Flake alloy powder / manganese zinc ferrite / carbon absorbing powder and preparation method thereof

Abstract

The present invention provides a flaky alloy powder / manganese zinc ferrite / carbon absorbing powder and a preparation method thereof. The method comprises: preparing flaky alloy powder; dispersing iron salt, manganese salt, zinc salt and a first solution, adding flaky alloy powder, stirring and drying to obtain flaky alloy powder / manganese zinc ferrite; dispersing it, adding tetraethyl orthosilicate, stirring and drying to obtain flaky alloy powder / manganese zinc ferrite / silicon dioxide; adding it to a solvent containing polyvinyl pyrrolidone, dispersing it, and drying to prepare modified flaky alloy powder / manganese zinc ferrite / silicon dioxide; under the action of a catalyst, coating a polypyrrole layer on its surface to prepare flaky alloy powder / manganese zinc ferrite / silicon dioxide / polypyrrole microspheres; calcining at high temperature in an inert gas to obtain flaky alloy powder / manganese zinc ferrite / silicon dioxide / carbon microspheres; etching, stirring and drying to obtain flaky alloy powder / manganese zinc ferrite / carbon absorbing powder.

Description

Technical Field

[0001] The invention relates to a wave absorbing material, in particular to a flaky alloy powder / manganese zinc ferrite / carbon wave absorbing powder and a preparation method thereof. Background Art

[0002] In recent years, absorbing materials have been widely studied and paid attention to by scholars at home and abroad in the field of military stealth technology. Material quality, magnetic loss capacity, dielectric loss capacity, bandwidth of electromagnetic waves that can be absorbed, and absorption strength are all key factors in measuring the performance of absorbing materials. At present, alloy powder has the advantages of low price, easy preparation, large industrial output, stable quality, high magnetic saturation intensity, high magnetic permeability, high real part of magnetic permeability, good imaginary dispersion characteristics, and can achieve high absorbing performance at low matching thickness. It is the most important electromagnetic wave absorber material, but the alloy powder itself has a high density, poor oxidation resistance and corrosion resistance, a high dielectric constant, and poor matching. These factors limit its application in special environments.

[0003] Existing literature provides a flaky Sendust composite structure magnetic powder and a preparation method thereof, which prepares a uniform and controllable Sendust / silicon dioxide / coupling agent composite structure, which not only improves the insulation of the magnetic powder, but also improves the dispersibility of the magnetic powder in the magnetic sheet.

[0004] Another existing document provides a method for preparing silica-coated sendust powder, and obtains silica-coated sendust powder. The preparation process of the coated powder has certain operability, the coating layer is relatively uniform, and the quality is controllable; the silica coating layer effectively improves the wave absorbing performance of the sendust powder.

[0005] Another existing document provides a method for preparing a high magnetic permeability GHz band absorbing material, including a method of compositeing flaky Sendust aluminum and Co2Z ferrite, utilizing the advantages of high magnetic permeability of flaky Sendust aluminum alloy and low dielectric constant of Co2Z ferrite, and effectively improving the absorbing performance of the composite absorbing material in the low frequency band by optimizing the preparation process.

[0006] However, the loss mechanism of the FeSiAl alloy powder absorber prepared by the above method is single, and the problem of high density, poor absorption efficiency and matching performance of the absorber at low frequency is not fundamentally solved. Therefore, it is necessary to develop an absorber that can simultaneously meet the requirements of low density, high absorption efficiency and good impedance matching performance at low frequency. Summary of the invention

[0007] The main purpose of the present invention is to provide a flaky alloy powder / manganese zinc ferrite / carbon absorbing powder and a preparation method thereof, so as to solve the problem that the existing iron silicon aluminum alloy powder absorber has a single loss mechanism and does not fundamentally solve the problem of high density of the absorber at low frequency, poor absorption efficiency and matching performance.

[0008] In order to achieve the above-mentioned object, the present invention provides a method for preparing a flaky alloy powder / manganese zinc ferrite / carbon absorbing powder, comprising: step S1, preparing a flaky alloy powder / manganese zinc ferrite / silicon dioxide; step S2, adding the flaky alloy powder / manganese zinc ferrite / silicon dioxide to an organic solvent containing polyvinyl pyrrolidone, dispersing and drying the flaky alloy powder / manganese zinc ferrite / silicon dioxide to prepare a modified flaky alloy powder / manganese zinc ferrite / silicon dioxide; under the action of a catalyst, adding the modified flaky alloy powder / manganese zinc ferrite / silicon dioxide to In an inorganic solution containing pyrrole, flaky alloy powder / manganese zinc ferrite / silicon dioxide / polypyrrole microspheres are prepared after stirring and drying; step S3, in an inert gas atmosphere, the flaky alloy powder / manganese zinc ferrite / silicon dioxide / polypyrrole microspheres are calcined at high temperature to obtain flaky alloy powder / manganese zinc ferrite / silicon dioxide / carbon microspheres; the flaky alloy powder / manganese zinc ferrite / silicon dioxide / carbon microspheres are added to an alkaline solution for etching, and then stirred and dried to obtain flaky alloy powder / manganese zinc ferrite / carbon absorbing powder.

[0009] Furthermore, the catalyst includes ferric chloride; step S2 specifically includes: adding flaky alloy powder / manganese zinc ferrite / silicon dioxide to an organic solvent and performing ultrasonic dispersion treatment; subsequently adding polyvinyl pyrrolidone, performing ultrasonic dispersion treatment, filtering, and drying to prepare modified flaky alloy powder / manganese zinc ferrite / silicon dioxide; adding the modified flaky alloy powder / manganese zinc ferrite / silicon dioxide to an inorganic solvent and performing ultrasonic dispersion treatment; subsequently adding ferric chloride, stirring, and then adding pyrrole, further stirring, filtering, and drying to prepare flaky alloy powder / manganese zinc ferrite / silicon dioxide / polypyrrole microspheres.

[0010] Furthermore, the organic solvent is ethanol or acetone, and the inorganic solvent is deionized water; in the step of preparing modified flaky alloy powder / manganese zinc ferrite / silicon dioxide, the flaky alloy powder / manganese zinc ferrite / silicon dioxide is 1 to 6 parts by weight, the ethanol is 50 to 400 parts by weight, and the polyvinyl pyrrolidone is 3 to 8 parts by weight; in the step of preparing flaky alloy powder / manganese zinc ferrite / silicon dioxide / polypyrrole microspheres, the modified flaky alloy powder / manganese zinc ferrite / silicon dioxide is 1 to 6 parts by weight, the deionized water is 100 to 400 parts by weight, the ferric chloride is 5 to 10 parts by weight, and the pyrrole is 1 to 5 parts by weight.

[0011] Furthermore, step S1 specifically includes: sub-step S11, preparing the alloy powder into flaky alloy powder; sub-step S12, adding iron salt, manganese salt and zinc salt into the first solution, dispersing the mixture to obtain a reaction solution; then adding the flaky alloy powder into the reaction solution, stirring and drying the mixture to obtain a flaky alloy powder / manganese zinc ferrite with a core / shell structure; sub-step S13, adding the flaky alloy powder / manganese zinc ferrite into the second solution, dispersing the mixture; then adding tetraethyl orthosilicate, stirring and drying the mixture to obtain a flaky alloy powder / manganese zinc ferrite / silicon dioxide with a core / shell / shell structure.

[0012] Furthermore, the iron salt, manganese salt and zinc salt are divalent iron salt, divalent manganese salt and divalent zinc salt respectively; sub-step S12 specifically includes: dissolving a surfactant in deionized water and mixing them evenly; then adding divalent iron salt, divalent manganese salt and divalent zinc salt, performing ultrasonic dispersion treatment to mix them evenly to obtain a reaction solution; adding flaky alloy powder to the reaction solution, keeping the reaction solution with the added flaky alloy powder in a constant temperature water bath, and performing a first stirring; then adding a first alkaline solution to the reaction solution to keep the pH value within a predetermined range, performing a second stirring to fully react it to obtain a first precipitate; washing the first precipitate with a first cleaning solution, and then drying it; grinding the dried first precipitate, and screening it through a vibrating screen to obtain flaky alloy powder / manganese-zinc ferrite.

[0013] Furthermore, the surfactant includes sodium dodecylbenzene sulfonate and polyethylene glycol, and the first cleaning liquid is deionized water; the sodium dodecylbenzene sulfonate and polyethylene glycol are both 1 to 5 parts by mass; the deionized water is 500 to 2000 parts by mass; the divalent iron salt, the divalent manganese salt and the divalent zinc salt are 50 to 80 parts by mass, 10 to 30 parts by mass and 10 to 30 parts by mass respectively; the alkaline solution is a NaOH solution, and the concentration of the NaOH solution is 0.4 to 0.6 mol / L.

[0014] Further, in sub-step S2, the ultrasonic dispersion treatment time is 5 to 15 minutes; in sub-step S2, the constant temperature water bath is 50 to 90 degrees Celsius, the first stirring speed is 600 to 1000 rpm, and the second stirring time is 4 to 10 hours; in sub-step S2, the pH value is maintained in the range of 10 to 11 during the reaction process of full reaction; in sub-step S2, the drying is dried at a temperature of 60 to 80 degrees Celsius for 8 to 12 hours.

[0015] Furthermore, sub-step S13 specifically includes: adding flaky alloy powder / manganese zinc ferrite to a solvent, water and a second alkaline solution, and ultrasonically dispersing the flaky alloy powder / manganese zinc ferrite; subsequently adding ethyl orthosilicate, and performing a third stirring in a water bath to react the flaky alloy powder to obtain a second precipitate; washing the second precipitate with a second washing liquid, and then drying the flaky alloy powder / manganese zinc ferrite / silicon dioxide absorbing powder.

[0016] Further, in sub-step S13, the solvent includes one or more of anhydrous ethanol and acetone; in sub-step S13, the second alkaline solution includes one or more of KOH solution, NaOH solution, and ammonia water; in sub-step S13, the second cleaning solution includes one or more of deionized water and ethanol.

[0017] Furthermore, in sub-step S13, the ultrasonic dispersion treatment time is 30 to 50 minutes, the rotation speed of the stirring process is 400 to 1000 rpm, the stirring time is 3 to 6 hours, and the drying process is drying at a temperature of 40 to 80 degrees Celsius for 8 to 15 hours; the temperature of the water bath is 40 to 80 degrees Celsius.

[0018] Another aspect of the present application also provides a flake alloy powder / manganese zinc ferrite / carbon absorbing powder prepared by the preparation method of the flake alloy powder / manganese zinc ferrite / carbon absorbing powder provided in the present application.

[0019] By applying the technical solution of the present invention, the flaky alloy powder / manganese-zinc ferrite / carbon absorbing powder prepared by the above-mentioned preparation method has a hollow structure, which can not only increase the multiple reflection loss of the absorber and reduce its density, but also reduce the dielectric constant while keeping the magnetic permeability basically unchanged, improve its impedance matching and the absorption intensity and bandwidth in the low frequency band; at the same time, the presence of the silicon dioxide coating layer is also conducive to improving the absorption performance of the absorber. In addition, the ferrite-carbon material coated on the surface of the alloy powder can greatly improve its compatibility and dispersibility with the matrix, improve the interface bonding force, and improve its corrosion resistance and oxidation resistance. In summary, the ferrite-carbon coated alloy absorber prepared by the above-mentioned preparation method has the advantages of high absorption intensity and large bandwidth in the low frequency band, low density, corrosion resistance and oxidation resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0021] Figure 1 A schematic diagram of a process flow chart of preparing a ferrite-carbon coated alloy absorber according to Example 1 of the present invention is shown; and

[0022] Figure 2 The structural spectrum of the ferrite-carbon coated alloy absorber prepared in Example 1 is shown.

[0023] The above drawings include the following reference numerals:

[0024] 1. Spherical alloy; 2. Flake alloy powder; 3. Manganese zinc ferrite; 4. Silicon dioxide; 5. PVP; 6. Polypyrrole; 7. Carbon layer. DETAILED DESCRIPTION

[0025] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0026] As described in the background technology, the loss mechanism of the existing iron-silicon-aluminum alloy powder absorber is single, and the problems of high density, poor absorption efficiency and matching performance of the absorber at low frequency are not fundamentally solved. In order to solve the above technical problems, the present application provides a method for preparing flaky alloy powder / manganese-zinc ferrite / carbon absorbing powder, including: step S1, preparing flaky alloy powder / manganese-zinc ferrite / silicon dioxide; step S2, adding the flaky alloy powder / manganese-zinc ferrite / silicon dioxide to an organic solvent containing polyvinyl pyrrolidone, dispersing and drying to prepare modified flaky alloy powder / manganese-zinc ferrite / silicon dioxide; under the action of a catalyst, adding the modified flaky alloy powder / manganese-zinc ferrite / silicon dioxide to In an inorganic solution containing pyrrole, flaky alloy powder / manganese zinc ferrite / silicon dioxide / polypyrrole microspheres are prepared after stirring and drying; step S3, in an inert gas atmosphere, the flaky alloy powder / manganese zinc ferrite / silicon dioxide / polypyrrole microspheres are calcined at high temperature to obtain flaky alloy powder / manganese zinc ferrite / silicon dioxide / carbon microspheres; the flaky alloy powder / manganese zinc ferrite / silicon dioxide / carbon microspheres are added to an alkaline solution for etching, and then stirred and dried to obtain flaky alloy powder / manganese zinc ferrite / carbon absorbing powder.

[0027] The flaky alloy powder / manganese-zinc ferrite / carbon absorbing powder prepared by the above preparation method has a hollow structure, which can not only increase the multiple reflection loss of the absorber and reduce its density, but also reduce the dielectric constant while keeping the magnetic permeability basically unchanged, improve its impedance matching and the absorption intensity and bandwidth in the low frequency band; at the same time, the presence of the silicon dioxide coating layer is also conducive to improving the absorption performance of the absorber. In addition, the ferrite-carbon material coated on the surface of the alloy powder can greatly improve its compatibility and dispersibility with the matrix, improve the interface bonding force, and improve its corrosion resistance and oxidation resistance. In summary, the ferrite-carbon coated alloy absorber prepared by the above preparation method has the advantages of high absorption intensity and large bandwidth in the low frequency band, low density, corrosion resistance and oxidation resistance.

[0028] The alloy powder can be selected from commonly used types in the art. Preferably, the alloy powder is one or more of FeSiAl alloy powder, FeCrAl alloy powder, and FeCo alloy powder. Compared with other alloy powders, the above alloy powders have better microwave absorption performance, which is conducive to further improving the microwave absorption performance of flaky alloy powder / manganese zinc ferrite / carbon microwave absorption powder.

[0029] In a preferred embodiment, the catalyst includes ferric chloride; step S2 specifically includes: adding flaky alloy powder / manganese zinc ferrite / silicon dioxide to an organic solvent and performing ultrasonic dispersion treatment; subsequently adding polyvinyl pyrrolidone, performing ultrasonic dispersion treatment, filtering, and drying to prepare modified flaky alloy powder / manganese zinc ferrite / silicon dioxide; adding the modified flaky alloy powder / manganese zinc ferrite / silicon dioxide to an inorganic solvent and performing ultrasonic dispersion treatment; subsequently adding ferric chloride, stirring, and then adding pyrrole, further stirring, filtering, and drying to prepare flaky alloy powder / manganese zinc ferrite / silicon dioxide / polypyrrole microspheres.

[0030] Through ultra-dispersion treatment, polyvinyl pyrrolidone can be grafted on the surface of alloy powder / manganese zinc ferrite / SiO2 to form modified flaky alloy powder / manganese zinc ferrite / silicon dioxide; then under the action of the catalyst ferric chloride, pyrrole can undergo self-polymerization reaction and be coated on the outside of the modified flaky alloy powder / manganese zinc ferrite / silicon dioxide to form a polypyrrole layer, thereby obtaining flaky alloy powder / manganese zinc ferrite / silicon dioxide / polypyrrole microspheres. At the same time, compared with other catalysts, the use of the above catalyst is conducive to improving the polymerization activity and reaction rate of pyrrole, thereby further improving the density of the polypyrrole layer, thereby further improving the absorbing strength of the above absorbing material in the low frequency band.

[0031] The absorbing material has a hollow structure, which is beneficial to improve its absorbing performance. Therefore, in order to further increase the proportion of the hollow structure and reduce its density, in a preferred embodiment, the organic solvent is ethanol and the inorganic solvent is deionized water; in the step of preparing the modified flaky alloy powder / manganese zinc ferrite / silicon dioxide, the flaky alloy powder / manganese zinc ferrite / silicon dioxide is 1 to 6 parts by weight, ethanol is 50 to 400 parts by weight, and polyvinyl pyrrolidone is 3 to 8 parts by weight; in the step of preparing the flaky alloy powder / manganese zinc ferrite / silicon dioxide / polypyrrole microspheres, the modified flaky alloy powder / manganese zinc ferrite / silicon dioxide is 1 to 6 parts by weight, deionized water is 100 to 400 parts by weight, ferric chloride is 5 to 10 parts by weight, and pyrrole is 1 to 5 parts by weight. More preferably, the pyrrole polymerization process includes reacting the mixture for 6 to 12 hours in a water bath at 30 to 50°C and a speed of 400 to 800 r / min. Carrying out the reaction under the above reaction conditions is conducive to further improving the coating uniformity and density of the polypyrrole layer, thereby further improving its absorption intensity and bandwidth in the low frequency band.

[0032] More preferably, step S1 specifically includes: sub-step S11, preparing the alloy powder into flaky alloy powder; sub-step S12, adding iron salt, manganese salt and zinc salt into the first solution, dispersing them to obtain a reaction solution; subsequently adding the flaky alloy powder into the reaction solution, stirring and drying them to obtain flaky alloy powder / manganese zinc ferrite with a core / shell structure; sub-step S13, adding the flaky alloy powder / manganese zinc ferrite into the second solution, dispersing them; subsequently adding tetraethyl orthosilicate, stirring and drying them to obtain flaky alloy powder / manganese zinc ferrite / silicon dioxide with a core / shell / shell structure.

[0033] It should be noted that:

[0034] The core / shell structured flaky alloy powder / manganese-zinc ferrite refers to the manganese-zinc ferrite generated by the reaction coating the outer surface of the flaky alloy powder; the core / shell / shell structured flaky alloy powder / manganese-zinc ferrite / silicon dioxide absorbing powder refers to the manganese-zinc ferrite coating the outer surface of the flaky alloy powder, and the silicon dioxide generated by the reaction coating the outer surface of the manganese-zinc ferrite.

[0035] More preferably, the iron salt, manganese salt and zinc salt are divalent iron salt, divalent manganese salt and divalent zinc salt respectively; sub-step S12 specifically includes: dissolving a surfactant in deionized water and mixing them evenly; then adding divalent iron salt, divalent manganese salt and divalent zinc salt, performing ultrasonic dispersion treatment to mix them evenly to obtain a reaction solution; adding flaky alloy powder to the reaction solution, keeping the reaction solution with the added flaky alloy powder in a constant temperature water bath, and performing a first stirring; then adding a first alkaline solution to the reaction solution to keep the pH value within a predetermined range, performing a second stirring to fully react it to obtain a first precipitate; washing the first precipitate with a first cleaning solution, and then drying it; grinding the dried first precipitate, and screening it through a vibrating screen to obtain flaky alloy powder / manganese-zinc ferrite.

[0036] In a preferred embodiment, the surfactant includes sodium dodecylbenzene sulfonate and polyethylene glycol. The addition of surfactant can improve the coating uniformity of the manganese zinc ferrite layer. In a preferred embodiment, the surfactant includes but is not limited to sodium dodecylbenzene sulfonate and polyethylene glycol. Compared with other surfactants. The above-mentioned surfactants have better surface activity, so the use of the above-mentioned surfactants is conducive to further improving the coating uniformity, thereby further improving the absorbing performance of the flaky alloy powder / manganese zinc ferrite / carbon absorbing powder.

[0037] The first cleaning solution may be any commonly used solution in the art, and deionized water is preferred to reduce costs.

[0038] In a preferred embodiment, sodium dodecylbenzene sulfonate and polyethylene glycol are both 1 to 5 parts by mass; deionized water is 500 to 2000 parts by mass; divalent iron salt, divalent manganese salt and divalent zinc salt are 50 to 80 parts by mass, 10 to 30 parts by mass and 10 to 30 parts by mass respectively; the alkaline solution is a NaOH solution, and the concentration of the NaOH solution is 0.4 to 0.6 mol / L. Limiting the amount of each component to the above range is conducive to further improving the coating amount and coating uniformity of the manganese zinc ferrite, thereby further improving the absorbing performance of the finally obtained flaky alloy powder / manganese zinc ferrite / carbon absorbing powder.

[0039] The silicon dioxide layer can be removed by etching with an alkaline solution. Preferably, in step S3, the inert gas is nitrogen, and the alkaline solution is one or more of a KOH solution, a NaOH solution, and an ammonia solution. The above alkaline solutions are conducive to improving the removal rate of silicon dioxide, thereby further improving the porosity of the flaky alloy powder / manganese-zinc ferrite / silicon dioxide, thereby further improving its wave loss.

[0040] In a preferred embodiment, in sub-step S2, the ultrasonic dispersion treatment time is 5 to 15 minutes. Limiting the ultrasonic dispersion treatment time within the above range is conducive to further improving the mixing uniformity of the reaction raw materials in sub-step S2, thereby further improving the conversion rate of the raw materials, the production rate of manganese zinc ferrite and the coating uniformity, thereby better improving the absorbing performance of the finally obtained flaky alloy powder / manganese zinc ferrite / carbon absorbing powder.

[0041] In a preferred embodiment, in sub-step S2, the constant temperature water bath is 50-90 degrees Celsius, the speed of the first stirring is 600-1000 rpm, and the time of the second stirring is 4-10 hours; the pH value is maintained in the range of 10-11 during the reaction process of full reaction; the drying in sub-step S2 is dried at a temperature of 60-80 degrees Celsius for 8-12 hours. Limiting the temperature, speed, time of the second stirring process and pH of the constant temperature water bath in sub-step S2 within the above range is beneficial to improving the generation rate of manganese zinc ferrite. Limiting the temperature and time of the drying process within the above range can further reduce the water content on the surface of the manganese zinc ferrite layer, thereby facilitating improving its bonding stability with the silicon dioxide layer, which can improve the structural stability of the flaky alloy powder / manganese zinc ferrite / carbon absorbing powder to a certain extent, thereby greatly improving the service life and absorbing performance stability of the flaky alloy powder / manganese zinc ferrite / carbon absorbing powder.

[0042] In a preferred embodiment, sub-step S13 specifically includes: adding flaky alloy powder / manganese zinc ferrite to a solvent, water and a second alkaline solution, and performing ultrasonic dispersion treatment; then adding ethyl orthosilicate, and performing a third stirring in a water bath to react to obtain a second precipitate; washing the second precipitate with a second cleaning liquid, and then drying to obtain a flaky alloy powder / manganese zinc ferrite / silicon dioxide absorbing powder. The silicon dioxide layer can be formed by a method commonly used in the art, and the above method is conducive to further improving the coating uniformity of the silicon dioxide layer, thereby further improving the absorbing loss of the finally formed flaky alloy powder / manganese zinc ferrite / carbon absorbing powder.

[0043] In sub-step S13, both solvent and water are used to disperse the flaky alloy powder / manganese-zinc ferrite, which needs to be removed later. According to the above-mentioned properties, a solvent in the art can be selected. Preferably, in sub-step S13, the solvent includes one or more of anhydrous ethanol and acetone. The addition of the second alkali solution can promote the hydrolysis of tetraethyl orthosilicate to form silicon dioxide. Preferably, in sub-step S13, the second alkaline solution includes one or more of KOH solution, NaOH solution, and ammonia water. The second cleaning solution can be selected from washing agents commonly used in the art, preferably in step S3, the second cleaning solution includes deionized water and / or ethanol.

[0044] In a preferred embodiment, in sub-step S13, the time of ultrasonic dispersion treatment is 30 to 50 minutes, the speed of the stirring process is 400 to 1000 rpm, the stirring time is 3 to 6 hours, and the drying process is dried at a temperature of 40 to 80 degrees Celsius for 8 to 15 hours; the temperature of the water bath is 40 to 80 degrees Celsius. Limiting the time of ultrasonic dispersion treatment, the water bath temperature, the speed and time of the stirring process within the above range is conducive to improving the mixing uniformity of the flaky alloy powder / manganese zinc ferrite, the solvent, water and the second alkali solution, thereby further improving the coating uniformity of the silicon dioxide layer during the hydrolysis of ethyl orthosilicate. Limiting the time and temperature of the drying process within the above range is conducive to further reducing the water content on the surface of the silicon dioxide layer, thereby further improving the bonding stability between the silicon dioxide layer and polypyrrole, thereby further improving the structural stability of the flaky alloy powder / manganese zinc ferrite / carbon absorbing powder obtained. Under the effects of the above two aspects, the above steps can greatly improve the stability of the absorbing performance and the absorbing strength of the flaky alloy powder / manganese zinc ferrite / carbon absorbing powder.

[0045] Another aspect of the present application also provides a flake alloy powder / manganese zinc ferrite / carbon absorbing powder prepared by the preparation method of the flake alloy powder / manganese zinc ferrite / carbon absorbing powder provided in the present application.

[0046] The flaky alloy powder / manganese-zinc ferrite / carbon absorbing powder prepared by the above preparation method has a hollow structure, which can not only increase the multiple reflection loss of the absorber and reduce its density, but also reduce the dielectric constant while keeping the magnetic permeability basically unchanged, improve its impedance matching and the absorption intensity and bandwidth in the low frequency band; at the same time, the presence of the silicon dioxide coating layer is also conducive to improving the absorption performance of the absorber. In addition, the ferrite-carbon material coated on the surface of the alloy powder can greatly improve its compatibility and dispersibility with the matrix, improve the interface bonding force, and improve its corrosion resistance and oxidation resistance. In summary, the ferrite-carbon coated alloy absorber prepared by the above preparation method has the advantages of high absorption intensity and large bandwidth in the low frequency band, low density, corrosion resistance and oxidation resistance.

[0047] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0048] Example 1

[0049] A method for preparing a hollow ferrite-carbon structure-coated flaky alloy microwave-absorbing powder comprises the following steps:

[0050] (1) Preparation of flaky alloy powder The preparation method is the same as that in Example 1.

[0051] (2) Preparation of alloy powder / manganese-zinc ferrite

[0052] Weigh 1 part of PEG and 1 part of SDBS as surfactants and dissolve them in 2000 parts of deionized water. After mixing well, add 50 parts of Fe 2+ of iron salt, 20 parts of Mn 2+ of manganese salt and 30 parts of Zn 2+ The zinc salt was treated with ultrasonic for 5 minutes to make it uniformly mixed to form a reaction solution, which was set aside for later use. A 0.5 mol / L sodium hydroxide solution was taken as a pH adjusting solution.

[0053] Add the pretreated alloy powder to the reaction solution, keep the reaction solution in a 70℃ constant temperature water bath and stir evenly at a speed of 600r / min, slowly and evenly add the pH adjusting solution to the reaction solution, control the pH value within the range of 10, continuously titrate the adjusting solution during the reaction, keep the pH value stable during the reaction, and continue stirring for 4 hours to make it fully react. After the reaction is completed, put the magnetic magnet at the bottom of the beaker, pour out the supernatant, add deionized water to the beaker to wash the precipitate, and repeat the above washing operation 6 times. Put the washed precipitate into a blast oven, dry it at 60℃ for 12 hours, and then grind it into powder particles, and then pass it through a 200-mesh vibrating screen to obtain alloy powder / manganese-zinc ferrite.

[0054] (3) Preparation of hollow Mn-Zn ferrite / C structure coated flake alloy powder

[0055] Preparation of Flake Alloy Powder / Mn-Zn Ferrite / SiO2

[0056] 10 parts of the prepared flaky alloy powder / manganese-zinc ferrite were added to a mixed solution of 1200 parts of anhydrous ethanol, 500 parts of water and 100 parts of ammonia water with a mass concentration of 25wt%, and ultrasonically treated for 30 minutes to make the pretreated flaky alloy powder / manganese-zinc ferrite particles evenly dispersed in the solution, and then 1 part of ethyl orthosilicate was dropped into the solution, and stirred continuously for 3-6 hours at a speed of 400r / min in a water bath pot at 60°C. After the reaction was completed, the precipitate was collected with a magnet, the supernatant was poured out, and washed with ethanol and deionized water for 6 times respectively, and the precipitate was placed in a 60°C blast oven for drying for 12 hours to complete the preparation of flaky alloy powder / manganese-zinc ferrite / SiO2.

[0057] Modification of flake alloy powder / Mn-Zn ferrite / SiO2

[0058] Disperse 6 parts of flaky alloy powder / manganese zinc ferrite in 400 parts of ethanol solution and ultrasonicate for 20 minutes, then add 3 parts of PVP (polyvinyl pyrrolidone), continue ultrasonicate for 40 minutes, then wash with distilled water 6 times for standby use, then put the washed precipitate into a 0℃ forced air oven and dry it for 12 hours to complete the modification of flaky alloy powder / manganese zinc ferrite / SiO2.

[0059] Preparation of hollow flake alloy powder / Mn-Zn ferrite / C

[0060] Disperse 6 parts of PVP-modified flaky alloy powder / manganese zinc ferrite / SiO2 into 400 parts of deionized water, add 10 parts of ferric chloride after ultrasonic treatment for 15 minutes, stir for 30 minutes, add 1 part of pyrrole, and react at a speed of 400r / min for 6 hours under stirring in a 40°C water bath. After the reaction is completed, collect the precipitate with a magnet, pour out the supernatant, wash it with distilled water and ethanol for 3 times respectively, and dry the precipitate in a blast oven at 60°C for 12 hours to obtain flaky alloy powder / manganese zinc ferrite / SiO2 / PPy (polypyrrole) microspheres.

[0061] The obtained flaky alloy powder / manganese zinc ferrite / SiO2 / PPy (polypyrrole) microspheres are calcined at 500°C for 4 hours under nitrogen conditions in a tubular furnace to obtain flaky alloy powder / manganese zinc ferrite / SiO2 / C microspheres; the obtained flaky alloy powder / manganese zinc ferrite / SiO2 / C microspheres are dispersed in 100 parts of a 10% sodium hydroxide solution for etching, stirred at 1000 r / min at 60°C for 12 hours, and the precipitate is collected with a magnet. The supernatant is poured out, washed with distilled water for 6 times, and the precipitate is dried in a blast oven at 60°C for 12 hours to obtain a hollow ferrite-carbon structure-coated flaky alloy absorbing powder.

[0062] Example 2

[0063] A method for preparing a hollow ferrite-carbon structure-coated flaky alloy microwave-absorbing powder comprises the following steps:

[0064] (1) Preparation of flaky alloy powder The preparation method is the same as that in Example 1.

[0065] (2) Preparation of alloy powder / manganese-zinc ferrite The preparation method is the same as that in Example 1.

[0066] (3) Preparation of hollow Mn-Zn ferrite / C structure coated flake alloy powder

[0067] Preparation of Flake Alloy Powder / Mn-Zn Ferrite / SiO2

[0068] 9 parts of the prepared flaky alloy powder / manganese-zinc ferrite were added to a mixed solution of 1000 parts of anhydrous ethanol, 400 parts of water and 600 parts of ammonia water with a mass concentration of 25wt%, and ultrasonically treated for 40 minutes to make the pretreated flaky alloy powder / manganese-zinc ferrite particles evenly dispersed in the solution, and then 3 parts of ethyl orthosilicate were dropped into the solution, and stirred continuously for 5 hours in a water bath at 60°C at a speed of 5000r / min. After the reaction was completed, the precipitate was collected with a magnet, the supernatant was poured out, and washed with ethanol and deionized water for 6 times respectively, and the precipitate was placed in a 60°C blast oven for drying for 12 hours to complete the preparation of flaky alloy powder / manganese-zinc ferrite / SiO2.

[0069] Modification of flake alloy powder / Mn-Zn ferrite / SiO2

[0070] Add 4 parts of alloy powder / manganese zinc ferrite to 200 parts of ethanol solution and ultrasonicate for 30 minutes, then add 6 parts of PVP (polyvinyl pyrrolidone), continue ultrasonication for 50 minutes, and then wash 6 times with distilled water for standby use. Then, place the washed precipitate in a 60°C forced air oven and dry it for 12 hours to complete the modification of flaky alloy powder / manganese zinc ferrite / SiO2.

[0071] Preparation of hollow flake alloy powder / Mn-Zn ferrite / C

[0072] Disperse 4 parts of PVP-modified flaky alloy powder / manganese-zinc ferrite / SiO2 into 200 parts of deionized water, add 8 parts of ferric chloride after ultrasonic treatment for 20 minutes, add 3 parts of pyrrole after stirring for 30 minutes, and react at a speed of 600 r / min for 10 hours under stirring in a 50°C water bath. After the reaction is completed, collect the precipitate with a magnet, pour out the supernatant, wash it with distilled water and ethanol for 6 times respectively, and dry the precipitate in a blast oven at 60°C for 12 hours to obtain flaky alloy powder / manganese-zinc ferrite / SiO2 / PPy (polypyrrole) microspheres.

[0073] The obtained flaky alloy powder / manganese zinc ferrite / SiO2 / PPy (polypyrrole) microspheres are calcined at 700°C for 3 hours under nitrogen conditions in a tubular furnace, and then the obtained flaky alloy powder / manganese zinc ferrite / SiO2 / C microspheres are dispersed in 300 parts of 20% sodium hydroxide solution for etching, stirred at 1200 r / min at 60°C for 10 hours, and the precipitate is collected with a magnet, the supernatant is poured out, and the precipitate is washed with distilled water for 6 times. The precipitate is placed in a blast oven at 60°C and dried for 12 hours to obtain a hollow ferrite-carbon structure-coated flaky alloy absorbing powder.

[0074] Example 3

[0075] A method for preparing a hollow ferrite-carbon structure-coated flaky alloy microwave-absorbing powder comprises the following steps:

[0076] (1) Preparation of flaky alloy powder The preparation method is the same as that in Example 1.

[0077] (2) Preparation of alloy powder / manganese-zinc ferrite

[0078] Weigh 5 parts of PEG and 5 parts of SDBS as surfactants and dissolve them in 500 parts of deionized water. After mixing well, add 80 parts of Fe 2+ of iron salt, 10 parts of Mn 2+ of manganese salt and 10 parts of Zn 2+ The zinc salt was treated with ultrasonic for 15 minutes to make it uniformly mixed to form a reaction solution, which was set aside for later use. A 0.5 mol / L sodium hydroxide solution was used as a pH adjusting solution.

[0079] Add the pretreated alloy powder to the reaction solution, keep the reaction solution in a 70℃ constant temperature water bath and stir evenly at a speed of 1000r / min, slowly and evenly add the pH adjusting solution to the reaction solution, control the pH value within the range of 11, continuously titrate the adjusting solution during the reaction, keep the pH value stable during the reaction, and continue stirring for 10 hours to make it fully react. After the reaction is completed, put the magnetic magnet at the bottom of the beaker, pour out the supernatant, add deionized water to the beaker to wash the precipitate, and repeat the above washing operation 6 times. Put the washed precipitate into a blast oven, dry it at 60℃ for 12 hours, and then grind it into powder particles, and then pass it through a 200-mesh vibrating screen to obtain alloy powder / manganese-zinc ferrite.

[0080] (3) Preparation of hollow Mn-Zn ferrite / C structure coated flake alloy powder

[0081] Preparation of Flake Alloy Powder / Mn-Zn Ferrite / SiO2

[0082] Add 2 parts of the prepared flaky alloy powder / manganese-zinc ferrite to a mixed solution of 800 parts of anhydrous ethanol, 200 parts of water and 20 parts of ammonia water with a mass concentration of 25wt%, and ultrasonically treat for 50 minutes to make the pretreated flaky alloy powder / manganese-zinc ferrite particles evenly dispersed in the solution, then drop 6 parts of ethyl orthosilicate into the solution, and stir continuously for 6 hours in a water bath at 60°C at a speed of 1000r / min. After the reaction is completed, collect the precipitate with a magnet, pour out the supernatant, wash it with ethanol and deionized water for 6 times respectively, and put the precipitate into a 60°C blast oven for drying for 12 hours to complete the preparation of flaky alloy powder / manganese-zinc ferrite / SiO2.

[0083] Modification of flake alloy powder / Mn-Zn ferrite / SiO2

[0084] Disperse 1 part of alloy powder / manganese zinc ferrite in 50 parts of ethanol solution and ultrasonicate for 30 minutes, then add 8 parts of PVP (polyvinyl pyrrolidone), continue ultrasonicate for 50 minutes, then wash with distilled water 6 times for standby use, then put the washed precipitate into a 60°C forced air oven and dry it for 12 hours to complete the modification of flaky alloy powder / manganese zinc ferrite / SiO2.

[0085] Preparation of hollow flake alloy powder / Mn-Zn ferrite / C

[0086] Disperse 1 part of PVP-modified flaky alloy powder / manganese-zinc ferrite / SiO2 into 100 parts of deionized water, add 10 parts of ferric chloride after ultrasonic treatment for 30 minutes, stir for 60 minutes, add 5 parts of pyrrole, and react at a speed of 800 r / min for 12 hours under stirring in a 50°C water bath. After the reaction is completed, collect the precipitate with a magnet, pour out the supernatant, wash it with distilled water and ethanol for 6 times respectively, and dry the precipitate in a blast oven at 60°C for 12 hours to obtain flaky alloy powder / manganese-zinc ferrite / SiO2 / PPy (polypyrrole) microspheres.

[0087] The obtained flaky alloy powder / manganese zinc ferrite / SiO2 / PPy (polypyrrole) microspheres are calcined at 800°C for 6 hours under nitrogen conditions in a tubular furnace, and then the obtained flaky alloy powder / manganese zinc ferrite / SiO2 / C microspheres are dispersed in 400 parts of 20% sodium hydroxide solution for etching, stirred at 1500r / min at 60°C for 16 hours, and the precipitate is collected with a magnet, the supernatant is poured out, and the precipitate is washed with distilled water for 6 times. The precipitate is placed in a blast oven at 60°C and dried for 12 hours to obtain a hollow ferrite-carbon structure-coated flaky alloy absorbing powder.

[0088] Example 4

[0089] A method for preparing a hollow ferrite-carbon structure-coated flaky alloy microwave-absorbing powder comprises the following steps:

[0090] (1) Preparation of flake alloy powder

[0091] Preparation of flake alloy powder

[0092] Add 200 parts of FeSiAl alloy powder with a particle size of 400 mesh to 300 parts of anhydrous ethanol, stir evenly and put it into a horizontal planetary ball mill for wet ball milling. The speed of the ball mill is 200r / min and the ball milling time is 62h. The mass ratio of agate beads to alloy powder used in the ball milling is 8:20. The agate beads are composed of three types of agate beads with diameters of 10mm, 6mm and 4mm, large, medium and small. The mass ratio of the three types of agate beads is 2:10:88. After the ball milling is completed, take out the slurry and dry it at 60°C for 12h to obtain flat alloy powder.

[0093] Alloy powder pretreatment

[0094] Add 150 parts of flaky alloy powder to 2% dilute hydrochloric acid and ultrasonically treat it for 8 minutes. Place a magnetic magnet at the bottom of the beaker, pour out the supernatant, add deionized water to the beaker to wash the powder, continue ultrasonic treatment, repeat the above operation 6 times until the pH of the powder solution is neutral, and dry it at 60°C for 12 hours after cleaning to complete the pretreatment of the alloy powder.

[0095] (2) Preparation of alloy powder / manganese-zinc ferrite The preparation method is the same as that in Example 1.

[0096] (3) Preparation of hollow manganese-zinc ferrite / C structure coated flaky alloy powder The preparation method is the same as that in Example 3.

[0097] Example 5

[0098] A method for preparing a hollow ferrite-carbon structure-coated flaky alloy microwave-absorbing powder comprises the following steps:

[0099] (1) Preparation of flake alloy powder

[0100] Preparation of flake alloy powder

[0101] Add 500 parts of FeSiAl alloy powder with a particle size of 400 mesh to 800 parts of anhydrous ethanol, stir evenly and put it into a horizontal planetary ball mill for wet ball milling. The speed of the ball mill is 500r / min and the ball milling time is 15h. The mass ratio of agate beads to alloy powder used in the ball milling is 15:4. The agate beads are composed of large, medium and small agate beads with diameters of 10mm, 6mm and 4mm. The mass ratio of large, medium and small agate beads is 10:30:60. After the ball milling is completed, take out the slurry and dry it at 60°C for 12h to obtain flat alloy powder.

[0102] Alloy powder pretreatment

[0103] Add 120 parts of flaky alloy powder to 10% dilute hydrochloric acid and ultrasonically treat it for 12 minutes. Place a magnetic magnet at the bottom of the beaker, pour out the supernatant, add deionized water to the beaker to wash the powder, continue ultrasonic treatment, repeat the above operation 5 times until the pH of the powder solution is neutral, and dry it at 60°C for 12 hours after cleaning to complete the pretreatment of the alloy powder.

[0104] (2) Preparation of alloy powder / manganese-zinc ferrite The preparation method is the same as that in Example 1.

[0105] (3) Preparation of hollow Mn-Zn ferrite / C structure coated flake alloy powder

[0106] The preparation method of flaky alloy powder / manganese zinc ferrite / SiO2 is the same as that of Example 3.

[0107] The modified preparation method of flaky alloy powder / manganese zinc ferrite / SiO2 is the same as that in Example 3.

[0108] Preparation of hollow flake alloy powder / Mn-Zn ferrite / C

[0109] Disperse 4 parts of PVP-modified flaky alloy powder / manganese-zinc ferrite / SiO2 into 200 parts of deionized water, add 8 parts of ferric chloride after ultrasonic treatment for 20 minutes, add 3 parts of pyrrole after stirring for 30 minutes, and react at a speed of 600 r / min for 10 hours under stirring in a 50°C water bath. After the reaction is completed, collect the precipitate with a magnet, pour out the supernatant, wash it with distilled water and ethanol for 6 times respectively, and dry the precipitate in a blast oven at 60°C for 12 hours to obtain flaky alloy powder / manganese-zinc ferrite / SiO2 / PPy (polypyrrole) microspheres.

[0110] The obtained flaky alloy powder / MnZn ferrite / SiO2 / PPy (polypyrrole) microspheres are calcined at 700°C for 3 hours under nitrogen conditions in a tubular furnace, and then the obtained flaky alloy powder / MnZn ferrite / SiO2 / C microspheres are dispersed in 300 parts of 20% sodium hydroxide solution for etching, and stirred at 1200 r / min at 60°C for 10 hours. The precipitate is collected with a magnet, the supernatant is poured out, and the precipitate is washed with distilled water for 6 times. The precipitate is placed in a blast oven at 60°C and dried for 12 hours to obtain a hollow ferrite-carbon structure-coated flaky alloy absorbing powder.

[0111] Comparative Example 1

[0112] A method for preparing flaky alloy microwave-absorbing powder comprises the following steps:

[0113] Preparation of flake alloy powder

[0114] Add 300 parts of FeSiAl alloy powder with a particle size of 400 mesh to 500 parts of anhydrous ethanol, stir evenly and put it into a horizontal planetary ball mill for wet ball milling. The speed of the ball mill is 300r / min and the ball milling time is 10h. The mass ratio of agate beads to alloy powder used in the ball milling is 10:8. The agate beads are composed of large, medium and small agate beads with diameters of 10mm, 6mm and 4mm. The mass ratio of large, medium and small agate beads is 6:15:79. After the ball milling is completed, take out the slurry and dry it at 60°C for 12h to obtain flat alloy powder.

[0115] Comparative Example 2

[0116] A method for preparing a ferrite-carbon structure-coated flaky alloy absorbing powder, the process flow is as follows: Figure 1 As shown, including:

[0117] (1) Preparation of flake alloy powder

[0118] Preparation of flake alloy powder

[0119] Add 300 parts of FeSiAl alloy powder with a particle size of 400 mesh to 500 parts of anhydrous ethanol, stir evenly and put it into a horizontal planetary ball mill for wet ball milling. The speed of the ball mill is 300r / min and the ball milling time is 10h. The mass ratio of agate beads to alloy powder used in the ball milling is 10:8. The agate beads are composed of large, medium and small agate beads with diameters of 10mm, 6mm and 4mm. The mass ratio of large, medium and small agate beads is 6:15:79. After the ball milling is completed, take out the slurry and dry it at 60°C for 12h to obtain flat alloy powder.

[0120] Alloy powder pretreatment

[0121] Add 120 parts of flaky alloy powder to 10% dilute hydrochloric acid and ultrasonically treat it for 12 minutes. Place a magnetic magnet at the bottom of the beaker, pour out the supernatant, add deionized water to the beaker to wash the powder, continue ultrasonic treatment, repeat the above operation 5 times until the pH of the powder solution is neutral, and dry it at 60°C for 12 hours after cleaning to complete the pretreatment of the alloy powder.

[0122] (2) Preparation of alloy powder / manganese-zinc ferrite

[0123] Weigh 2 parts of PEG and 3 parts of SDBS as surfactants and dissolve them in 1000 parts of deionized water. After mixing well, add 60 parts of Fe 2+ of iron salt, 20 parts of Mn 2+ of manganese salt and 20 parts of Zn 2+ The zinc salt was treated with ultrasonic for 10 min to make it uniformly mixed to form a reaction solution, which was set aside for later use. A 0.5 mol / L sodium hydroxide solution was taken as a pH adjusting solution.

[0124] Add the pretreated alloy powder to the reaction solution, keep the reaction solution in a constant temperature water bath at 70℃ and stir evenly at a speed of 800r / min, slowly and evenly add the pH adjusting solution to the reaction solution, control the pH value at 10.5, and continuously titrate the adjusting solution during the reaction to keep the pH value stable during the reaction. The reaction is stirred for 6 hours to make it fully react. After the reaction is completed, put the magnetic magnet at the bottom of the beaker, pour out the supernatant, add deionized water to the beaker to wash the precipitate, and repeat the above washing operation 5 times. Put the washed precipitate into a blast oven, dry it at 60℃ for 12 hours, and then grind it into powder particles, and then pass it through a 200-mesh vibrating screen to obtain alloy powder / manganese-zinc ferrite.

[0125] The formation and structure of the hollow ferrite-carbon structure-coated flaky alloy absorbing powder prepared in Examples 1 to 5 are shown in Figure 2, where 1 represents spherical alloy, 2 represents flake alloy powder; 3 represents manganese-zinc ferrite, 4 represents silicon dioxide, 5 represents PVP, 6 represents polypyrrole, and 7 represents carbon layer.

[0126] Performance Test:

[0127] The powders prepared in Examples 1 to 5 and Comparative Examples 1 to 2 were respectively mixed with paraffin wax to prepare 80% coaxial samples and tested. The main steps were: first, the powders were mixed with paraffin wax in a ratio of 8:2, and heated in a high-temperature oven at 65°C for 10 minutes. Then, the powders were quickly taken out and mixed and stirred evenly to form a viscous solid, which was filled into a coaxial ring mold (mold outer diameter 7mm, inner diameter 3.04mm), and samples with a thickness of 1-2mm were prepared respectively. The complex dielectric constant and complex magnetic permeability were measured by a network vector analyzer, and then the reflection loss of the test sample at a thickness of 2.5mm was calculated by MATLAB simulation according to the electromagnetic field transmission line theory. The frequency variation curve of the reflection loss

[0128] The tap density of the powders prepared in Examples 1 to 5 and Comparative Examples 1 to 2 was measured using a tap density meter. The powders prepared in Examples 1 to 5 and Comparative Examples 1 to 2 were added to 25% dilute hydrochloric acid, and the time for the solution to generate bubbles or change color was observed. The test results are shown in Table 1.

[0129] Table 1

[0130]

[0131] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: the ferrite-carbon-coated alloy absorber prepared by the above preparation method has the advantages of high absorption intensity and large bandwidth in the low frequency band, low density, corrosion resistance and oxidation resistance.

[0132] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those described herein, for example.

[0133] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing flaky alloy powder / manganese zinc ferrite / carbon absorbing powder, characterized in that: include: Step S1, preparing flaky alloy powder / manganese zinc ferrite / silicon dioxide; Step S2, adding the flaky alloy powder / manganese zinc ferrite / silicon dioxide into an organic solvent containing polyvinyl pyrrolidone, dispersing and drying to prepare modified flaky alloy powder / manganese zinc ferrite / silicon dioxide; adding the modified flaky alloy powder / manganese zinc ferrite / silicon dioxide into an inorganic solution containing pyrrole under the action of a catalyst, stirring and drying to prepare flaky alloy powder / manganese zinc ferrite / silicon dioxide / polypyrrole microspheres; Step S3, in an inert gas atmosphere, calcining the flaky alloy powder / manganese zinc ferrite / silicon dioxide / polypyrrole microspheres at high temperature to obtain flaky alloy powder / manganese zinc ferrite / silicon dioxide / carbon microspheres; adding the flaky alloy powder / manganese zinc ferrite / silicon dioxide / carbon microspheres to an alkaline solution for etching, and then stirring and drying to obtain the flaky alloy powder / manganese zinc ferrite / carbon absorbing powder; In the step S2, under the action of the catalyst, the pyrrole undergoes a self-polymerization reaction and is coated on the outside of the modified flaky alloy powder / manganese zinc ferrite / silicon dioxide to form a polypyrrole layer.

2. The method for preparing the flaky alloy powder / manganese zinc ferrite / silicon dioxide absorbing powder according to claim 1, characterized in that: The catalyst includes ferric chloride; the step S2 specifically includes: The flaky alloy powder / manganese zinc ferrite / silicon dioxide is added to an organic solvent and subjected to ultrasonic dispersion treatment; polyvinyl pyrrolidone is then added, subjected to ultrasonic dispersion treatment, filtered, and dried to prepare a modified flaky alloy powder / manganese zinc ferrite / silicon dioxide; The modified flaky alloy powder / manganese zinc ferrite / silicon dioxide is added to an inorganic solvent and subjected to ultrasonic dispersion treatment; subsequently, ferric chloride is added, stirred, and then pyrrole is added, and further stirred, filtered, and dried to prepare flaky alloy powder / manganese zinc ferrite / silicon dioxide / polypyrrole microspheres.

3. The method for preparing the flaky alloy powder / manganese zinc ferrite / silicon dioxide absorbing powder according to claim 2, characterized in that: The organic solvent is ethanol or acetone, and the inorganic solvent is deionized water; In the step of preparing the modified flaky alloy powder / manganese zinc ferrite / silicon dioxide, the flaky alloy powder / manganese zinc ferrite / silicon dioxide is 1 to 6 parts by weight, the ethanol is 50 to 400 parts by weight, and the polyvinyl pyrrolidone is 3 to 8 parts by weight; In the step of preparing flaky alloy powder / manganese zinc ferrite / silicon dioxide / polypyrrole microspheres, the modified flaky alloy powder / manganese zinc ferrite / silicon dioxide is 1 to 6 parts by weight, the deionized water is 100 to 400 parts by weight, the ferric chloride is 5 to 10 parts by weight, and the pyrrole is 1 to 5 parts by weight.

4. The method for preparing the flaky alloy powder / manganese zinc ferrite / silicon dioxide absorbing powder according to claim 1, characterized in that: The step S1 specifically includes: Sub-step S11, preparing the alloy powder into flake alloy powder; Sub-step S12, adding iron salt, manganese salt and zinc salt to the first solution, dispersing the solution to obtain a reaction solution; then adding the flaky alloy powder to the reaction solution, stirring and drying the solution to obtain a flaky alloy powder / manganese-zinc ferrite with a core / shell structure; Sub-step S13, adding the flaky alloy powder / manganese zinc ferrite into the second solution for dispersion treatment; then adding ethyl orthosilicate, stirring and drying to obtain flaky alloy powder / manganese zinc ferrite / silicon dioxide with a core / shell / shell structure.

5. The method for preparing the flaky alloy powder / manganese zinc ferrite / silicon dioxide absorbing powder according to claim 4, characterized in that: The iron salt, manganese salt and zinc salt are respectively a divalent iron salt, a divalent manganese salt and a divalent zinc salt; the sub-step S12 specifically includes: Dissolving a surfactant in deionized water and mixing the mixture evenly; then adding a divalent iron salt, a divalent manganese salt and a divalent zinc salt, performing ultrasonic dispersion treatment to mix the mixture evenly to obtain a reaction solution; The flaky alloy powder is added to the reaction solution, and the reaction solution with the flaky alloy powder added is kept in a constant temperature water bath and first stirred; then a first alkaline solution is added to the reaction solution to keep the pH value within a predetermined range, and a second stirring is performed to fully react to obtain a first precipitate; The first precipitate is cleaned with a first cleaning liquid and then dried; the dried first precipitate is ground and screened through a vibrating screen to obtain the flaky alloy powder / manganese-zinc ferrite.

6. The method for preparing the flaky alloy powder / manganese zinc ferrite / silicon dioxide absorbing powder according to claim 5, characterized in that: The surfactant includes sodium dodecylbenzene sulfonate and polyethylene glycol, and the first cleaning solution is deionized water; The sodium dodecylbenzene sulfonate and polyethylene glycol are both 1-5 parts by mass; the deionized water is 500-2000 parts by mass; the divalent iron salt, divalent manganese salt and divalent zinc salt are 50-80 parts by mass, 10-30 parts by mass and 10-30 parts by mass respectively; The alkaline solution is a NaOH solution, and the concentration of the NaOH solution is 0.4-0.6 mol / L.

7. The method for preparing the flaky alloy powder / manganese zinc ferrite / silicon dioxide absorbing powder according to claim 6, characterized in that: In the sub-step S2, the ultrasonic dispersion treatment time is 5 to 15 minutes; In the sub-step S2, the constant temperature water bath is 50-90 degrees Celsius, the first stirring speed is 600-1000 rpm, and the second stirring time is 4-10 hours; In the sub-step S2, the pH value is maintained in the range of 10 to 11 during the reaction process of the sufficient reaction; In the sub-step S2, the drying is performed at a temperature of 60 to 80 degrees Celsius for 8 to 12 hours.

8. The method for preparing the flaky alloy powder / manganese zinc ferrite / silicon dioxide absorbing powder according to claim 4, characterized in that: The sub-step S13 specifically includes: The flaky alloy powder / manganese-zinc ferrite is added to a solvent, water and a second alkaline solution, and subjected to ultrasonic dispersion treatment; then, ethyl orthosilicate is added, and a third stirring is performed in a water bath to react the flaky alloy powder and a second precipitate is obtained; The second precipitate is cleaned with a second cleaning liquid and then dried to obtain flaky alloy powder / manganese zinc ferrite / silicon dioxide absorbing powder.

9. The method for preparing the flaky alloy powder / manganese zinc ferrite / silicon dioxide absorbing powder according to claim 8, characterized in that: In the sub-step S13, the solvent includes one or more of anhydrous ethanol and acetone; In the sub-step S13, the second alkaline solution includes one or more of KOH solution, NaOH solution, and ammonia solution; In the sub-step S13, the second cleaning solution includes one or more of deionized water and ethanol.

10. The method for preparing the flaky alloy powder / manganese zinc ferrite / silicon dioxide absorbing powder according to claim 8, characterized in that: In the sub-step S13, the ultrasonic dispersion treatment time is 30 to 50 minutes, the rotation speed of the stirring process is 400 to 1000 rpm, the stirring time is 3 to 6 hours, the drying process is dried at a temperature of 40 to 80 degrees Celsius for 8 to 15 hours; the temperature of the water bath is 40 to 80 degrees Celsius.

11. A flake alloy powder / manganese zinc ferrite / carbon absorbing powder prepared according to the method for preparing flake alloy powder / manganese zinc ferrite / carbon absorbing powder according to any one of claims 1 to 10.

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