An Insulation Method for High-Performance, Self-Lubricating Soft Magnetic Metal Powder

Abstract

This invention discloses a method for insulating high-performance, self-lubricating soft magnetic metal powder, comprising the following steps: activating the soft magnetic metal powder with a complexing agent, simultaneously modifying MXene with a silicon source, and then immersing the activated soft magnetic metal powder and modified MXene together in an insulating liquid for insulation treatment, ultimately obtaining insulating soft magnetic metal powder with excellent magnetic properties and self-lubricating properties. The insulating soft magnetic metal powder prepared according to this invention exhibits high DC bias performance and low core loss, demonstrating excellent comprehensive magnetic properties, while also possessing good self-lubricating properties and excellent bonding strength, significantly improving the formability and mechanical properties of the insulating powder.

Description

Technical Field

[0001] This invention relates to the field of materials preparation, and in particular to an insulating method for high-performance, self-lubricating soft magnetic metal powder. Background Technology

[0002] Soft magnetic powder cores are composite materials composed of tiny metallic magnetic particles, typically encased in an insulating layer to reduce eddy current losses. Due to their excellent magnetic properties and adaptability to various application environments, soft magnetic powder cores play a crucial role in modern power electronics technology. They are widely used in power electronic devices, such as core components in transformers, inductors, and other high-frequency applications. With the increasing demand for high-efficiency electronic products, the demand for high-performance soft magnetic powder cores is expected to continue to rise in the future.

[0003] Improving the insulation process of soft magnetic metal powder is a crucial way to directly enhance the overall performance of soft magnetic metal powder cores. Currently, improvements to the insulation process mainly focus on the selection of insulating materials. Organic insulating materials are primarily various resins. This type of insulation process is relatively simple, and the presence of resin has a positive effect on improving the strength of the powder core. However, its disadvantages include uneven coating, poor thermal stability of the resin, and inability to undergo high-temperature heat treatment, which limits the performance of the powder core. Inorganic insulating materials are mainly various inorganic salts and metal oxides. They typically have advantages such as good thermal stability and high resistivity, but also disadvantages such as easy agglomeration of the insulating material and poor coating strength.

[0004] Therefore, if a suitable material can be selected that combines the advantages of organic and inorganic insulating materials, while maintaining the high strength of the magnetic core and possessing excellent thermal stability and magnetic properties, the overall performance of the soft magnetic powder can be further improved and its application range expanded. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the present invention provides a high-performance, self-lubricating insulating method for soft magnetic metal powder. By activating the soft magnetic metal powder and introducing modified MXene material for insulation, a dense, self-lubricating insulating layer is formed on the surface of the soft magnetic metal powder. This not only improves the resistivity of the soft magnetic metal powder and reduces losses, but also makes full use of the structural characteristics of MXene material to improve the formability of the insulating powder. The prepared soft magnetic metal powder core has the advantages of high DC bias performance, low loss and simple forming.

[0006] The technical solution adopted in this invention is as follows:

[0007] An insulation method for high-performance, self-lubricating soft magnetic metal powder includes the following steps:

[0008] (1) The metal soft magnetic powder is placed in the first solvent containing the complexing agent and stirred to activate the surface of the magnetic powder. Then it is dried to obtain activated metal soft magnetic powder.

[0009] The complexing agent used is at least one of ethylenediaminetetraacetic acid, citric acid, tartaric acid, aminotrimethylphosphoric acid, polyacrylic acid, and mercapto compounds. The mass of the complexing agent is 0.1-1% of the mass of the soft magnetic metal powder, and the mass of the first solvent is 7-25% of the mass of the soft magnetic metal powder.

[0010] (2) The MXene material is placed in a reaction vessel and a silicon source and a second solvent are added for modification treatment. A certain amount of nano-sized silica particles are generated in the structural voids of the MXene material, which ensures the excellent mechanical and magnetic properties of the MXene material while improving its resistivity. After the reaction is completed, the material is dried to obtain the modified MXene material.

[0011] The silicon source mass is 0.01 to 0.5% of the MXene material mass, and the second solvent mass is 10 to 30% of the MXene material mass.

[0012] (3) Prepare insulating liquid using main insulating agent, auxiliary insulating agent and third solvent;

[0013] The main insulating agent used is at least one of nitric acid, phosphoric acid, chromic acid, oxalic acid, acetic acid, and malic acid; the auxiliary insulating agent used is at least one of alumina, silicon oxide, magnesium oxide, calcium oxide, and glass powder; the amount of the main insulating agent added is 8-35% of the mass of the third solvent; and the amount of the auxiliary insulating agent added is 0.4-3% of the mass of the third solvent.

[0014] (4) Place the activated metal soft magnetic powder obtained in step (1) into a reaction vessel, add the insulating liquid from step (3) at 0.1-1.2% of the mass of the activated metal soft magnetic powder, and add the modified MXene material from step (2) at 0.05-0.6% of the mass of the activated metal soft magnetic powder; after all the raw materials are fully mixed in the reaction vessel, react at 15-45°C for 1-6 hours; after the reaction is completed, dry the powder to obtain the final insulating metal soft magnetic powder.

[0015] Preferably, in step (1), the soft magnetic metal powder is any one of iron-silicon powder, iron-silicon-aluminum powder, iron-silicon-chromium powder, and iron-nickel powder.

[0016] Preferably, in step (1), the stirring is ultrasonic stirring, and the stirring time is 0.5 to 3 hours.

[0017] Preferably, the first solvent is selected from at least one of ethanol, acetone, ethyl acetate, propylene glycol, and butanol; the second and third solvents are each independently selected from at least one of ethanol, acetone, deionized water, ethyl acetate, propylene glycol, and butanol.

[0018] Preferably, in step (2), the MXene material is Ti. n+1 C n T x V n+1 C n T x Cr n+1 C n T x Mo n+1 C n T x Ti n+1 N n T x V n+1 N n T x Cr n+1 N n T x Mo n+1 N n T x At least one of them, wherein the particle size of the MXene material used is 10–120 nm.

[0019] Preferably, in step (2), the silicon source is at least one of methyl orthosilicate, ethyl orthosilicate, butyl orthosilicate, potassium silicate, and sodium silicate.

[0020] Preferably, in step (2), the temperature of the modification treatment is 65-100℃ and the time is 0.5-8h, and the pH value of the mixed solution is controlled between 7.0 and 8.5 by adding ammonia dropwise (the purpose is to control the reaction rate).

[0021] Compared with existing technologies, the beneficial effects of this invention are reflected in:

[0022] This invention selects MXene, a material with a special two-dimensional structure, as an auxiliary insulating material. The excellent lubricity and strength of MXene enhance the physical properties and formability of the soft magnetic metal powder. Simultaneously, by modifying the MXene material to grow silica particles within its pores, the magnetic properties of the soft magnetic metal powder are improved. Ultimately, a soft magnetic metal insulating powder exhibiting both organic and inorganic insulation advantages, along with excellent magnetic properties and self-lubricating properties, is obtained. The insulating soft magnetic metal powder prepared according to this invention possesses high DC bias performance and low core loss, demonstrating excellent overall magnetic properties. It also exhibits good self-lubricating properties and excellent bonding strength, significantly improving the formability and mechanical properties of the insulating powder. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0024] Example 1

[0025] This embodiment provides a method for insulating high-performance, self-lubricating soft magnetic metal powder, comprising the following steps:

[0026] (1) The iron-silicon powder was placed in ethanol containing a complexing agent and ultrasonically stirred for 3 hours to activate the surface of the magnetic powder. Then it was dried at 90°C to obtain activated iron-silicon powder. The complexing agent (made by mixing citric acid and tartaric acid in a mass ratio of 1:1) was 0.2% of the mass of the iron-silicon powder, and the ethanol was 23.5% of the mass of the iron-silicon powder.

[0027] (2) Ti with a particle size of 12 nm n+1 C n T x MXene material was placed in a reaction vessel, and a silicon source (tetraethyl orthosilicate) and a solvent (a mixture of acetone and propylene glycol in a 2:1 mass ratio) were added for modification. The modification temperature was 100℃, and the modification time was 1.5 h. During the modification, the pH of the mixed solution was continuously controlled to 7.2 by adding ammonia dropwise. After the reaction, the mixture was dried at 80℃ to obtain the modified MXene material. The silicon source was added at 0.01% of the MXene material's mass, and the solvent was added at 28% of the MXene material's mass.

[0028] (3) An insulating solution is prepared using acetic acid as the main insulating agent, calcium oxide as the auxiliary insulating agent, and ethyl acetate and ethanol (in a mass ratio of 1:3) as solvents. The amount of the main insulating agent added is 11% of the solvent mass, and the amount of the auxiliary insulating agent added is 0.45% of the solvent mass.

[0029] (4) Place the activated iron-silicon powder obtained in step (1) into a reaction vessel, add the insulating liquid from step (3) at 0.2% of the mass of the activated iron-silicon powder, and add the modified MXene material obtained in step (2) at 0.15% of the mass of the activated iron-silicon powder. After all raw materials are thoroughly mixed in the reaction vessel, react at 18°C ​​for 2 hours. After the reaction is completed, dry at 120°C to obtain the final insulating iron-silicon powder.

[0030] 0.4% (by weight) of silicone resin powder was added as a binder to the prepared insulating iron-silicon powder, and the mixture was molded into a 1.06-inch standard magnetic ring under a pressure of 1860 MPa. The density of the prepared magnetic ring was measured to be 6.95 g / cm³. 3 The core blank has a tensile strength of 223 N, a permeability of 42%, a permeability percentage of 88% under a 100 Oe DC bias, and a loss of 220 mW / cm² under a 100 kHz 50 mT bias. 3 .

[0031] Example 2

[0032] This embodiment provides a method for insulating high-performance, self-lubricating soft magnetic metal powder, comprising the following steps:

[0033] (1) Iron-nickel powder was placed in ethyl acetate containing a complexing agent and ultrasonically stirred for 2 hours to activate the surface of the magnetic powder. Then, it was dried at 85°C to obtain activated iron-silicon powder. The complexing agent (ethylenediaminetetraacetic acid) was 0.9% of the mass of the iron-nickel powder, and the ethyl acetate was 15% of the mass of the iron-nickel powder.

[0034] (2) V with a particle size of 75nm n+1 N n T x MXene material was placed in a reaction vessel, and a silicon source (composed of potassium silicate and sodium silicate mixed in a mass ratio of 2.5:1) and solvent ethanol were added for modification treatment. The modification temperature was 90℃, and the modification time was 6 hours. During the modification, the pH of the mixed solution was continuously controlled to 8.5 by adding ammonia dropwise. After the reaction, the mixture was dried at 90℃ to obtain the modified MXene material. The silicon source was added at 0.2% of the mass of the MXene material, and the solvent was added at 20% of the mass of the MXene material.

[0035] (3) An insulating solution is prepared using phosphoric acid and oxalic acid (in a mass ratio of 5:1) as the main insulating agent, glass powder as the auxiliary insulating agent, and deionized water as the solvent. The amount of the main insulating agent added is 12% of the solvent mass, and the amount of the auxiliary insulating agent added is 2% of the solvent mass.

[0036] (4) Place the activated iron-nickel powder obtained in step (1) into a reaction vessel, add the insulating liquid from step (3) at 0.6% of the mass of the activated iron-nickel powder, and add the modified MXene material obtained in step (2) at 0.35% of the mass of the activated iron-nickel powder. After all raw materials are thoroughly mixed in the reaction vessel, react at 25°C for 4 hours. After the reaction is completed, dry at 95°C to obtain the final insulating iron-nickel powder.

[0037] 0.4% (by weight) of silicone resin powder was added as a binder to the prepared insulating iron-silicon powder, and the mixture was molded into a 1.06-inch standard magnetic ring under a pressure of 1550 MPa. The density of the prepared magnetic ring was measured to be 7.41 g / cm³. 3 The core blank has a tensile strength of 84 N, a permeability of 65%, a permeability percentage of 86% under a 100 Oe DC bias, and a loss of 243 mW / cm under a 50 kHz 100 mT condition. 3 .

[0038] Example 3

[0039] This embodiment provides a method for insulating high-performance, self-lubricating soft magnetic metal powder, comprising the following steps:

[0040] (1) The iron-silicon-aluminum powder was placed in an organic solution containing a complexing agent and ultrasonically stirred for 0.5 h to activate the surface of the magnetic powder. Then it was dried at 95 °C to obtain activated iron-silicon-aluminum powder. Among them, the mass of the complexing agent (polyacrylic acid) was 0.5% of the mass of the iron-silicon-aluminum powder, and the mass of the organic solution (made by mixing propylene glycol and butanol in a mass ratio of 1:3) was 7.5% of the mass of the iron-silicon-aluminum powder.

[0041] (2) Ti with a particle size of 115 nm n+1 N n T x +Mo n+1 N n T x MXene material was placed in a reaction vessel, and a silicon source (methyl orthosilicate) and a solvent (deionized water) were added for modification. The modification temperature was 70℃, and the modification time was 8 hours. During the modification process, the pH of the mixed solution was continuously controlled to 8 by adding ammonia dropwise. After the reaction, the mixture was dried at 95℃ to obtain the modified MXene material. The silicon source was added at 0.45% of the MXene material's mass, and the solvent was added at 10% of the MXene material's mass.

[0042] (3) An insulating solution is prepared using chromic acid as the main insulating agent, silica and alumina (in a mass ratio of 4:1) as auxiliary insulating agents, and propylene glycol as the solvent. The amount of the main insulating agent added is 18.5% of the solvent mass, and the amount of the auxiliary insulating agent added is 0.55% of the solvent mass.

[0043] (4) Place the activated iron-silicon-aluminum powder obtained in step 1 into a reaction vessel, add the insulating liquid from step (3) at 1.0% of the mass of the activated iron-silicon-aluminum powder, and simultaneously add the modified MXene material from step (2) at 0.6% of the mass of the activated iron-silicon-aluminum powder. After all raw materials are thoroughly mixed in the reaction vessel, react at 44°C for 6 hours. After the reaction is completed, dry at 115°C to obtain the final insulating iron-silicon-aluminum powder.

[0044] 0.4% (by weight) of silicone resin powder was added as a binder to the prepared insulating iron-silicon powder, and the mixture was molded into a 1.06-inch standard magnetic ring under a pressure of 1860 MPa. The magnetic ring density was measured to be 6.12 g / cm³. 3 The core blank has a tensile strength of 135 N, a permeability of 78%, a permeability percentage of 48.3% under a 100 Oe DC bias, and a loss of 240 mW / cm² under a 50 kHz 100 mT bias. 3 .

[0045] Comparative Example 1

[0046] This comparative example underwent insulation treatment of iron-silicon powder using the same method as in Example 1, the only difference being that the amount of modified MXene material added in step (4) was 0. The density of the prepared magnetic ring was tested to be 6.78 g / cm³. 3 The core blank has a tensile strength of 112 N, a permeability of 46%, a permeability percentage of 83% under a 100 Oe DC bias, and a loss of 293 mW / cm² under a 100 kHz 50 mT bias. 3 .

[0047] The magnetic core prepared in the comparative example has a density decrease of 0.17 g / cm³ while maintaining a very similar permeability to the magnetic core prepared in Example 1. 3 The tensile strength of the green billet decreased by 111 N, the percentage of permeability decreased by 5% under a 100 Oe DC bias, and the loss increased by 73 mW / cm under a 100 kHz 50 mT condition. 3 .

[0048] In summary, the method of the present invention has the following advantages:

[0049] Excellent formability: This invention uses MXene material to treat soft magnetic metal powder. The excellent lubricity of MXene material can effectively improve the formability of the magnetic powder. The lubricity of the magnetic powder after MXene treatment is improved, and it can be formed normally without the need for additional lubricant. There are no forming defects such as mold pulling or delamination. At the same time, the addition of MXene material is conducive to the rearrangement of powder during the pressing process, thereby improving the density and green strength of the prepared magnetic core.

[0050] Excellent product performance: The modified MXene material can effectively improve the resistivity of magnetic powder and reduce eddy current loss. At the same time, its low residue characteristics also avoid magnetic dilution of magnetic powder, improve saturation magnetization, and effectively improve the magnetic properties of magnetic core.

[0051] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments. It should be noted that many modifications and improvements can be made by those skilled in the art, and all modifications or improvements not exceeding the scope of the claims should be considered within the protection scope of the present invention.

Claims

1. A method for insulating high-performance, self-lubricating soft magnetic metal powder, characterized in that, Includes the following steps: (1) The metal soft magnetic powder is placed in the first solvent containing the complexing agent and stirred to activate the surface of the magnetic powder. Then it is dried to obtain activated metal soft magnetic powder. Wherein: the complexing agent used is at least one of ethylenediaminetetraacetic acid, citric acid, tartaric acid, aminotrimethylphosphoric acid, polyacrylic acid, and mercapto compounds, the mass of the complexing agent is 0.1 to 1% of the mass of the soft magnetic metal powder, and the mass of the first solvent is 7 to 25% of the mass of the soft magnetic metal powder; (2) The MXene material is placed in a reaction vessel and a silicon source and a second solvent are added for modification treatment to generate nano-sized silica particles in the pores of the MXene material structure; after the reaction is completed, the material is dried to obtain the modified MXene material. Wherein: the mass of the silicon source is 0.01 to 0.5% of the mass of the MXene material, and the mass of the second solvent is 10 to 30% of the mass of the MXene material; (3) Prepare insulating liquid using main insulating agent, auxiliary insulating agent and third solvent; The main insulating agent used is at least one of nitric acid, phosphoric acid, chromic acid, oxalic acid, acetic acid, and malic acid; the auxiliary insulating agent used is at least one of alumina, silicon oxide, magnesium oxide, calcium oxide, and glass powder; the amount of the main insulating agent added is 8-35% of the mass of the third solvent; and the amount of the auxiliary insulating agent added is 0.4-3% of the mass of the third solvent. (4) Place the activated metal soft magnetic powder obtained in step (1) into a reaction vessel, add the insulating liquid from step (3) at 0.1-1.2% of the mass of the activated metal soft magnetic powder, and add the modified MXene material from step (2) at 0.05-0.6% of the mass of the activated metal soft magnetic powder; after all raw materials are fully mixed in the reaction vessel, react at 15-45°C for 1-6 hours; after the reaction is completed, dry the mixture to obtain the final insulating metal soft magnetic powder.

2. The insulation method for soft magnetic metal powder according to claim 1, characterized in that, In step (1), the soft magnetic metal powder is any one of iron-silicon powder, iron-silicon-aluminum powder, iron-silicon-chromium powder, and iron-nickel powder.

3. The insulation method for soft magnetic metal powder according to claim 1, characterized in that, In step (1), the stirring is ultrasonic stirring, and the stirring time is 0.5 to 3 hours.

4. The insulation method of the soft magnetic metal powder according to claim 1, characterized in that, The first solvent is selected from at least one of ethanol, acetone, ethyl acetate, propylene glycol, and butanol; the second and third solvents are each independently selected from at least one of ethanol, acetone, deionized water, ethyl acetate, propylene glycol, and butanol.

5. The insulation method of the soft magnetic metal powder according to claim 1, characterized in that, In step (2), the MXene material is Ti. n+1 C n T x V n+1 C n T x Cr n+1 C n T x Mo n+1 C n T x Ti n+1 N n T x V n+1 N n T x Cr n+1 N n T x Mo n+1 N n T x At least one of them, wherein the particle size of the MXene material used is 10–120 nm.

6. The insulation method of the soft magnetic metal powder according to claim 1, characterized in that, In step (2), the silicon source is at least one of methyl orthosilicate, ethyl orthosilicate, butyl orthosilicate, potassium silicate, and sodium silicate.

7. The insulation method of the soft magnetic metal powder according to claim 1, characterized in that, In step (2), the temperature of the modification treatment is 65-100℃ and the time is 0.5-8h, and the pH value of the mixed solution is controlled between 7.0 and 8.5 by adding ammonia dropwise.

8. An insulating metal soft magnetic powder obtained by the insulating method according to any one of claims 1 to 7.