Iron-silicon magnetic powder material, iron-silicon magnetic powder core and preparation method and application of iron-silicon magnetic powder core

Abstract

The invention discloses an iron-silicon magnetic powder material, an iron-silicon magnetic powder core and a preparation method and application of the iron-silicon magnetic powder core, belongs to the technical field of soft magnetic composite materials, and solves the problems that in the prior art, an iron-silicon magnetic powder core is low in magnetic conductivity and large in coercive force. The iron-silicon magnetic powder material comprises the following components in percentage by mass: 93.4%-94.8% of iron, 3.8%-4.8% of silicon, 0.6%-0.8% of aluminum and 0.8%-1.0% of a doping element M, m comprises one or more of samarium and thulium. The iron-silicon magnetic powder core prepared by the method has low coercive force and high magnetic conductivity.

Description

Technical Field

[0001] The present invention belongs to the technical field of soft magnetic composite materials, and particularly relates to an iron-silicon magnetic powder material, an iron-silicon magnetic powder core, a preparation method thereof, and an application thereof. Background Art

[0002] Metal magnetic powder cores are an important part of inductor components. They are widely used in inverters in the new energy power field and are the soft magnetic materials that have developed most rapidly in recent years. In order to pursue faster transmission efficiency in the power conversion circuit in the new energy field, increasing the frequency or increasing the current are two common paths. In most inverters with large currents, the peak current is several times larger than normal, and there are many scenarios that require withstanding large voltages. When the current is too large, the instantaneous loss increases exponentially, and a large amount of heat accumulates inside the device, which will cause the copper wire to burn out and cause sudden accidents such as fires.

[0003] Iron-silicon magnetic powder cores have the advantages of high saturation magnetization intensity Bs, high large current resistance ability, and low price, and have become the first choice materials for large inverter inductor components.

[0004] However, the magnetic permeability of the existing iron-silicon magnetic powder cores is low (μ≤90) and the coercive force is large, resulting in low conduction efficiency and difficulty in miniaturization of the iron-silicon magnetic cores, which restricts their development. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the problems of low magnetic permeability and large coercive force of the existing iron-silicon magnetic powder cores, so as to provide an iron-silicon magnetic powder material, an iron-silicon magnetic powder core, a preparation method thereof, and an application thereof.

[0006] To this end, the present invention provides the following technical solutions.

[0007] In a first aspect, the present invention provides an iron-silicon magnetic powder material, which, by mass percentage, includes: 93.4% to 94.8% of iron, 3.8% to 4.8% of silicon, 0.6 to 0.8% of aluminum, and 0.8 to 1.0% of a doping element M;

[0008] M includes one or more of samarium and thulium. Exemplarily, the content of iron can be 93.4%, 93.5%, 93.6%, 93.7%, 93.8%, 93.9%, 94.0%, 94.1%, 94.2%, 94.3%, 94.5% or 94.8% etc. or any value between any two points; the content of silicon can be 3.8%, 4.0%, 4.2%, 4.4%, 4.6%, 4.8% etc. or any value between any two points; the content of aluminum can be 0.6, 0.65, 0.7, 0.75, 0.8 etc. or any value between any two points.

[0009] In a possible implementation, the particle size of the iron-silicon magnetic powder material is below 200 mesh, preferably 200 - 500 mesh.

[0010] In a second aspect, the present invention provides an iron-silicon magnetic powder core, comprising the iron-silicon magnetic powder material described above and an insulating coating agent.

[0011] In a possible implementation, the insulating coating agent includes one or more of mica powder and silica powder; the insulating coating agent of the present application has high temperature resistance and strong insulation. The present invention uses silica or mica as the insulating material, simplifies the high-temperature-resistant insulating material system, has good compatibility with the iron-silicon powder core, and has a simple preparation process, convenient operation, and high production efficiency.

[0012] And / or the dosage of the insulating coating agent is 0.5% - 1.2% of the mass of the iron-silicon magnetic powder material; exemplarily, it can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, etc. or any value between any two points.

[0013] And / or the particle size of the insulating coating agent is 1500 - 2000 mesh.

[0014] In a third aspect, the present application provides a method for preparing an iron-silicon magnetic powder core, comprising:

[0015] S1. Mix the iron-silicon magnetic powder material with a passivating agent for passivation;

[0016] S2. Mix the passivated iron-silicon magnetic powder material with the insulating coating agent;

[0017] S3. Mix the product of S2 with a lubricant and then press it into a blank;

[0018] S4. Heat-treat the blank to obtain the iron-silicon magnetic powder core.

[0019] In a possible implementation, the passivating agent includes one or more of phosphoric acid, chromic acid, and silicic acid;

[0020] In a possible implementation, the mass of the passivating agent is 0.4% - 1% of the mass of the iron-silicon magnetic powder material. Exemplarily, it can be 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, etc. or any value between any two points.

[0021] In a possible implementation, the lubricant includes one or more of zinc stearate, stearamide, and ethylene bisstearamide (EBS);

[0022] In a possible implementation, the mass of the lubricant is 0.3% - 0.5% of the mass of the product of S2. Exemplarily, it can be 0.3%, 0.4%, 0.5%, etc. or any value between any two points.

[0023] In a possible implementation, the pressure for pressing into a blank is 1200 - 1700 MPa. Exemplarily, it can be 1200 MPa, 1300 MPa, 1400 MPa, 1500 MPa, 1600 MPa, 1700 MPa, etc. or any value between any two points.

[0024] In a possible implementation, the heat treatment includes: heating at 700 - 850 °C for 30 - 40 min in a nitrogen atmosphere. Exemplarily, the heat treatment temperature can be 700 °C, 710 °C, 720 °C, 730 °C, 740 °C, 750 °C, 760, 770 °C, 780 °C, 790 °C, 800 °C, 810 °C, 820 °C, 830 °C, 840 °C, 850 °C, etc. or any value between any two points; the heating time can be 30 min, 31 min, 32 min, 35 min, 37 min, 40 min, etc. or any value between any two points.

[0025] Fourthly, the present application provides an application of an iron - silicon magnetic powder core in an inductive element.

[0026] A preparation method of an iron - silicon magnetic powder material, comprising: melting and atomizing raw materials according to a ratio to obtain powder.

[0027] The time for mixing the iron - silicon magnetic powder material with a passivator for passivation is 3 - 5 min, and it is quickly dried after passivation.

[0028] Prepare an iron - silicon magnetic powder material: add elemental materials of Fe and Si into a melting furnace according to a ratio for melting and smelting, then add Al and doping elements, and after the melting is completed, make powder by atomization; screen the obtained powder to obtain an iron - silicon magnetic powder material.

[0029] Optionally, a 200 - mesh or 500 - mesh stainless - steel screen is used for standard screening.

[0030] Before adding the passivator, dilute the passivator in a solvent. Optionally, the solvent is acetone, and the mass of the solvent is 2 - 4 times the mass of the passivator, and can be 3 times.

[0031] The present application obtains a blank with a high forming density under a relatively low forming pressure. Under a heat treatment process of 700 - 850 °C, the prepared iron - silicon magnetic powder core has few micro - defects, low coercivity, reduced hysteresis loss, high magnetic permeability, and high inductance of the inductor device.

[0032] The technical solution of the present invention has the following advantages:

[0033] 1. The iron-silicon magnetic powder material of the present invention, by mass percentage, comprises: 93.4% - 94.8% of iron, 3.8% - 4.8% of silicon, 0.6 - 0.8% of aluminum, and 0.8 - 1.0% of doping element M; M comprises one or more of samarium and thulium.

[0034] The present invention takes the high saturation magnetization intensity raw material formed by an iron-silicon binary alloy as the main body, and changes the alloy lattice structure by adding a small amount of aluminum and doping elements, thereby affecting the magnetic moment and magnetocrystalline anisotropy field of the iron-silicon alloy, and finally achieving the purpose of reducing the coercive force and increasing the magnetic permeability.

[0035] 2. The iron-silicon magnetic powder core of the present invention comprises the above-mentioned iron-silicon magnetic powder material and an insulating coating agent, and has a high magnetic permeability and a low coercive force. Generally, a high magnetic permeability represents a high inductance. Under the condition of the same volume, a higher inductance can be obtained, and higher efficiency can be achieved while reducing the device volume and compressing the cost. Specific Embodiments

[0036] The following embodiments are provided to better further understand the present invention. They are not limited to the best embodiments, and do not constitute a limitation to the content and protection scope of the present invention. Any product that is the same as or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with those of other prior arts falls within the protection scope of the present invention.

[0037] For those embodiments in which specific experimental steps or conditions are not indicated, the operations or conditions of the conventional experimental steps described in the literature in this field can be followed. For the reagents or instruments whose manufacturers are not indicated, they are all conventional reagent products that can be obtained through commercial purchase.

[0038] Example 1

[0039] This example provides a preparation method of an iron-silicon magnetic powder core, comprising:

[0040] (1) The iron-silicon alloy ingot is powdered and sieved in an air atomization powder-making device to obtain an iron-silicon magnetic powder material with a particle size below 200 mesh. The iron-silicon alloy ingot, by mass percentage, comprises 94.8% of iron (Fe), 3.8% of silicon (Si), 0.6% of aluminum (Al), and 0.8% of samarium (Sm).

[0041] (2) Weigh 1 kg of the iron-silicon magnetic powder material prepared by the above method, as well as 0.6 wt% (6 g) of passivating agent phosphoric acid (H3PO4) and 0.8 wt% (8 g) of insulating coating agent mica powder (with a particle size of 2000 mesh) based on the mass of the iron-silicon magnetic powder material.

[0042] Mix phosphoric acid with 18 g of acetone to obtain a phosphoric acid solution. Mix the iron-silicon magnetic powder material with the phosphoric acid solution and stir for 5 minutes. Then transfer it to a rotary kiln, heat it to 60 °C and stir-fry until dry. It is okay as long as the water content is detected to be less than 0.5% within 10 minutes. After that, add 8 g of mica powder and mix evenly. After detecting that the water content is less than 0.5%, transfer it out.

[0043] (3) Put 1 kg of the product from (2) in a mixing tank, add 4 g of zinc stearate as a lubricant, mix evenly, and then transfer it to a press to press it into an annular blank (26.9 mm OD × 14.7 mm ID × 11.2 mm Ht). OD is the outer diameter of the annular blank, ID is the inner diameter of the annular blank, and Ht is the height of the annular blank.

[0044] (4) Keep the annular blank at 770 °C for 30 minutes in a nitrogen atmosphere, and the total heating and holding time does not exceed 150 minutes to obtain an iron-silicon magnetic powder core.

[0045] Use the method of Example 1 to prepare 3 iron-silicon magnetic powder core samples, and conduct performance tests on the winding of the iron-silicon magnetic powder core. There are 25 turns each for the primary coil and the secondary coil. Measure the inductance and calculate the magnetic permeability with an inductance meter LCR CH3303; measure the loss (unit: mW / cm 3 ) under the conditions of a load of 100 mT and a frequency of 50 kHz with an alternating current B-H meter, and record the coercive force of the measured magnetic ring at the same time. The test results are shown in Table 1.

[0046] Table 1

[0047] Test Items Magnetic Permeability μ <![CDATA[Core loss mW / cm 3 > Coercivity A / m Sample 1 131 423.2 8.2 Sample 2 130.5 431.5 7.4 Sample 3 131.2 427.7 8.3

[0048] Example 2

[0049] This example provides a method for preparing an iron-silicon magnetic powder core, including:

[0050] (1) Powder the iron-silicon alloy ingot in an air atomization powder-making device and sieve it to obtain an iron-silicon magnetic powder material with a particle size below 200 mesh. The iron-silicon alloy ingot includes iron (Fe) 93.4%, silicon (Si) 4.8%, aluminum (Al) 0.8%, and samarium (Sm) 1.0% by mass percentage.

[0051] (2) Weigh 1 kg of the iron-silicon magnetic powder material prepared by the above method, 0.5 wt% (5 g) of the passivating agent phosphoric acid (H3PO4) based on the mass of the iron-silicon magnetic powder material, and 0.8 wt% (8 g) of the insulating coating agent mica powder based on the mass of the iron-silicon magnetic powder material.

[0052] Mix phosphoric acid with 15 g of acetone to obtain a phosphoric acid solution. Mix the iron-silicon magnetic powder material with the phosphoric acid solution and stir for 5 minutes. Then transfer it to a rotary kiln, heat it to 60 °C and stir-fry until dry. It is okay as long as the water content is detected to be less than 0.5% within 10 minutes. Then add 8 g of mica powder (particle size of 2000 mesh), mix evenly, and transfer it out after detecting that the water content is less than 0.5%.

[0053] (3) Put 1 kg of the product in (2) into a mixing tank, add 4 g of zinc stearate as a lubricant, mix evenly, and then transfer it to a press to press it into an annular blank (26.9 mm OD × 14.7 mm ID × 11.2 mm Ht) at 1500 MPa.

[0054] (4) Keep the annular blank at 770 °C for 30 minutes in a nitrogen atmosphere, and the total heating and holding time does not exceed 150 minutes to obtain an iron-silicon magnetic powder core.

[0055] Prepare 3 iron-silicon magnetic powder core samples by the method of Example 2. Perform performance tests on the winding of the iron-silicon magnetic powder core. There are 25 turns each for the primary coil and the secondary coil. Measure the inductance and convert the magnetic permeability with an inductance meter LCR CH3303; measure the loss (unit: mW / cm 3 ) under the conditions of a load of 100 mT and a frequency of 50 kHz with an alternating current B-H meter, and record the coercive force of the measured magnetic ring at the same time. The test results are shown in Table 2.

[0056] Table 2

[0057]

[0058]

[0059] Example 3

[0060] This example provides a method for preparing an iron-silicon magnetic powder core, including:

[0061] (1) Powder and screen the iron-silicon alloy ingot in a gas atomization powder-making device to obtain an iron-silicon magnetic powder material with a particle size of less than 200 mesh. The iron-silicon alloy ingot includes iron (Fe) 94.8%, silicon (Si) 3.8%, aluminum (Al) 0.6%, and thulium (Tm) 0.8% by mass percentage.

[0062] (2) Weigh 1 kg of the iron-silicon magnetic powder material prepared by the above method, 0.5 wt% (5 g) of the passivating agent phosphoric acid (H3PO4) based on the mass of the iron-silicon magnetic powder material, and 0.5 wt% (5 g) of the insulating coating agent mica powder based on the mass of the iron-silicon magnetic powder material.

[0063] Mix phosphoric acid with 21 g of acetone to obtain a phosphoric acid solution, mix the iron-silicon magnetic powder material with the phosphoric acid solution, and stir for 5 minutes; then introduce it into a rotary kiln, heat it to 60 °C and stir-fry until dry, and it can be detected that the water content is less than 0.5% within 10 minutes; then add 5 g of mica powder (particle size of 2000 mesh), mix evenly, and transfer it out after detecting that the water content is less than 0.5%.

[0064] (3) Put 1 kg of the product in (2) into a mixing tank, add 5 g of zinc stearate as a lubricant, mix evenly, and then transfer it to a press to press it into an annular blank (26.9 mm OD × 14.7 mm ID × 11.2 mm Ht) at 1500 MPa.

[0065] (4) Keep the annular blank at a maximum temperature of 770 °C for 30 minutes in a nitrogen atmosphere, and the total heating and holding time does not exceed 150 minutes to obtain an iron-silicon magnetic powder core.

[0066] Use the method of Example 3 to prepare 3 iron-silicon magnetic powder core samples, respectively test the performance of the winding of the iron-silicon magnetic powder core, with 25 turns each for the primary coil and the secondary coil, measure the inductance and convert the magnetic permeability with an inductance meter LCR CH3303; measure the loss (unit: mW / cm 3 ) under the conditions of a load of 100 mT and a frequency of 50 kHz with an AC B-H meter, and record the coercive force of the measured magnetic ring at the same time. The test results are shown in Table 3.

[0067] Table 3

[0068] Test Items Magnetic Permeability μ <![CDATA[Core loss mW / cm 3 > Coercivity A / m Sample 1 132.3 380.1 11.2 Sample 2 131.4 381.4 12.1 Sample 3 131.7 379.2 11.4

[0069] Example 4

[0070] This example provides a method for preparing an iron-silicon magnetic powder core, including:

[0071] (1) Powder the iron-silicon alloy ingot in an air atomization powder-making device and screen it to obtain an iron-silicon magnetic powder material with a particle size below 200 mesh. The iron-silicon alloy ingot includes iron (Fe) 93.4%, silicon (Si) 4.8%, aluminum (Al) 0.8%, and thulium (Tm) 1.0% by mass percentage.

[0072] (2) Weigh 1 kg of the iron-silicon magnetic powder material prepared by the above method, 0.5 wt% (5 g) of the passivating agent phosphoric acid (H3PO4) based on the mass of the iron-silicon magnetic powder material, and 0.8 wt% (8 g) of the insulating coating agent mica powder based on the mass of the iron-silicon magnetic powder material.

[0073] Mix phosphoric acid with 15 g of acetone to obtain a phosphoric acid solution. Mix the iron-silicon magnetic powder material with the phosphoric acid solution and stir for 5 minutes. Then transfer it to a rotary kiln, heat it to 60 °C and stir-fry until dry. It can be detected that the water content is less than 0.5% within 10 minutes. After that, add 8 g of mica powder (particle size of 2000 mesh), mix evenly, and transfer it out after detecting that the water content is less than 0.5%.

[0074] (3) Put 1 kg of the product in (2) into a mixing tank, add 4 g of zinc stearate as a lubricant, mix evenly, and then transfer it to a press to press it into an annular blank (26.9 mm OD × 14.7 mm ID × 11.2 mm Ht) at 1500 MPa.

[0075] (4) Keep the annular blank at a maximum temperature of 770 °C for 30 minutes in a nitrogen atmosphere, and the total heating and holding time does not exceed 150 minutes to obtain an iron-silicon magnetic powder core.

[0076] Use the method of Example 4 to prepare 3 iron-silicon magnetic powder core samples, and test the performance of the wire winding of the iron-silicon magnetic powder core respectively. There are 25 turns each for the primary coil and the secondary coil. Measure the inductance and convert the magnetic permeability with an inductance meter LCR CH3303; measure the loss (unit: mW / cm 3 ) under the conditions of a load of 100 mT and a frequency of 50 kHz with an AC B-H meter, and record the coercive force of the measured magnetic ring at the same time. The test results are shown in Table 4.

[0077] Table 4

[0078] Test Items Magnetic Permeability μ <![CDATA[Core loss mW / cm 3 > Coercivity A / m Sample 1 128.3 360.4 10.2 Sample 2 129.4 361.3 11.1 Sample 3 127.7 359.6 10.4

[0079] Example 5

[0080] This example provides a method for preparing an iron-silicon magnetic powder core, including:

[0081] (1) Powder and screen the iron-silicon alloy ingot in an air atomization powder-making device to obtain an iron-silicon magnetic powder material with a particle size below 200 mesh. The iron-silicon alloy ingot includes iron (Fe) 94.0%, silicon (Si) 4.4%, aluminum (Al) 0.7%, and samarium (Sm) 0.9% by mass percentage.

[0082] (2) Weigh 1 kg of the iron-silicon magnetic powder material prepared by the above method, 0.7 wt% (7 g) of the passivating agent phosphoric acid (H3PO4) based on the mass of the iron-silicon magnetic powder material, and 0.8 wt% (8 g) of the insulating coating agent mica powder based on the mass of the iron-silicon magnetic powder material.

[0083] Mix phosphoric acid with 15 g of acetone to obtain a phosphoric acid solution. Mix the iron-silicon magnetic powder material with the phosphoric acid solution and stir for 5 minutes. Then transfer it to a rotary kiln, heat it to 60 °C and stir-fry until dry. It can be detected that the water content is less than 0.5% within 10 minutes. After that, add 8 g of mica powder (particle size of 2000 mesh), mix evenly, and transfer it out after detecting that the water content is less than 0.5%.

[0084] (3) Put 1 kg of the product obtained in (2) in a mixing tank, add 4 g of zinc stearate as a lubricant, mix evenly, and then transfer it to a press to press it into an annular blank (26.9 mm OD × 14.7 mm ID × 11.2 mm Ht) at 1500 MPa.

[0085] (4) Keep the annular blank at a maximum temperature of 760 °C for 30 minutes in a nitrogen atmosphere, and the total heating and holding time does not exceed 150 minutes to obtain an iron-silicon magnetic powder core.

[0086] Use the method of Example 5 to prepare 3 iron-silicon magnetic powder core samples. Perform performance tests on the windings of the iron-silicon magnetic powder cores, with 25 turns each for the primary coil and the secondary coil. Measure the inductance and calculate the magnetic permeability using an LCR CH3303 inductance meter. Measure the loss (unit: mW / cm 3 ) under the conditions of a load of 100 mT and a frequency of 50 kHz using an AC B-H meter, and record the coercive force of the measured magnetic ring at the same time. The test results are shown in Table 3.

[0087] Table 5

[0088] Test Items Magnetic Permeability μ <![CDATA[Core loss mW / cm 3 > Coercivity A / m Sample 1 101 412.3 9.2 Sample 2 100.5 413.2 9.4 Sample 3 101.2 411.4 9.3

[0089] Example 6

[0090] This example provides a method for preparing an iron-silicon magnetic powder core, including:

[0091] (1) Powder and screen an iron-silicon alloy ingot in a gas atomization powder-making device to obtain an iron-silicon magnetic powder material with a particle size below 200 mesh. The iron-silicon alloy ingot includes iron (Fe) 94.0%, silicon (Si) 4.4%, aluminum (Al) 0.7%, and samarium (Sm) 0.9% by mass percentage.

[0092] (2) Weigh 1 kg of the iron-silicon magnetic powder material prepared by the above method, 0.4 wt% (4 g) of the passivating agent phosphoric acid (H3PO4) based on the mass of the iron-silicon magnetic powder material, and 0.5 wt% (5 g) of the insulating coating agent mica powder based on the mass of the iron-silicon magnetic powder material.

[0093] Mix phosphoric acid with 15 g of acetone to obtain a phosphoric acid solution. Mix the iron-silicon magnetic powder material with the phosphoric acid solution and stir for 5 minutes. Then introduce it into a rotary kiln, heat it to 60 °C and stir-fry until dry. It can be detected that the water content is less than 0.5% within 10 minutes. After that, add 5 g of mica powder (particle size of 2000 mesh), mix evenly, and transfer it out after detecting that the water content is less than 0.5%.

[0094] (3) Put 1 kg of the product of (2) in a mixing tank, add 4 g of zinc stearate as a lubricant, mix evenly, and then transfer it to a press to press it into an annular blank (26.9 mm OD × 14.7 mm ID × 11.2 mm Ht) at 1600 MPa.

[0095] (4) Keep the annular blank at a maximum temperature of 750 °C for 30 minutes in a nitrogen atmosphere, and the total heating and holding time does not exceed 150 minutes to obtain an iron-silicon magnetic powder core.

[0096] Prepare 3 iron-silicon magnetic powder core samples by the method of Example 6, and perform performance tests on the windings of the iron-silicon magnetic powder cores. There are 25 turns each for the primary coil and the secondary coil. Measure the inductance and calculate the magnetic permeability with an inductance meter LCR CH3303; measure the loss (unit: mW / cm 3 ) under the conditions of a load of 100 mT and a frequency of 50 kHz with an AC B-H meter, and record the coercive force of the measured magnetic ring at the same time. The test results are shown in Table 6.

[0097] Table 6

[0098] Test Items Magnetic Permeability μ <![CDATA[Core loss mW / cm 3 > Coercivity A / m Sample 1 139.7 401.3 8.8 Sample 2 140.5 402.2 8.9 Sample 3 138.2 401.4 8.9

[0099] Comparative Example 1

[0100] This comparative example provides a method for preparing an iron-silicon magnetic powder core, including:

[0101] (1) Powder the iron-silicon alloy ingot in a gas atomization powder-making device and sieve it to obtain an iron-silicon magnetic powder material with a particle size of less than 200 mesh. The iron-silicon alloy ingot includes 95.5% iron (Fe) and 4.5% silicon (Si) by mass percentage.

[0102] (2) Weigh 1 kg of the iron-silicon magnetic powder material prepared by the above method, 0.6 wt% (6 g) of the passivating agent phosphoric acid (H3PO4) and 0.8 wt% (8 g) of the insulating coating agent mica powder based on the mass of the iron-silicon magnetic powder material.

[0103] Mix phosphoric acid with 18 g of acetone to obtain a phosphoric acid solution. Mix the iron-silicon magnetic powder material with the phosphoric acid solution and stir for 5 minutes. Then transfer it to a rotary kiln, heat it to 60 °C and stir-fry until dry. It is okay as long as the water content is detected to be less than 0.5% within 10 minutes. After that, add 8 g of mica powder (particle size of 2000 mesh), mix evenly, and transfer it out after the water content is detected to be less than 0.5%.

[0104] (3) Put 1 kg of the product of (2) in a mixing tank, add 4 g of zinc stearate as a lubricant, mix evenly, and then transfer it to a press to press it into an annular blank (26.9 mm OD × 14.7 mm ID × 11.2 mm Ht) at 1800 MPa.

[0105] (4) Keep the annular blank at a maximum of 770 °C for 30 minutes in a nitrogen atmosphere, and the total heating and holding time does not exceed 150 minutes to obtain an iron-silicon magnetic powder core.

[0106] Use the method of Comparative Example 1 to prepare 3 iron-silicon magnetic powder core samples, and test the performance of the windings of the iron-silicon magnetic powder cores respectively. There are 25 turns each for the primary coil and the secondary coil. Measure the inductance and convert the magnetic permeability with an LCR CH3303 inductance meter; measure the loss (unit: mW / cm 3 ) under the conditions of a load of 100 mT and a frequency of 50 kHz with an AC B-H meter, and record the coercive force of the measured magnetic ring at the same time. The test results are shown in Table 7.

[0107] Table 7

[0108] Test Items Magnetic Permeability μ <![CDATA[Core loss mW / cm 3 > Coercivity A / m Sample 1 89.4 471.2 15.7 Sample 2 90.5 486.4 18.6 Sample 3 90.2 478.5 16.9

[0109] It can be seen from the comparison between the examples and the comparative examples that the present invention adopts specific components in the iron-silicon magnetic powder core, which can significantly reduce the coercive force of the iron-silicon soft magnetic alloy and increase the magnetocrystalline anisotropy field, thus improving the soft magnetic permeability characteristics of the iron-silicon alloy and reducing the total loss of the soft magnetic material.

[0110] Obviously, the above examples are only for clear illustration and not a limitation of the implementation manner. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. An iron-silicon magnetic powder material, characterized in that, By mass percentage, it includes: 93.4% - 94.8% of iron, 3.8% - 4.8% of silicon, 0.6 - 0.8% of aluminum, and 0.8 - 1.0% of doping element M; M includes one or more of samarium and thulium.

2. The iron-silicon magnetic powder material according to claim 1, wherein The particle size of the iron-silicon magnetic powder material is below 200 mesh, preferably 200 - 500 mesh.

3. An iron-silicon magnetic powder core, characterized in that, It includes the iron-silicon magnetic powder material described in claim 1 or 2 and an insulating coating agent.

4. The iron-silicon magnetic powder core according to claim 3, characterized in that, The insulating coating agent includes one or more of mica powder and silica powder; and / or the dosage of the insulating coating agent is 0.5% - 1.2% of the mass of the iron-silicon magnetic powder material; and / or the particle size of the insulating coating agent is 1500 - 2000 mesh.

5. A method for preparing the iron-silicon magnetic powder core according to claim 3 or 4, characterized in that, It includes: S1. Mix the iron-silicon magnetic powder material with a passivating agent for passivation; S2. Mix the passivated iron-silicon magnetic powder material with the insulating coating agent; S3. Mix the product of S2 with a lubricant and then press it into a blank; S4. Heat-treat the blank to obtain the iron-silicon magnetic powder core.

6. The preparation method of the iron-silicon magnetic powder core according to claim 5, characterized in that, The passivating agent includes one or more of phosphoric acid, chromic acid, and silicic acid; and / or the mass of the passivating agent is 0.4% - 1% of the mass of the iron-silicon magnetic powder material.

7. The preparation method of the iron-silicon magnetic powder core according to claim 5, characterized in that, The lubricant includes one or more of zinc stearate, stearic acid amide, and vinyl bis-stearamide; and / or the mass of the lubricant is 0.3% - 0.5% of the mass of the product of S2.

8. The preparation method of the iron-silicon magnetic powder core according to any one of claims 5-7, characterized in that, The pressure for pressing into a blank is 1200 - 1700 MPa.

9. The preparation method of the iron-silicon magnetic powder core according to any one of claims 5-7, characterized in that, The heat treatment includes: heating at 700 - 850 °C for 30 - 40 min in a nitrogen atmosphere.

10. Application of the iron-silicon magnetic powder core described in claim 3 or 4 or the iron-silicon magnetic powder core prepared by the preparation method according to any one of 5 - 9 in an inductive element.

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