Magnetic magnesium bulk, magnetic magnesium-based composite material and preparation method thereof

Abstract

The application relates to a magnetic magnesium block, a magnetic magnesium-based composite material and a preparation method thereof, and relates to the technical field of the magnetic magnesium-based composite material. The main technical scheme is as follows: the preparation method of the magnetic magnesium block comprises the following steps: mixing a base powder, a dispersing agent and a volatile solvent, performing first dispersion treatment, and obtaining a first dispersion treatment mixture; wherein the base powder is magnesium powder or magnesium alloy powder; mixing magnetic particle powder, a dispersing agent and a volatile solvent, performing second dispersion treatment, and obtaining a second dispersion treatment mixture; sequentially mixing the first dispersion treatment mixture and the second dispersion treatment mixture, performing ball milling treatment and drying treatment, and obtaining a dispersion-treated magnetic magnesium powder; and performing cold isostatic pressing treatment on the dispersion-treated magnetic magnesium powder, and obtaining the magnetic magnesium block. The application is mainly used for improving the uniformity of the distribution of magnetic reinforcing particles in the magnetic magnesium-based composite material.

Description

Technical Field

[0001] This invention relates to the field of magnetic magnesium-based composite materials, and in particular to a magnetic magnesium bulk, a magnetic magnesium-based composite material, and a method for preparing the same. Background Technology

[0002] Magnesium is a highly promising lightweight metal with low density, making it suitable for applications in aerospace, automotive manufacturing, and other fields where lightweighting is crucial. Magnesium also possesses excellent electromagnetic shielding properties and is recyclable. While there are trade-offs between magnesium's electromagnetic shielding and mechanical properties, magnesium-based composites offer new avenues for addressing these challenges. Magnesium is widely distributed in nature with relatively abundant reserves, providing a foundation for its widespread application. Its lightweight nature allows for products that improve energy efficiency while reducing weight, playing an increasingly important role in modern industry.

[0003] Magnetic magnesium-based composites are a novel type of material with unique properties. Magnesium alloys themselves possess advantages such as low density and high specific strength, while magnetic magnesium-based composites retain these properties while introducing magnetic functionality. From a magnetic perspective, the magnetic properties of magnetic magnesium-based composites offer new possibilities for their application in electronics, electrical engineering, and other fields. For example, they have potential applications in electromagnetic shielding, electromagnetic induction, and magnetic storage. Furthermore, their magnetic properties can be controlled through specific preparation processes and alloy compositions to meet the needs of different application scenarios. However, the development of magnetic magnesium-based composites also faces some challenges. Precisely controlling the introduction of magnetism and ensuring the stability of the material's performance are key issues during the preparation process.

[0004] The main technologies related to magnesium-based composite materials with magnetic particles as the reinforcing phase are as follows:

[0005] (1) The first technology discloses a method for preparing a bio-magnesium-based composite material reinforced with nano-silica / ferric oxide magnetic imaging particles. The main technical solution described therein is: silica and ferric oxide particles are mixed by high-temperature ball milling, then hot-pressed into a composite, and then the composite is added to magnesium slurry and heated to obtain a liquid magnesium-based composite material melt. Finally, magnesium blocks are added to the above-mentioned liquid magnesium-based composite material melt under the premise of ultrasonic and mechanical stirring, and finally hot-pressed to obtain a bio-magnesium-based composite material reinforced with silica / ferric oxide magnetic imaging particles.

[0006] (2) The second technology discloses a method for preparing iron microparticle-reinforced magnesium matrix composites. The main technical solution described is as follows: under a protective atmosphere, a certain proportion of iron particles and magnesium shavings are placed in a graphite crucible and melted at high temperature, and stirred with a low-carbon steel impeller to ensure uniform dispersion. Then, the mixture is discharged through the orifice at the bottom of the crucible into a steel mold for cooling and molding to obtain the iron microparticle-reinforced magnesium matrix composite.

[0007] The above describes two techniques for preparing magnetic magnesium-based composite materials, primarily ball milling and high-temperature melting. Specifically, the raw material powders are ball-milled to obtain a uniformly mixed powder, which is then dispersed through mechanical stirring during a high-temperature melting stage. Finally, the magnetic magnesium-based composite material is prepared by cold pressing or hot pressing.

[0008] In summary, the existing technologies for preparing magnetic magnesium-based composite materials have at least the following technical problems:

[0009] The powder is mixed using simple ball milling. However, when the reinforcing particles are nanoscale, the mixing of the powder becomes uneven, leading to agglomeration. Dispersion strengthening is the main strengthening mechanism of magnetic magnesium-based composites. Uneven mixing of the powder can lead to a significant decrease in plasticity, reduce the overall magnetization of the material, and may also alter the magnetocrystalline anisotropy of the material, causing a deflection of the most easily magnetized direction. Summary of the Invention

[0010] In view of this, the present invention provides a magnetic magnesium bulk, a magnetic magnesium-based composite material and a method for preparing the same, the main purpose of which is to improve the uniformity of the distribution of magnetic reinforcing particles in the magnetic magnesium-based composite material.

[0011] To achieve the above objectives, the present invention mainly provides the following technical solutions:

[0012] On one hand, embodiments of the present invention provide a method for preparing a magnetic magnesium block, wherein the method for preparing the magnetic magnesium block includes the following steps:

[0013] First dispersion treatment step: After mixing the matrix powder, dispersant, and volatile solvent, a first dispersion treatment is performed to obtain a mixture after the first dispersion treatment; wherein, the matrix powder is magnesium powder or magnesium alloy powder;

[0014] Second dispersion treatment step: After mixing the magnetic particle powder, dispersant, and volatile solvent, a second dispersion treatment is carried out to obtain a mixture after the second dispersion treatment;

[0015] Steps for preparing magnetic magnesium powder: The mixture after the first dispersion treatment and the mixture after the second dispersion treatment are mixed, ball-milled and dried sequentially to obtain the dispersed magnetic magnesium powder.

[0016] Cold isostatic pressing process: The dispersed magnetic magnesium powder is subjected to cold isostatic pressing to obtain a magnetic magnesium block.

[0017] Preferably, the first dispersion treatment includes sequential ultrasonic treatment and ball milling treatment; preferably, in the first dispersion treatment: the ultrasonic treatment time is not less than 1 hour, preferably 1-4 hours; preferably, in the first dispersion treatment: ultrasonic treatment is performed in an ultrasonic cell disruptor; preferably, in the first dispersion treatment: the ball milling speed is not less than 100 rpm / min, preferably 100-180 rpm / min; the ball milling time is not less than 18 hours, preferably 18-40 hours.

[0018] Preferably, the second dispersion treatment includes sequential ultrasonic treatment and ball milling treatment; preferably, in the second dispersion treatment: the ultrasonic treatment time is not less than 1 hour, preferably 1-4 hours; preferably, in the second dispersion treatment: ultrasonic treatment is performed in an ultrasonic cell disruptor; preferably, in the second dispersion treatment: the ball milling speed is not less than 100 rpm / min, preferably 100-180 rpm / min; the ball milling time is not less than 18 hours, preferably 18-40 hours.

[0019] Preferably, the magnetic particle powder is selected from iron, carbonyl iron, ferrite, barium ferrite (BaFe). 12 O 19 One or more of nickel.

[0020] Preferably, the dispersant is one or more of sorbitan stearate Span-60, polyvinylpyrrolidone PVP, tert-octylphenoxy polyethylene ethoxyethanol Triton X-100, and polyoxyethylene polyoxypropylene ether block copolymer Pluronic.

[0021] Preferably, the volatile solvent is selected from anhydrous ethanol, acetone and methanol.

[0022] Preferably, the average particle size of the matrix powder is 30 to 150 micrometers.

[0023] Preferably, the magnetic particle powder is nano-sized or micro-sized; preferably, the average particle size of the nano-sized magnetic particle powder is 15-100 nanometers.

[0024] Preferably, in the first dispersion treatment step: the mass ratio of matrix powder to volatile solvent is 1:2 to 1:25; the dispersant is 1 to 5 wt% of the mass of the volatile solvent.

[0025] Preferably, in the second dispersion treatment step: the mass ratio of magnetic particle powder to volatile solvent is 1:2 to 1:25; the dispersant is 1 to 5 wt% of the mass of the volatile solvent.

[0026] Preferably, in the step of preparing magnetic magnesium powder: the mixture of the second dispersion treatment is gradually added to the mixture of the first dispersion treatment for mixing; wherein, during the mixing process, continuous stirring is required; and / or the ball milling speed is not less than 100 rpm / min; the ball milling time is not less than 18 h; and / or the drying treatment is used to evaporate the volatile solvent in the mixture; and / or in the magnetic magnesium powder after dispersion treatment: the mass ratio of magnetic particle powder to matrix powder is 1:1.5 to 1:10.

[0027] Preferably, in the cold isostatic pressing step: the pressure of the cold isostatic pressing is not less than 180 MPa, preferably 180-300 MPa. The holding time is not less than 4 minutes, preferably 4-20 minutes. And / or the dispersed magnetic magnesium powder is loaded into a balloon and subjected to cold isostatic pressing under a set pressure to obtain a compacted magnetic magnesium block.

[0028] On the other hand, embodiments of the present invention provide a magnetic magnesium block, wherein the magnetic magnesium block is prepared by any of the above-described methods for preparing magnetic magnesium blocks; preferably, the magnetic magnesium block is spherical; preferably, the mass of each magnetic magnesium block is greater than 5g, more preferably 5g to 60g.

[0029] In another aspect, embodiments of the present invention provide a method for preparing a magnetic magnesium-based composite material, wherein the method for preparing the magnetic magnesium-based composite material includes the following steps:

[0030] Melting and casting steps: Under a protective atmosphere, the magnetic magnesium block is placed into molten magnesium liquid or magnesium alloy liquid for melting; after melting, casting is performed to obtain a magnetic magnesium-based composite material ingot; wherein, the magnetic magnesium block is the magnetic magnesium block mentioned above.

[0031] Preferably, in the melting and casting steps: the melting temperature is not lower than 770°C and not higher than 820°C; the casting temperature is not lower than 730°C and not higher than 755°C.

[0032] Preferably, during the smelting process: high-shear stirring is required, and the stirring speed is not less than 2000 rpm / min and not more than 4000 rpm / min, and the smelting time is not less than 10 min and not more than 30 min;

[0033] Preferably, after the melting and casting step, the method further includes:

[0034] Hot extrusion step: The magnetic magnesium-based composite material ingot is subjected to hot extrusion treatment to obtain magnetic magnesium-based composite material rods;

[0035] More preferably, in the hot extrusion step: the hot extrusion temperature is 250-400℃, and the extrusion ratio is 7:1 to 30:1.

[0036] In another aspect, embodiments of the present invention provide a magnetic magnesium-based composite material, wherein the magnetic magnesium-based composite material comprises a matrix material and a reinforcing phase; wherein the reinforcing phase is magnetic particles; the matrix material is magnesium or a magnesium alloy; wherein, in the magnetic magnesium-based composite material, the mass fraction of the reinforcing phase is 1-10 wt%, preferably, the reinforcing phase is uniformly distributed in the matrix of the magnetic magnesium-based composite material; preferably, the reinforcing phase is nanoscale or microscale; preferably, the matrix is ​​microscale; preferably, the magnetic magnesium-based composite material is prepared by the above-described method for preparing magnetic magnesium-based composite materials.

[0037] Compared with the prior art, the magnetic magnesium bulk material, magnetic magnesium-based composite material and preparation method of the present invention have at least the following beneficial effects:

[0038] On one hand, embodiments of the present invention provide a magnetic magnesium block and its preparation method, the main steps of which are as follows: A matrix powder, a dispersant, and a volatile solvent are mixed and subjected to a first dispersion treatment to obtain a mixture after the first dispersion treatment; wherein the matrix powder is magnesium powder or magnesium alloy powder; Magnetic particle powder, a dispersant, and a volatile solvent are mixed and subjected to a second dispersion treatment to obtain a mixture after the second dispersion treatment; The mixture after the first dispersion treatment and the mixture after the second dispersion treatment are sequentially mixed, ball-milled, and dried to obtain dispersed magnetic magnesium powder; The dispersed magnetic magnesium powder is subjected to cold isostatic pressing to obtain a magnetic magnesium block. It should be noted that: In the first dispersion treatment step, the dispersant coats the surface of the matrix powder particles to prevent agglomeration of the matrix powder; In the second dispersion treatment step, the dispersant coats the surface of the magnetic particles to prevent agglomeration of the matrix powder. Based on the first and second dispersion treatment steps, ultrasonication and ball milling are further performed to improve the uniformity of the mixture of the matrix powder and the magnetic powder, and because the dispersant is present on the particle surface, agglomeration can be effectively avoided. Then, a drying process is performed to evaporate the volatile solvent, resulting in uniformly dispersed magnetic magnesium powder (i.e., ensuring that the magnetic particles are uniformly dispersed in the magnesium matrix). If the magnetic magnesium powder is used directly as a raw material to prepare magnetic magnesium-based composite materials, the magnetic magnesium powder is added to molten magnesium or magnesium alloy liquid; however, the powder is prone to flashover. Therefore, to avoid flashover (ensuring effective addition of the magnetic material), the inventors subject the magnetic magnesium powder to cold isostatic pressing to prepare magnetic magnesium blocks, which are then used as raw materials for preparing magnetic magnesium-based composite materials. Thus, the magnetic particles in the magnetic magnesium blocks prepared in this embodiment are uniformly dispersed, and using them as raw materials to prepare magnetic magnesium-based composite materials can improve the uniformity of the magnetic reinforcing particle distribution in the magnetic magnesium-based composite materials.

[0039] On the other hand, embodiments of the present invention provide a magnetic magnesium-based composite material and its preparation method, comprising the following steps: under a protective atmosphere, a magnetic magnesium block is placed into molten magnesium liquid or magnesium alloy liquid for melting treatment, during which high-shear stirring is performed; after melting, casting treatment is performed to obtain an ingot; the ingot is hot-extruded to obtain the magnetic magnesium-based composite material. Here, the magnetic magnesium block is the aforementioned magnetic magnesium block. Because the magnetic material in the magnetic magnesium block is uniformly distributed, a dispersion strengthening mechanism can be ensured. At the same time, the high-shear stirring after adding the block further ensures dispersion, thereby ensuring the mechanical properties and magnetic characteristics of the magnetic magnesium-based composite material.

[0040] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0041] Figure 1 This is a TEM image of the magnetic particle distribution of a magnetic magnesium-based composite material prepared in Example 1 of the present invention;

[0042] Figure 2 This is a tensile stress-strain curve of a magnetic magnesium-based composite material prepared in Example 1 of the present invention;

[0043] Figure 3 This is a room temperature hysteresis loop diagram of a magnetic magnesium-based composite material prepared in Example 1 of the present invention;

[0044] Figure 4 This is a TEM image of the magnetic particle distribution of a magnetic magnesium-based composite material prepared in Example 2 of the present invention;

[0045] Figure 5 This is a tensile stress-strain curve of the magnetic magnesium-based composite material prepared in Example 2 of the present invention;

[0046] Figure 6 This is a room temperature hysteresis loop diagram of the magnetic magnesium-based composite material prepared in Example 1 of the present invention. Detailed Implementation

[0047] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments, structures, features, and effects according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0048] On one hand, embodiments of the present invention provide a magnetic magnesium bulk, a magnetic magnesium-based composite material, and a method for preparing the same, to achieve the preparation of a magnetic magnesium-based composite material with uniformly dispersed magnetic particles. The main solutions of the present invention are as follows:

[0049] On one hand, embodiments of the present invention provide a method for preparing a magnetic magnesium block, wherein the method for preparing the magnetic magnesium block includes the following steps:

[0050] First dispersion treatment step: After mixing the matrix powder, dispersant and volatile solvent, a first dispersion treatment is performed to obtain a mixture after the first dispersion treatment; wherein, the matrix powder is magnesium powder or magnesium alloy powder.

[0051] The first dispersion treatment includes sequential ultrasonic treatment and ball milling treatment; preferably, the ultrasonic treatment time is not less than 1 hour; preferably, the ultrasonic treatment is performed in an ultrasonic cell disruptor; the ball milling speed is not less than 100 rpm / min; and the ball milling time is not less than 18 hours.

[0052] Preferably, the dispersant is selected from one of the following: Span-60 sorbitan stearate, polyvinylpyrrolidone (PVP), tert-octylphenoxy polyethylene ethoxyethanol (Triton X-100), and polyoxyethylene polyoxypropylene ether block copolymer (Pluronic).

[0053] Preferably, the volatile solvent is selected from one of the following: anhydrous ethanol, acetone, methanol, etc.

[0054] Preferably, the magnesium alloy used is AZ31B magnesium alloy, etc.

[0055] The second dispersion treatment step: After mixing the magnetic particle powder, dispersant, and volatile solvent, a second dispersion treatment is carried out to obtain a mixture after the second dispersion treatment.

[0056] Preferably, the second dispersion treatment includes sequential ultrasonic treatment and ball milling treatment; the ultrasonic treatment time is not less than 1 hour; preferably, the ultrasonic treatment is performed in an ultrasonic cell disruptor; preferably, the ball milling speed is not less than 100 rpm / min, and the ball milling time is not less than 18 hours.

[0057] Preferably, the magnetic particle powder is selected from iron, carbonyl iron, ferrite, barium ferrite (BaFe). 12 O 19 Nickel, etc.

[0058] Steps for preparing magnetic magnesium powder: The mixture after the first dispersion treatment and the mixture after the second dispersion treatment are mixed, ball-milled and dried in sequence to obtain the dispersed magnetic magnesium powder.

[0059] The mixing method mainly involves slowly pouring the mixture from the second dispersion treatment into the mixture from the first dispersion treatment, and stirring is required during the mixing process.

[0060] The ball milling speed shall be no less than 100 rpm / min; the ball milling time shall be no less than 18 h.

[0061] The drying process is used to evaporate the volatile solvents in the mixture.

[0062] Cold isostatic pressing process: The dispersed magnetic magnesium powder is subjected to cold isostatic pressing to obtain a magnetic magnesium block.

[0063] Among them, the pressure of cold isostatic pressing shall not be less than 180 MPa, and the holding time shall not be less than 4 min; and / or

[0064] In this process, the dispersed magnetic magnesium powder is loaded into balloons (the balloons have more than 5 layers, preferably more than 8 layers, and more preferably 10 layers to avoid water leakage), and then subjected to cold isostatic pressing under a set pressure to obtain compacted magnetic magnesium blocks. A large quantity of magnetic magnesium powder can be cold isostatically pressed to prepare a large number of compacted magnetic magnesium blocks, which can then be used as raw materials for preparing magnetic magnesium-based composite materials.

[0065] It should be noted that:

[0066] (1) In the first dispersion step, the dispersant coats the surface of the matrix powder particles to prevent agglomeration of the matrix powder; in the second dispersion step, the dispersant coats the surface of the magnetic particles to prevent agglomeration of the matrix powder. Based on the first and second dispersion steps, ultrasonication and ball milling are further performed to improve the uniformity of the mixing of the matrix powder and the magnetic powder, and because the dispersant is present on the particle surface, agglomeration can be effectively prevented. Then, a drying process is performed to evaporate the volatile solvent, resulting in uniformly dispersed magnetic magnesium powder.

[0067] (2) If magnetic magnesium powder is used directly as a raw material to prepare magnetic magnesium-based composite materials, the magnetic magnesium powder is added to molten magnesium liquid or magnesium alloy liquid. However, the powder is prone to flashover. To avoid flashover, the inventors cold isostatically press the magnetic magnesium powder to prepare magnetic magnesium blocks, which are then used as raw materials for preparing magnetic magnesium-based composite materials. It should also be noted that the dispersant in the magnetic magnesium blocks will evaporate when added to the molten magnesium liquid or magnesium alloy liquid later.

[0068] On the other hand, embodiments of the present invention provide a method for preparing a magnetic magnesium-based composite material, wherein the method for preparing the magnetic magnesium-based composite material includes the following steps:

[0069] Melting and casting steps: Under a protective atmosphere, the magnetic magnesium block is placed into molten magnesium liquid or magnesium alloy liquid for melting; after melting, casting is performed to obtain a magnetic magnesium-based composite material ingot; wherein, the magnetic magnesium block is the magnetic magnesium block mentioned above.

[0070] Preferably, the smelting temperature is not lower than 770℃ and not higher than 820℃, and the casting temperature is not lower than 730℃ and not higher than 755℃; more preferably, during the smelting process, the stirring speed is not lower than 2000 rpm / min, and the stirring time is not lower than 10 min. Preferably, the stirring is a high-speed stirring with high shear of stainless steel to further ensure dispersibility.

[0071] The number of magnetic magnesium blocks added to the molten magnesium liquid is determined based on the mass fraction of magnetic particles in the required magnetic magnesium-based composite material, the mass of the magnesium liquid or magnesium alloy liquid, and the mass of each component in each magnetic magnesium block.

[0072] Hot extrusion step: The ingot is subjected to hot extrusion treatment to obtain magnetic magnesium-based composite material rods. Preferably, the hot extrusion temperature is 250-400℃, and the extrusion ratio is 7:1 to 30:1.

[0073] The present invention will be further illustrated below through specific experimental examples:

[0074] The following examples all use the same melting furnace and extruder to melt, cast and hot extrude the materials.

[0075] Example 1

[0076] This embodiment prepares a magnetic magnesium-based composite material. The raw materials used are: iron powder with an average particle size of 20 nm and a purity of 99.9%, magnesium powder with an average particle size of 75 μm and a purity of 99%, magnesium blocks with a purity of 99.995%, anhydrous ethanol (volatile solvent), and sorbitan stearate (Span-60, dispersant). The specific preparation steps include:

[0077] First and second dispersion treatment steps: First, weigh 11.83g of dispersant Span-60 (at a 1.5wt% ethanol ratio) and pour it into 1L of anhydrous ethanol. After preparing the dispersant solution by gently heating and stirring with a magnetic stirrer, pour the solution into two equal volumes. Weigh 20g of iron powder and 60g of magnesium powder. Add the magnesium powder to the first container containing the dispersant solution and the iron powder to the second container. Sonicate and ball mill the mixture in the first container to obtain the mixture after the first dispersion treatment; sonicate and ball mill the mixture in the second container to obtain the mixture after the second dispersion treatment. The ultrasonic cell disruptor was used for sonication at 1620W for 2 hours; the ball milling speed was 120rpm / min for 24 hours.

[0078] The steps for preparing magnetic magnesium powder are as follows: A solution containing iron powder (the mixture after the second dispersion treatment) is slowly poured into a solution containing magnesium powder (the mixture after the first dispersion treatment), and then ball-milled at 120 rpm / min for 24 hours. A uniformly mixed iron-magnesium solution is obtained. Finally, after the ethanol evaporates, magnetic magnesium powder is obtained.

[0079] Cold isostatic pressing process: The dried magnetic magnesium powder is loaded into a ten-layer balloon and pressed at 240 MPa for 5 minutes to obtain a compacted magnetic magnesium block (the mass of the magnetic magnesium block is 10-40 g).

[0080] Melting and casting: Under a protective atmosphere, 1152g of magnesium block is first placed in a graphite crucible and heated to 750℃ to form molten magnesium liquid. 50g of magnetic magnesium block is weighed and placed into the molten magnesium liquid. Then, stainless steel high-shear stirring is used to mix it evenly at a speed of 3030rpm / min for 15min. The heating is turned off and the temperature is reduced to 735℃ before casting to obtain an ingot.

[0081] Hot extrusion: The ingot is extruded at a temperature of 350℃; the extrusion ratio is 25:1, and a bar with a diameter of 8.7mm is extruded, finally obtaining a magnetic magnesium-based composite material (iron-magnesium composite bar) with an iron mass fraction of 1%.

[0082] Figure 1 This is a TEM image of the magnetic particle distribution in the magnetic magnesium-based composite material of Example 1. It can be seen that the iron particles are uniformly distributed in the magnesium matrix.

[0083] Figure 2 This is a tensile stress-strain curve of a magnetic magnesium-based composite material prepared in Example 1, with a tensile strength of 184 MPa.

[0084] Figure 3 The image shows the room temperature hysteresis loop of a magnetic magnesium-based composite material prepared in Example 1. It can be seen that the material has a significant response to the applied magnetic field, with a saturation magnetization of 1.5 emu / g.

[0085] Example 2

[0086] This embodiment prepares a magnetic magnesium-based composite material, wherein the raw material used is barium ferrite (BaFe) with an average particle size of 30 nm and a purity of 99.9%. 12 O 19 The preparation process includes AZ31B powder with an average particle size of 75 μm, AZ31B blocks, acetone, and polyvinylpyrrolidone (PVP, dispersant). The specific preparation steps are as follows:

[0087] First dispersion treatment step, second dispersion treatment step: First, weigh 11.83g of dispersant PVP (according to a 1.5wt.% acetone ratio), pour it into 1L of acetone, gently heat and stir with a magnetic stirrer to prepare the dispersion solution, then pour it into two equal volumes into two containers. Weigh 70g of barium ferrite (BaFe). 12 O 19 AZ31B powder and 130g AZ31B powder were added to a first container containing a dispersant solution, and barium ferrite (BaFe) was added to a second container containing a dispersant solution. 12 O 19The mixture in the first container was subjected to ultrasonication and ball milling to obtain a first dispersion treatment mixture; the mixture in the second container was subjected to ultrasonication and ball milling to obtain a second dispersion treatment mixture. Ultrasonication was performed using an ultrasonic cell disruptor at a power of 1620W for 2 hours; ball milling was performed at a speed of 120 rpm / min for 24 hours.

[0088] Steps for preparing magnetic magnesium powder: Barium-containing ferrite (BaFe) is used to prepare the magnetic magnesium powder. 12 O 19 The powder solution (the mixture after the second dispersion treatment) was slowly poured into the AZ31B powder solution (the mixture after the first dispersion treatment), and then ball-milled at 120 rpm / min for 24 hours. A homogeneous AZ31B-BaFe mixture was obtained. 12 O 19 The solution was then allowed to evaporate with acetone to obtain magnetic magnesium powder.

[0089] Cold isostatic pressing: The dried magnetic magnesium powder is loaded into a ten-layer balloon and pressed at 240 MPa for 5 minutes to obtain a compacted magnetic magnesium block (the mass of the magnetic magnesium block is 10-40 g).

[0090] Melting and Casting: Under a protective atmosphere, 1080g of AZ31B block is first placed in a graphite crucible and heated to 750℃ to form molten AZ31. 125g of magnetic magnesium block is weighed and added to the molten AZ31. The mixture is then stirred using a stainless steel high-shear mixer at 3030 rpm for 15 minutes. Heating is then stopped, and the temperature is allowed to drop to 735℃ before casting to obtain the ingot.

[0091] Hot extrusion: The ingot is extruded at 350℃ with an extrusion ratio of 25:1, resulting in an extrusion diameter of 8.7mm, ultimately yielding barium ferrite (BaFe). 12 O 19 AZ31B-BaFe with a mass fraction of 3.6% 12 O 19 Composite material rods (magnetic magnesium-based composite materials).

[0092] Figure 4 This is a TEM image of the magnetic particle distribution of a magnetic magnesium-based composite material prepared in Example 2. It can be seen that the barium ferrite particles are relatively uniformly distributed in the matrix.

[0093] Figure 5 This is a tensile stress-strain curve of the magnetic magnesium-based composite material prepared in Example 2, with a tensile strength of 217 MPa.

[0094] Figure 6The image shows the room temperature hysteresis loop of the magnetic magnesium-based composite material prepared in Example 2. The material has a significant response to the applied magnetic field, and its saturation magnetization is 3.3 emu / g.

[0095] Comparative Example 1

[0096] Comparative Example 1 involves preparing magnetic blocks by directly cold isostatic pressing magnetic particles, then adding them to molten magnesium liquid, casting them after high-shear stirring, and finally extruding them into rod-shaped magnetic magnesium-based composite materials.

[0097] Compared to the above embodiments, the main problem with Comparative Example 1 is that the magnetic particles already possess mutual forces, and then cold isostatic pressing causes them to completely agglomerate into a cold-pressed block. The bonding force between the particles is very strong, and even after high-temperature melting, a large number of particles will still agglomerate, severely affecting the mechanical properties and reducing the overall magnetization of the magnetic composite material. Secondly, when the cold-pressed block of pure magnetic particles is directly added to the molten magnesium, the oxidation and burning loss of the magnetic particles is quite severe, resulting in a large amount of slag before casting, making it impossible to guarantee the amount of magnetic particles added.

[0098] Comparative Example 2

[0099] In Comparative Example 2, magnesium powder and magnetic particles were directly added to a volatile solvent containing a dispersant. The mixture was then ball-milled and dried to obtain a mixed powder. The mixed powder was then cold-pressed into a cold-pressed block by cold isostatic pressing. This block was then added to molten magnesium liquid, stirred under high shear, and then cast. Finally, it was extruded into a rod-shaped magnetic magnesium-based composite material.

[0100] It should be noted that the first and second dispersion treatments in the above embodiments of the present invention, through ultrasonication and ball milling, can form a suspension with a certain proportion, while simultaneously achieving the effect of separation between powders. Comparative Example 2 omits the above steps. Since the powders of the same type are composed of the same substances and have the same physical and chemical properties, their interaction forces are more consistent, allowing for more effective bonding. This makes the interaction force between powders of the same type greater than the interaction force between powders of different types. Therefore, subsequent blending and ball milling alone are insufficient to achieve good dispersion of magnetic particles, resulting in severe agglomeration, which negatively impacts mechanical properties and magnetization.

[0101] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a magnetic magnesium bulk, characterized in that, The method for preparing the magnetic magnesium bulk material includes the following steps: First dispersion treatment step: The matrix powder, dispersant, and volatile solvent are mixed and then subjected to a first dispersion treatment to obtain a mixture after the first dispersion treatment; wherein, the matrix powder is magnesium powder or magnesium alloy powder; wherein, the first dispersion treatment includes ultrasonic treatment and ball milling treatment performed sequentially; in the first dispersion treatment step: the mass ratio of matrix powder to volatile solvent is 1:2 to 1:25; the dispersant is 1 to 5 wt% of the mass of the volatile solvent. The second dispersion treatment step involves mixing the magnetic particle powder, dispersant, and volatile solvent, followed by a second dispersion treatment to obtain a mixture after the second dispersion treatment. The second dispersion treatment includes sequential ultrasonic treatment and ball milling. In this second dispersion treatment step, the mass ratio of magnetic particle powder to volatile solvent is 1:2 to 1:25, and the dispersant is 1 to 5 wt% of the volatile solvent. Steps for preparing magnetic magnesium powder: The mixture after the first dispersion treatment and the mixture after the second dispersion treatment are mixed, ball-milled and dried sequentially to obtain the dispersed magnetic magnesium powder. Cold isostatic pressing process: The dispersed magnetic magnesium powder is subjected to cold isostatic pressing to obtain a magnetic magnesium block.

2. The method for preparing magnetic magnesium bulk material according to claim 1, characterized in that, In the first dispersion process: the ultrasonic treatment time is not less than 1 hour.

3. The method for preparing magnetic magnesium bulk material according to claim 2, characterized in that, In the first dispersion process: the ultrasonic treatment time is 1-4 hours.

4. The method for preparing magnetic magnesium bulk material according to claim 1, characterized in that, In the first dispersion process: ultrasonic treatment is performed in an ultrasonic cell disruptor.

5. The method for preparing magnetic magnesium bulk material according to claim 1, characterized in that, In the first dispersion process: the rotation speed of the ball milling process is not less than 100 rpm / min; the ball milling time is not less than 18 h.

6. The method for preparing magnetic magnesium bulk material according to claim 5, characterized in that, In the first dispersion process: the ball milling speed is 100-180 rpm / min.

7. The method for preparing the magnetic magnesium bulk body according to claim 5, characterized in that, The ball milling process takes 18-40 hours.

8. The method for preparing magnetic magnesium bulk material according to claim 1, characterized in that, In the second dispersion process: the ultrasonic treatment time is not less than 1 hour.

9. The method for preparing a magnetic magnesium bulk body according to claim 8, characterized in that, In the second dispersion treatment: the ultrasonic treatment time is 1-4 hours.

10. The method for preparing the magnetic magnesium bulk body according to claim 1, characterized in that, In the second dispersion process: ultrasonic treatment is performed in an ultrasonic cell disruptor.

11. The method for preparing magnetic magnesium bulk material according to claim 1, characterized in that, In the second dispersion process: the ball milling speed is not less than 100 rpm / min; the ball milling time is not less than 18 h.

12. The method for preparing a magnetic magnesium bulk body according to claim 11, characterized in that, In the second dispersion process: the ball milling speed is 100-180 rpm / min.

13. The method for preparing the magnetic magnesium bulk body according to claim 11, characterized in that, In the second dispersion process: the ball milling process takes 18-40 hours.

14. The method for preparing a magnetic magnesium bulk body according to claim 1, characterized in that, The magnetic particle powder is selected from iron, carbonyl iron, ferrite, barium ferrite (BaFe). 12 O 19 One or more of nickel; and / or The dispersant is selected from one or more of the following: Sorbitan stearate Span-60, polyvinylpyrrolidone PVP, tert-octylphenoxypolyvinylethoxyethanol Triton X-100, and polyoxyethylene polyoxypropylene ether block copolymer Pluronic; and / or The volatile solvent is selected from anhydrous ethanol, acetone, and methanol; and / or The matrix powder has an average particle size of 30-150 micrometers; and / or The magnetic particle powder is nano-sized or micro-sized; wherein, the average particle size of the nano-sized magnetic particle powder is 15~100 nanometers.

15. The method for preparing a magnetic magnesium bulk body according to claim 1, characterized in that, In the step of preparing magnetic magnesium powder: The mixture from the second dispersion treatment is gradually added to the mixture from the first dispersion treatment for mixing; wherein, during the mixing process, continuous stirring is required; and / or The ball milling speed is not less than 100 rpm / min; the ball milling time is not less than 18 h; and / or The drying process is used to evaporate the volatile solvents in the mixture; and / or In the dispersed magnetic magnesium powder, the mass ratio of magnetic particle powder to matrix powder is 1:1.5 to 1:

10.

16. The method for preparing a magnetic magnesium bulk body according to claim 1, characterized in that, In the cold isostatic pressing step: The pressure of the cold isostatic pressing shall not be less than 180 MPa, and the holding time shall not be less than 4 minutes.

17. The method for preparing a magnetic magnesium bulk body according to claim 16, characterized in that, The pressure of the cold isostatic pressing is 180-300 MPa, and the holding time is 4-20 min.

18. The method for preparing magnetic magnesium bulk material according to claim 1, characterized in that, In the cold isostatic pressing step: the dispersed magnetic magnesium powder is loaded into a balloon and subjected to cold isostatic pressing under a set pressure to obtain a compacted magnetic magnesium block.

19. A magnetic magnesium bulk body, characterized in that, The magnetic magnesium block is prepared by the method for preparing magnetic magnesium blocks according to any one of claims 1-18.

20. The magnetic magnesium bulk body according to claim 19, characterized in that, The magnetic magnesium block is spherical.

21. The magnetic magnesium bulk body according to claim 19, characterized in that, Each of the magnetic magnesium blocks has a mass greater than 5g.

22. The magnetic magnesium bulk body according to claim 21, characterized in that, The mass of each of the magnetic magnesium blocks is 5g to 60g.

23. A method for preparing a magnetic magnesium-based composite material, characterized in that, The preparation method of the magnetic magnesium-based composite material includes the following steps: Melting and casting steps: Under a protective atmosphere, the magnetic magnesium block is placed into molten magnesium liquid or magnesium alloy liquid for melting treatment; after melting, casting treatment is performed to obtain a magnetic magnesium-based composite material ingot; wherein, the magnetic magnesium block is the magnetic magnesium block according to any one of claims 19-22; wherein, during the melting treatment: high shear stirring is required, and the stirring speed is not less than 2000 rpm / min and not more than 4000 rpm / min, and the melting treatment time is not less than 10 min and not more than 30 min.

24. The method for preparing the magnetic magnesium-based composite material according to claim 23, characterized in that, In the melting and casting steps: the melting temperature is not lower than 770℃ and not higher than 820℃; the casting temperature is not lower than 730℃ and not higher than 755℃.

25. The method for preparing the magnetic magnesium-based composite material according to claim 23, characterized in that, Following the melting and casting step, the process further includes: Hot extrusion step: The magnetic magnesium-based composite material ingot is subjected to hot extrusion treatment to obtain magnetic magnesium-based composite material rods.

26. The method for preparing the magnetic magnesium-based composite material according to claim 25, characterized in that, In the hot extrusion step: the hot extrusion temperature is 250-400℃, and the extrusion ratio is 7:1~30:

1.

27. A magnetic magnesium-based composite material, characterized in that, The magnetic magnesium-based composite material comprises a matrix material and a reinforcing phase; wherein the reinforcing phase is magnetic particles; the matrix material is magnesium or a magnesium alloy; wherein the mass fraction of the reinforcing phase in the magnetic magnesium-based composite material is 1-10 wt%; wherein the magnetic magnesium-based composite material is prepared by the preparation method of the magnetic magnesium-based composite material according to any one of claims 23-26.

28. The magnetic magnesium-based composite material according to claim 27, characterized in that, The reinforcing phase is uniformly distributed in the matrix of the magnetic magnesium-based composite material; wherein the reinforcing phase is nanoscale or microscale.

Images