Iron-based amorphous, nanocrystalline soft magnetic alloy powder, nanocrystalline magnetic powder core and application thereof

Abstract

This invention discloses an iron-based amorphous soft magnetic alloy powder, which is composed of Fe... a Si b B c P d Cu e C f Ni g M m The alloy raw material, wherein a+b+c+d+e+f+g+m=100, is smelted to obtain a master alloy, which is then processed by gas atomization to prepare the alloy. M is at least one of the transition metal elements Sc, Ti, V, Cr, Mn, Co, Zr, and Nb, with the atomic percentages of each element being: 74≤a≤81, 0.5≤b≤7, 8.5≤c≤10.5, 5≤d≤7, 0.5≤e≤0.8, 0≤f≤2, 1≤g≤1.5, and 0≤m≤4. This invention also discloses nanocrystalline soft magnetic alloy powder and nanocrystalline magnetic powder cores prepared from the aforementioned iron-based amorphous soft magnetic alloy powder. This invention obtains iron-based amorphous soft magnetic alloy powder with good amorphous forming ability under certain high iron content conditions. The iron-based nanocrystalline soft magnetic alloy powder obtained after crystallization annealing has high saturation magnetic induction intensity, high magnetic permeability, and low loss. Moreover, the production process of this invention is simple, low-cost, and mature, making it suitable for large-scale production.

Description

Technical Field

[0001] This invention belongs to the field of soft magnetic materials technology, specifically relating to an iron-based amorphous and nanocrystalline soft magnetic alloy powder, a nanocrystalline magnetic powder core, and their applications. Background Technology

[0002] Iron-based amorphous and nanocrystalline alloys are characterized by their high saturation magnetic induction (B0). s Low coercivity (H) c ) and high effective permeability (μ e Soft magnetic materials have been widely used in the field of power equipment, where they can replace silicon steel in power transmission and conversion, which can promote the miniaturization and energy saving of devices. Among soft magnetic materials, soft magnetic composite materials combine the advantages of soft magnetic ferrites and soft magnetic alloys, possessing both good soft magnetic properties and good insulation properties, giving them good three-dimensional isotropy, high resistivity, high saturation magnetic induction, and low core loss.

[0003] Current methods for improving soft magnetic composite materials focus on insulation coating and composition control. Among these, the composition of soft magnetic alloy powder more directly determines the soft magnetic properties of the composite material. Furthermore, powders obtained through different preparation methods have different microstructures. Powders prepared by commonly used water atomization and mechanical ball milling methods have low sphericity, making them difficult to coat and thus affecting the loss of the magnetic powder core, reducing its performance. In contrast, powders prepared by gas atomization have better sphericity, smaller particle size, and more uniform distribution, which is beneficial for subsequent coating and reduces loss.

[0004] The Fe-Si-B-Nb-Cu nanocrystalline alloy system exhibits good soft magnetic properties and low H₂O. c high μ e The advantages, but B s The lower B content is a disadvantage for device miniaturization. Fe-Si-BP-Cu nanocrystalline alloys possess high B content. s However, modifying the alloy composition requires a heat treatment process with a relatively high heating rate, which is difficult to achieve in industrial mass production. The final nanocrystalline alloy powder H... c The high coercivity of Fe-Si-BP-Cu-C nanocrystalline alloys hinders the preparation and industrial application of high-frequency, low-loss magnetic powder cores. While the addition of carbon effectively reduces the necessary heating rate for heat treatment in the Fe-Si-BP-Cu-C nanocrystalline alloy system, the relatively slow cooling rate of the gas atomization method still makes it difficult to obtain alloy powders with excellent amorphous structures. Even after crystallization heat treatment, it remains difficult to achieve nanocrystalline structures with low average grain size, thus hindering the preparation of low-coercivity alloy powders.

[0005] In summary, amorphous and nanocrystalline powders have a wide range of applications, but most commercially available soft magnetic alloy powders are prepared by water atomization and mechanical crushing methods, resulting in powders with poor sphericity, difficulty in coating, and uneven particle size. Furthermore, existing iron-based amorphous and nanocrystalline alloys have low boron content. s or higher H c The difficulty in implementing heat treatment methods has hindered the application and industrialization of nanocrystalline magnetic powder cores. Therefore, developing a nanocrystalline alloy powder with high saturation magnetic induction, high permeability, high DC bias performance, and low loss composition has significant industrial value.

[0006] Patent document CN110541116B discloses a controllable crystallization iron-based nanocrystalline soft magnetic alloy, the chemical composition of which is Fe. 84 Si2B 13-x Cu1P x Where 1≤x≤4; after undergoing an amorphous state, this iron-based nanocrystalline soft magnetic alloy, through heat treatment, ultimately possesses a nanocrystalline structure with a grain size of 8-12 nm; the saturation magnetic induction intensity is 1.57-1.85 T. The alloy composition obtained by this method has poor amorphous forming ability, and the large amount of B element results in a large amount of Fe-B phase in the powder obtained by the gas atomization method, making H... c Relatively high.

[0007] Patent document CN115537684A discloses a novel iron-based amorphous nanocrystalline microwave absorbing material and its preparation method. It uses a high-Fe, high-C alloy raw material, which has poor amorphous forming ability. The powder with a diameter of less than 20 μm obtained by gas atomization contains the Fe-B phase. After crystallization heat treatment, the average α-Fe grain size is relatively large. This structure leads to the H... c The hysteresis loss is relatively high, and it cannot be maintained at a low level after being pressed and molded.

[0008] Patent document CN114045435B discloses an iron-based amorphous nanocrystalline microwave absorbing material and its preparation method, including induction melting, ultra-high pressure water-gas combined atomization, and subsequent mechanical ball milling and crystallization annealing processes. The amorphous powder obtained by this method has poor sphericity, which is detrimental to subsequent pressing and insulating coating processes.

[0009] In view of the shortcomings of the existing technologies, it is of great importance to develop amorphous and nanocrystalline powders with high saturation magnetic induction intensity and low loss by controlling the alloy composition and improving the preparation process, so as to improve the soft magnetic properties of the powder and meet the key requirements of magnetic powder cores in the current industrialization. Summary of the Invention

[0010] In view of the shortcomings of the prior art, the present invention provides an iron-based amorphous soft magnetic alloy powder with high sphericity and smooth surface, which is easy to be coated with insulation later.

[0011] A type of iron-based amorphous soft magnetic alloy powder, with the molecular formula Fe a Si b B c P d Cu e C f Ni g M m The alloy raw material with a+b+c+d+e+f+g+m=100 is smelted to obtain a master alloy, which is then processed by gas atomization. M is at least one of the transition metal elements Sc, Ti, V, Cr, Mn, Co, Zr, and Nb. The atomic percentage of each element is: 74≤a≤81, 0.5≤b≤7, 8.5≤c≤10.5, 5≤d≤7, 0.5≤e≤0.8, 0≤f≤2, 1≤g≤1.5, and 0≤m≤4.

[0012] This invention utilizes high-iron-content alloy raw materials to prepare iron-based amorphous soft magnetic alloy powder via gas atomization. The resulting powder exhibits higher sphericity and more uniform particle distribution, which is beneficial for subsequent pressing and insulating coating. This alloy composition possesses high amorphous forming ability, and the alloy powder prepared by gas atomization exhibits an excellent initial amorphous structure. After crystallization annealing heat treatment, a uniform nanocrystalline composite structure can be obtained. The average grain size of α-Fe grains in this structure is low, resulting in high permeability and low coercivity. Simultaneously, due to the precipitation of numerous α-Fe grains, the magnetic powder possesses high saturation magnetic induction. Smaller powder particle sizes can be obtained through pressure adjustment. Because this alloy system possesses intrinsic magnetic properties of high saturation magnetic induction, high permeability, and low coercivity, the magnetic powder core obtained after pressing exhibits low loss. The magnetic powder core obtained by pressing powder with smaller particle sizes demonstrates good high-frequency stability characteristics.

[0013] Preferably, in order to ensure that the prepared iron-based amorphous soft magnetic alloy powder has a high saturation magnetic induction intensity, the ferromagnetic elements should be kept at a high value, i.e., 77≤a+g≤81.5.

[0014] Preferably, in order to ensure that the prepared iron-based amorphous soft magnetic alloy powder has a high amorphous forming ability, the content of metalloid elements is also kept relatively large, that is, 11.5≤c+d≤15.5.

[0015] The atomic percentage of Fe is related to the saturation magnetic induction intensity. Alloy powders with high Fe content help to obtain high saturation magnetic induction intensity. The atomic percentage of Fe in the iron-based amorphous soft magnetic alloy powder is 74 ≤ a ≤ 81. By controlling the Fe content, the alloy can precipitate a higher content of α-Fe grains after heat treatment, and suppress the precipitation of Fe-B nonmagnetic phase grains, thereby improving the saturation magnetic induction intensity of the powder and obtaining excellent soft magnetic properties.

[0016] Si can broaden the annealing range, shifting the initial crystallization peak to higher temperatures and enhancing the thermal stability of the alloy. The addition of B, P, and C can improve the amorphous formation ability of the powder matrix, allowing α-Fe grains to precipitate more completely during heat treatment. However, excessive addition of B will narrow the annealing range between the two crystallization peaks. To obtain the ideal nanocrystalline structure, the atomic percentage of Si in the iron-based amorphous soft magnetic alloy powder is 0.5≤b≤7, the atomic percentage of B is 8.5≤c≤10.5, the atomic percentage of P is 5≤d≤7, and the atomic percentage of C is 0≤f≤2.

[0017] In the high-iron-content iron-based nanocrystalline alloy, Cu promotes the precipitation of α-Fe grains, which can refine the grains and promote the uniformity of particle dispersion. In addition, the addition of Cu can reduce the coercivity of the alloy powder. The atomic percentage of Cu in the iron-based amorphous soft magnetic alloy powder is 0.5≤e≤0.8.

[0018] Ni can improve the amorphous forming ability and enhance the stability of the high-temperature soft magnetic properties of iron-based alloys. The element M in the alloy is at least one of the transition metal elements Sc, Ti, V, Cr, Mn, Co, Zr, and Nb. However, due to its high cost, the atomic percentage content of Ni in the iron-based amorphous soft magnetic alloy powder is 1 ≤ g ≤ 1.5, and the atomic percentage content of M is 0 ≤ m ≤ 4.

[0019] Preferably, the median diameter D of the iron-based amorphous soft magnetic alloy powder is... 50 It is 17–18 μm.

[0020] Preferably, the atomizing gas pressure of the gas atomization method is 8-10 MPa. Too low a pressure will reduce the cooling rate of the sprayed melt, which will lead to a deterioration of the initial amorphous structure of the alloy powder, resulting in the precipitation of grains with larger grain sizes or even the precipitation of crystalline phases other than α-Fe grains.

[0021] Preferably, the nozzle angle used in the gas atomization method is 30–45°, and the quartz tube aperture is 0.8–1.0 mm. An excessively large aperture will result in a smaller median diameter D of the sprayed alloy powder particles. 50If the particles are too large, it will hinder the refinement of the powder; at the same time, the cooling time of excessively large powder particles is longer, making it difficult to obtain an excellent initial amorphous structure.

[0022] This invention also provides a nanocrystalline magnetic powder core, which is prepared by incorporating epoxy resin binder into the aforementioned iron-based amorphous soft magnetic alloy powder, pressing it into an amorphous magnetic powder core using a cold pressing method, and then heat-treating the amorphous magnetic powder core under vacuum. This nanocrystalline magnetic powder core exhibits high saturation magnetic induction, low loss, and excellent soft magnetic properties.

[0023] Preferably, the epoxy resin is W-6D epoxy resin, and the mass fraction of W-6D epoxy resin in the amorphous magnetic powder core is 2-3 wt.%.

[0024] Preferably, the heat treatment temperature is 400–500°C, and the time is 45–90 min. After heat treatment, the amorphous magnetic powder core forms a nanocrystalline structure, which can further improve its soft magnetic properties and reduce magnetic loss.

[0025] This invention also provides the application of the aforementioned nanocrystalline magnetic powder core in the field of integrally molded inductors. The nanocrystalline magnetic powder core of this invention possesses high saturation magnetic induction, excellent soft magnetic properties, and low loss, meeting the development needs of magnetic components towards high frequency, high efficiency, and miniaturization. It has broad application prospects in power transformers and high-frequency devices, and is a core basic material for improving power transmission efficiency.

[0026] This invention also discloses an iron-based nanocrystalline soft magnetic alloy powder, which is prepared by heat treatment of the aforementioned iron-based amorphous soft magnetic alloy powder under vacuum conditions. The iron-based nanocrystalline soft magnetic alloy powder of this invention has a uniform particle size distribution and excellent soft magnetic properties.

[0027] Preferably, the heat treatment temperature is 400–500°C and the time is 45–90 min.

[0028] Preferably, the saturation magnetic induction intensity B of the iron-based nanocrystalline soft magnetic alloy powder is... s It is 170-185 emu / g.

[0029] Preferably, the average α-Fe grain size of the iron-based nanocrystalline soft magnetic alloy powder is 25-27 nm.

[0030] The iron-based nanocrystalline soft magnetic alloy powder of the present invention can also be used to prepare nanocrystalline magnetic powder cores. The nanocrystalline magnetic powder cores prepared by iron-based nanocrystalline soft magnetic alloy powder are beneficial to the miniaturization and high frequency of devices, and can be applied to inductors, transformers, switching power supplies, etc.

[0031] Compared with the prior art, the present invention has at least the following beneficial effects:

[0032] (1) The present invention uses gas atomization to prepare iron-based amorphous soft magnetic alloy powder, and the resulting powder has higher sphericity and more uniform particle distribution, which is beneficial to subsequent pressing and insulation coating.

[0033] (2) The alloy composition of the present invention has good amorphous forming ability. The iron-based amorphous soft magnetic alloy powder prepared by the gas atomization method has excellent initial amorphous structure. After crystallization annealing heat treatment, a good nanocrystalline structure can be obtained. The average grain size of the nanocrystalline structure is low, and it has high saturation magnetic induction intensity and excellent soft magnetic properties. The magnetic powder core after pressing has high frequency and low loss characteristics, and its magnetic permeability has good high frequency stability characteristics.

[0034] (3) The production process of this invention is simple, low-cost, and mature, making it suitable for large-scale production. Attached Figure Description

[0035] Figure 1 This is a scanning electron microscope image of the iron-based amorphous soft magnetic alloy powder in Example 1.

[0036] Figure 2 The X-ray diffraction patterns are those of the iron-based amorphous soft magnetic alloy powder and the heat-treated nanocrystalline soft magnetic alloy powder in Example 1.

[0037] Figure 3 Differential scanning calorimetry (DSC) curves of the iron-based amorphous soft magnetic alloy powder and the heat-treated nanocrystalline soft magnetic alloy powder in Example 1.

[0038] Figure 4 The magnetometer curves of the vibrating samples of the iron-based amorphous soft magnetic alloy powder and the heat-treated nanocrystalline soft magnetic alloy powder in Example 1 are shown. Detailed Implementation

[0039] To further illustrate the technical solution of the present invention, the preferred embodiments of the present invention will be described below in conjunction with the examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the present invention.

[0040] Example 1

[0041] The alloy composition in this embodiment is Fe. 80.5 Si 0.5 B 10.5 P5Cu 0.5 The preparation methods of C2Ni1 iron-based amorphous soft magnetic alloy powder, iron-based nanocrystalline soft magnetic alloy powder, and nanocrystalline magnetic powder core are as follows:

[0042] S1. Ingredients: Fe, Si, B, Fe3P, Cu, C and Ni alloy raw materials with a purity of not less than 99% are prepared according to the atomic percentage formula Fe80.5 Si 0.5 B 10.5 P5Cu 0.5 C2Ni1 was used to weigh and prepare alloy raw materials;

[0043] S2. Melting the master alloy: The alloy raw materials prepared in step S1 are placed in an induction melting furnace, the vacuum is drawn to less than 1.0 Pa, and then the alloy is melted in an argon atmosphere with a purity of 99%. After melting, the temperature is held for 10 minutes. Each alloy ingot is repeatedly melted three times to ensure the uniformity of the alloy composition and form the master alloy.

[0044] S3. Preparation of iron-based amorphous soft magnetic alloy powder: The master alloy obtained in step S2 is placed in a gas atomization device, with a nozzle of 1.0 mm and a nozzle angle of 30-45°. The master alloy is heated and melted into a jetting state. After complete melting, it is held at this temperature for 10 seconds. The pressure of the atomizing gas is ≥8MPa to obtain iron-based amorphous soft magnetic alloy powder in an extremely cold state.

[0045] S4. Preparation of amorphous magnetic powder core: The iron-based amorphous soft magnetic alloy powder obtained in step S3 is mixed with 2wt.% epoxy resin and dissolved in acetone. The iron-based amorphous soft magnetic alloy powder is coated under ultrasonic vibration and pressed into an amorphous magnetic powder core with an inner diameter of 8mm, an outer diameter of 13mm and a thickness of 2mm by cold pressing at a pressure of 1.8GPa.

[0046] S5. Heat treatment: The iron-based amorphous soft magnetic alloy powder obtained in step S3 and the amorphous magnetic powder core obtained in step S4 are sealed in a vacuum (≤5×10). -3 The powder is placed in a vacuum tube furnace at a certain temperature and heat-treated for 60 minutes. The heat treatment temperature of the iron-based amorphous soft magnetic alloy powder is 420-500℃, and the heat treatment temperature of the amorphous magnetic powder core is 420-500℃, so as to obtain iron-based nanocrystalline soft magnetic alloy powder and nanocrystalline magnetic powder core.

[0047] The iron-based amorphous soft magnetic alloy powder, the iron-based nanocrystalline soft magnetic alloy powder obtained after heat treatment, and the nanocrystalline magnetic powder core were subjected to the following tests:

[0048] The iron-based amorphous soft magnetic alloy powder obtained in step S3 is sieved to obtain the median diameter D. 50 The surface morphology of the iron-based amorphous soft magnetic alloy powder, which is 17–18 μm in size, was observed using scanning electron microscopy (SEM). Figure 1 As shown, by Figure 1 It can be seen that the powder prepared by the gas atomization method has good sphericity and uniform particle distribution.

[0049] The microstructure of the iron-based amorphous soft magnetic alloy powder obtained in step S3 was analyzed by X-ray diffraction (XRD). Figure 2 The XRD pattern of the iron-based amorphous soft magnetic alloy powder obtained in step S3 shows a peak pattern with no crystal precipitation; the XRD pattern of the nanocrystalline soft magnetic alloy powder obtained after heat treatment in step S5 shows that at temperature T a Heat treatment at 420℃ for 60 min resulted in sharp diffraction peaks near 2θ = 45°, 65°, and 85°, indicating the precipitation of α-Fe grains with an average grain size of 27 nm. With increasing temperature, at temperature T... a At 500℃ and held for 60 minutes, Fe-B phase precipitates.

[0050] Differential scanning calorimetry (DSC) was used to analyze the thermal properties of the iron-based amorphous soft magnetic alloy powder obtained in step S3 and the nanocrystalline soft magnetic alloy powder obtained after heat treatment in step S5. The obtained DSC curves are shown below. Figure 3 As shown, by Figure 3 It can be seen that iron-based amorphous soft magnetic alloy powder at temperature T a Heat treatment at 420℃ for 60 minutes resulted in relatively complete precipitation of α-Fe grains; with increasing temperature, at temperature T... a Under the condition of 500℃ and holding for 60 min, the Fe-B phase was also completely precipitated.

[0051] The magnetic properties of the iron-based amorphous soft magnetic alloy powder prepared in step S3 and the nanocrystalline soft magnetic alloy powder after heat treatment in step S5 were analyzed using a vibrating sample magnetometer (VSM). The obtained VSM curves are shown below. Figure 4 As shown, the B of iron-based amorphous soft magnetic alloy powder s The B content of the nanocrystalline soft magnetic alloy powder after heat treatment at 420℃ is 171.48 emu / g. s The concentration was 180.02 emu / g, and the VSM image showed that the soft magnetic powder exhibited typical soft magnetic properties.

[0052] The iron-based nanocrystalline soft magnetic alloy powder prepared in this embodiment has an α-Fe average grain size (D) and a saturation magnetic induction intensity (B) of [missing information]. s ), coercivity (H) c The density (ρ) of the nanocrystalline magnetic powder core is shown in Table 1.

[0053] Example 2

[0054] The alloy composition in this embodiment is: Fe 80.5 Si 0.5 B 8.5 P7Cu 0.5 The method for preparing iron-based amorphous soft magnetic alloy powder, nanocrystalline soft magnetic alloy powder, and nanocrystalline magnetic powder core from C2Ni1 alloy raw materials conforming to the above proportions is the same as in Example 1.

[0055] The iron-based nanocrystalline soft magnetic alloy powder prepared in this embodiment has an α-Fe average grain size (D) and a saturation magnetic induction intensity (B) of [missing information]. s ), coercivity (H) c The density (ρ) of the nanocrystalline magnetic powder core is shown in Table 1.

[0056] Example 3

[0057] In this embodiment, the alloy composition is Fe. 80 Si 0.5 B 10.5 P5Cu 0.5 C2Ni 1.5 The method for preparing iron-based amorphous soft magnetic alloy powder, nanocrystalline soft magnetic alloy powder and nanocrystalline magnetic powder core from alloy raw materials that meet the above proportions is the same as in Example 1.

[0058] The iron-based nanocrystalline soft magnetic alloy powder prepared in this embodiment has an α-Fe average grain size (D) and a saturation magnetic induction intensity (B) of [missing information]. s ), coercivity (H) c The density (ρ) of the nanocrystalline magnetic powder core is shown in Table 1.

[0059] Example 4

[0060] In this embodiment, the alloy composition is: Fe 78.5 Si 0.5 B 8.5 P7Cu 0.5 The method for preparing iron-based amorphous soft magnetic alloy powder, nanocrystalline soft magnetic alloy powder, and nanocrystalline magnetic powder core from C2Ni1Co2 alloy raw materials in the above proportions is the same as in Example 1.

[0061] The iron-based nanocrystalline soft magnetic alloy powder prepared in this embodiment has an α-Fe average grain size (D) and a saturation magnetic induction intensity (B) of [missing information]. s ), coercivity (H) c The density (ρ) of the nanocrystalline magnetic powder core is shown in Table 1.

[0062] Example 5

[0063] In this embodiment, the alloy composition is: Fe 76.5 Si 0.5 B 8.5 P7Cu 0.5 The method for preparing iron-based amorphous soft magnetic alloy powder, nanocrystalline soft magnetic alloy powder, and nanocrystalline magnetic powder core from C2Ni1Co4 alloy raw materials in the above proportions is the same as in Example 1.

[0064] The α-Fe average grain size (D) and saturation magnetic induction intensity (B) of the nanocrystalline soft magnetic alloy powder prepared in this embodiment are shown to be... s), coercivity (H) c The density (ρ) of the nanocrystalline magnetic powder core is shown in Table 1.

[0065] Comparative Example 1

[0066] The alloy composition is Fe 81.5 Si 0.5 B 4.5 P 11 Cu 0.5 C2 powder, when prepared by gas atomization, has poor amorphous forming ability and cannot produce amorphous powder precursors. Therefore, after crystallization heat treatment, the average α-Fe grain size is too large, and the powder obtained by gas atomization contains a large amount of Fe-B phase, resulting in H... c The alloy properties of this comparative example are relatively high, and the test results are shown in Table 1.

[0067] Comparative Example 2

[0068] Preparation Example 1: Alloy composition is Fe 80.5 Si 0.5 B 10.5 P5Cu 0.5 The C2Ni1 powder was atomized using a gas atomization method at a pressure of 6 MPa. Due to this low atomization pressure, a high cooling rate could not be achieved, resulting in a relatively low amorphous degree in the solidified alloy powder. This led to a decrease in the H0 of the alloy powder after nanocrystallization heat treatment. c The high loss and large particle size of the powder are not conducive to the preparation of high-frequency, low-loss magnetic powder cores. The alloy performance test results of this comparative example are shown in Table 1.

[0069] Comparative Example 3

[0070] Preparation Example 1: Alloy composition is Fe 80.5 Si 0.5 B 10.5 P5Cu 0.5 C2Ni1 powder, with the nozzle angle adjusted to 60° in the gas atomization method, failed to achieve a high amorphous alloy powder due to the excessively large angle resulting in a low effective cooling rate. This led to the inability to obtain alloy powder with excellent amorphous properties, resulting in the H... c The alloy properties are relatively high, and it is difficult to obtain smaller particle sizes, which is not conducive to the preparation of high-frequency, low-loss magnetic powder cores. The alloy performance test results of this comparative example are shown in Table 1.

[0071] Comparative Example 4

[0072] Preparation Example 1: Alloy composition is Fe 80.5 Si 0.5 B 10.5 P5Cu 0.5C2Ni1 powder, prepared by gas atomization, was coated with 2 wt.% epoxy resin and then pressed into a magnetic powder core by cold pressing at a pressure of 1.1 GPa. Compared with Example 1, the density was reduced, the loss was increased, the permeability was reduced, and the soft magnetic properties were significantly reduced. The alloy performance test results of this comparative example are shown in Table 1.

[0073] Table 1. Average α-Fe grain size (D) and saturation magnetic induction (B) of the iron-based nanocrystalline soft magnetic alloy powders prepared in Examples 1-5. s ), coercivity (H) c and the density of the nanocrystalline magnetic powder core.

[0074]

Claims

1. A type of iron-based amorphous soft magnetic alloy powder, characterized in that, From the molecular formula Fe a Si b B c P d Cu e C f Ni g M m The alloy raw material with a+b+c+d+e+f+g+m=100 is smelted to obtain the master alloy, and then the master alloy is prepared by gas atomization. M is at least one of the transition metal elements Sc, Ti, V, Cr, Mn, Co, Zr, and Nb. The atomic percentage of each element is: 74≤a≤81, 0.5≤b≤7, 8.5≤c≤10.5, 5≤d≤7, 0.5≤e≤0.8, 0≤f≤2, 1≤g≤1.5, and 0≤m≤4. The percentage content of elements in the alloy raw material satisfies 77≤a+g≤81.5, 11.5≤c+d≤15.5; The atomizing gas pressure of the gas atomization method is 8-10 MPa, the nozzle angle is 30-45°, and the quartz tube aperture is 0.8-1.0 mm.

2. The iron-based amorphous soft magnetic alloy powder according to claim 1, characterized in that, The median diameter of the iron-based amorphous soft magnetic alloy powder is 17–18 μm.

3. A nanocrystalline magnetic powder core, comprising: an amorphous magnetic powder core formed by cold pressing an epoxy resin binder into an iron-based amorphous soft magnetic alloy powder as described in claim 1 or 2; and amorphous magnetic powder core prepared by heat treatment under vacuum.

4. The nanocrystalline magnetic powder core according to claim 3, characterized in that, The heat treatment temperature is 400–500℃, and the time is 45–90 min.

5. The application of the nanocrystalline magnetic powder core according to claim 3 or 4 in the field of integrally molded inductors.

6. An iron-based nanocrystalline soft magnetic alloy powder, prepared by heat treatment of the iron-based amorphous soft magnetic alloy powder according to claim 1 or 2 under vacuum conditions.

7. The iron-based nanocrystalline soft magnetic alloy powder according to claim 6, characterized in that, The heat treatment temperature is 400–500℃, and the time is 45–90 min.

8. The iron-based nanocrystalline soft magnetic alloy powder according to claim 6 or 7, characterized in that, The saturation magnetic induction intensity of the iron-based nanocrystalline soft magnetic alloy powder is 170-185 emu / g, and the average α-Fe grain size of the iron-based nanocrystalline soft magnetic alloy powder is 25-27 nm.

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