobium acetylacetonate, neodymium acetylacetonate, titanium acetylacetonate, or manganese acetylacetonate.
The organic transition metal may be selected from niobium acetylacetonate, for example.
Further, in the transition metal source, the molar ratio of the iron element to the transition element may be 1:0.01-0.4 to obtain the iron-based transition metal magnetic nano alloy.
Illustratively, the molar ratio of elemental iron to transition element may be 1:0.01, 1:0.05, 1:0.1, 1:0.15, 1:0.2, 1:0.25, 1:0.3, 1:0.35 or 1:0.4, or a range between any one or both.
In one possible embodiment, the sulfur source is selected from at least one of thiourea, thiosemicarbazide, sodium thiosulfate, thioacetamide or L-cysteine.
Further, the molar ratio of the metal element in the transition metal source to the sulfur element in the sulfur source may be 1:0.5-2.
Illustratively, the molar ratio of the metal element in the transition metal source to the sulfur element in the sulfur source may be 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1.0, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 2.0, or any two.
The sulfur source such as thiourea, sodium thiosulfate or thioacetamide is mixed with the organic iron such as ferric acetylacetonate and the organic transition metal such as niobium acetylacetonate in the organic amine solvent, and the precursor containing metal sulfide and having a specific morphology structure can be formed by reaction at a certain temperature.
Wherein the precursor contains organic matters, and part or all of the organic matters are partly from organic amine solvents and complex supports thereof.
Illustratively, the specific topographical structure includes at least one of a one-dimensional structure, a two-dimensional structure, and a three-dimensional structure.
Wherein, the one-dimensional structure refers to a linear fiber structure, the two-dimensional structure refers to a sheet-like structure, and the three-dimensional structure refers to a block-like structure, such as a particle structure.
Further, in order to facilitate the regulation of the morphology structure of the precursor, please continue to refer to fig. 1, and the preparation method provided by the example of the present application includes:
s101, preparation of one-dimensional structure
The sulfur source is selected from thioacetamide, and the organic amine solvent is selected from at least one of diethylenetriamine or hexamethylenediamine.
For example, the preset temperature may be 180-200 ℃ when preparing the precursor.
For example, when the sulfur source is selected from thioacetamide and the organic amine solvent is selected from diethylenetriamine, the temperature can be raised to 180 ℃, the preset temperature is lower than the boiling point of diethylenetriamine, and the transition metal source and the sulfur source can be enabled to separate out corresponding metal ions and sulfur element ions substantially simultaneously. After the reaction time is about 3 hours, centrifugally cleaning and drying, the nanofiber precursor containing the metal sulfide can be obtained.
For example, when the sulfur source is selected from thioacetamide and the organic amine solvent is selected from ethylenediamine, the temperature can be raised to 200 ℃, the preset temperature is lower than the boiling point of hexamethylenediamine, and the transition metal source and the sulfur source can be enabled to separate out corresponding metal ions and sulfur ions substantially simultaneously. After the reaction time is about 3 hours, centrifugally cleaning and drying, the nanofiber precursor containing the metal sulfide can be obtained.
Thioacetamide can precipitate-S in diethylenetriamine or hexamethylenediamine at about 200deg.C -2 Similar to the temperature of metal ions such as iron ions decomposed and separated out from organic metal sources such as ferric acetylacetonate in diethylenetriamine or hexamethylenediamine, small seed crystals for generating metal sulfides can be separated out almost simultaneously.
Compared with sulfur sources such as sodium thiosulfate, the thioacetamide and thiourea contain carbon-sulfur double bonds, the bond energy is about 577kJ/mol, and the bond energy is larger. The S in the sulfur source with high bond energy is slowly precipitated, and the reaction is more prone to form one-dimensional and two-dimensional nanocrystals; while S in the sulfur source with low bond energy precipitates faster to form a large amount of seed crystals, and tends to be stacked into a three-dimensional structure in the reaction. In addition, thioacetamide contains amino, thiourea does not contain amino, and thioacetamide containing amino tends to form one-dimensional crystals; thioureas without amino groups tend to form two-dimensional crystals.
Further, referring to fig. 1, the preparation method provided by the example of the present application includes:
s102, preparation of two-dimensional structure
The sulfur source is selected from thiourea, and the organic amine solvent is selected from triethylene tetramine; alternatively, the sulfur source is selected from sodium thiosulfate and the organic amine solvent is selected from diethylenetriamine.
For example, when the sulfur source is selected from thiourea and the organic amine solvent is selected from triethylene tetramine, the temperature can be raised to 200 ℃, the preset temperature is lower than the boiling point of the triethylene tetramine, and the transition metal source and the thiourea can be enabled to separate out corresponding metal ions and sulfur ions substantially simultaneously. After the reaction time is about 3 hours, centrifugally cleaning and drying, the nano-sheet precursor containing the metal sulfide can be obtained.
For example, when the sulfur source is selected from sodium thiosulfate and the organic amine solvent is selected from diethylenetriamine, the temperature can be raised to 180 ℃, the preset temperature is lower than the boiling point of the diethylenetriamine, and the transition metal source and thiourea can be enabled to separate out corresponding metal ions and sulfur ions substantially simultaneously. After the reaction time is about 3 hours, the precursor containing the metal sulfide in the nano sheet shape can be obtained by centrifugal cleaning.
The thioacetamide and the thiourea both contain carbon-sulfur double bonds, the bond energy is about 577kJ/mol, the bond energy is larger, but the thiourea does not contain an amino group, and sulfur ions are quickly separated out, so that the precursor in a sheet shape can be obtained after the reaction for about 3 hours at a preset temperature of about 200 ℃.
The bond energy of the sodium thiosulfate is relatively low, the speed of precipitating sulfide ions is high, and the nano-sheet precursor can be formed under the limiting action of diethylenetriamine.
Compared with triethylene tetramine, diethylene triamine can be matched with sodium thiosulfate, and can be matched with the sodium thiosulfate to limit the growth of metal sulfides in the reaction process so as to obtain a nano-sheet precursor.
Further, referring to fig. 1, the preparation method provided by the example of the present application includes:
s103, preparation of three-dimensional structure
The sulfur source is selected from sodium thiosulfate, and the organic amine solvent is selected from triethylene tetramine.
For example, when the sulfur source is selected from sodium thiosulfate and the organic amine solvent is selected from triethylene tetramine, the temperature can be raised to 200 ℃, the preset temperature is lower than the boiling point of the triethylene tetramine, and the transition metal source and thiourea can be enabled to separate out corresponding metal ions and sulfur ions substantially simultaneously. After a reaction time of about 3 hours, a precursor containing a metal sulfide in a block form can be obtained by centrifugal cleaning. Further, referring to fig. 1, the preparation method provided by the example of the present application includes:
s2, preparing magnetic nano alloy
Under the protection of inert gas, the precursor reacts with the tri-coordination phosphorus compound to carry out desulfurization, and organic matters in the precursor are removed, so that the magnetic nano alloy is prepared in situ.
The sulfur element in the precursor can be removed at high temperature by utilizing the reaction of the tri-coordination phosphorus compound and the precursor. Meanwhile, under the temperature condition of desulfurization reaction of the tri-coordination phosphorus compound, organic matters in the precursor can be removed, for example, the organic amine solvent support is decomposed, and the magnetic nano alloy which basically does not contain sulfur and organic matters and is basically consistent with the precursor shape structure is obtained.
The magnetic nano alloy which is basically consistent with the precursor shape structure refers to, for example, the precursor is of a one-dimensional fiber structure, and the magnetic nano alloy of the one-dimensional fiber structure can be prepared in situ; for example, the precursor is of a two-dimensional lamellar structure, and the magnetic nano alloy of the two-dimensional lamellar structure can be prepared in situ; the precursor is in a three-dimensional block structure, and the magnetic nano alloy with the three-dimensional block structure can be prepared in situ.
Illustratively, the tri-ligating phosphorus compound may be selected from at least one of tri-n-octylphosphine, tricyclohexylphosphine, trialkylphosphine, tris (4-trifluorotolyl) phosphine, or tri-t-butylphosphine.
Illustratively, the tridentate phosphorus compound is selected from trialkyl phosphine, and when in desulfurization reaction, the tridentate phosphorus compound is heated to 280 ℃ for reaction for 3 hours, and the magnetic nano alloy is obtained.
Through the preparation method, the application provides a magnetic nano alloy which comprises at least one of a one-dimensional structure or a two-dimensional structure. The magnetic nano alloy chemical component of the magnetic nano alloy contains Fe element and at least one of Co, ni, ag, cu, pt, cr, nb, ti or Mn element.
Further, the magnetic nanoalloy may also include a three-dimensional structure.
The magnetic nanoalloy may be, for example, a one-dimensional nanofiber-like FeNb alloy, feCo alloy, feNi alloy, feAg alloy, feCu alloy, fePt alloy, feCr alloy, feNd alloy, feTi alloy, feMn alloy, feCoNi alloy, feCoNb alloy, feCoNbMn alloy, or FeCoNiMn alloy.
By way of example, the magnetic nanoalloy may be a two-dimensional nanoplatelet-shaped FeNb alloy, feCo alloy, feNi alloy, feAg alloy, feCu alloy, fePt alloy, feCr alloy, feNd alloy, feTi alloy, feMn alloy, feCoNi alloy, feCoNb alloy, feCoNbMn alloy, or FeCoNiMn alloy.
By way of example, the magnetic nanoalloy may be a three-dimensional bulk FeNb alloy, feCo alloy, feNi alloy, feAg alloy, feCu alloy, fePt alloy, feCr alloy, feNd alloy, feTi alloy, feMn alloy, feCoNi alloy, feCoNb alloy, feCoNbMn alloy, or FeCoNiMn alloy.
Further, in order to facilitate the subsequent obtaining of the magnetic nano alloy having two or three structures of the one-dimensional fiber structure, the two-dimensional sheet structure and the three-dimensional block structure at the same time, two or three of the corresponding one-dimensional precursor, the two-dimensional precursor and the three-dimensional precursor may be mixed, and then desulfurization reaction may be performed to remove the organic matters in the precursors.
Further, the application also provides a microwave absorber, which is prepared from the magnetic nano alloy provided by the application.
For example, the magnetic nano alloy and the epoxy resin solution can be uniformly mixed, and the microwave absorbing film can be obtained by casting.
The magnetic nanoalloy provided by the present application is described in further detail below with reference to examples.
Example 1
Example 1 provides a magnetic nano alloy, the preparation method is as follows:
(1) Raw material preparation: 70mmol of iron acetylacetonate, 30mmol of niobium acetylacetonate and 100mmol of sodium thiosulfate are mixed in 150mL of diethylenetriamine. The solution was poured into a 250mL three-necked flask and vigorously stirred until completely dissolved. The specific components are shown in Table 1.
(2) Precursor preparation: ar gas was continuously introduced into the three-necked flask, and the reaction was carried out in an inert gas. And heating the mixed solution to 200 ℃ for reaction for 3 hours, and naturally cooling after the reaction is finished. And (5) centrifugally cleaning to obtain the nano sheet precursor.
(3) Preparing a magnetic nano alloy: and (3) placing 10g of the nanofiber precursor powder obtained in the step (2) in 20mL of trialkylphosphine solution, uniformly stirring, introducing argon, heating to 280 ℃ in an argon atmosphere for reaction for 3 hours, and centrifuging and cleaning after natural cooling. The SEM image of the product is shown in fig. 2, and two-dimensional FeNb nanoplatelet powder is obtained.
Example 2
Example 2 differs from example 1 in that in step (1), 70mmol of iron acetylacetonate, 30mmol of niobium acetylacetonate and 100mmol of thioacetamide are mixed in 150mL of hexamethylenediamine. The specific components are shown in Table 1. The SEM image of the product is shown in fig. 3, and one-dimensional FeNb nanofiber powder is obtained.
Example 3
Example 3 differs from example 1 in that in step (1), 70mmol of iron acetylacetonate, 30mmol of niobium acetylacetonate and 100mmol of sodium thiosulfate are mixed in 150mL of triethylenetetramine. The specific components are shown in Table 1. The SEM image of the product is shown in fig. 4, and a three-dimensional FeNb granular powder is obtained.
Example 4
Example 4 differs from example 1 in that in step (1), 70mmol of iron acetylacetonate, 30mmol of niobium acetylacetonate and 100mmol of thiourea are mixed in 150mL of triethylenetetramine. The specific components are shown in Table 1. Obtaining the two-dimensional FeNb nano-flake powder.
Example 5
Example 5 differs from example 1 in that in step (1), 70mmol of iron acetylacetonate, 30mmol of niobium acetylacetonate and 100mmol of thioacetamide are mixed in 150mL of diethylenetriamine. The specific components are shown in Table 1. Obtaining the one-dimensional FeNb nanofiber powder.
Test case
The magnetic nanoalloys provided in examples 1 to 5 were prepared as 1.5mm thick films with Fe 2 O 3 The film prepared from the microsphere powder was used as comparative example 1, the film prepared from carbonyl iron powder was used as comparative example 2, and the film prepared from the micron flaky iron-nickel powder was used as comparative example 3. The preparation method comprises the following steps: 6g of the target powder was uniformly mixed with 4g of the epoxy resin solution, and 10-20mg of the curing agent was added thereto, and a film having a thickness of 1.5mm was cast on a glass plate. As comparative example 4, ferrite-filled neoprene, which is commercially available, was used.
The films prepared according to examples 1 to 5 and comparative example 4 were tested for magnetization curves, respectively, using a vibrating sample magnetometer (VSM-8604), with magnetic field strengths of-2T to 2T. The results of the test are shown in fig. 5. In fig. 5, (a) is example 1, (b) is example 2, (c) is example 3, (d) is example 4, (e) is example 5, and (f) is comparative example 4.
Analysis of results: the microwave absorbing films prepared according to examples 1 to 5 had a higher saturation magnetization (about 180 emu/g) than the neoprene film of ferrite of comparative example 4, which was much greater than the saturation magnetization of ferrite (about 90 emu/g).
The microwave absorbing films prepared according to examples 1 to 5 and the ferrite-filled epoxy resin microwave absorbers of comparative example 4 were tested for electromagnetic performance and microwave absorption strength using Agilent N5227B to examine the electromagnetic wave loss performance of the microwave absorbers. The test temperature was 25℃and the test frequency was 2-18GHz, and the results are shown in FIG. 6. In fig. 6, (a) is example 1, (b) is example 2, (c) is example 3, (d) is example 4, (e) is example 5, and (f) is comparative example 4.
By adopting the method, electromagnetic performance and microwave absorption intensity tests are carried out on the microwave absorption films provided in the comparative examples 1-3, wherein the saturation magnetization of ferrite in the comparative example I is 90emu/g, the microwave absorption intensity is-32 dB, and the microwave absorption bandwidth is 5.5GHz; the saturation magnetization intensity of the second comparative example is 120emu/g, the microwave absorption intensity is-45 dB, and the microwave absorption bandwidth is 3GHz; the saturation magnetization of comparative example 3 was 120emu/g, the microwave absorption strength was-40 dB, and the microwave absorption bandwidth was 3.5GHz.
Analysis of results: as can be seen from FIG. 6, the films prepared from the magnetic nanoalloys provided in examples 1-5 have higher microwave absorption strength (RL < -50 dB) and wider microwave absorption bandwidth (greater than 6 GHz) than the ferrite rubber film in comparative example IV.
The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims (10)

1. The preparation method of the magnetic nano alloy with controllable morphology is characterized by comprising the following steps:
preparing a precursor: mixing a transition metal source, a sulfur source and an organic amine solvent, heating to a preset temperature under the protection of inert gas for reaction, carrying out solid-liquid separation, and drying to obtain a precursor containing metal sulfide; the transition metal source comprises organic iron and organic transition metal, wherein the transition element in the organic transition metal is not iron element; the preset temperature is not higher than the boiling point of the organic amine solvent;
preparing a magnetic nano alloy: under the protection of inert gas, the precursor reacts with a tri-coordination phosphorus compound to carry out desulfurization, and organic matters in the precursor are removed, so that the magnetic nano alloy is prepared in situ.
2. The method according to claim 1, wherein the transition element in the organic transition metal is at least one selected from Co, ni, ag, cu, pt, cr, nb, nd, ti and Mn.
3. The method according to claim 2, wherein the organic iron is at least one selected from iron acetylacetonate and ferrous acetylacetonate;
the organic transition metal is at least one selected from cobalt acetylacetonate, nickel acetylacetonate, silver acetylacetonate, copper acetylacetonate, platinum acetylacetonate, chromium acetylacetonate, niobium acetylacetonate, neodymium acetylacetonate, titanium acetylacetonate and manganese acetylacetonate.
4. The method according to claim 3, wherein the sulfur source is at least one selected from thiourea, thiosemicarbazide, sodium thiosulfate, thioacetamide, or L-cysteine.
5. The method according to claim 4, wherein the organic amine solvent is at least one selected from diethylenetriamine, triethylenetetramine, hexamethylenediamine and propylenediamine.
6. The production method according to claim 5, wherein the tri-coordinated phosphorus compound is at least one selected from tri-n-octylphosphine, tricyclohexylphosphine, trialkylphosphine, tris (4-trifluorotolyl) phosphine, and tri-t-butylphosphine;
optionally, the precursor is reacted with a tri-dentate phosphorus compound to perform desulfurization, and the temperature for removing the organic matters is 270-290 ℃ for 2-4 hours.
7. The production method according to claim 6, wherein in the transition metal source, a molar ratio of the iron element to the transition element is 1:0.01-0.4; the molar ratio of the metal element in the transition metal source to the sulfur element in the sulfur source is 1:0.5-2;
optionally, the preset temperature is not lower than 180 ℃;
optionally, the preset temperature is 180-200 ℃.
8. The method according to claim 7, wherein,
the structure of the magnetic nano alloy is a one-dimensional structure, the sulfur source is selected from thioacetamide, and the organic amine solvent is selected from at least one of diethylenetriamine or hexamethylenediamine;
the structure of the magnetic nano alloy is a two-dimensional structure, the sulfur source is selected from thiourea, and the organic amine solvent is selected from triethylene tetramine; alternatively, the sulfur source is selected from sodium thiosulfate and the organic amine solvent is selected from diethylenetriamine;
the structure of the magnetic nano alloy is a three-dimensional structure, the sulfur source is selected from sodium thiosulfate, and the organic amine solvent is selected from triethylene tetramine.
9. A magnetic nanoalloy prepared by the preparation method according to any one of claims 1 to 8, wherein the chemical composition of the magnetic nanoalloy comprises at least one of iron element and transition metal element other than iron, and the structure of the magnetic nanoalloy comprises one-dimensional and/or two-dimensional structure.
10. Use of a magnetic nano-alloy according to claim 9 for the preparation of a microwave absorber.
CN202311072439.0A 2023-08-23 2023-08-23 Preparation method of morphology-controllable magnetic nano alloy and application of morphology-controllable magnetic nano alloy in microwave absorption Pending CN117070794A (en)

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