Method for preparing magnetic powder core through multi-granularity regulation and control, magnetic powder core and application of magnetic powder core

Abstract

The invention provides a method for preparing a magnetic powder core through multi-granularity regulation and control, the magnetic powder core and application of the magnetic powder core, and the method comprises the following steps that multiple parts of alloy powder are subjected to multiple times of granularity testing till N parts of powder with the particle size D50 being different numerical value ranges are obtained, and N is larger than or equal to 2; and selecting at least two parts of alloy powder with different particle size D50 numerical ranges from the obtained powder, then mixing to obtain a mixture, and then carrying out passivating treatment, coating treatment, compression molding and sintering to obtain the magnetic powder core. According to the method, at least two kinds of alloy powder are adopted for particle size regulation and control to prepare the magnetic powder core, different kinds of alloy powder have the particle size D50 in different numerical value ranges, and therefore the powder with the particle size D50 in different numerical value ranges can be selected according to requirements, and the characteristics of the target magnetic powder core are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of soft magnetic materials and relates to a method for preparing a magnetic powder core by controlling multiple particle sizes, a magnetic powder core and applications thereof. Background Art

[0002] As a soft magnetic material with high saturation magnetic induction intensity, good frequency characteristics and temperature stability, magnetic powder cores are widely used in devices such as power factor correctors (PFC inductors), pulse flyback transformers and energy storage filter inductors. With the rapid development of science and technology, the miniaturization and lightness of equipment have led to the miniaturization and high power density of electronic devices. Therefore, magnetic powder core materials with high flux density, high DC bias performance, high frequency and low loss must be used.

[0003] In the prior art, the properties of magnetic powder cores are generally optimized by compounding different alloy powder cores, or adding different types of elements and different proportions of elements. For example, CN117393261A discloses a FeSiNi soft magnetic composite material and a preparation method thereof, wherein FeSi magnetic powder is uniformly mixed with KH550 coupling agent, deionized water and anhydrous ethanol, a layer of nickel oxide or nickel hydroxide is precipitated on the surface of the FeSi magnetic powder by coprecipitation, and then a high-temperature heat treatment is performed to obtain FeSiNi coated powder, KH550 coupling agent is added to the FeSiNi coated powder, and then a layer of high-temperature resistant silicone resin is coated, and then a lubricant is added, and finally the FeSiNi soft magnetic composite material is obtained after pressing and forming in a mold, annealing and stress relief heat treatment.

[0004] For example, CN117238625A discloses a powder metallurgy high-density magnetic core and its preparation process, which is made of the following components in weight percentage: rare earth powder 0.01wt%-0.03wt%, silicon powder 1wt%-2wt%, boron powder 0.001wt%-0.003wt%, manganese powder 0.5wt%-0.8wt%, nickel powder 5wt%-8wt%, molybdenum powder 0.8wt%-1.5wt%, cobalt powder 0.5wt%-0.8wt%, zinc powder 0.1wt%-0.3wt%, M powder 0.01wt%-0.03wt%, nano-ferroferric oxide 0.01wt%-0.03wt%, nano-chromium oxide 0.003wt%-0.005wt%, and the balance is iron powder.

[0005] However, in the preparation process of magnetic powder core, although the insulation coating of powder is an important link in the performance of powder characteristics, the particle size of the powder itself is also the most core influencing factor. In the preparation process of magnetic powder core powder, it is affected by multiple spray parameters. After spraying, the characteristics have been finalized. For powder with special needs, the characteristics have been finalized after spraying. If you want to get powder with excellent performance in different frequency bands, the powder obtained by the original spraying cannot meet the requirements. In addition, there is a deviation in the characteristics during the powder making process.

[0006] Based on the above research, it is necessary to provide a method for preparing magnetic powder cores with multi-particle size control, which can achieve the diversity of magnetic powder core properties according to different needs, and achieve flexibility and ease of operation in powder preparation on the basis of low ingredients. Summary of the invention

[0007] The object of the present invention is to provide a method for preparing a magnetic powder core by multi-particle size control, a magnetic powder core and an application thereof. The method prepares a magnetic powder core by using at least two alloy powders to control the particle size, wherein different alloy powders have particle sizes D50 in different numerical ranges, so that powders with different particle size D50 numerical ranges can be selected according to needs to achieve the characteristics of the target magnetic powder core.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing a magnetic powder core by controlling multiple particle sizes, the method comprising the following steps:

[0010] (1) performing multiple particle size tests on multiple portions of alloy powders until N portions of powders having D50 values ​​in different ranges are obtained, where N ≥ 2;

[0011] (2) Select at least two alloy powders with different particle size D50 value ranges from the powder obtained in step (1), mix them to obtain a mixture, and then perform passivation treatment, coating treatment, press molding and sintering to obtain the magnetic powder core, which includes particles of different particle sizes.

[0012] Since the particle size D50 refers to the particle size corresponding to when the cumulative particle size distribution percentage of a sample reaches 50%, when a portion of powder is subjected to multiple particle size D50 tests, the measured particle size D50 may be different, and not all of them are a constant particle size D50. Therefore, the particle size D50 of the portion of powder can be obtained as a numerical range. In the present invention, the numerical range of the particle size D50 is tested on multiple portions of powder to obtain multiple portions of powder with different numerical ranges of D50, and then at least two portions of powder with different numerical ranges are selected from them for the preparation of magnetic powder cores. Therefore, according to According to the performance requirements of powder, different particle size D50 value ranges are selected for matching. Powders with specific functions can be achieved through the adjustment of particle size, thereby producing products with better characteristics and better cost performance. Even if you are not a powder supplier, you can achieve the desired magnetic powder core characteristics through particle size adjustment. There is no need to continuously adjust the equipment parameters during powder preparation to achieve the diversity of characteristics. In addition, the flexibility and ease of powder adjustment can be achieved on the basis of achieving good powder characteristics and low ingredients. Powder can be selected according to actual needs.

[0013] The magnetic powder core obtained by the present invention comprises particles of different particle sizes, the large and small particles are matched with each other, the small particles are distributed around the large particles, and the obtained magnetic powder core has excellent density.

[0014] In the present invention, multiple portions of alloy powders are subjected to multiple particle size tests respectively. The number of the multiple portions of alloy powders is not specifically limited, and the number of the multiple particle size tests is not specifically limited. As long as powder within the target particle size D50 range can be obtained, it should be understood that the number of the multiple portions of alloy powders is more than two, and the multiple particle size tests are tests performed more than twice.

[0015] Exemplarily, the particle size of the magnetic powder core is sieved and then split into multiple parts for multiple particle size tests, such as obtaining powder with a particle size D50 of 1-5μm, 5-10μm, 10-15μm, 15-20μm...95-100μm powder for use, and then 5-10μm powder, 10-15μm powder, 15-20μm powder and 35-40μm powder are selected and mixed to prepare the magnetic powder core.

[0016] The N≥2, for example, can be 2, 3, 4, 5 or 6, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] Preferably, in the N portions of powders with particle sizes D50 in different numerical ranges in step (1), the difference between the maximum D50 value and the minimum D50 value of any portion of powder is greater than 0 μm, for example, it can be 4 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm or 150 μm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable, preferably greater than 0 μm and ≤ 150 μm.

[0018] The present invention preferably selects a difference between the maximum D50 and the minimum D50 of any powder material to be ≥4 μm to ensure the particle size matching effect.

[0019] In the present invention, the difference between the maximum value of D50 and the minimum value of D50 is ≥4 μm. Exemplarily, when the difference between the maximum value of D50 and the minimum value of D50 is 4 μm, the numerical range of the particle size D50 can be 1-5 μm.

[0020] Preferably, the D10 of the powder obtained in step (1) is also in different numerical ranges.

[0021] Preferably, the D90 of the powder obtained in step (1) is also in different numerical ranges.

[0022] Similarly, D10 and D90 of the powder of the present invention may be similar to D50, and also be in different numerical ranges.

[0023] Preferably, among the powders obtained in step (1), at least two of a first alloy powder with a particle size D50 within the first range, a second alloy powder with a particle size D50 within the second range, a third alloy powder with a particle size D50 within the third range, and a fourth alloy powder with a particle size D50 within the fourth range are selected for mixing, passivation, press molding and sintering, and preferably, the second alloy powder with a particle size D50 within the second range and the third alloy powder with a particle size D50 within the third range are selected.

[0024] Preferably, the mass ratio of any two of the first alloy powder, the second alloy powder, the third alloy powder and the fourth alloy powder is 1:(0.5-2), for example, it can be 1:0.5, 1:1, 1:1.5 or 1:2, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] When the present invention selects alloy powders with different particle size D50 value ranges, the mass ratio of different powders is within a specific range, which can further improve the particle size matching effect.

[0026] Preferably, the particle size D50 of the first alloy powder is within a range below 5 μm, which means that the maximum value of the particle size D50 of the first alloy powder is below 5 μm, for example, it can be 5 μm, 4 μm, 3 μm, 2 μm or 1 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] Preferably, the particle size D50 of the second alloy powder is in the range of 1-20μm, which means that the minimum value of the particle size D50 of the second alloy powder is above 1μm, for example, it can be 1μm, 2μm, 3μm, 4μm, 5μm or 6μm, and the maximum value is below 20μm, for example, it can be 20μm, 19μm, 18μm, 17μm, 16μm, 15μm, 14μm, 13μm or 12μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable. Exemplarily, the particle size D50 of the second alloy powder ranges from 1-5μm, or can be 5-10μm, or can also be 15-20μm.

[0028] Preferably, the particle size D50 of the third alloy powder is in the range of 10-100μm, which means that the minimum value of the particle size D50 of the third alloy powder is above 10μm, for example, it can be 10μm, 12μm, 14μm, 16μm, 18μm, 20μm, 22μm, 24μm or 26μm, and the maximum value is below 100μm, for example, it can be 100μm, 95μm, 90μm, 85μm, 80μm, 75μm, 70μm or 65μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] Preferably, the particle size D50 of the fourth alloy powder is in the range of 50-150μm, which means that the minimum value of the particle size D50 of the fourth alloy powder is above 50μm, for example, it can be 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm or 95μm, and the maximum value is below 150μm, for example, it can be 150μm, 140μm, 130μm, 120μm or 110μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] The present invention preferably uses a second alloy powder with a particle size D50 in the range of 1-20 μm and a third alloy powder with a particle size D50 in the range of 10-100 μm to prepare the magnetic powder core, which is conducive to obtaining a high-overlay, low-loss, and low-cost magnetic powder core.

[0031] Preferably, the alloy powder in step (1) comprises any one of FeNi powder, FeSiAl powder or FeSi powder, or a combination of at least two of them.

[0032] Preferably, the passivation treatment in step (2) includes mixing the passivation solution with the mixed material for passivation, drying and a first screening.

[0033] Preferably, the passivation solution includes a phosphoric acid solution.

[0034] Preferably, the concentration of the passivation solution is 0.1-0.3wt%, for example, 0.1wt%, 0.2wt% or 0.3wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0035] Preferably, the mixed passivation time is 10-25 min, for example, 10 min, 15 min, 20 min or 25 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0036] Preferably, the mesh size of the first sieving is 150-250 meshes, for example, 150 meshes, 200 meshes or 250 meshes, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Preferably, the coating treatment in step (2) comprises mixing the passivation material obtained by the passivation treatment with an inorganic filler and performing a second screening to obtain an inorganic coating material, and mixing the inorganic coating material with an insulating material, drying and performing a third screening.

[0038] Preferably, the inorganic filler is 0.01-0.03wt% of the mass of the mixed material, for example, it can be 0.01wt%, 0.02wt% or 0.03wt%, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, the inorganic filler includes any one of mica powder, kaolin or quartz powder, or a combination of at least two of them.

[0040] Preferably, the time for mixing the passivating material and the inorganic filler is 5-15 minutes, for example, 5 minutes, 10 minutes or 15 minutes, but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0041] Preferably, the insulating material is 0.01-0.03wt% of the mass of the mixture, for example, it can be 0.01wt%, 0.02wt% or 0.03wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0042] Preferably, the insulating material comprises PVB.

[0043] Preferably, the drying temperature is 110-130° C., for example, 110° C., 120° C. or 130° C., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0044] Preferably, the mesh sizes of the second sieving and the third sieving are independently 60-100 meshes, for example, 60 meshes, 80 meshes or 100 meshes, but are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0045] Preferably, the pressure of the press molding in step (2) is 1800-2200 MPa, for example, 1800 MPa, 2000 MPa or 2200 MPa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0046] Preferably, the sintering in step (2) is carried out in a protective gas.

[0047] Preferably, the sintering temperature in step (2) is 600-800°C, for example, 600°C, 700°C or 800°C, and the sintering time is 0.5-1.5h, for example, 0.5h, 1.0h or 1.5h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0048] In a second aspect, the present invention provides a magnetic powder core, which is prepared by the method described in the first aspect.

[0049] In a third aspect, the present invention provides an application of the magnetic powder core as described in the second aspect, wherein the application of the magnetic powder core includes use in electronic devices.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The present invention can select powders with different particle size D50 value ranges according to performance requirements, and realize powders with specific functions through particle size adjustment, so as to produce products with better characteristics and better cost performance. It can solve the problem that even if the powder supplier is not a powder supplier, the desired magnetic powder core characteristics can be achieved through particle size adjustment, and the diversity of characteristics can be achieved without constantly adjusting the equipment parameters during powder preparation. In addition, the flexibility and ease of powder preparation can be achieved on the basis of achieving good powder characteristics and low ingredients through powder adjustment, and powder can be selected according to actual needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a SEM image of the magnetic powder core described in Example 1 of the present invention. DETAILED DESCRIPTION

[0053] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0054] Example 1

[0055] This embodiment provides a method for preparing a magnetic powder core by controlling multiple particle sizes, the method comprising the following steps:

[0056] (1) performing multiple particle size tests on multiple portions of iron-nickel powders respectively until multiple portions of iron-nickel powders with particle sizes D50 in different numerical ranges are obtained, and iron-nickel powders with a particle size D50 of less than 3 μm, iron-nickel powders with a particle size D50 of 3-14 μm, iron-nickel powders with a particle size D50 of 14-75 μm, and iron-nickel powders with a particle size D50 of 75-150 μm are selected for standby use;

[0057] (2) 250 g of iron-nickel powder with a particle size D50 of 3-14 μm and 250 g of iron-nickel powder with a particle size D50 of 14-75 μm were mixed to obtain a mixture, 1 g of phosphoric acid was poured into a beaker containing 500 g of water, and the mixture was stirred to form a phosphoric acid passivation solution with a concentration of 0.2 wt%, and the mixture was added to the phosphoric acid passivation solution, stirred for 15 min, dried overnight in an oven at 60° C., sieved with a 200-mesh sieve, and 0.5 g of mica powder was added to the powder after sieving (the amount of mica powder added was 0.01 wt% of the mass of the mixture), stirred for 10 min, sieved with 80 mesh after the stirring was completed, and then added to a glue solution with a concentration of 2 wt% prepared by 0.5 g of PVB and 25 g of water (PVB was 0.01 wt% of the mass of the mixture), stirred evenly, and placed in an oven at 120° C. for 2 hours, and the dried powder was sieved with an 80-mesh sieve;

[0058] (3) pressing the powder obtained in step (2) under a 2000 MPa press to obtain a sample ring;

[0059] (4) The sample ring of step (3) was placed in a 700° C. nitrogen atmosphere furnace and kept warm for 1 hour to obtain the magnetic powder core. The SEM image of the magnetic powder core is as follows: Figure 1 As shown, the particles include particles of different sizes, and the large and small particles are evenly distributed.

[0060] Example 2

[0061] This embodiment provides a method for preparing a magnetic powder core by controlling multiple particle sizes, the method comprising the following steps:

[0062] (1) performing multiple particle size tests on multiple portions of iron-nickel powders respectively until multiple portions of iron-nickel powders with particle sizes D50 in different numerical ranges are obtained, and iron-nickel powders with a particle size D50 of less than 1 μm, iron-nickel powders with a particle size D50 of 1-20 μm, iron-nickel powders with a particle size D50 of 10-100 μm, and iron-nickel powders with a particle size D50 of 50-150 μm are selected for standby use;

[0063] (2) 100 g of iron-nickel powder with a particle size D50 of 1-20 μm and 400 g of iron-nickel powder with a particle size D50 of 20-100 μm were selected, mixed to obtain a mixture, added to a phosphoric acid passivation solution with a concentration of 0.3 wt%, stirred for 10 min, dried overnight in an oven at 60° C., sieved with a 150-mesh sieve, and added mica powder to the powder after sieving (the amount of mica powder added was 0.02 wt% of the mass of the mixture), stirred for 5 min, sieved with a 60-mesh sieve after the stirring was completed, and then added to a PVB glue solution (PVB was 0.02 wt% of the mass of the mixture), stirred evenly, placed in an oven at 110° C., kept warm for 2 hours, and the dried powder was sieved with a 100-mesh sieve;

[0064] (3) pressing the powder obtained in step (2) under a 2200 MPa press to obtain a sample ring;

[0065] (4) placing the sample ring described in step (3) in a nitrogen atmosphere furnace at 800° C. and keeping the temperature for 0.5 h to obtain the magnetic powder core.

[0066] Example 3

[0067] This embodiment provides a method for preparing a magnetic powder core by controlling multiple particle sizes, the method comprising the following steps:

[0068] (1) performing multiple particle size tests on multiple portions of iron-nickel powders respectively until multiple portions of iron-nickel powders with particle sizes D50 in different numerical ranges are obtained, and iron-nickel powders with a particle size D50 of less than 3 μm, iron-nickel powders with a particle size D50 of 3-14 μm, iron-nickel powders with a particle size D50 of 14-75 μm, and iron-nickel powders with a particle size D50 of 75-150 μm are selected for standby use;

[0069] (2) 100 g of iron-nickel powder with a particle size D50 of 3-14 μm and 400 g of iron-nickel powder with a particle size D50 of 14-75 μm were selected, mixed to obtain a mixture, added to a phosphoric acid passivation solution with a concentration of 0.1 wt%, stirred for 25 min, dried overnight in an oven at 60° C., sieved with a 250-mesh sieve, and added mica powder to the powder after sieving (the amount of mica powder added was 0.03 wt% of the mass of the mixture), stirred for 15 min, sieved with 100 mesh after the stirring was completed, and then added to a PVB glue solution (PVB was 0.03 wt% of the mass of the mixture), stirred evenly, placed in a 130° C. oven, kept warm for 2 hours, and the dried powder was sieved through an 80-mesh sieve;

[0070] (3) pressing the powder obtained in step (2) under a 1800 MPa press to obtain a sample ring;

[0071] (4) Place the sample ring described in step (3) in a 600° C. nitrogen atmosphere furnace and keep it warm for 1.5 hours to obtain the magnetic powder core.

[0072] Example 4

[0073] This embodiment provides a method for preparing a magnetic powder core by controlling multiple particle sizes. The method is the same as that of Embodiment 1 except that step (2) uses 250 g of iron-nickel powder with a particle size D50 of 3-14 μm and 250 g of iron-nickel powder with a particle size D50 of 75-150 μm to mix to obtain a mixture.

[0074] Example 5

[0075] This embodiment provides a method for preparing a magnetic powder core by controlling multiple particle sizes. The method is the same as that of Embodiment 1 except that step (2) uses 250 g of iron-nickel powder with a particle size D50 of less than 3 μm and 250 g of iron-nickel powder with a particle size D50 of 14-75 μm to mix to obtain a mixture.

[0076] Example 6

[0077] This embodiment provides a method for preparing a magnetic powder core by controlling multiple particle sizes. The method is the same as that of Embodiment 1 except that step (2) uses 250 g of iron-nickel powder below 3 μm and 250 g of iron-nickel powder with a particle size D50 of 3-14 μm to mix to obtain a mixture.

[0078] Example 7

[0079] This embodiment provides a method for preparing a magnetic powder core by multi-particle size control, which is the same as that of Embodiment 1 except that step (2) uses 250 g of iron-nickel powder with a particle size D50 of 14-75 μm and 250 g of iron-nickel powder with a particle size D50 of 75-150 μm to mix to obtain a mixture.

[0080] Example 8

[0081] The present embodiment provides a method for preparing a magnetic powder core by multi-particle size control, the method is the same as that of Embodiment 1 except that step (2) uses 166g of iron-nickel powder with a particle size D50 of less than 3μm, 166g of iron-nickel powder with a particle size D50 of 3-14μm, and 166g of iron-nickel powder with a particle size D50 of 14-75μm to mix to obtain a mixture.

[0082] Example 9

[0083] The present embodiment provides a method for preparing a magnetic powder core by multi-particle size control, the method is the same as that of Embodiment 1 except that step (2) uses 166g of iron-nickel powder with a particle size D50 of 3-14μm, 166g of iron-nickel powder with a particle size D50 of 14-75μm, and 166g of iron-nickel powder with a particle size D50 of 75-150μm to mix to obtain a mixture.

[0084] Example 10

[0085] This embodiment provides a method for preparing a magnetic powder core by controlling multiple particle sizes. The method is the same as that of Embodiment 1 except that the iron-nickel powder is replaced by the iron-silicon-aluminum powder.

[0086] Embodiment 11

[0087] This embodiment provides a method for preparing a magnetic powder core by controlling multiple particle sizes. The method is the same as that of Embodiment 1 except that the iron-nickel powder is replaced by iron-silicon powder.

[0088] Comparative Example 1

[0089] This comparative example provides a method for preparing a magnetic powder core by controlling multiple particle sizes. The method is the same as Example 1 except that step (2) uses 500 g of iron-nickel powder with a particle size D50 of 3-14 μm for subsequent steps.

[0090] Comparative Example 2

[0091] This comparative example provides a method for preparing a magnetic powder core by controlling multiple particle sizes. The method is the same as Example 1 except that step (2) uses 500 g of iron-nickel powder with a particle size D50 of 14-75 μm for subsequent steps.

[0092] The magnetic powder cores obtained in the above embodiments and comparative examples were subjected to performance tests, wherein the inductance test method was as follows: test instrument: CH3302 inductance tester, test frequency voltage: 100 khz / 1V, test number of turns: 0.4 mm25 Ts.

[0093] The DC superposition test method is: test instrument: CH3302 inductance tester, test frequency voltage: 100khz / 1V, test number of turns: 0.4mm 25Ts, test current: 0A, 20A.

[0094] The loss test method is: test instrument: SY8218 power consumption tester, test conditions: 50khz / 100mT, test turns 0.4mm 22×22Ts.

[0095] Among them, the test results of magnetic permeability, DC superposition (100Oe) and loss test (50k / 100mT) are shown in Table 1:

[0096] Table 1

[0097]

[0098] From Table 1 above, we can see that:

[0099] It can be seen from Example 1 and Comparative Examples 1-2 that the present invention uses powders with different particle size D50 ranges to achieve multi-particle size matching and obtain a magnetic powder core with high superposition, low loss and low cost; it can be seen from Example 1 and Examples 4-5 that the difference in the powder particle size D50 range should not be too large, which will affect the particle size matching effect and thus affect the performance of the magnetic powder core; it can be seen from Example 1 and Examples 6-7 that the powder particle size D50 range should not be too small or too large, otherwise it will not be conducive to the preparation of high superposition and low loss magnetic powder cores; it can be seen from Example 1 and Examples 8-9 that the span of the powder particle size D50 should not be too large, which will also affect the performance of the magnetic powder core; it can be seen from Example 1 and Examples 10-11 that the powder of the present invention can be FeNi powder, FeSiAl powder or FeSi powder.

[0100] In summary, the present invention provides a method for preparing a magnetic powder core by multi-particle size control, a magnetic powder core and an application thereof. The method prepares a magnetic powder core by using at least two alloy powders to control the particle size, wherein different alloy powders have particle sizes D50 in different numerical ranges, so that powders with different particle size D50 numerical ranges can be selected according to needs to achieve the characteristics of the target magnetic powder core.

[0101] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a magnetic powder core by controlling multiple particle sizes, characterized in that: The method comprises the following steps: (1) performing multiple particle size tests on multiple portions of alloy powders, respectively, until N portions of powders having particle sizes D50 in different numerical ranges are obtained, where N ≥ 2; (2) Select at least two alloy powders with different particle size D50 value ranges from the powder obtained in step (1), mix them to obtain a mixture, and then perform passivation treatment, coating treatment, press molding and sintering to obtain the magnetic powder core, which includes particles of different particle sizes.

2. The method according to claim 1, characterized in that In step (1), among the N portions of powders having particle sizes D50 in different numerical ranges, the difference between the maximum D50 and the minimum D50 of any portion of the powder is >0 μm and ≤150 μm.

3. The method according to claim 1 or 2, characterized in that: The D10 of the powder obtained in step (1) is also in different numerical ranges; The D90 of the powder obtained in step (1) is also in different numerical ranges.

4. The method according to claim 1 or 2, characterized in that: Among the powders obtained in step (1), at least two of a first alloy powder having a particle size D50 within a first range, a second alloy powder having a particle size D50 within a second range, a third alloy powder having a particle size D50 within a third range, and a fourth alloy powder having a particle size D50 within a fourth range are selected, and the mixture is mixed, passivated, pressed and sintered; Among the first alloy powder, the second alloy powder, the third alloy powder and the fourth alloy powder, the mass ratio of any two alloy powders is 1:(0.5-2).

5. The method according to claim 4, characterized in that The particle size D50 of the first alloy powder is within the range of 5 μm or less; The particle size D50 of the second alloy powder is in the range of 1-20 μm; The particle size D50 of the third alloy powder is in the range of 10-100 μm; The particle size D50 of the fourth alloy powder is in the range of 50-150 μm.

6. The method according to claim 1 or 2, characterized in that: The alloy powder in step (1) comprises any one of FeNi powder, FeSiAl powder or FeSi powder, or a combination of at least two thereof; The passivation treatment in step (2) includes mixing the passivation solution with the mixed material for passivation, drying and first screening; The passivation solution includes a phosphoric acid solution; The concentration of the passivation solution is 0.1-0.3wt%; The mixing and passivation time is 10-25min; The mesh number of the first sieving is 150-250 meshes.

7. The method according to claim 1 or 2, characterized in that: The coating treatment in step (2) comprises mixing the passivation material obtained by the passivation treatment with an inorganic filler and performing a second screening to obtain an inorganic coating material, and mixing the inorganic coating material with an insulating material, drying and performing a third screening; The inorganic filler is 0.01-0.03wt% of the mass of the mixed material; The inorganic filler includes any one of mica powder, kaolin or quartz powder or a combination of at least two thereof; The time for mixing the passivating material and the inorganic filler is 5-15 minutes.

8. The method according to claim 7, characterized in that The insulating material is 0.01-0.03wt% of the mass of the mixed material; The insulating material includes PVB; The drying temperature is 110-130°C; The mesh sizes of the second sieving and the third sieving are independently 60-100 meshes; The pressure of the compression molding in step (2) is 1800-2200 MPa; The sintering in step (2) is carried out in a protective gas; The sintering temperature in step (2) is 600-800° C. and the sintering time is 0.5-1.5 h.

9. A magnetic powder core, characterized in that: The magnetic powder core is prepared by the method according to any one of claims 1 to 8.

10. An application of the magnetic powder core as claimed in claim 9, characterized in that: Applications of the magnetic powder core include use in electronic devices.

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