Method for producing a small magnetic powder core having high flux magnetic ring performance

Abstract

The application relates to the technical field of soft magnetic materials, and discloses a preparation method of a small magnetic powder core with high magnetic flux magnetic ring performance, which comprises the following steps: preparing a formula with the following weight parts of raw materials: diiron trioxide, nickel oxide, zinc oxide, manganese zinc ferrite, carbonyl iron powder, iron-nickel alloy powder, iron-silicon-aluminum alloy powder, nano magnetic alloy particles, additives, lubricants, insulating film materials and shell materials; carrying out raw material pretreatment, mixing, sintering, surface treatment, shell packaging, magnetic field polarization and quality detection; and the small magnetic powder core prepared according to the above steps can realize higher density, magnetic permeability, saturation magnetic induction intensity and Curie temperature, and can also maintain a lower loss factor and higher hardness, so that the formula and the preparation process are more suitable for the preparation of high-performance small magnetic powder cores, especially in application scenarios requiring high magnetic field intensity, high magnetic permeability and high stability.

Description

Technical Field

[0001] This invention relates to the field of soft magnetic materials technology, specifically to a method for preparing a small magnetic powder core with high magnetic flux ring performance. Background Technology

[0002] Depression, a common mental health issue, has seen continuous exploration and innovation in its treatment methods. Transcranial magnetic stimulation (TMS), with its advantages of being painless, non-invasive, and environmentally friendly, has become a new trend in depression treatment. However, traditional TMS devices, due to their large size and magnetic stimulation coils, are primarily suitable for hospital environments, significantly limiting their potential application in home settings. With increasing demands for convenient and personalized treatment of depression, developing small TMS devices suitable for home use is particularly important. Therefore, designing a small magnetic powder core with high magnetic flux ring performance is crucial. This small magnetic powder core needs to achieve miniaturization of the magnetic stimulation coil while maintaining magnetic field strength, thereby meeting the convenience requirements for home use, further expanding the application range of TMS, and providing more flexible and efficient treatment options for patients with depression. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] To address the shortcomings of existing technologies, this invention provides a method for preparing a small magnetic powder core with high magnetic flux ring performance. This method possesses the advantages of high magnetic flux ring performance and a small magnetic powder core, thus solving the problems of large size and large magnetic stimulation coils in traditional transcranial magnetic stimulators.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a small magnetic powder core with high magnetic flux ring performance, comprising the following steps:

[0007] Step 1: Raw material preparation: Prepare the following ingredients by weight: ferric oxide, nickel oxide, zinc oxide, manganese zinc ferrite, carbonyl iron powder, iron-nickel alloy powder, iron-silicon-aluminum alloy powder, nano magnetic alloy particles, additives, lubricants, insulating film materials, and shell materials.

[0008] Step 2, Raw material pretreatment: Pretreatment of ferric oxide, nickel oxide, zinc oxide and insulating film material;

[0009] Step 3: Raw material mixing: Mix manganese zinc ferrite, carbonyl iron powder, iron-nickel alloy powder, iron-silicon-aluminum alloy powder and nano magnetic alloy particles, add anhydrous ethanol, and use a ball mill at 300-400 rpm to mix and grind for 1.0-1.5 hours. Then add pretreated ferric oxide, nickel oxide and zinc oxide, and continue mixing and grinding for 2.5-3.0 hours. Finally, add additives and mix for 15-20 minutes to obtain mixed powder.

[0010] Step 4, Pre-pressing: Spray lubricant on the inner surface of the pre-prepared mold, load the mixed powder into the mold, and pre-press the mixed powder into a blank under a pressure of 100-150MPa.

[0011] Step 5, Sintering: Transfer the green body to a sintering furnace and heat it to 950-1000℃ at a rate of 5-10℃ / min under nitrogen protection of greater than 99.9%. Hold it at that temperature for 30-60 minutes, then continue to heat it to 1200-1250℃ and hold it for 1-1.5 hours.

[0012] Step 6, Surface treatment: The pretreated insulating film material is coated onto the surface of the sintered blank using an electrostatic spraying process, with a thickness of 2-4.5 μm.

[0013] Step 7, Shell Encapsulation: Add the shell material according to the formula ratio, inject it into the mold containing the blank, and cure it at a temperature of 75-80℃ for 1.5-1.8 hours to form a shell of 1-1.5mm, finally obtaining a small magnetic powder core;

[0014] Step 8: Magnetic field polarization: The small magnetic powder core is placed in an external magnetic field for directional polarization to optimize the magnetic domain arrangement;

[0015] Step 9: Quality Inspection: Conduct magnetic performance tests, insulation performance tests, and physical performance tests on the small magnetic powder core.

[0016] Preferably, the raw materials and their weight proportions of the small magnetic powder core are as follows: 8%–11% ferric oxide; 11%–14% nickel oxide; 4%–8% zinc oxide; 7%–10% manganese-zinc ferrite; 6%–9% carbonyl iron powder; 9.5%–13% iron-nickel alloy powder; 12%–14% iron-silicon-aluminum alloy powder; 5%–10% nano-magnetic alloy particles; 0.3%–0.5% additives; 0.5%–1.1% lubricant; 2.3%–3.6% insulating film material; and 5%–6% shell material.

[0017] Preferably, the particle size of the iron-nickel alloy powder and the iron-silicon-aluminum alloy powder is controlled between -200 mesh and -400 mesh, and the particle size of the nano-magnetic alloy particles is controlled between 10-40 nm.

[0018] Preferably, the additive is composed of samarium, neodymium, cobalt and nitrogen in a ratio of 1:2:3:2, and the lubricant is composed of molybdenum disulfide and graphite in a ratio of 1:6.

[0019] Preferably, the insulating film material is composed of a polytetrafluoroethylene film.

[0020] Preferably, the outer shell material is made of epoxy resin.

[0021] Preferably, the raw materials and their weight proportions of the small magnetic powder core are as follows: 8.5% ferric oxide; 12.5% ​​nickel oxide; 6% zinc oxide; 8.5% manganese-zinc ferrite; 7.5% carbonyl iron powder; 11% iron-nickel alloy powder; 13% iron-silicon-aluminum alloy powder; 6% nano-magnetic alloy particles; 0.4% additives; 0.8% lubricant; 3% insulating film material; and 5.8% shell material.

[0022] Preferably, the pretreatment process of ferric oxide, nickel oxide, and zinc oxide involves mixing ferric oxide, nickel oxide, and zinc oxide evenly, feeding them into a muffle furnace, and pre-firing them at a temperature of 850-950°C for 1.5-2 hours.

[0023] Preferably, the pretreatment process of the insulating film material involves: passivating the tetrafluoroethylene film for 10-15 minutes with a mixture of 0.1mol / L-0.5mol / L potassium permanganate solution and 0.01mol / L-0.2mol / L nitric acid in a volume ratio of 1:1, and then repairing the insulating layer with nano-titanium oxide powder.

[0024] Compared with the prior art, the present invention provides a method for preparing a small magnetic powder core with high magnetic flux ring performance, which has the following beneficial effects:

[0025] 1. The raw material formulation of this invention, through strict control of the particle size of iron-nickel alloy powder, iron-silicon-aluminum alloy powder, and nano-magnetic alloy particles, can prepare small magnetic powder cores with high magnetic permeability, low hysteresis loss, good insulation performance, and excellent formability. By adding manganese-zinc ferrite and iron-nickel alloy powder to the raw materials and controlling the content of ferric oxide, the proportion of each component can be reasonably balanced. While achieving higher density, magnetic permeability, saturation magnetic induction intensity, and Curie temperature, it can also maintain a low loss factor and high hardness. Therefore, the formulation and preparation process of this invention are more suitable for the preparation of high-performance small magnetic powder cores, especially in application scenarios that require high magnetic field strength, high magnetic permeability, and high stability.

[0026] 2. The preparation process of this invention reduces impurities and improves insulation performance by pre-firing and passivating some raw materials at high temperatures. In the mixing stage, staged mixing and ball milling are carried out to ensure uniform dispersion of components. In the sintering stage, high-purity nitrogen protection and staged heating are used to optimize the microstructure. In the surface treatment, electrostatic spraying is used to precisely control the thickness of the insulating film. Finally, after the small magnetic powder core is made, the performance of the small magnetic powder core is improved by optimizing the magnetic domain arrangement. Attached Figure Description

[0027] Figure 1 This is a flowchart of the steps of the present invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 scope of protection of the present invention.

[0029] Please see Figure 1 A method for preparing a small magnetic powder core with high magnetic flux ring performance includes the following steps:

[0030] Step 1: Raw material preparation: Prepare the following ingredients by weight: ferric oxide, nickel oxide, zinc oxide, manganese zinc ferrite, carbonyl iron powder, iron-nickel alloy powder, iron-silicon-aluminum alloy powder, nano magnetic alloy particles, additives, lubricants, insulating film materials, and shell materials.

[0031] Step 2, Raw material pretreatment: Pretreatment of ferric oxide, nickel oxide, zinc oxide and insulating film material;

[0032] Step 3: Raw material mixing: Mix manganese zinc ferrite, carbonyl iron powder, iron-nickel alloy powder, iron-silicon-aluminum alloy powder and nano magnetic alloy particles, add anhydrous ethanol, and use a ball mill at 300-400 rpm to mix and grind for 1.0-1.5 hours. Then add pretreated ferric oxide, nickel oxide and zinc oxide, and continue mixing and grinding for 2.5-3.0 hours. Finally, add additives and mix for 15-20 minutes to obtain mixed powder, ensuring that each component is fully dispersed.

[0033] Step 4, Pre-pressing: Spray lubricant on the inner surface of the pre-prepared mold, load the mixed powder into the mold, and pre-press the mixed powder into a blank under a pressure of 100-150MPa to reduce mold adhesion;

[0034] Step 5, Sintering: Transfer the green body to a sintering furnace and heat it to 950-1000℃ at a rate of 5-10℃ / min under nitrogen protection of greater than 99.9%. Hold it at that temperature for 30-60 minutes, then continue to heat it to 1200-1250℃ and hold it for 1-1.5 hours.

[0035] Step 6, Surface treatment: The pretreated insulating film material is coated onto the surface of the sintered blank using an electrostatic spraying process, with a thickness of 2-4.5 μm.

[0036] Step 7, Shell Encapsulation: Add the shell material according to the formula ratio, inject it into the mold containing the blank, and cure it at a temperature of 75-80℃ for 1.5-1.8 hours to form a shell of 1-1.5mm, finally obtaining a small magnetic powder core, ensuring biological safety;

[0037] Step 8: Magnetic field polarization: The small magnetic powder core is placed in an external magnetic field for directional polarization to optimize the magnetic domain arrangement and improve remanence;

[0038] Step 9: Quality Inspection: Conduct magnetic performance tests, insulation performance tests, and physical performance tests on the small magnetic powder core.

[0039] Specifically, the particle size of both iron-nickel alloy powder and iron-silicon-aluminum alloy powder is controlled between -200 mesh and -400 mesh, while the particle size of nano-magnetic alloy particles is controlled between 10-40 nm.

[0040] Specifically, the additives consist of samarium, neodymium, cobalt, and nitrogen in a ratio of 1:2:3:2, while the lubricant consists of molybdenum disulfide and graphite in a ratio of 1:6.

[0041] Specifically, the insulating film material is composed of a polytetrafluoroethylene (PTFE) film.

[0042] Specifically, the outer shell material is made of epoxy resin.

[0043] Specifically, the raw materials and their weight proportions for small magnetic powder cores are as follows: 8.5% ferric oxide; 12.5% ​​nickel oxide; 6% zinc oxide; 8.5% manganese-zinc ferrite; 7.5% carbonyl iron powder; 11% iron-nickel alloy powder; 13% iron-silicon-aluminum alloy powder; 6% nano-magnetic alloy particles; 0.4% additives; 0.8% lubricant; 3% insulating film material; and 5.8% shell material.

[0044] Specifically, the pretreatment process for ferric oxide, nickel oxide, and zinc oxide involves mixing ferric oxide, nickel oxide, and zinc oxide evenly, feeding them into a muffle furnace, and pre-firing them at 850-950℃ for 1.5-2 hours to eliminate impurities and form a uniform ferrite phase.

[0045] Specifically, the pretreatment process for insulating film materials involves passing through a PTFE film for 10-15 minutes with a mixture of 0.1 mol / L-0.5 mol / L potassium permanganate solution and 0.01 mol / L-0.2 mol / L nitric acid in a 1:1 volume ratio, followed by repairing the insulating layer with nano-titanium oxide powder to improve insulation performance.

[0046] Example 1

[0047] Specifically, the raw materials and their weight range for small magnetic powder cores are as follows: ferric oxide 8%–11%; nickel oxide 11%–14%; zinc oxide 4%–8%; manganese-zinc ferrite 7%–10%; carbonyl iron powder 6%–9%; iron-nickel alloy powder 9.5%–13%; iron-silicon-aluminum alloy powder 12%–14%; nano-magnetic alloy particles 5%–10%; additives 0.3%–0.5%; lubricant 0.5%–1.1%; insulating film material 2.3%–3.6%; and shell material 5%–6% (the particle size of both iron-nickel alloy powder and iron-silicon-aluminum alloy powder is controlled between -200 mesh and -400 mesh, and the particle size of nano-magnetic alloy particles is controlled between 10–40 nm).

[0048] Comparative Example 1

[0049] Specifically, the raw materials and their weight ranges for the small magnetic powder core are as follows: 8%–11% ferric oxide; 11%–14% nickel oxide; 4%–8% zinc oxide; 7%–10% manganese-zinc ferrite; 6%–9% carbonyl iron powder; 9.5%–13% iron-nickel alloy powder; 12%–14% iron-silicon-aluminum alloy powder; 5%–10% nano-magnetic alloy particles; 0.3%–0.5% additives; 0.5%–1.1% lubricant; 2.3%–3.6% insulating film material; and 5%–6% shell material (the particle size of the iron-nickel alloy powder, iron-silicon-aluminum alloy powder, and nano-magnetic alloy particles in Example 1 was not controlled).

[0050] The performance of the small magnetic powder cores prepared in Example 1 and Comparative Example 1 was tested, and the comparison results are shown in Table 1 below:

[0051] Table 1

[0052]

[0053]

[0054] In summary, the formulation in Example 1, through strict control of the particle size of iron-nickel alloy powder, iron-silicon-aluminum alloy powder, and nano-magnetic alloy particles, can prepare small magnetic powder cores with high magnetic permeability, low hysteresis loss, good insulation properties, and excellent formability. The optimized properties of the raw materials make it more suitable for medical applications of transcranial magnetic stimulation for the treatment of depression in home settings.

[0055] Example 2

[0056] The raw materials and their weight proportions for small magnetic powder cores are as follows: 8% ferric oxide; 12% nickel oxide; 6% zinc oxide; 8% manganese-zinc ferrite; 7% carbonyl iron powder; 11% iron-nickel alloy powder; 13% iron-silicon-aluminum alloy powder; 8% nano-magnetic alloy particles; 0.4% additives; 0.8% lubricant; 3% insulating film material; and 5.4% shell material.

[0057] Comparative Example 2

[0058] The raw materials and their weight parts for the small magnetic powder core are as follows: 5% ferric oxide; 12% nickel oxide; 6% zinc oxide; 12% manganese-zinc ferrite; 7% carbonyl iron powder; 15% iron-nickel alloy powder; 13% iron-silicon-aluminum alloy powder; 8% nano-magnetic alloy particles; 0.4% additives; 0.8% lubricant; 3% insulating film material; and 5.4% shell material (the content of manganese-zinc ferrite in Example 2 is increased to 12%, while the content of iron-nickel alloy powder is increased to 15%, and the content of ferric oxide is reduced to 5%).

[0059] Table 2

[0060]

[0061]

[0062] In summary, even after increasing the content of manganese-zinc ferrite and iron-nickel alloy powder and decreasing the content of ferric oxide in Comparative Example 2, its overall performance was still lower than that of Example 2. This indicates that reducing the content of ferric oxide in the material composition affects the overall performance. Furthermore, simply increasing the content of manganese-zinc ferrite and iron-nickel alloy powder does not improve performance but instead leads to a decrease in performance. In contrast, Example 2, by reasonably balancing the proportions of each component, achieves higher density, permeability, saturation magnetic induction, and Curie temperature, while maintaining a lower loss factor and higher hardness. Therefore, the formulation and process of Example 2 are more suitable for the preparation of high-performance small magnetic powder cores, especially in applications requiring high magnetic field strength, high permeability, and high stability.

[0063] Example 3 and Comparative Example 3

[0064]

[0065]

[0066] In summary, Example 3 reduced impurities and improved insulation performance by pre-firing and passivating some raw materials at high temperatures. During the mixing stage, staged mixing and ball milling ensured uniform dispersion of components. High-purity nitrogen protection and staged heating were used during the sintering stage to optimize the microstructure. Electrostatic spraying was employed for surface treatment to precisely control the insulation film thickness. Finally, after the small magnetic powder core was fabricated, the performance of the small magnetic powder core was improved by optimizing the magnetic domain arrangement. In contrast, Comparative Example 3 (traditional method) failed to optimize several key steps, resulting in lower material performance and failing to meet the requirements for high-performance small magnetic powder cores.

[0067] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a small magnetic powder core with high magnetic flux ring performance, characterized in that, Includes the following steps: Step 1: Raw material preparation: Prepare the following ingredients by weight: ferric oxide, nickel oxide, zinc oxide, manganese zinc ferrite, carbonyl iron powder, iron-nickel alloy powder, iron-silicon-aluminum alloy powder, nano magnetic alloy particles, additives, lubricants, insulating film materials, and shell materials. Step 2, Raw material pretreatment: Pretreatment of ferric oxide, nickel oxide, zinc oxide and insulating film material; Step 3: Raw material mixing: Mix manganese zinc ferrite, carbonyl iron powder, iron-nickel alloy powder, iron-silicon-aluminum alloy powder and nano magnetic alloy particles, add anhydrous ethanol, and use a ball mill at 300-400 rpm to mix and grind for 1.0-1.5 hours. Then add pretreated ferric oxide, nickel oxide and zinc oxide, and continue mixing and grinding for 2.5-3.0 hours. Finally, add additives and mix for 15-20 minutes to obtain mixed powder. Step 4, Pre-pressing: Spray lubricant on the inner surface of the pre-prepared mold, load the mixed powder into the mold, and pre-press the mixed powder into a blank under a pressure of 100-150MPa. Step 5, Sintering: Transfer the green body to a sintering furnace and heat it to 950-1000℃ at a rate of 5-10℃ / min under nitrogen protection of greater than 99.9%. Hold it at that temperature for 30-60 minutes, then continue to heat it to 1200-1250℃ and hold it for 1-1.5 hours. Step 6, Surface treatment: The pretreated insulating film material is coated onto the surface of the sintered blank using an electrostatic spraying process, with a thickness of 2-4.5 μm. Step 7, Shell Encapsulation: Add the shell material according to the formula ratio, inject it into the mold containing the blank, and cure it at a temperature of 75-80℃ for 1.5-1.8 hours to form a shell of 1-1.5mm, finally obtaining a small magnetic powder core; Step 8: Magnetic field polarization: The small magnetic powder core is placed in an external magnetic field for directional polarization to optimize the magnetic domain arrangement; Step 9: Quality Inspection: Conduct magnetic performance tests, insulation performance tests, and physical performance tests on the small magnetic powder core.

2. The method for preparing a small magnetic powder core with high magnetic flux ring performance according to claim 1, characterized in that: The raw materials and their weight ranges for the small magnetic powder core are as follows: 8%–11% ferric oxide; 11%–14% nickel oxide; 4%–8% zinc oxide; 7%–10% manganese-zinc ferrite; 6%–9% carbonyl iron powder; 9.5%–13% iron-nickel alloy powder; 12%–14% iron-silicon-aluminum alloy powder; 5%–10% nano-magnetic alloy particles; 0.3%–0.5% additives; 0.5%–1.1% lubricant; 2.3%–3.6% insulating film material; and 5%–6% shell material.

3. The method for preparing a small magnetic powder core with high magnetic flux ring performance according to claim 2, characterized in that: The particle size of the iron-nickel alloy powder and the iron-silicon-aluminum alloy powder is controlled between -200 mesh and -400 mesh, and the particle size of the nano-magnetic alloy particles is controlled between 10-40 nm.

4. The method for preparing a small magnetic powder core with high magnetic flux ring performance according to claim 2, characterized in that: The additive is composed of samarium, neodymium, cobalt and nitrogen in a ratio of 1:2:3:2, and the lubricant is composed of molybdenum disulfide and graphite in a ratio of 1:

6.

5. The method for preparing a small magnetic powder core with high magnetic flux ring performance according to claim 2, characterized in that: The insulating film material is composed of a polytetrafluoroethylene film.

6. The method for preparing a small magnetic powder core with high magnetic flux ring performance according to claim 2, characterized in that: The outer shell material is made of epoxy resin.

7. The method for preparing a small magnetic powder core with high magnetic flux ring performance according to claim 2, characterized in that: The raw materials and their weight proportions for the small magnetic powder core are as follows: 8.5% ferric oxide; 12.5% ​​nickel oxide; 6% zinc oxide; 8.5% manganese-zinc ferrite; 7.5% carbonyl iron powder; 11% iron-nickel alloy powder; 13% iron-silicon-aluminum alloy powder; 6% nano-magnetic alloy particles; 0.4% additives; 0.8% lubricant; 3% insulating film material; and 5.8% shell material.

8. The method for preparing a small magnetic powder core with high magnetic flux ring performance according to claim 1, characterized in that: The pretreatment process of ferric oxide, nickel oxide, and zinc oxide involves mixing ferric oxide, nickel oxide, and zinc oxide evenly, feeding them into a muffle furnace, and pre-firing at a temperature of 850-950℃ for 1.5-2 hours.

9. The method for preparing a small magnetic powder core with high magnetic flux ring performance according to claim 1, characterized in that: The pretreatment process of the insulating film material is as follows: the tetrafluoroethylene film is passivated for 10-15 minutes using a mixture of 0.1mol / L-0.5mol / L potassium permanganate solution and 0.01mol / L-0.2mol / L nitric acid in a volume ratio of 1:1, and then the insulating layer is repaired with nano-titanium oxide powder.

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