Iron-based nanocrystalline soft magnetic alloy powder, soft magnetic composite material and preparation method therefor

Abstract

Disclosed are an iron-based nanocrystalline soft magnetic alloy powder, a soft magnetic composite material, and a preparation method therefor. The atomic percentage molecular formula of the iron-based nanocrystalline soft magnetic alloy powder is: FeaBbCcSidCueMmQqZzXx, M being at least one of Co and Ni, Q being at least one of a pre-transition element, a semi-metal element, a rare earth element and Al, Z being at least one of Au, Ag and a platinum group metal element, X being at least one of O, N, S and a halogen element, 70≤a+m≤75, 8≤b≤18, 0≤c≤5, 10≤d≤15, 0≤m≤10, 1.3≤e≤2.5, 0≤q≤2, 0≤z≤1, 0≤x≤0.2, 22≤b+c+d≤30, and a+b+c+d+e+m+q+z+x=100. The soft magnetic composite material is composed of the described iron-based nanocrystalline soft magnetic alloy powder, an alloy-state soft magnetic powder, a binder and the like. The provided iron-based nanocrystalline soft magnetic alloy powder and soft magnetic composite material exhibit excellent soft magnetic performance, good processability and low cost.

Description

Iron-based nanocrystalline soft magnetic alloy powder, soft magnetic composite material and preparation method thereof

[0001] This application claims priority to the Chinese patent application filed with the Patent Office of China on June 27, 2023, with application number 202310766598.4, and invention name “A kind of iron-based nanocrystalline soft magnetic alloy powder, soft magnetic composite material and preparation method thereof”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of soft magnetic materials, and in particular to an iron-based nanocrystalline soft magnetic alloy powder, a soft magnetic composite material and a preparation method thereof. Background Art

[0003] The rapid development of new energy vehicles, 5G communications and smart homes has put higher and higher requirements on the performance of power electronic devices. It is necessary to develop new soft magnetic materials to meet the requirements of high frequency, energy saving and miniaturization. This requires the realization of high frequency stability, low coercivity, low loss and high saturation magnetization (M) in soft magnetic materials. s ) performance indicators. The currently commonly used high M s The powders are mainly iron silicon powder, iron silicon chromium and permalloy powder, but they all have the problem of high high-frequency loss, which does not conform to the current trend of energy saving and high frequency of power electronic equipment. In addition, the cost of permalloy powder is relatively high, which to some extent hinders their application scope.

[0004] Soft magnetic composite materials are made by pressing ferromagnetic particles coated with insulating agents through powder metallurgy technology. They have excellent soft magnetic properties, low eddy current loss, high resistivity, easy machining, wide operating frequency range, etc., and are widely used in inductors in electronic components. As inductors develop towards miniaturization, soft magnetic composite materials will inevitably be required to develop in a direction that is conducive to the miniaturization of inductors. This requires soft magnetic composite materials to have low core loss, high magnetic permeability and high saturation magnetization, and excellent high-frequency magnetic properties. The properties of soft magnetic powders and the selection of insulating agents and binders have a crucial influence on the performance of soft magnetic composites. The compounding of soft magnetic powders of different types, particle sizes and hardnesses can greatly increase the filling density of soft magnetic composites and reduce the gaps between powders, which will be beneficial to improving the magnetic permeability of electronic devices. The compounding of small-particle powders can reduce the average particle size of the powders and reduce the eddy current loss between particles of soft magnetic composites, thereby significantly reducing high-frequency losses. The currently used high M s Soft magnetic composite materials are mainly iron-silicon and iron-nickel soft magnetic composite materials, but both have the problem of high high-frequency loss, which is not conducive to the high-frequency development of power electronic devices. In addition, the high composition of iron-nickel soft magnetic composite materials limits their application range.

[0005] Iron-based nanocrystalline soft magnetic alloys have low magnetostriction coefficient, low loss, high magnetic permeability, high M s The soft magnetic composite material has attracted extensive attention from scientists and industry due to its excellent high-frequency magnetic properties. s Higher advantages. The iron-based nanocrystalline soft magnetic alloy is prepared into a powder and then prepared into a soft magnetic composite material using a powder metallurgy process. This can combine the dual advantages of the iron-based nanocrystalline soft magnetic alloy and the soft magnetic composite material to become a new generation of high-performance soft magnetic materials - nanocrystalline soft magnetic composite materials, which will promote the development of high-frequency, high-performance electronic devices and power equipment and related industries. At present, iron-based nanocrystalline soft magnetic alloys are mainly designed and developed for the single-roll belt spinning method with a very high cooling rate. The amorphous formation ability is weak. It is necessary to first obtain a completely amorphous precursor thin strip through the single-roll belt spinning method, heat treat it to obtain a nanocrystalline alloy, and then crush it through the ball milling method to obtain soft magnetic powder. However, these strip crushed powders have sharp edges and corners, which are difficult to insulate and coat, resulting in high losses in the soft magnetic composite material, limiting its application in higher frequency bands. The spherical or ellipsoidal powders obtained by the atomization method have good coatability and can effectively reduce the loss of soft magnetic composite materials at high frequencies.

[0006] Typical iron-based nanocrystalline soft magnetic alloy systems include Fe-Si-B-Nb-Cu alloys and Fe-Si-BP-Cu alloys. For Fe-Si-B-Nb-Cu alloys, their advantages are lower coercivity, high magnetic permeability and low loss, which are derived from their nucleation mechanism: Cu atoms separate and act as nucleation centers. The addition of Nb or other slowly diffusing components (such as Ta, V and W) limits the growth of crystals, thereby reducing the grain size. Niobium and boron are excluded from the α-Fe primary particles and are distributed into the remaining amorphous phase. Since the enrichment of Nb and B stabilizes the remaining amorphous phase, the growth of α-Fe primary crystals is suppressed. However, the M of Fe-Si-B-Nb-Cu nanocrystalline alloys s The power density of the soft magnetic composite material is only 1.2T, which is not conducive to the miniaturization and high current of electronic devices and power equipment. In addition, the process of this type of nanocrystalline alloy powder is relatively complicated. It is necessary to first prepare an amorphous precursor and then heat treat it at about 600℃ for one hour to obtain excellent soft magnetic properties. sAs high as 1.9T, but it is difficult to obtain a completely amorphous precursor through the atomization method, and it requires a faster heating rate to obtain a dense and uniform fine nanocrystalline structure. The nanocrystalline structure and soft magnetic properties of the powder are very demanding on the heat treatment process, requiring a high heating rate (200-9000℃ / min) heat treatment that is difficult to achieve under industrial conditions. The magnetic properties are very poor under conventional heat treatment processes; and the alloy contains volatile and flammable P elements. The volatilization of P elements during the alloy preparation process makes it difficult to control the alloy composition and there is a risk of flammability. The poor processability seriously hinders the large-scale production of its powder and soft magnetic composite materials.

[0007] In summary, nanocrystalline soft magnetic composite materials have excellent soft magnetic properties, which are very consistent with the current development direction of smart terminals, 5G communications, industrial Internet and new energy vehicles. However, the inventors realized that the low Ms or poor processability of existing iron-based nanocrystalline soft magnetic alloys seriously restricts the application scope and industrialization of nanocrystalline powder cores. Therefore, it is necessary to develop a nanocrystalline soft magnetic composite material with both high Ms and poor processability. s Nanocrystalline alloy powders with excellent soft magnetic properties and processability, and the development of high-performance soft magnetic composite materials based on them will have very important industrial value.

[0008] Summary of the Invention

[0009] In view of the shortcomings of current nanocrystalline alloy powders and soft magnetic composite materials, this application provides a high M s , iron-based nanocrystalline soft magnetic alloy powder with excellent soft magnetic properties and processability and low cost. The application also provides a soft magnetic composite material and a preparation method thereof.

[0010] According to one embodiment of the present invention, there is provided an iron-based nanocrystalline soft magnetic alloy powder, the atomic percentage formula of which is: Fe a B b C c Si d Cu e M m Q q Z z X x, wherein M is at least one of Co and Ni, Q is at least one of an early transition element, a semi-metal element, a rare earth element, and Al, the early transition element is Ti, V, Cr, Mn, Y, Zr, Nb, Mo, Hf, Ta, or W, the semi-metal element is Ge, Sn, As, or Sb, Z is at least one of Au, Ag, and a platinum group metal element, X is at least one of O, N, S, and a halogen element, 70≤a+m≤75, 8≤b≤18, 0≤c≤5, 10≤d≤15, 0≤m≤10, 1.3≤e≤2.5, 0≤q≤2, 0≤z≤1, 0≤x≤0.2, and 22≤b+c+d≤30, a+b+c+d+e+m+q+z+x=100.

[0011] Based on the combined effect of the elements and their contents provided in this application, the iron-based nanocrystalline soft magnetic alloy powder provided by the present invention can be directly prepared from the master alloy by an atomization method, and does not require subsequent heat treatment. The atomization method includes but is not limited to gas atomization, water atomization, water-gas combined atomization, rotary water atomization and multi-stage crushing atomization, and the preparation process is short and the process is simple.

[0012] According to one embodiment of the present application, the iron-based nanocrystalline soft magnetic alloy powder does not contain volatile P elements, and the composition is easy to control; and does not contain or contains only a small amount of relatively expensive elements such as Co, Ni and Nb, so the material cost is low.

[0013] According to one embodiment of the present application, the iron-based nanocrystalline soft magnetic alloy powder is spherical or ellipsoidal, with a smooth surface and no sharp edges, which is convenient for insulation coating treatment, helps to reduce the loss of the soft magnetic composite material, and improves the stability of the soft magnetic composite material in high-frequency applications.

[0014] According to one embodiment of the present application, the iron-based nanocrystalline soft magnetic alloy powder has excellent soft magnetic properties, the average size of the α-Fe grains in the powder is 10-18 nm, and the saturation magnetization intensity M of the powder is s 150.0-170.0emu / g, coercive force H c 3.0-7.0Oe.

[0015] According to one embodiment of the present application, the sum of the atomic percentages of Fe and M is 72≤a+m≤74, and the atomic percentage of M is 0≤m≤5. The Fe-based nanocrystalline soft magnetic alloy powder uses Fe as a magnetic source, and a higher Fe content helps to obtain a high M sNanocrystalline alloy. By controlling the content of Cu, the types and contents of metalloid elements and other trace elements, and coordinating them with Fe, the alloy powder can form a complex phase structure with fine α-Fe grains distributed in the amorphous phase during the atomization process. The interaction between the grains and the amorphous phase can significantly reduce the magnetocrystalline anisotropy and magnetostriction coefficient, thereby giving the powder excellent soft magnetic properties. Co and Ni are also common ferromagnetic elements, but their costs are relatively high, and a large amount of addition will reduce the M of the alloy powder. s Therefore, replacing Fe element with a small amount of at least one of Co or Ni in the iron-based nanocrystalline soft magnetic alloy powder can also make the powder have a higher M s And the raw material cost of the alloy powder will not be greatly increased.

[0016] According to one embodiment of the present application, the atomic percentage of B in the iron-based nanocrystalline soft magnetic alloy powder is 10≤b≤15, the atomic percentage of C in the iron-based nanocrystalline soft magnetic alloy powder is 0≤c≤3, and the atomic percentage of Si in the iron-based nanocrystalline soft magnetic alloy powder is 11≤d≤14, and 24<b+c+d≤28. By regulating the content of specific metalloid elements and the total content of metalloid elements in the iron-based nanocrystalline soft magnetic alloy powder, it is helpful for the alloy to obtain good amorphous forming ability, thereby inhibiting the precipitation of non-soft magnetic material Fe-B compounds during the atomization process, forming a nanocrystalline structure containing only nanoscale α-Fe grains and amorphous phases, so that the powder obtains high M s And excellent soft magnetic properties.

[0017] According to one embodiment of the present application, the atomic percentage of Cu in the iron-based nanocrystalline soft magnetic alloy powder is 1.5≤f≤2.0. The Cu element in the iron-based nanocrystalline soft magnetic alloy promotes the nucleation of the α-Fe phase. A sufficient amount of Cu is necessary for the formation of fine α-Fe grains during the atomization process, but an excessive amount of Cu can also lead to the formation of non-soft magnetic Fe-B compounds in the powder. Therefore, an appropriate Cu content in the iron-based nanocrystalline soft magnetic alloy powder is conducive to the formation of high-density and fine-sized nano-α-Fe grains, which makes the powder exhibit excellent soft magnetic properties.

[0018] Optionally, the atomic percentage of the Q element in the iron-based nanocrystalline soft magnetic alloy powder is 0≤q≤1. Adding the Q element to the iron-based nanocrystalline soft magnetic alloy powder helps to suppress the precipitation of non-soft magnetic Fe-B compounds, but excessive addition will significantly reduce the M of the alloy. s Therefore, the iron-based nanocrystalline soft magnetic alloy powder contains a small amount of Q element, which helps the powder to form a complex phase structure with nano-α-Fe grains distributed in the amorphous phase and excellent soft magnetic properties, and will not excessively reduce the powder M s .

[0019] According to one embodiment of the present application, the atomic percentage of the Z element in the iron-based nanocrystalline soft magnetic alloy powder is 0≤z≤0.5. Adding Au, Ag, and platinum group metal elements to the nanocrystalline alloy can also promote the nucleation of the α-Fe phase, but the effect is less than that of Cu and the cost is higher. Therefore, the inclusion of a small amount of the Z element in the iron-based nanocrystalline soft magnetic alloy powder can also cause the powder to form fine α-Fe grains and exhibit excellent soft magnetic properties, while not excessively increasing the raw material cost of the alloy powder.

[0020] According to one embodiment of the present application, the atomic percentage of the X element in the iron-based nanocrystalline soft magnetic alloy powder is 0≤x≤0.1. Common industrial raw materials often contain impurities such as O, N, S, and halogen elements. Although small amounts of these elements do not significantly affect the structure and magnetic properties of the nanocrystalline powder, excessive amounts can lead to serious deterioration of the alloy's structure and performance. Therefore, the inclusion of a small amount of the X element in the iron-based nanocrystalline soft magnetic alloy powder can also form fine α-Fe grains and exhibit excellent soft magnetic properties, and the alloy powder can be produced using raw materials of lower purity.

[0021] According to another embodiment of the present invention, a soft magnetic composite material is provided, comprising a mixed powder and a binder coating the mixed powder, wherein the mixed powder is the above-mentioned iron-based nanocrystalline soft magnetic alloy powder and alloy-state soft magnetic powder; wherein the alloy-state soft magnetic powder is selected from at least one of carbonyl iron powder, iron silicon powder, iron silicon chromium powder, sendustine aluminum powder, and iron nickel powder, and the mass of the alloy-state soft magnetic powder accounts for 0-95% of the total mass of the mixed powder; the binder is selected from at least one of epoxy resin, phenolic resin, polyamide resin, and silicone resin, and the mass of the binder accounts for 1-5% of the total mass of the mixed powder.

[0022] The iron-based nanocrystalline soft magnetic alloy powder in the soft magnetic composite material provided by this application has high M s and excellent soft magnetic properties, which helps the soft magnetic composite material to obtain low loss and high magnetic permeability under high frequency conditions. The carbonyl iron powder in the soft magnetic composite material provided by the present invention usually has a smaller particle size, which can effectively reduce the eddy current loss within the particles under high frequency conditions, and can reduce the porosity of the soft magnetic composite material, thereby helping to reduce the high-frequency loss of the soft magnetic composite material and improve its magnetic permeability. The carbonyl iron powder, iron silicon powder, iron silicon chromium powder, iron silicon aluminum powder, and iron nickel powder in the soft magnetic composite material provided by the present invention usually have a smaller hardness, which helps to increase the pressing density of the soft magnetic composite material, so that the soft magnetic composite material has a higher magnetic permeability.

[0023] The soft magnetic composite material provided by this application has excellent high-frequency magnetic properties, and its loss (1MHz / 50mT) is as low as 2000-4000mW / cm 3The magnetic permeability (@100kHz) can reach 30-70, which has broad application prospects in high-performance power electronic devices.

[0024] According to another embodiment of the present invention, there is provided a method for preparing a soft magnetic composite material, comprising:

[0025] (1) preparing the materials according to the atomic percentage composition formula of the iron-based nanocrystalline soft magnetic powder, smelting them uniformly, and preparing a master alloy;

[0026] (2) preparing the master alloy into an iron-based nanocrystalline soft magnetic powder by an atomization method;

[0027] (3) mixing the iron-based nanocrystalline soft magnetic powder obtained in step (2) with the alloy soft magnetic powder, and adding a binder for coating to obtain a coated mixed soft magnetic powder;

[0028] (4) Pressing the coated mixed soft magnetic powder obtained in step (3) into a soft magnetic composite material and heat treating the composite material.

[0029] Optionally, the heat treatment process of the soft magnetic composite material in step (3) is: vacuum heating at 300-600° C. for 30-120 min.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] (1) The iron-based nanocrystalline soft magnetic alloy powder provided in this application can be directly prepared from the master alloy by the atomization method, without the need for subsequent heat treatment. The process is simple and short, which can significantly improve production efficiency and reduce process costs. It does not contain volatile P elements and its composition is easy to control.

[0032] (2) The iron-based nanocrystalline soft magnetic alloy powder provided in this application has high saturation magnetization intensity, low coercive force, low magnetic loss and high magnetic permeability.

[0033] (3) The nanocrystalline alloy powder provided in this application is spherical or ellipsoidal in shape, which is easy to coat and helps the soft magnetic composite material prepared therefrom to obtain lower loss.

[0034] (4) The nanocrystalline alloy powder provided in this application does not contain or contains low amounts of high-cost raw materials such as Co, Ni and Nb, so the material cost is low.

[0035] (5) The soft magnetic composite material provided in this application has both low loss and high magnetic permeability, which is conducive to the miniaturization and high frequency of power electronic devices, and has broad application prospects and good industrialization potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG1 is a scanning electron microscope (SEM) image of the iron-based nanocrystalline soft magnetic alloy powder prepared in Example 1;

[0037] FIG2 is an X-ray diffraction (XRD) pattern of the iron-based nanocrystalline soft magnetic alloy powder prepared in Example 1;

[0038] FIG3 is a transmission electron microscope (TEM) image of the iron-based nanocrystalline soft magnetic alloy powder prepared in Example 1;

[0039] FIG4 is a vibrating sample magnetometer (VSM) graph of the soft magnetic powders obtained in Example 1 and Comparative Example 1;

[0040] FIG5 is a loss graph of the soft magnetic composite materials prepared in Examples 1, 10 and Comparative Example 1;

[0041] FIG6 is a graph showing the change in magnetic permeability of the soft magnetic composite materials obtained in Examples 1, 10 and Comparative Example 1 as a function of frequency. DETAILED DESCRIPTION

[0042] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, specific embodiments of the present application are described in detail below with reference to the accompanying drawings. However, the scope of protection of the present application is not limited to the following embodiments. Examples 1-9 illustrate the preparation and performance testing processes of the iron-based nanocrystalline soft magnetic alloy powder and soft magnetic composite material disclosed in this application. Comparative Examples 1-6 list the performance of common soft magnetic powders and their soft magnetic composite materials for comparison.

[0043] Example 1

[0044] In this embodiment, the alloy composition expression is: Fe 73.3 Si 12 B 13 Cu 1.7 The preparation and performance testing methods and steps of iron-based nanocrystalline soft magnetic alloy powder and soft magnetic composite materials are as follows:

[0045] (1) Ingredients: Fe, Si, Cu and FeB alloy raw materials with a mass percentage purity of not less than 99% are mixed according to the atomic percentage formula Fe 73.3 Si 12 B 13 Cu 1.7 Weighing and preparing alloy raw materials;

[0046] (2) Melting the master alloy: Place the alloy raw materials prepared in step 1 into a melting furnace, evacuate to less than 1.0 Pa, introduce argon to 0.05 MPa, and melt at a temperature of 1400°C. After melting evenly, hold the temperature for 5 minutes to ensure chemical uniformity of the alloy ingot to form a master alloy;

[0047] (3) Preparation of Fe-based nanocrystalline soft magnetic alloy powder: The master alloy prepared in step 2 was placed in an atomization device with a nozzle diameter of 1.0 mm. The master alloy was heated to 1500°C, completely melted, and then held at this temperature for 10 seconds before being atomized. The spray pressure used was 0.2 MPa and the atomizing gas pressure was 8 MPa to obtain Fe-based nanocrystalline soft magnetic alloy powder.

[0048] (4) Coating: Use epoxy resin with a mass fraction of 3% of magnetic powder as a binder and dissolve it in acetone. Take an appropriate amount of the nanocrystalline alloy powder obtained in step 3, add it to acetone and disperse it evenly by ultrasonic dispersion. After the acetone is completely evaporated, the nanocrystalline alloy coated powder is obtained, and the powder is placed in a vacuum oven at 60-80°C and dried for 1 hour.

[0049] (5) Ring making: The nanocrystalline alloy coated powder prepared in step 4 was pressed into a magnetic ring with an inner diameter of 12.7 mm, an outer diameter of 20.3 mm and a height of 2.3 mm using a pressure of 1800 MPa, and then subjected to vacuum heat treatment at 480°C for 60 min to obtain an iron-based nanocrystalline soft magnetic composite material.

[0050] The following tests were performed on the iron-based nanocrystalline soft magnetic alloy powder and the soft magnetic composite material prepared above:

[0051] (1) The obtained iron-based nanocrystalline soft magnetic alloy powder is sieved to obtain an average particle size D 50 The powder is 13-15 μm in size, and the morphology of the iron-based nanocrystalline soft magnetic alloy powder is observed using a scanning electron microscope (SEM). The morphology of the obtained iron-based nanocrystalline soft magnetic alloy powder is shown in Figure 1, from which it can be seen that the obtained iron-based nanocrystalline soft magnetic alloy powder has good sphericity.

[0052] (2) XRD was used to analyze the structure of the iron-based nanocrystalline soft magnetic alloy powder, and the analysis results are shown in Figure 2. The XRD spectrum contains three sharp diffraction peaks corresponding to the α-Fe phase and a diffuse scattering peak, indicating that the structure of the powder is a two-phase composite structure in which the α-Fe nanocrystalline phase is distributed in the amorphous matrix.

[0053] (3) TEM was used to analyze the microstructure of the iron-based nanocrystalline soft magnetic alloy powder. The TEM analysis results are shown in Figure 3. As can be seen from the figure, the powder structure is a two-phase composite structure with a crystalline phase uniformly distributed in an amorphous matrix, with an average crystal size of 15.1 nm. Selected area electron diffraction shows that the generated crystalline phase is an α-Fe phase.

[0054] (4) The magnetic properties of Fe-based nanocrystalline soft magnetic alloy powder were analyzed by VSM. The results are shown in Figure 4. s and H cAs shown in Table 1, the VSM curve of the Fe-based nanocrystalline soft magnetic alloy powder is narrow and its coercive force is very small, indicating that it has typical soft magnetic characteristics. s and H c They are 156.2emu / g and 6.3Oe respectively.

[0055] (5) As shown in FIG5 , the iron-based nanocrystalline soft magnetic alloy powder provided in the embodiment of the present application exhibits excellent soft magnetic properties, with a low magnetic field strength of 3650 mW / cm 3 (50mT / 1MHz) loss, while Fe 50 Ni 50 (Mass percentage composition formula, the same below) The loss of the soft magnetic composite material is 7885mW / cm 3 (50mT / 1MHz).

[0056] (6) As shown in FIG6 , the iron-based nanocrystalline soft magnetic alloy powder provided in the embodiment of the present application exhibits excellent high-frequency stability within 10 MHz, and the magnetic permeability μ e 43.1, Fe 50 Ni 50 The magnetic permeability of the soft magnetic composite material is 42.5, and the frequency stability is poor.

[0057] Examples 2-9

[0058] The preparation and performance testing methods and steps of Fe-based nanocrystalline soft magnetic alloy powder and soft magnetic composite material are as follows:

[0059] (1) Ingredients: Raw materials with a mass percentage purity of not less than 99% are weighed according to the atomic percentage formula in Table 1 to prepare alloy raw materials;

[0060] (2) Melting the master alloy: the same as step 2 in Example 1;

[0061] (3) Preparation of iron-based nanocrystalline soft magnetic alloy powder: the same as step 3 in Example 1;

[0062] (4) Coating: the same as step 4 in Example 1;

[0063] (5) Ring making: the same as step 5 in Example 1.

[0064] The structural and magnetic property tests of the iron-based nanocrystalline soft magnetic alloy powder and the soft magnetic composite material prepared above were the same as those in Example 1:

[0065] Comparative Example 1

[0066] This comparative example is commercial Fe 50 Ni 50 Alloy powder has excellent comprehensive magnetic properties, but high loss and cost.

[0067] Comparative Example 2

[0068] This comparative example is commercial Fe 73.5 Si 13.5 B9Nb3Cu1 nanocrystalline powder has excellent comprehensive magnetic properties, but low Ms.

[0069] Comparative Example 3

[0070] This comparative example comes from patent CN101263240B. Its amorphous forming ability is poor, and the atomized powder contains a large amount of non-soft magnetic Fe-B phase, resulting in powder H c Very high, the performance of soft magnetic composite materials is poor.

[0071] Comparative Example 4

[0072] This comparative example comes from patent CN101641455B. Its amorphous forming ability is poor, and the atomized powder contains a large amount of non-soft magnetic Fe-B phase, resulting in powder H c Very high, the performance of soft magnetic composite materials is poor.

[0073] Comparative Example 5

[0074] This comparative example comes from patent CN101663410A. Its amorphous forming ability is poor, and the atomized powder contains a large amount of non-soft magnetic Fe-B phase, resulting in powder H c Very high, the performance of soft magnetic composite materials is poor.

[0075] Comparative Example 6

[0076] This comparative example comes from the literature Journal of Applied Physics 109,07A302 (2011). Its amorphous forming ability is poor, and the atomized powder contains a large amount of non-soft magnetic Fe-B phase, which leads to the powder H c Very high, the performance of soft magnetic composite materials is poor.

[0077] Table 1: Average size (D) of α-Fe phase, saturation magnetization (M) and saturation magnetization (M) of the alloys in Examples 1-9 and Comparative Examples 1-6. s ) and coercivity (H c ) and the loss of soft magnetic composite materials at 50mT / 1MHz (P cv ) and the magnetic permeability at 100kHz (μ e )

[0078] Examples 10-29 illustrate the preparation and performance testing process of the soft magnetic composite material prepared by compounding the iron-based nanocrystalline powder and the alloy-state soft magnetic powder provided in this application.

[0079] Example 10

[0080] (1) Powder compounding: Fe 73.3 Si 12 B 13 Cu 1.7 Nanocrystalline powder and carbonyl iron powder are compounded in a mass ratio of 4:6 and mixed evenly to obtain mixed powder, wherein Fe 73.3 Si 12 B 13 Cu 1.7 D of nanocrystalline powder 50 The D of carbonyl iron powder is 13-15μm. 50 4-5μm.

[0081] (2) Coating: Epoxy resin with a mass fraction of 3% of magnetic powder is used as a binder and dissolved in acetone. The compounded mixed powder is added to acetone and dispersed evenly by ultrasonic dispersion. After the acetone is completely evaporated, the nanocrystalline alloy coated powder is obtained and vacuum dried at 60-80°C for 1 hour.

[0082] (3) Ring making: The coated powder prepared in step (2) is pressed into a magnetic ring with an inner diameter of 12.7 mm, an outer diameter of 20.3 mm and a height of 2.3 mm using a pressure of 1800 MPa, and then subjected to vacuum heat treatment at 480°C for 60 min to obtain a soft magnetic composite material.

[0083] The soft magnetic composite material prepared above was subjected to the following tests:

[0084] (1) The AC BH meter was used to characterize the soft magnetic composite material. The curve of its loss versus test frequency is shown in Figure 5. The soft magnetic composite material heat-treated at 480°C showed excellent soft magnetic properties. Its loss at 50mT / 1MHz was 2530mW / cm 3 .

[0085] (2) The soft magnetic composite material was characterized by an impedance analyzer. The curve of its magnetic permeability versus frequency is shown in Figure 6. The soft magnetic composite material heat-treated at 480°C showed excellent high-frequency stability within 10 MHz. The magnetic permeability μ e It is 53.4.

[0086] Examples 11-29

[0087] (1) Powder compounding: The types and proportions of powders are in accordance with Table 2, and the process steps are the same as step 1 in Example 10.

[0088] (2) Coating: The same as step 2 in Example 10.

[0089] (3) Ring making: the same as step 3 in Example 10.

[0090] The magnetic properties characterization of the soft magnetic composite material was the same as that of Example 10, and the measured data are listed in Table 2.

[0091] Table 2 Magnetic powder types, compounding ratios and losses (P) at 50 mT / 1 MHz of the soft magnetic composite materials in Examples 10-29 cv ) and the magnetic permeability at 100kHz (μ e )

[0092] Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will fall within the protection scope of this application.

Claims

1. An iron-based nanocrystalline soft magnetic alloy powder, characterized in that: Atomic percentage of the molecular formula is Fe a B b C c Si d Cu e M m Q q Z z X x , wherein M is at least one of Co and Ni, Q is at least one of an early transition element, a semi-metal element, a rare earth element and Al, the early transition element is Ti, V, Cr, Mn, Y, Zr, Nb, Mo, Hf, Ta or W, the semi-metal element is Ge, Sn, As or Sb, Z is at least one of Au, Ag and a platinum group metal element, X is at least one of O, N, S and a halogen element, 70≤a+m≤75, 8≤b≤18, 0≤c≤5, 10≤d≤15, 0≤m≤10, 1.3≤e≤2.5, 0≤q≤2, 0≤z≤1, 0≤x≤0.2, and 22≤b+c+d≤30, a+b+c+d+e+m+q+z+x=100.

2. The iron-based nanocrystalline soft magnetic alloy powder according to claim 1, characterized in that: The sum of the atomic percentages of the Fe element and the M element is 72≤a+m≤74, and the atomic percentage of the M element is 0≤m≤5.

3. The iron-based nanocrystalline soft magnetic alloy powder according to claim 1, characterized in that: The atomic percentage of element B is 10≤b≤15, the atomic percentage of Si is 11≤d≤14, the atomic percentage of C is 0≤c≤3, and 24≤b+c+d+e≤28.

4. The iron-based nanocrystalline soft magnetic alloy powder according to claim 1, characterized in that: The atomic percentage of Cu is 1.5≤e≤2.

0.

5. The iron-based nanocrystalline soft magnetic alloy powder according to claim 1, characterized in that: The atomic percentage content of the Q element is 0≤q≤1.

6. The iron-based nanocrystalline soft magnetic alloy powder according to claim 1, characterized in that: The atomic percentage of the Z element is 0≤z≤0.

5.

7. The iron-based nanocrystalline soft magnetic alloy powder according to claim 1, characterized in that: The atomic percentage of element X is 0≤x≤0.

1.

8. The iron-based nanocrystalline soft magnetic alloy powder according to claim 1, characterized in that: The average size of α-Fe grains in the iron-based nanocrystalline soft magnetic alloy powder is 10-18 nm, and the saturation magnetization and coercive force are 150.0-170.0 emu / g and 3.0-7.0 Oe respectively.

9. A soft magnetic composite material, characterized in that: It comprises a mixed powder and a binder coating the mixed powder, wherein the mixed powder comprises the iron-based nanocrystalline soft magnetic alloy powder and alloy-state soft magnetic powder as described in any one of claims 1 to 8; wherein the alloy-state soft magnetic powder is selected from at least one of carbonyl iron powder, iron silicon powder, iron silicon chromium powder, iron silicon aluminum powder and iron nickel powder, and its mass accounts for 0-95% of the total mass of the mixed powder; and the binder is selected from at least one of epoxy resin, phenolic resin, polyamide resin and silicone resin, and its mass accounts for 1-5% of the total mass of the mixed powder.

10. A method for preparing the soft magnetic composite material according to claim 9, comprising: (1) preparing ingredients according to the atomic percentage composition formula of the iron-based nanocrystalline soft magnetic powder, smelting them uniformly, and preparing a master alloy; (2) using an atomization method to prepare the master alloy into an iron-based nanocrystalline soft magnetic powder; (3) mixing the iron-based nanocrystalline soft magnetic powder obtained in step (2) with the alloy soft magnetic powder, and adding a binder for coating to obtain a coated mixed soft magnetic powder; (4) Pressing the coated mixed soft magnetic powder obtained in step (3) into a soft magnetic composite material and subjecting it to heat treatment.

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