Iron-based amorphous soft magnetic powder core, preparation method thereof and electronic device

Abstract

The invention provides an iron-based amorphous soft magnetic powder core, a preparation method of the iron-based amorphous soft magnetic powder core and an electronic device, and the preparation method comprises the following steps: (1) smelting and gas atomizing a master alloy ingot in sequence to obtain iron-based amorphous powder; (2) passivating the iron-based amorphous powder obtained in the step (1) through a passivator and carrying out insulating coating on the iron-based amorphous powder through resin in sequence to obtain coated powder; and (3) the coated powder obtained in the step (2) is subjected to compression molding and rotating magnetic field heat treatment in sequence, and the iron-based amorphous soft magnetic powder core is obtained. According to the method, the iron-based amorphous powder is prepared through gas atomization, passivation, insulation coating, compression molding and rotating magnetic field heat treatment are carried out, all the steps are matched with one another, the comprehensive magnetic performance of the iron-based amorphous soft magnetic powder core can be remarkably improved, and the application prospect is wide.

Description

Technical Field

[0001] The invention relates to the technical field of iron-based amorphous powder, in particular to an iron-based amorphous soft magnetic powder core and a preparation method thereof and an electronic device. Background Art

[0002] With the rapid development of third-generation semiconductors, new energy, 5G terminals and other fields, power electronic equipment faces the challenges of high application frequency, high power conversion, and high energy flux density, which puts higher requirements on the soft magnetic materials that match them. Soft magnetic composite materials, also known as magnetic powder cores, are made by insulating and coating magnetic powders and pressing them into the desired shape using powder metallurgy. As a new generation of soft magnetic materials, its notable features are rich interfaces and distributed air gaps.

[0003] Therefore, magnetic powder cores have the performance characteristics of traditional metal soft magnetic materials and soft magnetic ferrites, which are manifested in higher saturation magnetization and magnetic permeability, high cutoff frequency and low eddy current loss, as well as good formability. They are widely used in power inductors, one-piece molded inductors and other fields. Compared with traditional metal magnetic powder cores such as FeSi, FeSiAl, and FiNi, iron-based amorphous magnetic powder cores have higher resistivity due to their unique long-range disordered and short-range ordered atomic structure, which is more conducive to reducing high-frequency eddy current losses. At the same time, due to its high iron content and typical ferromagnetic characteristics, the saturation magnetization of iron-based amorphous magnetic powder cores is 2 to 3 times that of soft magnetic ferrites, which helps to achieve miniaturization of electronic devices. In addition, the comprehensive soft magnetic properties of iron-based amorphous magnetic powder cores can be further improved by appropriate nanocrystallization.

[0004] Therefore, iron-based amorphous powder and magnetic powder cores are considered to be ideal soft magnetic materials in the medium and high frequency fields.

[0005] CN117497278A discloses a high permeability and low loss iron-based amorphous composite magnetic powder core and its preparation method. The core has a loss of 1000mW / cm at 100mT and 100kHz. 3 about.

[0006] CN114823034A discloses an atomized amorphous magnetic powder core and its preparation method and application. Amorphous powder can only be prepared by water atomization, there are irregular powders, the heat treatment method is ordinary high temperature annealing, and the effective magnetic permeability of the magnetic core is about 25.

[0007] CN116435085A discloses a method for preparing an iron-based amorphous magnetic powder core, which uses a silane coupling agent for surface modification pretreatment and a sol-gel method for insulation coating, and the effective magnetic permeability of the magnetic core is 23.

[0008] In summary, the magnetization strength of iron-based amorphous magnetic powder cores needs to be improved, and high magnetic permeability and low loss are often not achieved at the same time. At present, most of the research focuses on the optimization of molding process and insulation coating, how to improve its intrinsic soft magnetic properties, obtain some materials with excellent comprehensive soft magnetic properties, break the inverted relationship between the magnetization strength / magnetic permeability and loss of iron-based amorphous soft magnetic composite materials, and develop new components suitable for industrial gas atomization powder making, which is of great significance for its wide application. Summary of the invention

[0009] In order to solve the above technical problems, the present invention provides an iron-based amorphous soft magnetic powder core, a preparation method thereof and an electronic device. Iron-based amorphous powder with high sphericity is prepared by atomization, and the pressed magnetic material is subjected to a rotating magnetic field heat treatment, which significantly improves the magnetization intensity and magnetic permeability of the iron-based amorphous soft magnetic composite material, reduces the magnetic loss, and significantly improves the comprehensive performance of the iron-based amorphous soft magnetic powder core.

[0010] To achieve this object, the present invention adopts the following technical solutions:

[0011] In a first aspect, the present invention provides a method for preparing an iron-based amorphous soft magnetic powder core, the preparation method comprising the following steps:

[0012] (1) The master alloy ingot is sequentially smelted and gas-atomized to obtain an iron-based amorphous powder;

[0013] (2) the iron-based amorphous powder of step (1) is passivated with a passivating agent and then insulated and coated with a resin to obtain a coated powder;

[0014] (3) The coated powder in step (2) is successively subjected to pressing and rotating magnetic field heat treatment to obtain the iron-based amorphous soft magnetic powder core.

[0015] In the present invention, amorphous powder with high sphericity and wide particle size range (less than 150 μm) is prepared by a gas atomization method, and the iron-based amorphous powder is passivated, coated, pressed and heat treated in a rotating magnetic field in sequence to achieve high magnetization strength, high magnetic permeability and low loss of the amorphous magnetic powder core. The comprehensive soft magnetic properties are better than most of the amorphous soft magnetic powder cores reported so far, and the application prospect is broad.

[0016] In the process of rotating magnetic field heat treatment, adding rotation and magnetic field during heat treatment can better improve the comprehensive magnetic properties of the amorphous magnetic powder core.

[0017] Preferably, the chemical formula of the master alloy ingot in step (1) is Fe a B b C c Si d P e Cu f Co g TMh , a+b+c+d+e+f+g=100, wherein 70<a≤80, 0<b≤10, 0<c≤10, 0<d≤10, 0<e≤10, 0<f≤1, 0<g≤1, 0<h≤1, wherein TM is selected from any one or a combination of at least two of Nb, Cr, V, Mo or Zr, wherein typical but non-limiting combinations are a combination of Nb and Cr, a combination of V and Cr, a combination of Nb and V, a combination of Mo and Cr, a combination of Nb and Mo, and a combination of Zr and Cr.

[0018] The value range of a may be, for example, 71, 72, 73, 74, 75, 76, 77, 78, 79 or 80, but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0019] The value range of b may be, for example, 0.1, 1.2, 2.3, 3.4, 4.5, 5.6, 6.7, 7.8, 8.9 or 10, but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0020] The value range of c can be, for example, 0.1, 1.2, 2.3, 3.4, 4.5, 5.6, 6.7, 7.8, 8.9 or 10, but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0021] The value range of d can be, for example, 0.1, 1.2, 2.3, 3.4, 4.5, 5.6, 6.7, 7.8, 8.9 or 10, but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0022] The value range of e can be, for example, 0.1, 1.2, 2.3, 3.4, 4.5, 5.6, 6.7, 7.8, 8.9 or 10, but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0023] The value range of f may be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1, but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0024] The value range of g may be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1, but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0025] The value range of h may be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1, but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0026] The preferred chemical formula of the master alloy ingot of the present invention is Fe 75.7 B 5 C 7 Si 3.3 P 8.4 Cu 0.3 Nb 0.3 , Fe 74.3 Co 0.5 B 9.9 Si 8.9 P 4.9 Cu 0.5 Mo 0.3 Nb 0.7 or Fe 76.1 C 7 Si 3.3 B 5 P 8 Cu 0.3 Cr 0.3 The master alloy ingots formed by these molecular formulas have good amorphous forming ability and can be better used to prepare amorphous powders with high sphericity and a wide particle size range (less than 150 μm) by conventional gas atomization method.

[0027] Preferably, the smelting comprises induction smelting.

[0028] Preferably, the iron-based amorphous powder having a screening particle size of less than 200 mesh is used in step (2).

[0029] Preferably, the aerosolization pressure in step (2) is 8 to 10 MPa, for example, 8 MPa, 8.3 MPa, 8.5 MPa, 8.7 MPa, 8.9 MPa, 9.2 MPa, 9.4 MPa, 9.6 MPa, 9.8 MPa or 10 MPa.

[0030] Preferably, the aerosolizing gas comprises argon.

[0031] Preferably, the temperature of the atomization is 1200-1500°C, for example, it can be 1200°C, 1220°C, 1230°C, 1250°C, 1280°C, 1300°C, 1320°C, 1350°C, 1380°C, 1400°C, 1450°C, 1480°C or 1500°C.

[0032] Preferably, the passivating agent in step (2) comprises phosphoric acid.

[0033] Preferably, the mass proportion of the phosphoric acid in the iron-based amorphous powder in step (1) is 0.1-1%, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, etc.

[0034] Preferably, the concentration of the phosphoric acid is 0.5 wt.%.

[0035] Preferably, the resin in step (2) comprises epoxy resin and / or silicone resin.

[0036] Preferably, the resin accounts for 1-5% by mass of the iron-based amorphous powder in step (1), for example, it can be 1%, 1.5%, 1.9%, 2.4%, 2.8%, 3.3%, 3.7%, 4.2%, 4.6% or 5%, etc.

[0037] Preferably, the passivation and insulation coating in step (2) are each independently carried out in an acetone solution.

[0038] Preferably, the passivation and the insulation coating are each independently performed by ultrasound.

[0039] Preferably, the frequency of ultrasound in the passivation is 40-48 kHz, for example, 40 kHz, 41 kHz, 42 kHz, 43 kHz, 44 kHz, 45 kHz, 46 kHz, 47 kHz or 48 kHz.

[0040] Preferably, the ultrasonic time in the passivation is 10 to 30 min, for example, 10 min, 13 min, 15 min, 17 min, 19 min, 22 min, 24 min, 26 min, 28 min or 30 min.

[0041] Preferably, the frequency of the ultrasound in the insulating coating is 40-48 kHz, for example, 40 kHz, 41 kHz, 42 kHz, 43 kHz, 44 kHz, 45 kHz, 46 kHz, 47 kHz or 48 kHz.

[0042] Preferably, the ultrasonic time in the insulating coating is 10 to 30 minutes, for example, it can be 10 minutes, 13 minutes, 15 minutes, 17 minutes, 19 minutes, 22 minutes, 24 minutes, 26 minutes, 28 minutes or 30 minutes.

[0043] Preferably, the passivation in step (2) comprises: dissolving the passivating agent in an acetone solution and performing a first ultrasound to obtain a first system. The iron-based amorphous powder is mixed with the first system, and subjected to a second ultrasound, solid-liquid separation and drying to obtain a passivated powder.

[0044] Preferably, the press-forming comprises cold press-forming.

[0045] Preferably, the compression-molded 1.5 to 2.2 GPa may be, for example, 1.5 GPa, 1.6 GPa, 1.7 GPa, 1.8 GPa, 1.9 GPa, 2 GPa, 2.1 GPa or 2.2 GPa, etc.

[0046] Preferably, the rotating magnetic field heat treatment comprises: heat treating the pressed sample.

[0047] Preferably, the heat treatment includes first heating the temperature to a first temperature at a first heating rate for a first heat preservation, and then heating the temperature to a second temperature at a second heating rate for a second heat preservation.

[0048] Preferably, the first heating rate is 20 to 100 K / min, for example, it can be 20 K / min, 29 K / min, 38 K / min, 47 K / min, 56 K / min, 65 K / min, 74 K / min, 83 K / min, 92 K / min or 100 K / min, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0049] Preferably, the first temperature is 150-250°C, for example, it may be 150°C, 162°C, 173°C, 184°C, 195°C, 206°C, 217°C, 228°C, 239°C or 250°C.

[0050] Preferably, the first insulation time is 15 to 50 min, for example, it can be 15 min, 19 min, 23 min, 27 min, 31 min, 35 min, 39 min, 43 min, 47 min or 50 min.

[0051] Preferably, the second heating rate is 20 to 100 K / min, for example, it can be 20 K / min, 29 K / min, 38 K / min, 47 K / min, 56 K / min, 65 K / min, 74 K / min, 83 K / min, 92 K / min or 100 K / min, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0052] Preferably, the second temperature is 300-550°C, for example, 300°C, 328°C, 356°C, 384°C, 412°C, 439°C, 467°C, 495°C, 523°C or 550°C.

[0053] In the present invention, the second temperature is preferably within the above range. When the second temperature is too high, the amorphous powder may crystallize, thereby deteriorating the soft magnetic properties. When the second temperature is too low, the internal stress of the powder may be too large, and the soft magnetic properties may not reach the optimum.

[0054] Preferably, the second insulation time is 10 to 30 minutes, for example, it can be 10 minutes, 13 minutes, 15 minutes, 17 minutes, 19 minutes, 22 minutes, 24 minutes, 26 minutes, 28 minutes or 30 minutes, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0055] Preferably, during the second incubation stage, rotation and magnetic field conditions are added.

[0056] Preferably, the rotation speed is 10 to 100 r / min, for example, it can be 10 r / min, 20 r / min, 30 r / min, 40 r / min, 50 r / min, 60 r / min, 70 r / min, 80 r / min, 90 r / min or 100 r / min, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0057] The rotation speed in the present invention is preferably within the above range, which can better improve the comprehensive magnetic properties of the iron-based amorphous soft magnetic powder core.

[0058] Preferably, the magnetic field strength of the magnetic field condition is 0 to 0.1 T, for example, it can be 0.01 T, 0.02 T, 0.03 T, 0.04 T, 0.05 T, 0.06 T, 0.07 T, 0.08 T, 0.09 T or 0.1 T, etc., and does not include 0, and is preferably 0.02 to 0.1 T.

[0059] In the present invention, the magnetic field intensity is preferably within the above range, which can better improve the comprehensive magnetic properties of the iron-based amorphous soft magnetic powder core.

[0060] Preferably, after the rotating magnetic field heat treatment, the preparation method further comprises: cooling the sample.

[0061] Preferably, the cooling comprises water cooling.

[0062] In a second aspect, the present invention provides an iron-based amorphous soft magnetic powder core, wherein the iron-based amorphous soft magnetic powder core is prepared by the preparation method of the iron-based amorphous soft magnetic powder core described in the first aspect.

[0063] The iron-based amorphous soft magnetic powder core prepared in the second aspect of the present invention has excellent saturation magnetization intensity, effective magnetic permeability and frequency stability, low magnetic loss and excellent comprehensive magnetic properties.

[0064] Preferably, the saturation magnetization intensity of the iron-based amorphous soft magnetic powder core is above 170emu / g, for example, it can be 170emu / g, 176emu / g, 182emu / g, 187emu / g, 193emu / g, 198emu / g, 204emu / g, 209emu / g, 215emu / g or 220emu / g.

[0065] Preferably, the effective magnetic permeability of the iron-based amorphous soft magnetic powder core is above 32, for example, it may be 32, 33, 34, 35, 36, 37, 38, 39, 40 or 41.

[0066] Preferably, the frequency stability of the iron-based amorphous soft magnetic powder core is above 2 MHz, for example, it may be 2 MHz, 4 MHz, 5 MHz, 6 MHz, 7 MHz, 8 MHz, 9 MHz, 10 MHz, 11 MHz or 12 MHz.

[0067] Preferably, the core loss of the iron-based amorphous soft magnetic powder core at 0.1T and 100kHz is ≤980mW / cm 3 , for example, it can be 500mW / cm 3 、554mW / cm 3 、607mW / cm 3 、660mW / cm 3 、714mW / cm 3 、767mW / cm 3 、820mW / cm 3 、874mW / cm 3 、927mW / cm 3 or 980mW / cm 3 wait.

[0068] Preferably, the core loss of the iron-based amorphous soft magnetic powder core at 0.05T and 100kHz is ≤255mW / cm 3 , for example, it can be 100mW / cm 3 、118mW / cm 3 、135mW / cm 3 、152mW / cm 3 、169mW / cm 3 、187mW / cm 3 、204mW / cm 3 、221mW / cm 3 、238mW / cm 3 Or 255mW / cm3, etc.

[0069] Preferably, the particle size of the iron-based amorphous soft magnetic powder core is within 200 meshes, for example, it can be 200 meshes, 180 meshes, 170 meshes, 160 meshes, 150 meshes or 40 meshes.

[0070] In a second aspect, the present invention provides an electronic device, comprising the iron-based amorphous soft magnetic powder core described in the second aspect.

[0071] Compared with the prior art, the present invention has at least the following beneficial effects:

[0072] The preparation method of the iron-based amorphous soft magnetic powder core provided by the present invention adopts gas atomization to prepare amorphous alloy powder, and through passivation, coating, cold pressing and rotating magnetic field of the amorphous alloy powder, the amorphous magnetic powder core has high magnetic strength, high magnetic permeability and low loss, and the comprehensive soft magnetic properties are better than most of the amorphous soft magnetic powder cores reported currently; under the preferred conditions, the effective magnetic permeability of the iron-based amorphous soft magnetic powder core is above 30, the cut-off frequency exceeds 2MHz, and the M s (@800kA / m) above 170emu / g; P cv (0.05T, 100kHz) at 250mW / cm 3 Within, P cv (0.1T, 100kHz) at 870mW / cm 3 Within. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 For aerosolized Fe 75.7 B 5 C 7 Si 3.3 P 8.4 Cu 0.3 Nb 0.3 SEM image of amorphous powder.

[0074] Figure 2 Fe 75.7 B 5 C 7 Si 3.3 P 8.4 Cu 0.3 Nb 0.3 XRD pattern of amorphous powder.

[0075] Figure 3 Fe 75.7 B 5 C 7 Si 3.3 P 8.4 Cu 0.3 Nb 0.3 DSC curve of amorphous powder, heating rate is 40K / min.

[0076] Figure 4 Fe after phosphoric acid passivation and silicone resin insulation coating 75.7 B 5 C 7 Si 3.3 P 8.4 Cu 0.3 Nb 0.3 SEM image of powder.

[0077] Figure 5 Fe after 425℃ rotating magnetic field heat treatment 75.7 B 5 C 7 Si 3.3 P 8.4 Cu 0.3 Nb 0.3 Powder hysteresis loop.

[0078] Figure 6 Fe after 425℃ rotating magnetic field heat treatment 75.7 B 5 C 7 Si 3.3 P 8.4 Cu 0.3 Nb 0.3 Plot of effective magnetic permeability of powder cores versus frequency.

[0079] Figure 7 Fe after 425℃ rotating magnetic field heat treatment 75.7 B 5 C 7 Si 3.3 P 8.4 Cu 0.3 Nb 0.3 The loss of the magnetic powder core varies with frequency, and the test external field is 0.1T.

[0080] Figure 8 For aerosolized Fe 74.3 Co 0.5 B 9.9 Si 8.9 P 4.9 Cu 0.5 Mo 0.3 Nb 0.7 SEM image of amorphous powder.

[0081] Fig. 9 Fe 74.3 Co 0.5 B 9.9 Si 8.9 P 4.9 Cu 0.5 Mo 0.3 Nb 0.7 XRD pattern of amorphous powder.

[0082] Fig.10 Fe 74.3 Co 0.5 B 9.9 Si 8.9 P 4.9 Cu 0.5 Mo 0.3 Nb 0.7 DSC curve of amorphous powder, heating rate is 40K / min.

[0083] Fig.11 Fe after phosphoric acid passivation and silicone resin insulation coating 74.3 Co 0.5 B 9.9 Si 8.9 P 4.9 Cu 0.5 Mo 0.3 Nb 0.7 SEM image of powder.

[0084] Fig.12 Fe after 470℃ rotating magnetic field heat treatment 74.3 Co 0.5 B 9.9 Si 8.9 P 4.9 Cu 0.5 Mo 0.3 Nb 0.7 Powder hysteresis loop.

[0085] Fig.13 Fe after 470℃ rotating magnetic field heat treatment 74.3 Co 0.5 B 9.9 Si 8.9 P 4.9 Cu 0.5 Mo 0.3 Nb 0.7 Plot of effective magnetic permeability of powder cores versus frequency.

[0086] Fig.14 Fe after 470℃ rotating magnetic field heat treatment 74.3 Co 0.5 B 9.9 Si 8.9 P 4.9 Cu 0.5 Mo 0.3 Nb 0.7 The loss of the magnetic powder core varies with frequency, and the test external field is 0.05T.

[0087] Fig.15 For aerosolized Fe 76.1 C 7 Si 3.3 B5 P 8 Cu 0.3 Cr 0.3 SEM image of amorphous powder.

[0088] Fig.16 Fe 76.1 C 7 Si 3.3 B 5 P 8 Cu 0.3 Cr 0.3 XRD pattern of amorphous powder.

[0089] Fig.17 Fe 76.1 C 7 Si 3.3 B 5 P 8 Cu 0.3 Cr 0.3 DSC curve of amorphous powder, heating rate is 40K / min.

[0090] Fig.18 Fe after phosphoric acid passivation and silicone resin insulation coating 76.1 C 7 Si 3.3 B 5 P 8 Cu 0.3 Cr 0.3 SEM image of powder.

[0091] Fig.19 Fe after 420℃ rotating magnetic field heat treatment 76.1 C 7 Si 3.3 B 5 P 8 Cu 0.3 Cr 0.3 Powder hysteresis loop.

[0092] Fig. 20 Fe after 420℃ rotating magnetic field heat treatment 76.1 C 7 Si 3.3 B 5 P 8 Cu 0.3 Cr 0.3 Plot of effective magnetic permeability of powder cores versus frequency.

[0093] Fig.21 Fe after 420℃ rotating magnetic field heat treatment 76.1 C 7 Si 3.3 B 5 P 8Cu 0.3 Cr 0.3 The loss of the magnetic powder core varies with frequency, and the test external field is 0.1T. DETAILED DESCRIPTION

[0094] For the convenience of understanding the present invention, the present invention lists the following embodiments. 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.

[0095] It should be understood that the terms "first", "second", etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly indicate the number of technical features indicated. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0096] Unless otherwise specified, the equipment used in the present invention is conventional equipment in the art. All operations not mentioned in the present invention are conventional operations in the art.

[0097] The test method used in the embodiment is as follows:

[0098] (1) Iron-based amorphous powder was prepared using a small-scale gas atomization equipment.

[0099] (2) Use a beaker, ultrasonic cleaning machine, etc. to complete the phosphoric acid passivation and epoxy resin coating of the amorphous powder.

[0100] (3) Use a hydraulic press to cold press the amorphous magnetic powder core.

[0101] (4) Use the self-developed composite heat treatment furnace to carry out rotating magnetic field heat treatment.

[0102] (5) Use X-ray diffraction (XRD) to determine the phase structure of the sample.

[0103] (6) The sample morphology was characterized by scanning electron microscopy (SEM).

[0104] (7) The microstructure of the samples was characterized by transmission electron microscopy (TEM) and selected area electron diffraction (SAED).

[0105] (8) The thermal properties of the amorphous powder were measured using a differential scanning calorimeter (DSC). The iron-based amorphous powder was heated at a heating rate of 40 K / min until it was completely crystallized, and the Curie temperature (T C ) and crystallization temperature (T x ) to guide the setting of heat treatment parameters.

[0106] (9) The hysteresis loop of the sample was measured by a magnetic measurement system (MPMS) to obtain the saturation magnetization intensity. The effective magnetic permeability of the powder core was measured with an impedance analyzer. The loss of the powder core was measured with an AC BH meter. The test external fields were 0.05T and 0.1T.

[0107] Example 1

[0108] This embodiment provides a method for preparing an iron-based amorphous soft magnetic powder core, the preparation method comprising the following steps:

[0109] Step 1, press Fe 75.7 B 5 C 7 Si 3.3 P 8.4 Cu 0.3 Nb 0.3 The alloy components are batched and the master alloy ingot is induction melted. The melted master alloy ingot is placed in a quartz tube with an opening at the bottom, the cavity is closed, and the cavity is vacuumed to 5×10 -3 Pa, filled with high-purity argon gas for protection, turned on the heating power supply and added current to remelt the alloy ingot, and the molten droplets were broken into Fe under the spray of high-pressure argon gas (9.5MPa, 1400℃) and cooled into 75.7 B 5 C 7 Si 3.3 P 8.4 Cu 0.3 Nb 0.3 Amorphous powder was sieved through a 200-mesh sieve for subsequent experiments.

[0110] The Fe prepared above 75.7 B 5 C 7 Si 3.3 P 8.4 Cu 0.3 Nb 0.3 SEM images of amorphous powder Figure 1 As shown in Figure 1, most of the powder is spherical. The XRD spectrum of powder with a particle size less than 150 μm is shown in Figure 1. Figure 2 As shown in the figure, only two broad peaks (~45° and ~80°) were observed without any sharp crystallization peaks, indicating that the sample has a completely amorphous structure. This further shows that the alloy system developed in this patent has good forming ability and can meet the needs of industrial atomization powder production. The powder DSC curve is shown in Figure 3 As shown, T C =350℃, Tg=470℃, T x1 =490℃, T x2 =560℃.

[0111] Step 2, weigh 10g of Fe prepared in step 1 75.7 B5 C 7 Si 3.3 P 8.4 Cu 0.3 Nb 0.3 Amorphous powder; weigh 0.05g concentrated phosphoric acid and dissolve it in acetone solution, stir thoroughly and assist with 45kHz ultrasound for 8min until it is evenly dissolved; 75.7 B 5 C 7 Si 3.3 P 8.4 Cu 0.3 Nb 0.3 The amorphous powder was poured into acetone phosphate solution, stirred and assisted with 45kHz ultrasound for 15 minutes to complete the powder passivation; 0.2g silicone resin was weighed, dissolved in acetone solution, fully stirred and assisted with 45kHz ultrasound for 8 minutes until it was evenly dissolved, poured into the passivated amorphous powder, and continuously stirred and assisted with 45kHz ultrasound for 18 minutes until the solution was completely volatilized to complete the powder insulation coating; the coated powder was placed in an oven, set the temperature to 60°C, and kept warm for 12 hours until the powder was completely dry; the powder was taken out and ground through a 200-mesh sieve for subsequent powder core molding.

[0112] The SEM images of the coated powders are shown in Figure 4 As shown, there is a coating layer on the surface.

[0113] Step 3, weigh 1.5g of the coated powder from step 2 and put it into a cold pressing mold, and use a hydraulic press to press it into a ring-shaped sample. The outer diameter of the magnetic ring is 13mm, the inner diameter is 8mm, the thickness is 3mm, and the pressing force is 2GPa.

[0114] Step 4: Place the magnetic powder core formed in step 3 into the sample stage of the composite magnetic field heat treatment furnace and evacuate the cavity to 5×10 -3 Pa, the sample was heated to 200 °C at a heating rate of 40 K / min and kept at this temperature for 30 min to complete the curing;

[0115] The solidified magnetic core is heated to 425°C at a heating rate of 40K / min, and a 0.1T magnetic field is applied. The sample is rotated at a speed of 60r / min and kept warm for 30 minutes to complete the rotating magnetic field heat treatment to obtain the heat-treated sample. The heat-treated sample is placed in water and cooled to room temperature to obtain the iron-based amorphous soft magnetic powder core.

[0116] The hysteresis loop of the iron-based amorphous soft magnetic powder core in Example 1 is measured by MPMS. Figure 5 As shown, it is a typical S-shaped curve, indicating the soft magnetic properties of the sample, M s (@800kA / m)=181emu / g.

[0117] The magnetic permeability curve of the iron-based amorphous soft magnetic powder core in Example 1 measured by an impedance analyzer is as follows: Figure 6 As shown, the effective permeability is 36 and the cut-off frequency exceeds 10MHz.

[0118] The core loss of the iron-based amorphous soft magnetic powder core in Example 1 varies with frequency using a BH instrument. Figure 7 As shown, as the frequency increases, the core loss increases rapidly, P cv (0.1T,100kHz)=877mW / cm 3 .

[0119] Example 2

[0120] This embodiment provides a method for preparing an iron-based amorphous soft magnetic powder core, the preparation method comprising the following steps:

[0121] Step 1, press Fe 74.3 Co 0.5 B 9.9 Si 8.9 P 4.9 Cu 0.5 Mo 0.3 Nb 0.7 The alloy components are batched and the master alloy ingot is induction melted. The melted master alloy ingot is placed in a quartz tube with an opening at the bottom, the cavity is closed, and the cavity is vacuumed to 5×10 -3 Pa, filled with high-purity argon gas for protection, turned on the heating power supply and added current to remelt the alloy ingot, and the molten droplets were broken into Fe under the high-pressure argon gas (10MPa, 1500℃) spray. 74.3 Co 0.5 B 9.9 Si 8.9 P 4.9 Cu 0.5 Mo 0.3 Nb 0.7 Amorphous powder was sieved through 200 mesh for subsequent experiments.

[0122] The Fe prepared above 74.3 Co 0.5 B 9.9 Si 8.9 P 4.9 Cu 0.5 Mo 0.3 Nb 0.7 SEM images of amorphous powder Figure 8 As shown in Figure 1, most of the powder is spherical. The XRD spectrum of powder with a particle size less than 150 μm is shown in Figure 1. Fig. 9As shown in the figure, only two broad peaks (~45° and ~80°) were observed without any sharp crystallization peaks, indicating that the sample has a completely amorphous structure. This further shows that the alloy system developed in this patent has good forming ability and can meet the needs of industrial atomization powder production. The powder DSC curve is shown in Fig.10 As shown, T C =375℃, T x1 =514℃, T x2 =580℃.

[0123] Step 2, weigh 10g of Fe prepared in step 1 74.3 Co 0.5 B 9.9 Si 8.9 P 4.9 Cu 0.5 Mo 0.3 Nb 0.7 Amorphous powder; weigh 0.05g concentrated phosphoric acid and dissolve it in acetone solution, stir thoroughly with 40kHz ultrasound for 10min until it is evenly dissolved; 74.3 Co 0.5 B 9.9 Si 8.9 P 4.9 Cu 0.5 Mo 0.3 Nb 0.7 The amorphous powder was poured into acetone phosphate solution, stirred and assisted with 40kHz ultrasound for 15 minutes to complete the powder passivation; 0.2g silicone resin was weighed, dissolved in acetone solution, fully stirred and assisted with 40kHz ultrasound for 5 minutes until it was evenly dissolved, and the passivated amorphous powder was poured in, and the solution was continuously stirred and assisted with 40kHz ultrasound for 20 minutes until the solution was completely volatilized to complete the powder insulation coating; the coated powder was placed in an oven, set the temperature to 60°C, and kept warm for 12 hours until the powder was completely dry; the powder was taken out and ground through a 200-mesh sieve for subsequent powder core molding.

[0124] The SEM image of the amorphous powder after the above coating is as follows Fig.11 As shown, there is a coating layer on the surface.

[0125] Step 3, weigh 1.5g of the coated powder from step 2 and put it into a cold pressing mold, and use a hydraulic press to press it into a ring-shaped sample. The outer diameter of the magnetic ring is 13mm, the inner diameter is 8mm, the thickness is 3mm, and the pressing force is 2.0GPa.

[0126] Step 4: Place the magnetic powder core formed in step 3 into the sample stage of the composite magnetic field heat treatment furnace and evacuate the cavity to 5×10 -3 Pa, the sample was heated to 180 °C at a heating rate of 65 K / min and kept at this temperature for 50 min to complete the curing;

[0127] The solidified magnetic core is heated to 330°C at a heating rate of 70K / min, and a 0.1T magnetic field is applied. The sample is rotated at a speed of 30r / min and kept warm for 25 minutes to complete the rotating magnetic field heat treatment to obtain the heat-treated sample. The heat-treated sample is placed in water and cooled to room temperature to obtain the iron-based amorphous soft magnetic powder core.

[0128] The hysteresis loop of the iron-based amorphous soft magnetic powder core in Example 2 was measured by MPMS. Fig.12 As shown, it is a typical S-shaped curve, indicating the soft magnetic properties of the sample, M s (@800kA / m)=170emu / g.

[0129] The magnetic permeability curve of the iron-based amorphous soft magnetic powder core in Example 2 measured by an impedance analyzer is as follows: Fig.13 As shown, the effective permeability is 35 and the cut-off frequency exceeds 3MHz.

[0130] The core loss of the iron-based amorphous soft magnetic powder core in Example 2 varies with frequency using a BH instrument. Fig.14 As shown, as the frequency increases, the core loss increases rapidly, P cv (0.05T,100kHz)=250mW / cm 3 .

[0131] Example 3

[0132] This embodiment provides a method for preparing an iron-based amorphous soft magnetic powder core, the preparation method comprising the following steps:

[0133] Step 1, press Fe 76.1 C 7 Si 3.3 B 5 P 8 Cu 0.3 Cr 0.3 The alloy components are batched and the master alloy ingot is induction melted. The melted master alloy ingot is placed in a quartz tube with an opening at the bottom, the cavity is closed, and the cavity is vacuumed to 5×10 -3 Pa, filled with high-purity argon gas for protection, turned on the heating power supply and added current to remelt the alloy ingot, and the molten droplets were broken into Fe under the high-pressure argon gas (8MPa, 1200℃) spray. 76.1 C 7 Si 3.3 B 5 P 8 Cu 0.3 Cr 0.3 Amorphous powder was sieved through 200 mesh for subsequent experiments.

[0134] The Fe prepared above 76.1 C 7Si 3.3 B 5 P 8 Cu 0.3 Cr 0.3 SEM images of amorphous powder Fig.15 As shown in Figure 1, most of the powder is spherical. The XRD spectrum of powder with a particle size less than 150 μm is shown in Figure 1. Fig.16 As shown in the figure, only two broad peaks (~45° and ~80°) were observed without any sharp crystallization peaks, indicating that the sample has a completely amorphous structure. This further shows that the alloy system developed in this patent has good forming ability and can meet the needs of industrial atomization powder production. The powder DSC curve is shown in Fig.17 As shown, T C =350℃, Tg=460℃, T x1 =490℃, T x2 =550℃.

[0135] Step 2, weigh 10g of Fe prepared in step 1 76.1 C 7 Si 3.3 B 5 P 8 Cu 0.3 Cr 0.3 Amorphous powder; weigh 0.05g concentrated phosphoric acid and dissolve it in acetone solution, stir thoroughly and 48kHz ultrasonic for 5min until it is evenly dissolved; 76.1 C 7 Si 3.3 B 5 P 8 Cu 0.3 Cr 0.3 The amorphous powder was poured into acetone phosphate solution, stirred and assisted with 48kHz ultrasound for 15 minutes to complete the powder passivation; 0.2g silicone resin was weighed, dissolved in acetone solution, fully stirred and assisted with 48kHz ultrasound for 5 minutes until it was evenly dissolved, poured into the passivated amorphous powder, and continuously stirred and assisted with 48kHz ultrasound for 15 minutes until the solution was completely volatilized to complete the powder insulation coating; the coated powder was placed in an oven, set the temperature to 60°C, and kept warm for 12 hours until the powder was completely dry; the powder was taken out and ground through a 200-mesh sieve for subsequent powder core molding.

[0136] The SEM image of the amorphous powder after the above coating is as follows Fig.18 As shown, there is a coating layer on the surface.

[0137] Step 3, weigh 1.5g of the coated powder from step 2 and put it into a cold pressing mold, and use a hydraulic press to press it into a ring-shaped sample. The outer diameter of the magnetic ring is 13mm, the inner diameter is 8mm, the thickness is 3mm, and the pressing force is 1.8GPa.

[0138] Step 4: Place the magnetic powder core formed in step 3 into the sample stage of the composite magnetic field heat treatment furnace and evacuate the cavity to 5×10 -3 Pa, the sample was heated to 250 °C at a heating rate of 20 K / min and kept at this temperature for 15 min to complete the curing;

[0139] The solidified magnetic core is heated to 550°C at a heating rate of 60K / min, and a 0.1T magnetic field is applied. The sample is rotated at a speed of 100r / min and kept warm for 10 minutes to complete the rotating magnetic field heat treatment to obtain the heat-treated sample. The heat-treated sample is placed in water and cooled to room temperature to obtain the iron-based amorphous soft magnetic powder core.

[0140] The hysteresis loop of the iron-based amorphous soft magnetic powder core in Example 3 was measured by MPMS. Fig.19 As shown, it is a typical S-shaped curve, indicating the soft magnetic properties of the sample, M s (@800kA / m)=172.5emu / g.

[0141] The magnetic permeability curve of the iron-based amorphous soft magnetic powder core in Example 3 measured by an impedance analyzer is as follows: Fig. 20 As shown, the effective permeability is 32 and the cut-off frequency exceeds 2MHz.

[0142] Fe 76.1 C 7 Si 3.3 B 5 P 8 Cu 0.3 Cr 0.3 See the graph of powder core loss versus frequency for Fig.21 , the test external field is 0.1T.

[0143] Example 4

[0144] This embodiment provides a method for preparing an iron-based amorphous soft magnetic powder core. The preparation method is the same as that of Embodiment 1 except that a 0.01 T magnetic field is applied in step 4, and will not be described in detail here.

[0145] In this embodiment, the core loss will be increased to 900-1200 mW / cm 3 Within this range, the magnetic permeability will drop to 30.

[0146] Example 5

[0147] The present embodiment provides a method for preparing an iron-based amorphous soft magnetic powder core. The preparation method is the same as that of Embodiment 1 except that in step 4, the temperature of the solidified magnetic core is increased to 225° C. at a heating rate of 40 K / min, and will not be described again.

[0148] In this embodiment, the magnetic permeability will drop to between 10 and 20.

[0149] Example 6

[0150] The present embodiment provides a method for preparing an iron-based amorphous soft magnetic powder core. The preparation method is the same as that of Embodiment 1 except that in step 4, the temperature of the solidified magnetic core is raised to 600° C. at a heating rate of 40 K / min, and will not be described again.

[0151] In this embodiment, the magnetic permeability will drop very quickly to close to 0.

[0152] Example 7

[0153] This embodiment provides a method for preparing an iron-based amorphous soft magnetic powder core. The preparation method is the same as that of Embodiment 1 except that the rotation speed in step 4 is 5 r / min, and will not be described again.

[0154] In this embodiment, the magnetic permeability is only 30, and the magnetic loss is significantly increased compared with that in Embodiment 1.

[0155] Example 8

[0156] This embodiment provides a method for preparing an iron-based amorphous soft magnetic powder core. The preparation method is the same as that of Embodiment 1 except that the rotation speed in step 4 is 150 r / min, and will not be described in detail here.

[0157] In this embodiment, the magnetic permeability is reduced compared to that in Embodiment 1 and the magnetic loss is significantly increased.

[0158] Comparative Example 1

[0159] This comparative example provides a method for preparing an iron-based amorphous soft magnetic powder core. The preparation method is the same as Example 1 except that no magnetic field is added in step 4, and the details are not repeated here.

[0160] In this embodiment, the magnetic permeability will drop below 10.

[0161] Comparative Example 2

[0162] This comparative example provides a method for preparing an iron-based amorphous soft magnetic powder core. The preparation method is the same as that of Example 1 except that no rotation is performed in step 4, and will not be described in detail here.

[0163] In this embodiment, the magnetic permeability is only 25, and the magnetic loss is significantly improved compared with that in Embodiment 7.

[0164] Comparative Example 3

[0165] This comparative example provides a method for preparing an iron-based amorphous soft magnetic powder core. The preparation method is the same as Example 1 except that no rotation and no magnetic field are added in step 4, and the details are not repeated here.

[0166] This comparative example not only has a very low magnetic permeability, but also has a higher magnetic loss than comparative example 2.

[0167] Test method: The iron-based amorphous soft magnetic powder cores in the above examples and comparative examples were tested using the same method as in Example 1.

[0168] In summary, it can be seen that the preparation method of the iron-based amorphous soft magnetic powder core provided by the present invention prepares amorphous alloy powder by gas atomization, and selects amorphous alloy powder of specific components, so that the amorphous magnetic powder core can have the effects of high magnetization intensity, high magnetic permeability and low loss at the same time, has excellent comprehensive soft magnetic properties, and has broad application prospects.

[0169] The present invention illustrates the detailed features of the present invention through the above embodiments, but the present invention is not limited to the above detailed features, that is, it does not mean that the present invention must rely on the above detailed features to be implemented. Those skilled in the art should understand that any improvement to the present invention, equivalent replacement of the technical features selected by the present invention, addition of auxiliary technical features, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing an iron-based amorphous soft magnetic powder core, characterized in that: The preparation method comprises the following steps: (1) The master alloy ingot is sequentially smelted and gas-atomized to obtain an iron-based amorphous powder; (2) the iron-based amorphous powder of step (1) is passivated with a passivating agent and then insulated and coated with a resin to obtain a coated powder; (3) The coated powder in step (2) is successively subjected to pressing and rotating magnetic field heat treatment to obtain the iron-based amorphous soft magnetic powder core.

2. The preparation method according to claim 1, characterized in that: The chemical formula of the master alloy ingot in step (1) is Fe a B b C c Si d P e Cu f Co g TM h , a+b+c+d+e+f+g=100, wherein 70<a≤80, 0<b≤10, 0<c≤10, 0<d≤10, 0<e≤10, 0<f≤1, 0<g≤1, 0<h≤1, wherein TM is selected from any one of Nb, Cr, V, Mo or Zr or a combination of at least two thereof; Preferably, the smelting comprises induction smelting; Preferably, the iron-based amorphous powder having a screening particle size of less than 200 mesh is used in step (2).

3. The preparation method according to claim 1 or 2, characterized in that: The atomization pressure in step (2) is 8-10 MPa; Preferably, the aerosolized gas comprises argon; Preferably, the temperature of the gas atomization is 1200-1500°C.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The passivating agent in step (2) includes phosphoric acid; Preferably, the phosphoric acid accounts for 0.1-1% by mass of the iron-based amorphous powder in step (1); Preferably, the concentration of the phosphoric acid is 0.5 wt.%.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The resin in step (2) includes epoxy resin and / or silicone resin; Preferably, the resin accounts for 1-5% by mass of the iron-based amorphous powder in step (1).

6. The preparation method according to any one of claims 1 to 5, characterized in that: The passivation and insulation coating in step (2) are each independently carried out in an acetone solution; Preferably, the passivation and insulation coating are each independently performed by ultrasound; Preferably, the frequency of ultrasound in the passivation is 40 to 48 kHz; Preferably, the ultrasonic time in the passivation is 10 to 30 minutes; Preferably, the frequency of the ultrasound in the insulating coating is 40 to 48 kHz; Preferably, the ultrasonic time in the insulating coating is 10 to 30 minutes; Preferably, the passivation in step (2) comprises: dissolving the passivating agent in an acetone solution and performing a first ultrasound to obtain a first system; mixing the iron-based amorphous powder with the first system, and performing a second ultrasound, solid-liquid separation and drying to obtain a passivated powder.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The press forming comprises cold press forming; Preferably, the compression molding is 1.5 to 2.2 GPa; Preferably, the rotating magnetic field heat treatment comprises: heat treating the pressed sample; Preferably, the heat treatment includes first heating the temperature to a first temperature at a first heating rate for a first heat preservation, and then heating the temperature to a second temperature at a second heating rate for a second heat preservation; Preferably, the first heating rate is 20-100K / min; Preferably, the first temperature is 150-250°C; Preferably, the first insulation time is 15 to 50 minutes; Preferably, the second heating rate is 20-100K / min; Preferably, the second temperature is 300-550°C; Preferably, the second insulation time is 10 to 30 minutes; Preferably, in the second insulation stage, rotation and magnetic field conditions are added; Preferably, the rotation speed is 10 to 100 r / min; Preferably, the magnetic field strength of the magnetic field condition is 0 to 0.1 T, excluding 0; Preferably, after the rotating magnetic field heat treatment, the preparation method further comprises: cooling the sample; Preferably, the cooling comprises water cooling.

8. An iron-based amorphous soft magnetic powder core, characterized in that: The iron-based amorphous soft magnetic powder core is prepared by the preparation method of the iron-based amorphous soft magnetic powder core according to any one of claims 1 to 7.

9. The iron-based amorphous soft magnetic powder core according to claim 8, characterized in that: The saturation magnetization intensity of the iron-based amorphous soft magnetic powder core is above 170emu / g; Preferably, the effective magnetic permeability of the iron-based amorphous soft magnetic powder core is above 32; Preferably, the frequency stability of the iron-based amorphous soft magnetic powder core is above 2 MHz; Preferably, the core loss of the iron-based amorphous soft magnetic powder core at 0.1T and 100kHz is ≤980mW / cm 3 ; Preferably, the core loss of the iron-based amorphous soft magnetic powder core at 0.05T and 100kHz is ≤255mW / cm 3 ; Preferably, the particle size of the iron-based amorphous soft magnetic powder core is within 200 meshes.

10. An electronic device, characterized in that: The electronic device comprises the iron-based amorphous soft magnetic powder core according to claim 8 or 9.

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