Amorphous nanocrystalline magnetic soft alloy and preparation method therefor

Abstract

Provided in the present invention are an amorphous nanocrystalline magnetic soft alloy and a preparation method therefor. The molecular formula of the amorphous nanocrystalline magnetic soft alloy is FegMnaSibBcCdCueNbf, wherein 0.5≤a≤2, 12≤b≤16, 7≤c≤11, 0.25≤d≤1, 0.5≤e≤1.5, and 2≤f≤4; and the sum of a to g is 100. An amorphous nanocrystalline magnetic soft material having high frequency and high magnetic conductivity is obtained by means of the component design of an amorphous nanocrystalline magnetic soft alloy in the present invention, and the market's requirements for miniaturization and high frequency of magnetic devices can be satisfied.

Description

Amorphous nanocrystalline soft magnetic alloy and preparation method thereof

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 2024113856521 entitled "Amorphous nanocrystalline soft magnetic alloy and preparation method thereof" filed on September 30, 2024, the entire disclosure of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the field of high-frequency filtering electronic devices, in particular to an amorphous nanocrystalline soft magnetic alloy and a preparation method thereof. BACKGROUND

[0004] Amorphous alloy is an alloy material obtained by cooling a metal in a molten state at a very fast cooling rate. Due to the very fast cooling rate, the atoms in the alloy do not have time to arrange regularly to form crystals and have become solid, and the alloy after complete solidification retains the structure of the atoms in the liquid state. Due to this structure feature of long-range disordered arrangement of atoms, it has a small structure correlation size, and its anisotropy is much lower than that of similar crystal materials, thus having very small coercivity and exhibiting more excellent performance. However, this state is a non-equilibrium state, and when the external conditions change, the alloy tends to form a stable crystal structure, and the atoms inside the alloy nucleate and grow on the amorphous matrix. Proper crystallization treatment can control the size and structure of the crystals precipitated inside the alloy, which has certain improvement on the performance of the alloy, especially when the grain size is at the nanometer level, the existence of nanocrystalline grains makes the alloy exhibit more excellent soft magnetic performance.

[0005] The amorphous nanocrystalline soft magnetic alloy has good comprehensive soft magnetic performance: high saturation magnetic flux density (1.1-1.7T), high effective permeability (10 5 The device made of the amorphous nanocrystalline soft magnetic alloy has the characteristics of good high-frequency performance, small size, and low loss, and is currently widely used in common-mode inductors, wireless charging, transformers, new energy vehicles, transformers, and other fields.

[0006] With the continuous development of electronic power devices towards high frequency, and the rapid development of new energy vehicles, the market demand for the effective permeability μe of filter devices at high frequency (above 100KHz) is becoming higher and higher. The higher the magnetic permeability of the filter device, the better the filtering effect. The current mainstream method to improve the high-frequency magnetic permeability is to reduce the thickness of the nanocrystalline strip, which is limited by production equipment and process. It is very difficult to prepare nanocrystalline strip with a thickness of less than 14μm, and it cannot be mass-produced and applied. There is an increasing demand for a new type of high-frequency high-magnetic-permeability nanocrystalline alloy in industrial applications. SUMMARY

[0007] In order to solve the above problems, the present application provides an amorphous nanocrystalline soft magnetic alloy with high frequency and high permeability, a magnetic core and a preparation method thereof.

[0008] In a first aspect, the present application provides an amorphous nanocrystalline soft magnetic alloy, the molecular formula of the amorphous nanocrystalline soft magnetic alloy is Fe g Mn a Si b B c C d Cu e Nb f ; wherein 0.5≤a≤2, 12≤b≤16, 7≤c≤11, 0.25≤d≤1, 0.5≤e≤1.5, 2≤f≤4, and the sum of a-g is 100.

[0009] The amorphous nanocrystalline alloy of the present application is based on Fe, composed of Mn, Si, B, C, Cu, Nb and other elements in a specific ratio, and its atomic formula is Fe100-a-b-c-d-fMn a Si b B c C d Cu e Nb f ; wherein the atomic mole percentage of each element is: 0.5≤a≤2, 12≤b≤16, 7≤c≤11, 0.25≤d≤1, 0.5≤e≤1.5, 2≤f≤4, and the rest is Fe and unavoidable impurities. The specific alloy uses Fe g Mn a Si b B c C d Cu e Nb f , the antiferromagnetic element manganese (Mn) modulates the ferromagnetic coupling effect, and at the same time, the high resistivity element carbon (C) is added to improve the resistivity of the material, thereby effectively reducing the magnetic permeability frequency loss caused by eddy current at high frequency 100kHz. The amorphous nanocrystalline soft magnetic material with high frequency and high permeability provided by the present application can meet the market demand for miniaturization and high frequency of magnetic devices.

[0010] As preferred, 0.5≤a≤1.2; and / or, 0.25≤d≤0.6. The present application further optimizes the microstructure of the alloy by using the preferred range of Mn and C content, so that the magnetic properties of the material at high frequency are better modulated. The preferred content of Mn further ensures the modulation effect of the antiferromagnetic element, while the preferred content of carbon further improves the resistivity of the material, thereby more effectively suppressing the high-frequency eddy current loss and significantly improving the permeability stability.

[0011] As preferred, b is 14-15; and / or, c is 7.5-8.5.

[0012] The present application provides more precise element ratio, which ensures the best performance of the alloy in high-frequency applications. By precisely controlling the content of Mn, the ferromagnetic coupling effect is more effectively modulated, while the content of carbon in a specific range has a better effect on improving the resistivity of the material, and the precise adjustment of the content of Si and B further optimizes the microstructure of the alloy, so that the high-frequency permeability of the material is maximized while maintaining a low coercivity.

[0013] Further preferably, a is 1±0.1; and / or, d is 0.5±0.1; and / or, b is 14.5±0.1; and / or, c is 8±0.1.

[0014] Preferably, the amorphous nanocrystalline soft magnetic alloy is Fe 71.5 Mn1Si 14.5 B8Nb 3.5 Cu1C 0.5 By reasonable element combination, the stability of the alloy is ensured, which can meet the application requirements of miniaturization and high-frequency magnetic devices. Especially, the alloy of this specific formula shows the best high-frequency magnetic performance under the synergistic combination of the content of each element, and has good comprehensive performance. The alloy has low eddy current loss and excellent permeability at high frequency of 100 kHz.

[0015] As preferred, the thickness of the ribbon of the high-frequency high-permeability amorphous nanocrystalline soft magnetic alloy is ≤20μm; preferably 14-18μm, more preferably 14-16μm.

[0016] In the second aspect, the present application provides a preparation method of the high-frequency high-permeability amorphous nanocrystalline soft magnetic alloy, which comprises preparing an amorphous thin ribbon by plane flow casting; preferably, further comprising winding the amorphous thin ribbon into a circular magnetic core and performing heat treatment, and the heat treatment is preferably transverse magnetic heat treatment.

[0017] The application obtains a high-frequency high-magnetic permeability amorphous nanocrystalline soft magnetic alloy through component design, plane flow casting process and transverse magnetic heat treatment process. The component is prepared into amorphous strip of certain thickness through plane flow casting method with beryllium copper alloy as cooling crystallizer, the strip is sheared and wound into ring sample, and the high-frequency high-magnetic permeability amorphous nanocrystalline soft magnetic alloy obtained through specific heat treatment process meets 14-16 μm nanocrystalline magnetic core 100KHz effective magnetic permeability μe>40000, 16-18 μm nanocrystalline magnetic core 100KHz effective magnetic permeability μe>36000, and 18-20 μm nanocrystalline magnetic core 100KHz effective magnetic permeability μe>31000.

[0018] Preferably, the heat treatment comprises first holding at a first temperature and then holding at a second temperature.

[0019] Preferably, the heat treatment comprises heating to the first temperature at a first rate and holding; heating to the second temperature at a second rate and holding; and cooling to room temperature at a third rate; and the second temperature is preferably 550-590 ℃.

[0020] Further preferably, the first temperature is 400-420 ℃, the second temperature is 560-580 ℃, preferably 560-570 ℃, and more preferably 570 ℃.

[0021] Further preferably, the first rate is not higher than 5 ℃ / min.

[0022] Preferably, the second rate and the third rate are not higher than 3 ℃ / min.

[0023] Preferably, the holding at the first temperature is for 60-100 min.

[0024] Preferably, the holding at the second temperature is for 60-150 min.

[0025] Preferably, the cooling is performed under magnetic field, and the magnetic field application time is 30-120 min, preferably 90-120 min.

[0026] By adopting the optimized heat treatment process, the microstructure of the amorphous nanocrystalline soft magnetic alloy is significantly improved, and the magnetic performance of the material is further improved. First, the material is heated to a first temperature at a certain rate and is kept for a certain time, which can effectively remove the stress in the material and promote the preliminary grain refinement; then, the material is heated to a second temperature at a second rate and is kept for a certain time, which further optimizes the growth of the nanocrystals of the alloy composition, so that the alloy has higher magnetic permeability and lower loss at high frequency. Then, the cooling process is controlled at a certain rate, and a magnetic field is applied, which can further enhance the magnetic domain structure of the material and significantly improve the directionality and stability of the magnetic permeability. The overall process further ensures the excellent performance of the alloy in high-frequency applications, better meeting the market demand for high-frequency and high-magnetic-permeability soft magnetic materials.

[0027] Preferably, the outer diameter of the circular ring-shaped magnetic core is 25±2mm, the inner diameter is 20±2mm, and the height is 30±2mm.

[0028] Preferably, the preparation method of the high-frequency and high-magnetic-permeability amorphous nanocrystalline soft magnetic alloy comprises.

[0029] 1) Raw material smelting: the raw materials are added into a medium-frequency induction heating furnace according to the proportion, melted and smelted under an argon atmosphere, then staticized for 30±5min to ensure uniform composition of the molten steel without segregation.

[0030] 2) Amorphous ribbon preparation: the staticized molten steel is cast at 1400-1500℃, and an amorphous thin ribbon with a width of 80-140mm and a thickness of 14-20μm is prepared by a copper mold single-roll spinning method.

[0031] 3) Magnetic core manufacturing: the prepared amorphous wide ribbon is cut into a narrow ribbon with a width of 30±2mm, and then an automatic winding machine is used to wind the narrow ribbon into a circular ring-shaped magnetic core with an inner diameter of 20±2mm and an outer diameter of 25±2mm, and the specification is defined as 25*20*30.

[0032] 4) Heat treatment: the circular ring-shaped magnetic cores are strung into a string of 20-30 and vertically placed in a vertical transverse magnetic heat treatment annealing furnace for the heat treatment and magnetic treatment.

[0033] In a third aspect, the application provides a magnetic core comprising the amorphous nanocrystalline soft magnetic alloy or the amorphous nanocrystalline soft magnetic alloy prepared by the preparation method.

[0034] Preferably, the effective magnetic permeability of the magnetic core at 100KHz is >26000; preferably 33192-42000, more preferably 37746-41078.

[0035] The thinner the nanocrystalline alloy strip, the higher its magnetic permeability at 100 kHz after heat treatment. Finemet-based amorphous nanocrystalline soft magnetic alloys (typical composition 1K107:Fe) 73.5 Si 13.5 B9Nb3Cu1;1K107B:Fe 73.5 Si 15.5 The upper limit of the effective permeability μe at 100 kHz for B7Nb3Cu1) tape thickness of 14–16 μm is approximately 38,000; for 16–18 μm tape thickness, it is approximately 33,000; and for 18–20 μm tape thickness, it is approximately 28,000. This invention provides a novel high-frequency, high-permeability nanocrystalline soft magnetic alloy with an effective permeability at 100 kHz that is more than 10% higher than that of Finemet alloys under the same tape thickness, and its preparation method. As the frequency increases, the deteriorating effect of high-frequency eddy currents on the material's permeability becomes greater. Reducing high-frequency eddy current losses is an important method to improve the effective permeability at 100 kHz. Reducing the tape thickness can significantly improve the high-frequency permeability of nanocrystalline tapes; however, due to manufacturing process limitations, nanocrystalline tapes below 14 μm are very difficult to mass-produce. Improving the resistivity of the alloy from the compositional perspective becomes another feasible direction. By adding Mn to the Finemet alloy system to modulate the ferromagnetic exchange coupling between elements and adding C to increase the resistivity of the alloy system, a novel amorphous nanocrystalline soft magnetic alloy with high frequency and high magnetic permeability is obtained.

[0036] The amorphous nanocrystalline alloy composition of the present invention is prepared into amorphous ribbons with thicknesses of 14-16 μm, 16-18 μm, and 18-20 μm by planar flow casting method using beryllium copper alloy as a cooling crystallizer. Through specific heat treatment processes, the effective permeability μe of the 14-16 μm nanocrystalline magnetic core at 100 kHz is greater than 40000, the effective permeability μe of the 16-18 μm nanocrystalline magnetic core at 100 kHz is greater than 36000, and the effective permeability μe of the 18-20 μm nanocrystalline magnetic core at 100 kHz is greater than 31000. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0038] Figure 1 shows the XRD curves of the Fe-based amorphous nanocrystalline soft magnetic alloys provided in Examples 7-9 of this invention.

[0039] Fig. 2 is a DSC curve of the Fe-based amorphous nanocrystalline soft magnetic alloy provided by embodiments 2, 4 and 7 of the present application. DETAILED DESCRIPTION

[0040] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below with reference to the drawings in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0041] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods. If no specific technique or condition is indicated in the examples, the conventional method or the technique or condition described in the literature in the art or according to the product manual is used. If no manufacturer of the reagent or instrument is indicated, the reagent or instrument is a conventional product that can be purchased from a regular channel.

[0042] The testing method of the amorphous nanocrystalline soft magnetic alloy for transformers in the following examples is as follows:

[0043] 1) The X-ray diffraction analysis (XRD) method is used to verify whether the prepared alloy ribbon is a complete amorphous structure. In order to ensure that the alloy ribbon is a complete amorphous structure, the XRD pattern of all samples is from the free surface of the alloy ribbon (the other side relative to the copper roll surface). The related testing conditions and parameters are as follows: X-ray wavelength graphite monochromator filtering, tube voltage 40 kV, tube current 30 mA, testing range 20-90°, step 0.02°, scanning speed 8° / min. In the present application, the amorphous alloy ribbon can be determined by the XRD spectrum. If the characteristic spectrum presents a broad diffraction peak (also called "steamed bun peak"), it can be determined that the ribbon is a complete amorphous structure. The size of the nanocrystalline grain after crystallization heat treatment is also obtained from the X-ray diffraction analysis spectrum, and the size of the crystallized phase is calculated according to the Scherrer formula.

[0044] 2) Differential scanning calorimetry (DSC) is used to analyze the alloy strip, and the crystallization behavior and thermal stability of the alloy strip are investigated. Before testing, the strip is cut into small pieces with an area of less than 1 mm x 1 mm, weighed about 20 mg, and placed on a sample platform in an alumina crucible. The sample is heated under the protection of N2 atmosphere, the heating rate is 20 ℃ / min, and the heating range is 300-800 ℃. Through the analysis of the DSC curve of the sample, the phase change of each sample during heating can be obtained, and the thermal characteristic temperature parameter values such as Curie temperature Tc, glass transition temperature Tg and the crystallization initiation temperature Tx of the alloy strip can be obtained. According to the characteristic temperature values of the DSC curve of the alloy strip, the thermal stability of the alloy strip can be reflected, which provides a reference for the determination of the heat treatment process of the amorphous strip, and the approximate annealing temperature range is determined. The first stage crystallization initiation temperature of the alloy strip is marked as Tx1, and the second stage crystallization initiation temperature is marked as Tx2 (i.e. the Fe-(B, P) compound begins to precipitate at the temperature point), and the difference between the two stage crystallization initiation temperatures is marked as ΔTx (definition: ΔTx = Tx2-Tx1).

[0045] 3) The inductance value of the sample is tested using an LCR tester, and then the effective permeability μe value is obtained through the permeability calculation formula μ e =(L*L e ) / (N 2 *Ae*μ0), wherein L is inductance (unit: H), Le is effective magnetic circuit length, N is test winding turns, Ae is cross-sectional area, and μ0 is vacuum permeability (μ0 = 4π*10 -7 H / m). The thickness of the strip is tested by a micrometer.

[0046] Example 1

[0047] The Fe-based amorphous nanocrystalline soft magnetic alloy provided in this embodiment has a molecular formula of Fe 72.75 Mn 0.5 Si 14.5 B8Nb3Cu1C 0.25 .

[0048] The preparation method of the Fe-based amorphous nanocrystalline soft magnetic alloy is as follows.

[0049] (1) Industrial pure iron, ferrosilicon, boron iron, niobium iron, copper, carbon, manganese and other raw materials are used according to the molecular formula Fe 72.75 Mn 0.5 Si 14.5 B8Nb3Cu1C 0.25The proportioning and weighing of ingredients were put into a medium frequency induction melting furnace in sequence, melted and smelted for 180 min, then the molten steel was kept for 30 min, the molten steel temperature was kept at 1450℃, and the casting was started, and the amorphous ribbon with a width of 90-140 mm was prepared by a single roll spin casting method with a beryllium copper alloy as a cooling crystallizer, and the copper roll rotating speed was 30 m / s. The casting thickness at the start of ribbon preparation was 32 μm, and the brittle fracture area was determined by tearing the ribbon transversely to judge the ductile-brittle transition thickness of the ribbon, the thickness of the ribbon was measured by a micrometer, Fe 72.75 Mn 0.5 Si 14.5 B8Nb3Cu1C 0.25 The ductile-brittle transition thickness of the amorphous alloy ribbon was 25 μm, the ribbon with a thickness of 18-20 μm was taken as the experimental sample ribbon, the experimental sample ribbon was cut into a narrow ribbon with a width of 30 mm, and the ribbon was wound into a magnetic core by an automatic winding machine, the width was 30 mm, the inner diameter was 20 mm, and the outer diameter was 25 mm.

[0050] (2) The Fe 72.75 Mn 0.5 Si 14.5 B8Nb3Cu1C 0.25 alloy was subjected to crystallization heat treatment, and the heat treatment equipment was a vertical transverse magnetic heat treatment annealing furnace. The magnetic core was heated to 400℃ at a heating rate of 4℃ / min, and kept for 80 min; then heated to 560℃ at a rate of 3℃ / min, and kept for 120 min; then decreased to room temperature at a rate of 3℃ / min, and the magnetic field was added when the temperature was 500℃, the magnetic field was added for 60 min, and the magnetic field size was 1000Gs.

[0051] (3) The Fe 72.75 Mn 0.5 Si 14.5 B8Nb3Cu1C 0.25 alloy magnetic core was stored in a shell to ensure the roundness of the magnetic core and reduce the error of the test. The inductance value of the sample at a frequency of 100 KHz and a test voltage of 0.3V was obtained by using an LCR tester, and then the effective permeability μ e of the magnetic core at 100 KHz was obtained by a permeability calculation formula μ e =(L*L 2 ) / (N e *Ae*μ0), and the value of μ e (100 KHz) was calculated to be 28229.

[0052] Example 2

[0053] The composition and preparation method of this example are the same as those of Example 1, except that the heat treatment process is different. The process is to heat the magnetic core to 400°C at a heating rate of 4°C / min, keep it at this temperature for 80 min; then heat it to 570°C at a rate of 3°C / min, keep it at this temperature for 120 min; then cool it to room temperature at a cooling rate of 3°C / min, and start to apply the transverse magnetic field when the temperature is 500°C, the magnetic field application time is 60 min, and the magnetic field strength is 1000 Gs. The test calculation gives μ e (100 kHz) = 30184.

[0054] Example 3

[0055] The composition and preparation method of this example are the same as those of Example 1, except that the heat treatment process is different. The process is to heat the magnetic core to 400°C at a heating rate of 4°C / min, keep it at this temperature for 80 min; then heat it to 580°C at a rate of 3°C / min, keep it at this temperature for 120 min; then cool it to room temperature at a cooling rate of 3°C / min, and start to apply the transverse magnetic field when the temperature is 500°C, the magnetic field application time is 60 min, and the magnetic field strength is 1000 Gs. The test calculation gives μ e (100 kHz) = 26337.

[0056] Comparative Example 1

[0057] The composition of this comparative example has the formula Fe 73.5 Si 14.5 B8Nb3Cu1, and the preparation method is the same as that of Example 1, and the ductile-brittle transition thickness is 25 μm. The heat treatment process is to heat the magnetic core to 400°C at a heating rate of 4°C / min, keep it at this temperature for 80 min; then heat it to 560°C at a rate of 3°C / min, keep it at this temperature for 120 min; then cool it to room temperature at a cooling rate of 3°C / min, and start to apply the transverse magnetic field when the temperature is 500°C, the magnetic field application time is 60 min, and the magnetic field strength is 1000 Gs. The test calculation gives μ e (100 kHz) = 26917.

[0058] Comparative Example 2

[0059] The composition and preparation method of this comparative example are the same as those of Comparative Example 1, except that the heat treatment process is different. The process is to heat the magnetic core to 400°C at a heating rate of 4°C / min, keep it at this temperature for 80 min; then heat it to 570°C at a rate of 3°C / min, keep it at this temperature for 120 min; then cool it to room temperature at a cooling rate of 3°C / min, and start to apply the transverse magnetic field when the temperature is 500°C, the magnetic field application time is 60 min, and the magnetic field strength is 1000 Gs. The test calculation gives μ e (100 kHz) = 28468.

[0060] Comparative Example 3

[0061] The components and preparation method in this comparative example are the same as Comparative Example 1, only the heat treatment process is different. The heat treatment process is to heat the magnetic core to 400°C at a heating rate of 4°C / min, keep for 80 min; then heat to 580°C at a rate of 3°C / min, keep for 120 min; then decrease to room temperature at a rate of 3°C / min, during the decreasing process, when the temperature is 500°C, start to apply transverse magnetic field, the applying time is 60 min, the magnetic field strength is 1000 Gs. The calculated μ e (100 kHz) = 25798.

[0062] Comparative Example 4

[0063] The component molecular formula in this comparative example is: Fe 73.5 Si 15.5 B7Nb3Cu1, the preparation method is the same as Example 1, the ductile-brittle transition thickness is 24 μm. The heat treatment process is to heat the magnetic core to 400°C at a heating rate of 4°C / min, keep for 80 min; then heat to 560°C at a rate of 3°C / min, keep for 120 min; then decrease to room temperature at a rate of 3°C / min, during the decreasing process, when the temperature is 500°C, start to apply transverse magnetic field, the applying time is 60 min, the magnetic field strength is 1000 Gs. The calculated μ e (100 kHz) = 25501.

[0064] Comparative Example 5

[0065] The component molecular formula in this comparative example is: Fe 73.5 Si 15.5 B7Nb3Cu1, the preparation method is the same as Example 1. The heat treatment process is to heat the magnetic core to 400°C at a heating rate of 4°C / min, keep for 80 min; then heat to 570°C at a rate of 3°C / min, keep for 120 min; then decrease to room temperature at a rate of 3°C / min, during the decreasing process, when the temperature is 500°C, start to apply transverse magnetic field, the applying time is 60 min, the magnetic field strength is 1000 Gs. The calculated μ e (100 kHz) = 27523.

[0066] Comparative Example 6

[0067] The component molecular formula in this comparative example is: Fe 73.5 Si 15.5B7Nb3Cu1, the preparation method is the same as that of Example 1. The heat treatment process is to heat the magnetic core to 400°C at a heating rate of 4°C / min, keep for 80 min; then heat to 580°C at a rate of 3°C / min, keep for 120 min; then decrease to room temperature at a rate of 3°C / min, during the decreasing process, when the temperature is 500°C, start to add transverse magnetic field, the adding time is 60 min, the magnetic field size is 1000 Gs. The test calculation results show that μ e (100 kHz) = 26722.

[0068] Comparative Example 7

[0069] The component molecular formula in the present comparative example is Fe 73.5 Si 13.5 B9Nb3Cu1, the preparation method is the same as that of Example 1, the ductile-brittle transition thickness is 25 μm. The heat treatment process is to heat the magnetic core to 400°C at a heating rate of 4°C / min, keep for 80 min; then heat to 560°C at a rate of 3°C / min, keep for 120 min; then decrease to room temperature at a rate of 3°C / min, during the decreasing process, when the temperature is 500°C, start to add transverse magnetic field, the adding time is 60 min, the magnetic field size is 1000 Gs. The test calculation results show that μ e (100 kHz) = 24884.

[0070] Comparative Example 8

[0071] The component molecular formula in the present comparative example is Fe 73.5 Si 13.5 B9Nb3Cu1, the preparation method is the same as that of Example 1. The heat treatment process is to heat the magnetic core to 400°C at a heating rate of 4°C / min, keep for 80 min; then heat to 570°C at a rate of 3°C / min, keep for 120 min; then decrease to room temperature at a rate of 3°C / min, during the decreasing process, when the temperature is 500°C, start to add transverse magnetic field, the adding time is 60 min, the magnetic field size is 1000 Gs. The test calculation results show that μ e (100 kHz) = 26791.

[0072] Comparative Example 9

[0073] The component molecular formula in the present comparative example is Fe 73.5 Si 13.5B9Nb3Cu1, the preparation method is the same as example 1. The heat treatment process is to heat the magnetic core to 400℃ at a heating rate of 4℃ / min, keep for 80min; then heat to 580℃ at a rate of 3℃ / min, keep for 120min; then reduce to room temperature at a rate of 3℃ / min, during the cooling process, start to magnetize when the temperature is 500℃, the magnetizing time is 60min, the magnetizing magnetic field size is 1000Gs. The test calculation gets μ e (100KHz) = 25031.

[0074] The performance specific results of examples 1-3 and comparative examples 1-9 are shown in table 1.

[0075] Table 1

[0076] The above examples and comparative examples have the highest magnetic permeability at 100KHz when heat treated at 570℃, the performance of Si 14.5%, B 8% composition is the best, adding Mn, C can effectively improve the 100KHz effective magnetic permeability of the alloy composition.

[0077] Example 4

[0078] The composition molecular formula in this example is: Fe 72.25 Mn 0.5 Si 14.5 B8Nb 3.5 Cu1C 0.25 .

[0079] The preparation method of the Fe-based amorphous nanocrystalline soft magnetic alloy is as follows.

[0080] (1) The industrial pure industrial pure iron, ferrosilicon, boron iron, niobium iron, copper, carbon, manganese and other raw materials are weighed and mixed according to the molecular formula Fe 72.25 Mn 0.5 Si 14.5 B8Nb 3.5 Cu1C 0.25 The ratio is weighed and mixed, and then sequentially put into a medium frequency induction melting furnace for melting and smelting for 180min, then the molten steel is kept for 30min, the molten steel temperature is kept at 1450℃, and the width of the quenched amorphous strip is 90-140mm, the copper roll rotating speed is 30m / s. The pouring thickness at the beginning of the strip preparation is 32μm, whether there is brittle fracture area is judged by tearing the strip transversely, the thickness of the strip is measured by a micrometer, Fe 72.25 Mn 0.5 Si 14.5 B8Nb 3.5 Cu1C 0.25The brittle-ductile transition thickness of the amorphous alloy strip is 25 μm, and the strip with a thickness of 18-20 μm is cut into a narrow strip with a width of 30 mm, and the strip is wound into a magnetic core by an automatic winding machine, with a width of 30 mm, an inner diameter of 20 mm, and an outer diameter of 25 mm.

[0081] (2) Fe 72.25 Mn 0.5 Si 14.5 B8Nb 3.5 Cu1C 0.25 alloy is subjected to crystallization heat treatment, and the heat treatment equipment is a vertical transverse magnetic heat treatment annealing furnace. The magnetic core is heated to 400 ℃ at a heating rate of 4 ℃ / min, and is kept for 80 min; then heated to 570 ℃ at a rate of 3 ℃ / min and kept for 120 min; and then cooled to room temperature at a cooling rate of 3 ℃ / min, and the magnetic field is added when the temperature is 500 ℃, and the magnetic field is added for 60 min, and the magnetic field size is 1000 Gs.

[0082] (3) The Fe 72.25 Mn 0.5 Si 14.5 B8Nb 3.5 Cu1C 0.25 alloy magnetic core is stored in a shell to ensure the roundness of the magnetic core and reduce the test error. The inductance value of the sample at a frequency of 100 KHz and a test voltage of 0.3 V is obtained by using an LCR tester, and then the effective permeability μ e of the magnetic core at 100 KHz is obtained by the permeability calculation formula μ e =(L*L 2 ) / (N e *Ae*μ0), and the value of μ e (100 KHz) is calculated to be 31427.

[0083] Example 5

[0084] The composition formula in this embodiment is: Fe 72 Mn 0.5 Si 14.5 B8Nb 3.5 Cu1C 0.5 , and the preparation method is the same as that in Example 4, and the brittle-ductile transition thickness is 24 μm. The heat treatment process is to heat the magnetic core to 400 ℃ at a heating rate of 4 ℃ / min, and keep for 80 min; then heated to 570 ℃ at a rate of 3 ℃ / min and kept for 120 min; and then cooled to room temperature at a cooling rate of 3 ℃ / min, and the magnetic field is added when the temperature is 500 ℃, and the magnetic field is added for 60 min, and the magnetic field size is 1000 Gs. The value of μ e (100 KHz) is calculated to be 32974.

[0085] Example 6

[0086] The composition of this example is: Fe 71.75 Mn1Si 14.5 B8Nb 3.5 Cu1C 0.25 The preparation method is the same as that of Example 4, and the ductile-brittle transition thickness is 24 μm. The heat treatment process is to heat the magnetic core to 400 °C at a heating rate of 4 °C / min, keep for 80 min; then heat to 570 °C at a rate of 3 °C / min, keep for 120 min; then decrease to room temperature at a rate of 3 °C / min, and start to add transverse magnetic field when the temperature is 500 °C, the magnetic field strength is 1000 Gs, and the magnetic field adding time is 60 min. The test calculation gives μ e (100 KHz) = 33026.

[0087] Example 7

[0088] The composition of this example is: Fe 71.5 Mn1Si 14.5 B8Nb 3.5 Cu1C 0.5 The preparation method is the same as that of Example 4, and the ductile-brittle transition thickness is 23 μm. The heat treatment process is to heat the magnetic core to 400 °C at a heating rate of 4 °C / min, keep for 80 min; then heat to 570 °C at a rate of 3 °C / min, keep for 120 min; then decrease to room temperature at a rate of 3 °C / min, and start to add transverse magnetic field when the temperature is 500 °C, the magnetic field strength is 1000 Gs, and the magnetic field adding time is 60 min. The test calculation gives μ e (100 KHz) = 33192.

[0089] Comparative Example 10

[0090] The composition of this example is: Fe 71 Mn 1.5 Si 14.5 B8Nb 3.5 Cu1C 0.5 The preparation method is the same as that of Example 4, and the ductile-brittle transition thickness is 23 μm. The heat treatment process is to heat the magnetic core to 400 °C at a heating rate of 4 °C / min, keep for 80 min; then heat to 570 °C at a rate of 3 °C / min, keep for 120 min; then decrease to room temperature at a rate of 3 °C / min, and start to add transverse magnetic field when the temperature is 500 °C, the magnetic field strength is 1000 Gs, and the magnetic field adding time is 60 min. The test calculation gives μ e (100 KHz) = 28874.

[0091] Comparative Example 11

[0092] The composition in this comparative example has the formula: Fe 70.5 Mn2Si 14.5 B8Nb 3.5 Cu1C 0.5 The preparation method is the same as that of Example 4, and the ductile-brittle transition thickness is 23 μm. The heat treatment process is to heat the magnetic core to 400°C at a heating rate of 4°C / min, keep the temperature for 80 min; then heat to 570°C at a rate of 3°C / min, keep the temperature for 120 min; then decrease to room temperature at a rate of 3°C / min, and start to apply the transverse magnetic field when the temperature is 500°C, the magnetic field application time is 60 min, and the magnetic field size is 1000 Gs. The test calculation results show that μ e (100 kHz) = 26483.

[0093] Comparative Example 12

[0094] The composition in this comparative example has the formula: Fe 71.25 Mn1Si 14.5 B8Nb 3.5 Cu1C 0.75 The preparation method is the same as that of Example 4, and the ductile-brittle transition thickness is 23 μm. The heat treatment process is to heat the magnetic core to 400°C at a heating rate of 4°C / min, keep the temperature for 80 min; then heat to 570°C at a rate of 3°C / min, keep the temperature for 120 min; then decrease to room temperature at a rate of 3°C / min, and start to apply the transverse magnetic field when the temperature is 500°C, the magnetic field application time is 60 min, and the magnetic field size is 1000 Gs. The test calculation results show that μ e (100 kHz) = 29604.

[0095] Comparative Example 13

[0096] The composition in this comparative example has the formula: Fe 71 Mn1Si 14.5 B8Nb 3.5 Cu1C1, The preparation method is the same as that of Example 4, and the ductile-brittle transition thickness is 22 μm. The heat treatment process is to heat the magnetic core to 400°C at a heating rate of 4°C / min, keep the temperature for 80 min; then heat to 570°C at a rate of 3°C / min, keep the temperature for 120 min; then decrease to room temperature at a rate of 3°C / min, and start to apply the transverse magnetic field when the temperature is 500°C, the magnetic field application time is 60 min, and the magnetic field size is 1000 Gs. The test calculation results show that μ e (100 kHz) = 27748.

[0097] Comparative Example 14

[0098] The component molecular formula in the present comparative example is: Fe 70 Mn2Si 14.5 B8Nb 3.5 Cu1C1, the preparation method is the same as that in Example 4, and the ductile-brittle transition thickness is 22 μm. The heat treatment process is to heat the magnetic core to 400 ℃ at a heating rate of 4 ℃ / min, keep for 80 min; then heat to 570 ℃ at a rate of 3 ℃ / min, keep for 120 min; and then decrease to room temperature at a rate of 3 ℃ / min, and start to magnetize when the temperature is 500 ℃, the magnetizing time is 60 min, and the magnetizing magnetic field size is 1000 Gs. The μ e (100KHz) = 25531.

[0099] The performance specific results of Examples 2, 4-7 and Comparative Examples 10-14 are shown in Table 2.

[0100] Table 2

[0101] The component in Example 7 is Fe 71.5 Mn1Si 14.5 B8Nb 3.5 Cu1C 0.5 The sample of the component of Example 7 has the highest effective magnetic permeability of 100 KHz under the same thickness, which can reach 33192. The amorphous ability is weakened and the effective magnetic permeability of 100 KHz is also reduced by continuously adding Mn and C to the component of Example 7.

[0102] Example 8

[0103] The component molecular formula in the present example is: Fe 71.5 Mn1Si 14.5 B8Nb 3.5 Cu1C 0.5 .

[0104] The preparation method of the Fe-based amorphous nanocrystalline soft magnetic alloy is as follows.

[0105] (1) The industrial pure iron, ferrosilicon, boron iron, niobium iron, copper, carbon, manganese and other raw materials are mixed according to the molecular formula Fe 71.5 Mn1Si 14.5 B8Nb 3.5 Cu1C 0.5The proportioning and weighing of ingredients were put into a medium frequency induction melting furnace in sequence, melted and smelted for 180 min, then the molten steel was kept for 30 min, the molten steel temperature was kept at 1450℃, and the casting was started, the width of the quenched amorphous ribbon was 90-140 mm, the copper roller speed was 30 m / s. The casting thickness at the beginning of the ribbon was 30 μm, the brittle fracture area was determined by tearing the ribbon in the transverse direction, the thickness of the ribbon was measured by a micrometer, Fe 71.5 Mn1Si 14.5 B8Nb 3.5 Cu1C 0.5 The ductile-brittle transition thickness of the amorphous alloy ribbon was 23 μm, the ribbon with a thickness of 16-18 μm was taken as the experimental sample ribbon, the experimental sample ribbon was cut into a narrow ribbon with a width of 30 mm, and the ribbon was wound into a magnetic core by an automatic winding machine, the width of the magnetic core was 30 mm, the inner diameter was 20 mm, and the outer diameter was 25 mm.

[0106] (2) The Fe 71.5 Mn1Si 14.5 B8Nb 3.5 Cu1C 0.5 alloy was subjected to crystallization heat treatment, the heat treatment equipment was a vertical transverse magnetic heat treatment annealing furnace. The magnetic core was heated to 400℃ at a heating rate of 4℃ / min, and kept for 80 min; then heated to 570℃ at a rate of 3℃ / min, and kept for 120 min; then cooled to room temperature at a cooling rate of 3℃ / min, and the magnetic field was added when the temperature was 500℃, the magnetic field was added for 60 min, and the magnetic field size was 1000Gs.

[0107] (3) The Fe 71.5 Mn1Si 14.5 B8Nb 3.5 Cu1C 0.5 alloy magnetic core was stored in a shell to ensure the roundness of the magnetic core and reduce the test error. The inductance value of the sample at a frequency of 100KHz and a test voltage of 0.3V was obtained by using an LCR tester, and then the effective permeability μ e of the magnetic core at 100KHz was obtained by the permeability calculation formula μ e =(L*L 2 ) / (N e *Ae*μ0), and the value of μ e (100KHz) was calculated to be 37746.

[0108] Example 9

[0109] The composition molecular formula in this embodiment is: Fe 71.5 Mn1Si 14.5 B8Nb 3.5 Cu1C 0.5.

[0110] The preparation method of this Fe-based amorphous nanocrystalline soft magnetic alloy is as follows.

[0111] (1) Industrial-grade pure iron, ferrosilicon, ferroboron, ferroniobium, copper, carbon, manganese, and other raw materials are classified according to their molecular formula as Fe. 71.5 Mn1Si 14.5 B8Nb 3.5 Cu1C 0.5 The ingredients were weighed and batched, then sequentially placed into a medium-frequency induction melting furnace for 180 minutes of melting and smelting. The molten steel was then calmed for 30 minutes, maintaining the temperature at 1450℃. Aqueous strips with a width of 90–140 mm were prepared using a single-roll rotary quenching method with a beryllium copper alloy as the cooling crystallizer, at a copper roll speed of 30 m / s. The initial casting thickness was 27 μm. The ductile-brittle transition thickness of the strip was determined by the presence of brittle fracture zones during transverse tearing. The strip thickness was measured using a micrometer. (Fe...) 71.5 Mn1Si 14.5 B8Nb 3.5 Cu1C 0.5 The ductile-brittle transition thickness of the amorphous alloy strip is 23 μm. Strips with a thickness of 14–16 μm are used as experimental samples. The experimental samples are cut into narrow strips 30 mm wide and wound into magnetic cores with an automatic winding machine. The cores have a width of 30 mm, an inner diameter of 20 mm, and an outer diameter of 25 mm.

[0112] (2) Fe 71.5 Mn1Si 14.5 B8Nb 3.5 Cu1C 0.5 The alloy underwent crystallization heat treatment using a vertical transverse magnetic heat treatment annealing furnace. The magnetic core was heated to 400℃ at a heating rate of 4℃ / min and held for 80 min; then heated to 570℃ at a rate of 3℃ / min and held for 120 min; then cooled to room temperature at a cooling rate of 3℃ / min. During the cooling process, transverse magnetization was started at 500℃ and lasted for 60 min at a magnetic field strength of 1000 Gs.

[0113] (3) Fe after heat treatment 71.5 Mn1Si 14.5 B8Nb 3.5 Cu1C 0.5 The alloy magnetic core was stored under a protective casing to ensure its roundness and reduce testing errors. The inductance of the sample at 100kHz frequency and 0.3V test voltage was measured using an LCR meter, and then the permeability was calculated using the formula μ. e =(L*L) e ) / (N 2 *Ae*μ0) yields the effective permeability μ of the magnetic core at 100kHz.e μeff(100KHz) = 41078. e (100KHz) = 33243.

[0114] Comparative Example 15

[0115] The composition in this comparative example is: Fe 73.5 Si 14.5 B8Nb3Cu1, the preparation method is the same as that in Example 8, and the ductile-brittle transition thickness is 25 μm. The heat treatment process is to heat the magnetic core to 400 °C at a heating rate of 4 °C / min, keep for 80 min; then heat to 570 °C at a rate of 3 °C / min, keep for 120 min; and then decrease to room temperature at a rate of 3 °C / min, and during the cooling process, when the temperature is 500 °C, start to apply transverse magnetism, the magnetism application time is 60 min, and the magnetism field size is 1000 Gs. The tested calculation results are that μeff(100KHz) = 37508. e (100KHz) = 33243.

[0116] Comparative Example 16

[0117] The composition in this comparative example is: Fe 73.5 Si 14.5 B8Nb3Cu1, the preparation method is the same as that in Example 9, and the ductile-brittle transition thickness is 25 μm. The heat treatment process is to heat the magnetic core to 400 °C at a heating rate of 4 °C / min, keep for 80 min; then heat to 570 °C at a rate of 3 °C / min, keep for 120 min; and then decrease to room temperature at a rate of 3 °C / min, and during the cooling process, when the temperature is 500 °C, start to apply transverse magnetism, the magnetism application time is 60 min, and the magnetism field size is 1000 Gs. The tested calculation results are that μeff(100KHz) = 37508. e (100KHz) = 33243.

[0118] The performance specific results of Examples 7-9 and Comparative Examples 12, 15-16 are shown in Table 3.

[0119] Table 3

[0120] As shown in Table 3, the thinner the amorphous nanocrystalline strip thickness, the higher the effective permeability at high frequency 100 KHz, and the influence of eddy current effect is smaller, so the improvement of the composition resistivity on the high frequency permeability is more obvious on the thick strip.

[0121] It should be finally pointed out that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features thereof can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application. Industrial applicability

[0122] The present application provides a kind of amorphous nanocrystalline soft magnetic alloy and its preparation method.The molecular formula of the amorphous nanocrystalline soft magnetic alloy is Fe g Mn a Si b B c C d Cu e Nb f ; wherein, 0.5≤a≤2, 12≤b≤16, 7≤c≤11, 0.25≤d≤1, 0.5≤e≤1.5, 2≤f≤4, the sum of a-g is 100.The present application obtains amorphous nanocrystalline soft magnetic material with high frequency and high permeability through amorphous nanocrystalline soft magnetic alloy component design, can meet the demand of market to magnetic device miniaturization, high frequency, has good economic value and application prospect.

Claims

1. An amorphous nanocrystalline soft magnetic alloy, characterized in that, The non-crystalline nanocrystalline soft magnetic alloy has a molecular formula of Fe g Mn a Si b B c C d Cu e Nb f ; wherein 0.5≤a≤2, 12≤b≤16, 7≤c≤11, 0.25≤d≤1, 0.5≤e≤1.5, 2≤f≤4, and the sum of a-g is 100.

2. The high-frequency high-magnetic permeability amorphous nanocrystalline soft magnetic alloy according to claim 1, characterized by 0.5≤a≤1.2; and / or, 0.25≤d≤0.

6.

3. The high-frequency high-magnetic permeability amorphous nanocrystalline soft magnetic alloy according to claim 1 or 2, characterized in that, b is 14-15; and / or, c is 7.5-8.

5.

4. The high-frequency high-magnetic permeability amorphous nanocrystalline soft magnetic alloy according to any one of claims 1 to 3, characterized in that, a is 1±0.1; and / or, d is 0.5±0.1; and / or, b is 14.5±0.1; and / or, c is 8±0.1; Preferably, the amorphous nanocrystalline soft magnetic alloy is Fe 71.5 Mn1Si 14.5 B8Nb 3.5 Cu1C 0.5 .

5. The high-frequency high-magnetic permeability amorphous nanocrystalline soft magnetic alloy according to any one of claims 1 to 4, characterized in that, The thickness of the high-frequency high-permeability amorphous nanocrystalline soft magnetic alloy strip is ≤20μm; preferably, 14-18μm, more preferably, 14-16μm.

6. The method for preparing the high-frequency, high-permeability amorphous nanocrystalline soft magnetic alloy according to any one of claims 1-5, characterized in that, The method comprises preparing amorphous thin strips by plane flow casting; preferably, further comprising winding the amorphous thin strips into toroidal cores and performing heat treatment, wherein the heat treatment is preferably transverse magnetic heat treatment.

7. The method for preparing high-frequency, high-permeability amorphous nanocrystalline soft magnetic alloy according to claim 6, characterized in that, The heat treatment comprises first heat treatment at a first temperature and then heat treatment at a second temperature. Preferably, the heat treatment comprises heating to the first temperature at a first rate and heat treatment; heating to the second temperature at a second rate and heat treatment; and cooling to room temperature at a third rate; the second temperature is preferably 550-590℃.

8. The method for preparing high-frequency, high-permeability amorphous nanocrystalline soft magnetic alloy according to claim 7, characterized in that, The first temperature is 400-420℃, the second temperature is 560-580℃, preferably 560-570℃, more preferably 570℃.

9. The method for preparing high-frequency, high-permeability amorphous nanocrystalline soft magnetic alloy according to claim 7 or 8, characterized in that, The first rate is not higher than 5℃ / min; The second rate and the third rate are not higher than 3℃ / min; The heat treatment at the first temperature is 60-100min; The heat treatment at the second temperature is 60-150min; During the cooling, a magnetic field is applied, and the time of applying the magnetic field is 30-120min, preferably 90-120min.

10. A magnetic core, characterized by, The magnetic core has an effective permeability of 100KHz >26000; preferably, 33192-42000, more preferably, 37746-41078.

Images