WO2024183502A1 - High-saturation magnetic-induction nanocrystalline soft magnetic alloy, and preparation method therefor and use thereof - Google Patents

Abstract

A high-saturation magnetic-induction nanocrystalline soft magnetic alloy. The high-saturation magnetic-induction nanocrystalline soft magnetic alloy has a chemical formula of Fe_aSi_bB_cNb_dCu_eM_fN_g, wherein M is one of Ge, Al and Ni, and N is one of rare earth elements Ce, Gd, Tb, Er and Yb; and a, b, c, d, e, f, and g are respectively atomic percentages of corresponding elements, and a+b+c+d+e+f+g=100. The alloy defines the composition of the high-saturation magnetic-induction nanocrystalline soft magnetic alloy, which has a good effect when used in a high-frequency transformer or wireless charging.

Description

A high saturation magnetic induction nanocrystalline soft magnetic alloy and its preparation method and application

Cross-references to related publications

The embodiments of the present disclosure are based on Chinese patent applications with application number 202310256894.X, application date March 8, 2023, application name “A nanocrystalline soft magnetic alloy, its preparation method and application”, application number 202310220629.6, application date March 8, 2023, application name “A nanocrystalline soft magnetic alloy strip, its preparation method and application”, and application number 202310239352.1, application date March 8, 2023, application name “A iron-based nanocrystalline soft magnetic alloy, its preparation method and application”, and claim the priority of the Chinese patent application, the entire content of which is hereby introduced into the present disclosure as a reference.

Technical Field

The disclosed embodiments relate to the field of magnetic functional materials, and in particular to a high saturation magnetic induction nanocrystalline soft magnetic alloy and a preparation method and application thereof.

Background Art

With global warming and energy crisis, the world is promoting energy management measures to improve environmental quality. my country has also proposed a "dual carbon" policy to reduce carbon emissions, guide green technology innovation, and improve the global competitiveness of industry and economy. In the field of power electronics, high-end inductive magnetic components are required to continue to develop in the direction of large capacity, miniaturization, high frequency, and low loss. Traditional soft magnetic materials such as silicon steel are suitable for medium and low frequency applications because their magnetic properties are mainly determined by magnetocrystalline anisotropy and they are thick (greater than 50μm). However, their losses will increase sharply when used at high frequencies.

Summary of the invention

Based on this, in view of the defect that the prior art is difficult to achieve both high saturation magnetic induction intensity and low loss and low annealing brittleness, the embodiments of the present disclosure provide a high saturation magnetic induction nanocrystalline soft magnetic alloy and a preparation method and application thereof.

To this end, the present disclosure is implemented through the following technical solutions:

_An embodiment of the present disclosure provides a high saturation magnetic induction nanocrystalline soft magnetic alloy, wherein the chemical formula of the high saturation magnetic _{induction nanocrystalline soft} magnetic _alloy is _{FeaSibBcNbdCueMfNg} , where M is one of Ge, Al and Ni, and N is one of the rare earth elements Ce, Gd, Tb, Er and Yb; wherein a, b, c, d _, e, f and g are the atomic percentages of the corresponding elements, and a+b+c+d+e+f+g=100.

In some embodiments, 74≤a≤80, 3≤b≤12, 4≤c≤12, 1≤d≤4, 0.5≤e≤1.5, 0.1≤f≤2.5, and 0.01≤g≤2.5.

The disclosed embodiments also provide for the application of the high saturation magnetic induction nanocrystalline soft magnetic alloy in high frequency transformers or wireless charging.

In some embodiments, the high saturation magnetic induction nanocrystalline soft magnetic alloy has a thickness of 10 to 16 μm, a width of 200 to 300 mm, and a lateral thickness deviation of less than ±0.001 mm.

The disclosed embodiments also provide for the application of the high saturation magnetic induction nanocrystalline soft magnetic alloy in high frequency transformers or wireless charging.

The disclosed embodiment provides a method for preparing a high saturation magnetic induction nanocrystalline soft magnetic alloy, the preparation comprising: smelting, cooling treatment, foil rolling, core winding, magnetic field heat treatment and micro-scratching;

The smelting comprises: using an induction melting furnace to melt the material after the component matching ratio to obtain a molten alloy; the material after the component matching ratio comprises: elements for preparing the high saturation magnetic induction nanocrystalline soft magnetic alloy and the atomic percentages corresponding to the elements;

The cooling process includes: spraying the molten alloy onto a high-speed rotating copper roller, and controlling the copper roller to cool the molten alloy at a preset speed to obtain a first alloy;

The foil rolling comprises: rolling the first alloy for a preset number of passes to obtain a second alloy;

The core winding comprises: using an automatic winding machine to wind the second alloy to obtain a third alloy;

The magnetic field heat treatment comprises: performing magnetic field heat treatment on the third alloy using a magnetic field heat treatment furnace to obtain a fourth alloy;

The micro-scratching comprises: performing micro-scratching treatment on the fourth alloy by using a laser to obtain the high saturation magnetic induction nanocrystalline soft magnetic alloy.

In some embodiments, the use of an induction melting furnace to melt the material with a component matching ratio to obtain a molten alloy includes: at a melting temperature of 2000° C., using an induction melting furnace to dissolve the material with a component matching ratio four times to obtain the molten alloy.

In some embodiments, the cooling process includes single-roller rapid quenching, double-roller rapid quenching and inhomogeneous crystallization method, wherein the molten alloy is sprayed onto a high-speed rotating copper roller, and the copper roller is controlled to cool the molten alloy at a preset speed to obtain a first alloy, including but not limited to:

The single-roller rapid quenching includes: spraying the molten alloy uniformly from a quartz nozzle into a rotating single-roll gap, cooling the molten alloy at a cooling rate of 10 ⁵ to 10 ⁷ °C/s, and obtaining the first alloy with a thickness of 12 to 16 μm, a width of 150 mm, and a transverse thickness deviation of less than ±0.001 mm;

The double-roller rapid quenching includes: spraying the molten alloy uniformly from the quartz nozzle into the gap between the rotating double rolls, cooling the molten alloy at a cooling rate of 10 ⁵ to 10 ⁷ °C/s, and obtaining the first alloy with a thickness of 0.5 mm and a width of 40 mm;

The inhomogeneous crystallization method comprises: in an argon atmosphere, uniformly spraying the molten alloy from the quartz nozzle onto a rotating single roller, cooling the molten alloy at a cooling rate lower than 10 ⁵ ℃/s, and obtaining the first alloy with a thickness of 12 to 16 μm, a width of 150 mm, and a lateral thickness deviation of less than ±0.001 mm.

In some embodiments, the rolling of the first alloy by a preset number of passes to obtain the second alloy includes: rolling the first alloy by 4 to 6 passes with a total reduction rate of 60% to 70%, to obtain the second alloy with a thickness of 8 to 12 μm and a width of 200 to 300 mm.

In some embodiments, the method of using an automatic winding machine to wind the second alloy to obtain a third alloy includes: using an automatic winding machine to wind the second alloy into the third alloy with an outer diameter of 40 mm, an inner diameter of 30 mm, and a height of 150 mm; the third alloy is a nanocrystalline iron core; during winding, the roller surface of the second alloy is inside and the free surface of the second alloy is outside.

In some embodiments, the magnetic field heat treatment includes ordinary magnetic field heat treatment and rapid cycle magnetic field heat treatment, and the magnetic field heat treatment is performed on the third alloy using a magnetic field heat treatment furnace to obtain a fourth alloy, including but not limited to:

Placing the third alloy in a magnetic field heat treatment furnace in a nitrogen atmosphere to perform pretreatment and the ordinary magnetic field heat treatment to obtain the fourth alloy;

The third alloy is placed in a magnetic field heat treatment furnace in a nitrogen atmosphere to undergo pretreatment and the rapid cycle magnetic field heat treatment to obtain the fourth alloy.

In some embodiments, placing the third alloy in a magnetic field heat treatment furnace in a nitrogen atmosphere includes: inserting the third alloy into a copper tube with an outer diameter of 42 mm and an inner diameter of 41 mm, so that a gap of 0.9 to 1.1 mm is maintained between the outer diameter of the third alloy and the inner diameter of the copper tube;

The pretreatment includes heating the third alloy to 270-330°C at a rate of 40-60°C/min, keeping the temperature for 10-20 minutes, and then cooling the temperature to below 200°C to obtain a pretreated alloy;

The conventional magnetic field heat treatment comprises: a stress relief stage and a nanocrystallization stage, wherein the stress relief stage comprises: heating the pretreated alloy to 350-460°C at a rate of 40-60°C/min, keeping the temperature for 20-40 minutes, and applying a transverse magnetic field with a magnetic field strength of 40-60mT to the pretreated alloy at the same time; the nanocrystallization stage comprises: heating the alloy after the stress relief stage to 520-580°C at a rate of 80-120°C/min, keeping the temperature for 10-30 minutes, and then taking out the alloy after cooling to 200°C in the magnetic field heat treatment furnace, and adding a magnetic field with a strength of 40-60mT to the alloy during the whole process of the nanocrystallization stage. 40-60mT transverse magnetic field;

The rapid cycle magnetic field heat treatment includes: a first stage and a second stage, wherein the first stage includes: heating the pretreated alloy to 400-450°C at a rate of 100-200°C/min, keeping the temperature for 10-20 minutes, applying a transverse magnetic field with a magnetic field strength of 30-60mT to the pretreated alloy while keeping the temperature, and cooling the alloy to 200°C in the magnetic field heat treatment furnace after the insulation is completed; the second stage includes: heating the alloy cooled to 200°C to 400-450°C at a rate of 100-200°C/min, keeping the temperature for 10-20 minutes, applying a transverse magnetic field with a magnetic field strength of 30-60mT to the alloy while heating and keeping the temperature, and cooling the alloy to 200°C in the magnetic field heat treatment furnace after the insulation is completed; and cooling the alloy after the second stage is cycled 2-4 times to 200°C in the magnetic field heat treatment furnace, taking it out and closing the magnetic field to obtain the fourth alloy, wherein the fourth alloy is an iron-based high saturation magnetic induction nanocrystalline soft magnetic alloy.

In some embodiments, the use of a laser to perform micro-scratching on the fourth alloy to obtain the high saturation magnetic induction nanocrystalline soft magnetic alloy includes: scoring the fourth alloy through a laser magnetic domain refinement system to obtain the high saturation magnetic induction nanocrystalline soft magnetic alloy with a scoring groove width of 10 to 50 nm, a scoring groove depth of 20 to 50 nm, and a spacing between two adjacent scoring grooves of 1 to 10 mm.

In some embodiments, the width of the notched groove is 20-30 nm, the depth of the groove is 30-50 nm, and the interval between two adjacent notched grooves is 3-5 mm.

The technical solution of the embodiment of the present disclosure has the following advantages:

(1) In the disclosed embodiment, the chemical formula of the amorphous precursor strip composition for preparing high saturation magnetic induction nanocrystalline soft magnetic alloy is: Fe _a Si _b B _c Nb _d Cu _e M _f N _g , M is one of Ge, Al and Ni, and N is one of the rare earth elements Ce, Gd, Tb, Er and Yb. The appropriate Fe content can ensure that the alloy has a high saturation magnetic induction intensity, while avoiding the decrease of amorphous forming ability due to excessive Fe content; Si and B-type metal elements can ensure that the alloy can be formed in an amorphous state; the appropriate addition of large-sized Nb elements can reduce the coercive force of the alloy after heat treatment, while expanding the heat treatment window; the addition of Cu elements is conducive to the precipitation and refinement of micro grains, but excessive addition will lead to deterioration of strip performance. In addition to these typical elements, a small amount of one of Ge, Al and Ni elements, and one of the rare earth elements Ce, Gd, Tb, Er and Yb are also added. Among them, the addition of Ge, Al, and Ni elements effectively inhibits the excessive growth of α-Fe grains, improves the amorphous forming ability, and can improve the thermal stability of the amorphous matrix, showing good ductility, but if added in excess, it will lead to a decrease in saturation magnetic induction. Ce, Gd, Tb, Er, and Yb rare earth elements are more active. Compared with other rare earth elements, they are more likely to react with impurity elements such as sulfur and oxygen in the alloy to form compounds that float into the slag, and at the same time form a dense oxide film on the surface of the material, thereby improving the corrosion resistance of the alloy, making it less likely to be damaged by the laser structure, and facilitating rolling. At the same time, adding an appropriate amount of rare earth elements can also effectively refine the grains. On the one hand, the alloy has high saturation magnetic induction, low coercive force, and low loss; on the other hand, grain refinement can passivate cracks and reduce the crack propagation rate, thereby inhibiting its embrittlement, further delaying the tough-brittle transition, and maintaining high soft magnetic properties. However, if added in excess, it will lead to a decrease in saturation magnetic induction.

(2) In the embodiment of the present disclosure, after determining the alloy composition and materials, considering that rare earth elements are not easy to dissolve and will react with impurities, the alloy material is fully dissolved by vacuum induction melting for 3 to 5 times, and the surface impurities are removed at the end of each melting, and finally a molten alloy with uniform composition is formed. The molten alloy is then sprayed onto a high-speed rotating copper roller by the uneven crystallization method under the condition of argon gas atmosphere after high vacuum. By controlling the copper roller speed and the spraying pressure to make the cooling rate of the molten alloy lower than 10 ⁵ ℃/s, a strip with a thickness of 12 to 16 μm and a width of 150 mm can be obtained, and the transverse thickness deviation of the strip is less than ±0.001 mm. Using an XRD diffractometer, it is found that the roller-attached surface of the strip is amorphous and the free surface is crystallized. This is because the cooling rate of the roller-attached surface is higher than that of the free surface, causing the cross-section of the strip to show a temperature gradient, forming uneven crystallization. Using uneven crystallization, it can be found that the free surface of the strip presents a uniform and large number of primary crystal phases, and the roller surface presents a completely amorphous structure. This also makes the crystallization activation energy of the free surface lower than that of the roller surface, which is beneficial to increase the soft impact and competition between grains. In the subsequent heat treatment, a high-density, small-size, uniform nanocrystalline structure can be obtained, thereby improving the soft magnetic properties of the material.

(3) The embodiment of the present disclosure uses a nitrogen cooling device to control the rolling temperature to prevent the strip from crystallizing due to excessive temperature. The hydraulic pressure device is used to stably control and change the pressure at each end of the roller, so that the reduction rate is between 60% and 70%. Considering that too large a rolling reduction rate will cause shear bands in the strip, affecting the performance of the strip, and too small a reduction rate will make the rolling efficiency too low, controlling the reduction rate between 60% and 70% can ensure that the thickness of the strip after rolling is uniform and the surface has good finish, while preventing defects such as crystallization and dislocation caused by excessive reduction rate. As rolling proceeds, the atomic disorder in the alloy will decrease, and the disorder will turn to order, making the amorphous precursor strip move towards the direction of easy crystallization. The observation of the strip using an X-ray diffractometer also shows the diffuse scattering peaks of amorphous materials, indicating that the strip after rolling has not crystallized.

(4) The embodiment of the present disclosure specifies that the core is wound in such a way that the roller surface is inside and the free surface is outside. Thus, in the subsequent heat treatment process, the core temperature increases from the inside to the outside, thereby filling the temperature difference between the roller surface and the free surface, thereby improving the temperature distribution. At the same time, the tension and speed of the winding machine are controlled so that the core can rebound with a slight pinch, and the lamination coefficient is greater than 0.85, thereby avoiding affecting the performance of the core.

(5) In the preparation method of the embodiment of the present disclosure, the pretreatment can produce structural relaxation inside the material, remove internal stress, and enhance the structural stability of the material. It is followed by rapid cyclic magnetic field heat treatment, and the temperature is rapidly raised to 400-450°C at a rate of 100-200°C/min. This temperature is between the primary and secondary crystallization temperatures. The temperature is kept for 10-20 minutes. While keeping the temperature, a transverse magnetic field with a magnetic field strength of 30-60mT is applied to the material. After the insulation is completed, the strip is cooled to 200°C in the furnace without turning off the magnetic field and the same heat treatment steps are continued. The cycle is repeated 3-5 times. After the end, the strip is cooled to 200°C in the furnace and the magnetic field is taken out and turned off. By utilizing rapid cycle magnetic field heat treatment, on the one hand, grains can be quickly precipitated on the roller surface of the strip and a shorter holding time can control the grain growth rate and inhibit further growth of free surface grains, so that uniform and fine nanocrystalline particles are obtained as a whole, thereby inhibiting its annealing brittleness and improving soft magnetic properties; on the other hand, the added transverse magnetic field can effectively change the direction of the magnetic domain and reduce high-frequency losses; on the other hand, in the preparation method, uneven crystallization method and foil rolling, as well as specific heat treatment methods and micro-scratching technology are added on the basis of high-temperature heat treatment to further improve the magnetic domain structure of the strip, reduce iron loss, and optimize the soft magnetic properties of the alloy.

(6) In the embodiment of the present disclosure, micro-grooving is performed on the strip after heat treatment. The width and depth of the grooves have a bidirectional effect on the reduction of iron loss. If the width and depth of the grooves are too small, the iron loss will not change significantly. If the width and depth of the grooves are too large, the nanocrystalline matrix structure will deteriorate and even cause the strip to break. The groove spacing also interacts with the pulse energy. A suitable spacing can refine the magnetic domain structure and reduce the 180° main magnetic domain width, thereby reducing iron loss on the basis of magnetic field heat treatment. At the same time, due to the reduction in the angle between the magnetic domains after notching, the magnetostrictive performance of the strip is improved and the noise is reduced.

(7) The disclosed embodiment obtains an iron-based nanocrystalline soft magnetic alloy with high saturation magnetic induction intensity and low loss. The strip thickness is 8 to 12 μm, the width is 200 to 300 mm, and the transverse thickness deviation of the strip is less than ±0.001 mm. The saturation magnetic induction Bs of the nanocrystalline soft magnetic alloy finally prepared reaches 1.78 T to 1.92 T, and the loss is P1T/1 kHz = 0.8 W/kg to 1.7 W/kg. It has excellent effects when applied to high-frequency transformers or wireless charging.

It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and are not intended to limit the technical solutions of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a flat plate bending test device in Test Example 1 of the present disclosure;

FIG2-1 is an X-ray diffraction diagram of the precursor strip in Example 21 of the present disclosure;

FIG2-2 is a transmission electron microscope image of the precursor strip in Example 21 of the present disclosure;

FIG2-3 is a diagram of the magnetic domain structure of the precursor strip in Example 21 of the present disclosure;

2-4 is a diagram showing the magnetic domain structure of the nanocrystalline soft magnetic alloy after micro-scratching in Example 21 of the present disclosure;

FIG3-1 is an X-ray diffraction diagram of the precursor strip in Example 31 of the present disclosure;

FIG3-2 is an X-ray diffraction diagram of the precursor strip in Comparative Example 31 of the present disclosure;

FIG3-3 is a graph showing the change in magnetic permeability and frequency of the nanocrystalline soft magnetic alloy in Example 31 of the present disclosure;

3-4 is a graph showing the change in magnetic permeability and frequency of the nanocrystalline soft magnetic alloy in Comparative Example 31 of the present disclosure;

Figure 4-1 is an X-ray diffraction diagram of the precursor strip in Example 41 of the present disclosure

Figure 4-2 is a transmission electron microscope image of the roller surface of the precursor strip in Example 42 of the present disclosure

Figure 4-3 is a transmission electron microscope image of the free surface of the precursor tape in Example 43 of the present disclosure.

DETAILED DESCRIPTION

The following examples are provided to further better understand the present disclosure, but are not limited to the best implementation mode described herein, and do not limit the content and protection scope of the present disclosure. Any product identical or similar to the present disclosure that is derived by anyone under the inspiration of the present disclosure or by combining the present disclosure with features of other prior arts shall fall within the protection scope of the present disclosure.

If no specific experimental steps or conditions are specified in the examples, the experiments can be carried out according to the conventional experimental steps or conditions described in the literature in the art.

Iron-based nanocrystalline alloy is a new type of soft magnetic material, first reported by Yoshizawa et al. in 1988. Its standard composition is Fe _73.5 Cu ₁ Nb ₃ Si _13.5 B ₉ , and it was patented under the trademark Finemet. As soon as the alloy came out, it opened the door to new soft magnetic materials with high magnetic permeability, low coercivity and low loss. However, due to the low saturation magnetic induction intensity, researchers are also constantly improving it. The study found that the saturation magnetic induction intensity of nanocrystalline soft magnetic alloys is mainly determined by ferromagnetic elements, and metalloid elements determine its amorphous formation ability. When the saturation magnetic induction intensity is increased, the coercive force and loss will also increase at the same time, thereby deteriorating the magnetic properties. Therefore, the saturation magnetic induction intensity and low loss are mutually restricted. At the same time, annealing brittleness is a common problem of Fe-based nanocrystalline alloys. After the amorphous precursor strip is heat-treated to precipitate the α-Fe phase, the alloy hardness increases and becomes brittle, which increases the difficulty of preparing the core and is not conducive to the large size of the core. In particular, the core is prone to fracture and failure under actual working conditions, which greatly limits the application of nanocrystalline alloys. Therefore, a nanocrystalline soft magnetic alloy that maintains high saturation magnetic induction intensity and has low coercive force, low loss, and low annealing brittleness has been developed, which has good application prospects.

_An embodiment of the present disclosure provides a high saturation magnetic induction nanocrystalline soft magnetic alloy, wherein the chemical formula of the high saturation magnetic _{induction nanocrystalline soft} magnetic _alloy is _{FeaSibBcNbdCueMfNg} , where M is one of Ge, Al and Ni, and N is one of the rare earth elements Ce, Gd, Tb, Er and Yb; wherein a, b, c, d _, e, f and g are the atomic percentages of the corresponding elements, and a+b+c+d+e+f+g=100.

_{Here ,} if the chemical formula is _{FeaSibBcNbdCueAlfMg ,} and M is one _{of the rare} earth elements Ce or Gd, then the corresponding alloy is a nanocrystalline soft magnetic alloy; if the chemical formula is _{FeaSibBcNbdCueGefMg} , _and M is a rare earth element Tb or Gd, then the corresponding alloy is a nanocrystalline soft magnetic alloy; if the chemical formula is (Fe1 _{-xNix ) aSibBcNbdCueMf , and M} is _{a rare} earth element Er or _Yb , then the corresponding alloy _{is an iron} - _based nanocrystalline soft magnetic alloy.

In some embodiments, the atomic percentages of different elements are in the range of 74≤a≤80, 3≤b≤12, 4≤c≤12, 1≤d≤4, 0.5≤e≤1.5, 0.1≤f≤2.5, and 0.01≤g≤2.5.

In the embodiments of the present disclosure, a suitable Fe content can ensure that the alloy has a higher saturation magnetic induction intensity; Si and B-type metal elements can ensure that the alloy can be formed in an amorphous state; Nb element can reduce the coercive force of the alloy after heat treatment and expand the heat treatment window; the appropriate addition of Cu element is beneficial to the precipitation and refinement of micro grains; a small amount of addition of one of Ge, Al and Ni elements can effectively inhibit the excessive growth of α-Fe grains, improve the amorphous forming ability and at the same time improve the thermal stability of the amorphous matrix, showing good ductility; the appropriate addition of one of Ce, Gd, Tb, Er and Yb rare earth elements can effectively refine the grains.

In some embodiments, the high saturation magnetic induction nanocrystalline soft magnetic alloy has a thickness of 10 to 16 μm, a width of 200 to 300 mm, and a lateral thickness deviation of less than ±0.001 mm.

Here, if the alloy is a nanocrystalline soft magnetic alloy, its thickness is 10-16 μm, its width is 200-300 mm, and its lateral thickness deviation is less than ±0.001 mm; if the alloy is an iron-based nanocrystalline soft magnetic alloy, its thickness is 12-16 μm and its width is 150 mm.

The disclosed embodiments also provide for the application of the high saturation magnetic induction nanocrystalline soft magnetic alloy in high frequency transformers or wireless charging.

The present disclosure provides a method for preparing a high saturation magnetic induction nanocrystalline soft magnetic alloy, the preparation method comprising: Melting, cooling treatment, foil rolling, core winding, magnetic field heat treatment and micro-scoring;

The smelting comprises: using an induction melting furnace to melt the material after the component matching ratio to obtain a molten alloy; the material after the component matching ratio comprises: elements for preparing the high saturation magnetic induction nanocrystalline soft magnetic alloy and the atomic percentages corresponding to the elements;

The cooling process includes: spraying the molten alloy onto a high-speed rotating copper roller, and controlling the copper roller to cool the molten alloy at a preset speed to obtain a first alloy;

The foil rolling comprises: rolling the first alloy for a preset number of passes to obtain a second alloy;

The core winding comprises: using an automatic winding machine to wind the second alloy to obtain a third alloy;

The magnetic field heat treatment comprises: performing magnetic field heat treatment on the third alloy using a magnetic field heat treatment furnace to obtain a fourth alloy;

The micro-scratching comprises: performing micro-scratching treatment on the fourth alloy by using a laser to obtain the high saturation magnetic induction nanocrystalline soft magnetic alloy.

In the embodiments of the present disclosure, by adopting cooling treatment and foil rolling, as well as a specific magnetic field heat treatment method in the preparation method of a high saturation magnetic induction nanocrystalline soft magnetic alloy, and adding micro-scratching technology on the basis of high temperature heat treatment, the magnetic domain structure of the alloy is further improved, the iron loss is reduced, and the soft magnetic properties of the alloy are optimized.

In some embodiments, the use of an induction melting furnace to melt the material with a component matching ratio to obtain a molten alloy includes: at a melting temperature of 2000° C., using an induction melting furnace to dissolve the material with a component matching ratio four times to obtain the molten alloy.

Here, at a melting temperature of 2000° C., the material with a matching composition ratio is melted four times using an induction melting furnace to prepare a molten alloy with uniform composition.

In the embodiment of the present disclosure, after the alloy composition and materials are determined, considering that rare earth elements are not easily soluble and will react with impurities, the alloy material is fully dissolved through vacuum induction melting for 3 to 5 times, and the impurities on the surface are removed at the end of each time, ultimately forming a molten alloy with uniform composition.

In some embodiments, the cooling process includes single-roller rapid quenching, double-roller rapid quenching and inhomogeneous crystallization method, wherein the molten alloy is sprayed onto a high-speed rotating copper roller, and the copper roller is controlled to cool the molten alloy at a preset speed to obtain a first alloy, including but not limited to:

The single-roller rapid quenching includes: spraying the molten alloy uniformly from a quartz nozzle into a rotating single-roll gap, cooling the molten alloy at a cooling rate of 10 ⁵ to 10 ⁷ °C/s, and obtaining the first alloy with a thickness of 12 to 16 μm, a width of 150 mm, and a transverse thickness deviation of less than ±0.001 mm;

The double-roller rapid quenching includes: spraying the molten alloy uniformly from the quartz nozzle into the gap between the rotating double rolls, cooling the molten alloy at a cooling rate of 10 ⁵ to 10 ⁷ °C/s, and obtaining the first alloy with a thickness of 0.5 mm and a width of 40 mm;

The inhomogeneous crystallization method comprises: in an argon atmosphere, uniformly spraying the molten alloy from the quartz nozzle onto a rotating single roller, cooling the molten alloy at a cooling rate lower than 10 ⁵ ℃/s, and obtaining the first alloy with a thickness of 12 to 16 μm, a width of 150 mm, and a lateral thickness deviation of less than ±0.001 mm.

In the embodiments of the present disclosure, the molten alloy is cooled by any one of the cooling treatment methods to obtain a cooled alloy. Different cooling methods may result in alloys of different thicknesses and widths. This makes it convenient to select different cooling methods according to the required thickness and width of the alloy.

In some embodiments, the rolling of the first alloy by a preset number of passes to obtain the second alloy includes: rolling the first alloy by 4 to 6 passes with a total reduction rate of 60% to 70%, to obtain the second alloy with a thickness of 8 to 12 μm and a width of 200 to 300 mm.

In the embodiment of the present disclosure, a nitrogen cooling device is used to control the rolling temperature to prevent the first alloy from crystallizing due to excessive temperature, and a hydraulic pressure reduction device is used to stably control and change the pressure at each end of the roller so that the reduction rate is between 60% and 70%. Considering that an excessive rolling reduction rate may cause a shear band to be generated in the first alloy, which may affect the performance of the first alloy, Too small a reduction rate results in too low rolling efficiency. Controlling the reduction rate between 60% and 70% can ensure that the thickness of the second alloy after rolling is uniform and the surface has good smoothness, while preventing defects such as crystallization and dislocation caused by excessive reduction rate.

In some embodiments, the method of using an automatic winding machine to wind the second alloy to obtain a third alloy includes: using an automatic winding machine to wind the second alloy into the third alloy with an outer diameter of 40 mm, an inner diameter of 30 mm, and a height of 200-300 mm; the third alloy is a nanocrystalline iron core; during winding, the roller surface of the second alloy is inside and the free surface of the second alloy is outside.

In the disclosed embodiment, the second alloy is wound with the roller surface inside and the free surface outside. In this way, in the subsequent magnetic field heat treatment process, the alloy temperature changes from the inside to the outside, filling the temperature difference between the roller surface and the free surface, thereby improving the temperature distribution. At the same time, the tension and speed of the automatic winding machine are controlled so that the alloy can rebound with a light pinch, and the stacking coefficient is greater than 0.85, so as to avoid affecting the performance of the alloy.

In some embodiments, the magnetic field heat treatment includes ordinary magnetic field heat treatment and rapid cycle magnetic field heat treatment, and the third alloy is subjected to cycle magnetic field heat treatment using a magnetic field heat treatment furnace to obtain a fourth alloy, including but not limited to:

Placing the third alloy in a magnetic field heat treatment furnace in a nitrogen atmosphere to perform pretreatment and the ordinary magnetic field heat treatment to obtain the fourth alloy;

The third alloy is placed in a magnetic field heat treatment furnace in a nitrogen atmosphere for pretreatment and rapid cycle magnetic field heat treatment to obtain the fourth alloy.

In the disclosed embodiments, pretreatment can produce structural relaxation inside the material, remove internal stress, and enhance the structural stability of the material; the alloy after ordinary magnetic field heat treatment still maintains good toughness, which has a positive effect on the subsequent micro-scratching treatment; cyclic magnetic field heat treatment, on the one hand, can make the alloy's roller surface quickly precipitate grains and the shorter holding time can control the grain growth rate and inhibit the further growth of free surface grains, so as to obtain uniform and fine nanocrystalline particles as a whole, thereby inhibiting its annealing brittleness and improving its soft magnetic properties; on the other hand, the added transverse magnetic field can effectively change the direction of the magnetic domain and reduce high-frequency losses.

In some embodiments, placing the third alloy in a magnetic field heat treatment furnace in a nitrogen atmosphere includes: inserting the third alloy into a copper tube with an outer diameter of 42 mm and an inner diameter of 41 mm, so that a gap of 0.9 to 1.1 mm is maintained between the outer diameter of the third alloy and the inner diameter of the copper tube;

The pretreatment comprises: raising the temperature of the third alloy to 270-330° C. at a rate of 40-60° C./min, keeping the temperature for 10-20 minutes, and then lowering the temperature to below 200° C. to obtain a pretreated alloy;

The conventional magnetic field heat treatment comprises: a stress relief stage and a nano-crystallization stage, wherein the stress relief stage comprises: heating the pre-treated alloy to 350-460°C at a rate of 40-60°C/min, keeping the temperature for 20-40 minutes, and applying a transverse magnetic field with a magnetic field strength of 40-60mT to the pre-treated alloy while keeping the temperature; the nano-crystallization stage comprises: heating the alloy after the stress relief stage to 520-580°C at a rate of 80-120°C/min, keeping the temperature for 10-30 minutes, and then cooling the alloy to 200°C in the magnetic field heat treatment furnace and taking it out, and adding a transverse magnetic field with a magnetic field strength of 40-60mT throughout the nano-crystallization stage;

The rapid cycle magnetic field heat treatment includes: a first stage and a second stage, wherein the first stage includes: heating the pretreated alloy to 400-450°C at a rate of 100-200°C/min, keeping the temperature for 10-20 minutes, applying a transverse magnetic field with a magnetic field strength of 30-60mT to the pretreated alloy while keeping the temperature, and cooling the alloy to 200°C in the magnetic field heat treatment furnace after the insulation is completed; the second stage includes: heating the alloy cooled to 200°C to 400-450°C at a rate of 100-200°C/min, keeping the temperature for 10-20 minutes, applying a transverse magnetic field with a magnetic field strength of 30-60mT to the alloy while heating and keeping the temperature, and cooling the alloy to 200°C in the magnetic field heat treatment furnace after the insulation is completed; and cooling the alloy after the second stage is cycled 2-4 times to 200°C in the magnetic field heat treatment furnace, taking it out and closing the magnetic field to obtain the fourth alloy, wherein the fourth alloy is an iron-based high saturation magnetic induction nanocrystalline soft magnetic alloy.

In the embodiment of the present disclosure, for the ordinary magnetic field heat treatment, the temperature in the stress relief stage does not reach the crystallization temperature of the alloy, which can produce structural relaxation inside the material and enhance the structural stability of the material. The field helps to further improve the internal stress of the material, and at the same time, it can make the easy magnetization direction of the alloy consistent with the direction of the magnetic field, and the magnetic domain wall moves, thereby improving the magnetic domain structure and enhancing the high-frequency performance of the material. When the magnetic field strength is 40-60mT, the magnetic domain structure is most uniform; the holding temperature in the nanocrystallization stage needs to be between the primary crystallization and secondary crystallization temperatures, during which α-Fe grains will precipitate in the amorphous matrix. Through the stress relief in the stress relief stage, there is no residual stress inside the grains, the precipitated grains are smaller and more uniform, and the performance is more stable.

In some embodiments, the use of a laser to perform micro-scratching on the fourth alloy to obtain the high saturation magnetic induction nanocrystalline soft magnetic alloy includes: scoring the fourth alloy through a laser magnetic domain refinement system to obtain the high saturation magnetic induction nanocrystalline soft magnetic alloy with a scoring groove width of 10 to 50 nm, a scoring groove depth of 20 to 50 nm, and a spacing between two adjacent scoring grooves of 1 to 10 mm.

Here, the laser magnetic domain refinement system can be a low-power yttrium aluminum garnet (YAG) laser. In some embodiments, the width of the notched groove is 20 to 30 nm, the depth of the notched groove is 30 to 50 nm, and the interval between two adjacent notched grooves is 3 to 5 mm.

In the embodiments of the present disclosure, considering that the iron loss of the alloy caused by the micro-scratching technology is affected by multiple factors, such as laser devices, scoring processes, etc., a low-power YAG laser is used to micro-scratch the free surface of the alloy, and argon is used as a pump source medium, thereby effectively improving the efficiency and life of the laser. The pulse energy is changed by adjusting the pulse frequency. At a pulse frequency of 200 Hz to 1 kHz, the energy of a single pulse can be lower than 4 mJ, and the width and depth of the scoring groove can be easily controlled. The moving trajectory of the laser can be controlled by adjusting the scoring speed, and the interval between the two grooves of the alloy can be determined. The scoring speed can be adjusted within the range of 20 to 80 mm/s, and the continuity of the scoring groove will be better, the alloy surface will be flat and smooth, and the magnetic domain will be more refined.

Embodiment 11:

The present embodiment provides a high saturation magnetic induction nanocrystalline soft magnetic alloy, whose chemical formula is Fe ₇₉ Si ₁₀ B ₆ Nb ₁ Cu ₁ Al ₁ Ce ₂ . The required raw materials include industrial pure iron, pure silicon, ferroboron alloy, ferroniobium alloy, pure copper, pure aluminum, and ferrocerium alloy, all of which are purchased from the market. The specific preparation method is as follows: after the raw materials are proportioned, a master alloy with uniform composition is prepared by using an induction melting furnace, and then the liquid molten alloy is uniformly sprayed onto a high-speed rotating copper roller by using a non-uniform crystallization method. The cooling rate of the molten alloy is lower than 10 ⁵ ℃/s by controlling the rotation speed of the copper roller and the pressure of the spraying belt, so as to obtain a strip with a thickness of 13μm, a width of 150mm, and a transverse thickness deviation of less than ±0.001mm, so that the roller-contacting surface of the strip is amorphous, and the free surface is crystallized, forming non-uniform crystallization. Then, the foil is rolled 5 times to form an ultra-thin and ultra-wide amorphous precursor strip with a thickness of 10μm, a width of 250mm, and a lateral thickness deviation of less than ±0.001mm. The prepared precursor strip is then wound into an iron core with an outer diameter of 40mm, an inner diameter of 30mm, and a height of 250mm using an automatic winding machine. The nanocrystalline iron core is then placed in a magnetic field heat treatment furnace in a nitrogen atmosphere for pretreatment and rapid cycle magnetic field heat treatment. First, the iron core needs to be inserted into a copper tube with an outer diameter of 42mm and an inner diameter of 41mm, and the good thermal conductivity of copper is used to make the temperature inside and outside the core uniform. Then, pretreatment is performed, the temperature is rapidly raised to 300℃ at a rate of 50℃/min, kept at this temperature for 10min, and then dropped to below 200℃. Pretreatment can produce structural relaxation inside the material, remove internal stress, and enhance the structural stability of the material. Then, rapid cyclic magnetic field heat treatment is performed, the temperature is rapidly raised to 430℃ at a rate of 150℃/min, which is the temperature between the primary and secondary crystallization temperatures, kept at this temperature for 10min, and a transverse magnetic field with a magnetic field strength of 55mT is applied to the material at the same time. After the heat treatment, the strip is cooled to 200℃ with the furnace without closing the magnetic field and the same heat treatment steps are continued. The cycle is repeated 4 times, and the strip is cooled to 200℃ with the furnace and the magnetic field is taken out and closed. After heat treatment, the nanocrystalline strip is micro-scored, and the free surface of the precursor strip is scored with a low-power YAG laser. By adjusting the pulse frequency, scoring speed and other parameters, uniform parallel grooves are formed, with a groove width of 30nm, a depth of 40nm, and a spacing of 3mm between two adjacent grooves.

Embodiment 12:

This embodiment provides a high saturation magnetic induction nanocrystalline soft magnetic alloy, whose chemical formula is Fe _78.5 Si ₅ B ₁₁ Nb ₁ Cu ₁ Ge _1.5 Tb ₂ . The specific preparation method is: after the raw material components are proportioned, a master alloy with uniform composition is prepared by using an induction melting furnace, and then the liquid molten alloy is uniformly sprayed by using a non-uniform crystallization method. On a high-speed rotating copper roller, the cooling rate of the molten alloy is lower than 10 ⁵ ℃/s by controlling the copper roller speed and the spray pressure, and a strip with a thickness of 12μm, a width of 150mm, and a transverse thickness deviation of less than ±0.001mm is obtained, so that the roller surface of the strip is amorphous, and the free surface is crystallized, forming uneven crystallization. Then, the foil rolling method is used to roll 5 passes to form an ultra-thin and ultra-wide amorphous precursor strip with a thickness of 9μm, a width of 250mm, and a transverse thickness deviation of the strip less than ±0.001mm. The prepared precursor strip is then wound into an iron core with an outer diameter of 40mm, an inner diameter of 30mm, and a height of 250mm using an automatic winding machine. Subsequently, the nanocrystalline iron core is placed in a magnetic field heat treatment furnace in a nitrogen atmosphere for pretreatment and rapid cycle magnetic field heat treatment. First, the iron core needs to be inserted into a copper tube with an outer diameter of 42mm and an inner diameter of 41mm, and the good thermal conductivity of copper is used to make the temperature inside and outside the iron core uniform. Then, pretreatment is performed, the temperature is rapidly raised to 300℃ at a rate of 50℃/min, kept for 15min, and then dropped to below 200℃. Pretreatment can produce structural relaxation inside the material, remove internal stress, and enhance the structural stability of the material. Then, rapid cyclic magnetic field heat treatment is performed, the temperature is rapidly raised to 420℃ at a rate of 100℃/min, which is the temperature between the primary and secondary crystallization temperatures, kept for 15min, and a transverse magnetic field with a magnetic field strength of 55mT is applied to the material at the same time. After the heat preservation, the strip is cooled to 200℃ with the furnace without turning off the magnetic field and the same heat treatment steps are continued. The cycle is repeated 4 times. After the strip is cooled to 200℃ with the furnace, the magnetic field is taken out and turned off. After heat treatment, the nanocrystalline strip is micro-scored. The free surface of the precursor strip is scored with a low-power YAG laser. By adjusting the pulse frequency, scoring speed and other parameters, uniform parallel grooves are formed. The groove width is 40nm, the depth is 50nm, and the spacing between two adjacent grooves is 3mm.

Embodiment 13:

This embodiment provides a high saturation magnetic induction nanocrystalline soft magnetic alloy, whose chemical formula is Fe ₈₀ Si ₅ B ₁₀ Nb ₁ Cu ₁ Ge _1.5 Gd _1.5 . The specific preparation method is: after the raw material components are proportioned, a master alloy with uniform composition is prepared by an induction melting furnace, and then the liquid molten alloy is uniformly sprayed onto a high-speed rotating copper roller by a non-uniform crystallization method. The cooling rate of the molten alloy is lower than 10 ⁵ ℃/s by controlling the copper roller speed and the spraying pressure, and a strip with a thickness of 14μm, a width of 150mm, and a transverse thickness deviation of less than ±0.001mm is obtained, so that the roller-attached surface of the strip is amorphous, and the free surface is crystallized, forming non-uniform crystallization. Then, the foil rolling method is used to roll 5 times to form an ultra-thin and ultra-wide amorphous precursor strip with a thickness of 8μm, a width of 250mm, and a transverse thickness deviation of the strip less than ±0.001mm. The prepared precursor strip is then wound into an iron core with an outer diameter of 40mm, an inner diameter of 30mm, and a height of 250mm using an automatic winding machine. The nanocrystalline iron core is then placed in a magnetic field heat treatment furnace in a nitrogen atmosphere for pretreatment and rapid cycle magnetic field heat treatment. First, the iron core needs to be inserted into a copper tube with an outer diameter of 42mm and an inner diameter of 41mm to make the temperature inside and outside the iron core uniform by using the good thermal conductivity of copper. Then, pretreatment is performed, the temperature is rapidly raised to 300℃ at a rate of 50℃/min, kept for 10min, and then dropped to below 200℃. Pretreatment can produce structural relaxation inside the material, remove internal stress, and enhance the structural stability of the material. Then, rapid cyclic magnetic field heat treatment is performed, the temperature is rapidly raised to 450℃ at a rate of 200℃/min, which is the temperature between the primary and secondary crystallization temperatures, kept for 20min, and a transverse magnetic field with a magnetic field strength of 55mT is applied to the material at the same time. After the heat preservation, the strip is cooled to 200℃ with the furnace without turning off the magnetic field and the same heat treatment steps are continued. The cycle is repeated 4 times. After the strip is cooled to 200℃ with the furnace, the magnetic field is taken out and turned off. After heat treatment, the nanocrystalline strip is micro-scored. The free surface of the precursor strip is scored with a low-power YAG laser. By adjusting the pulse frequency, scoring speed and other parameters, uniform parallel grooves are formed. The groove width is 20nm, the depth is 30nm, and the spacing between two adjacent grooves is 4mm.

Embodiment 14:

This embodiment provides a high saturation magnetic induction nanocrystalline soft magnetic alloy, whose chemical formula is (Fe _0.9 Ni _0.1 ) _80.8 Si ₅ B ₁₁ Nb ₂ Cu ₁ Er _0.2 . The specific preparation method is as follows: after the raw material components are proportioned, a master alloy with uniform composition is prepared by using an induction melting furnace, and then the liquid molten alloy is uniformly sprayed onto a high-speed rotating copper roller by using an uneven crystallization method. By controlling the copper roller speed and the spraying pressure, the cooling rate of the molten alloy is lower than 10 ⁵ ℃/s, and a strip with a thickness of 13μm, a width of 150mm, and a transverse thickness deviation of less than ±0.001mm is obtained, so that the roller-attached surface of the strip is amorphous, and the free surface is crystallized, forming uneven crystallization. Then, the foil rolling method is used to roll 5 times to form an ultra-thin and ultra-wide amorphous strip with a thickness of 11μm, a width of 250mm, and a transverse thickness deviation of less than ±0.001mm. The precursor strip is then wound into an iron core with an outer diameter of 40 mm, an inner diameter of 30 mm, and a height of 250 mm using an automatic winding machine. The nanocrystalline iron core is then placed in a magnetic field heat treatment furnace in a nitrogen atmosphere for pretreatment and rapid cycle magnetic field heat treatment. First, the iron core needs to be inserted into a copper tube with an outer diameter of 42 mm and an inner diameter of 41 mm, and the good thermal conductivity of copper is used to make the temperature inside and outside the iron core uniform. Then, pretreatment is performed, the temperature is rapidly raised to 300℃ at a rate of 50℃/min, kept at this temperature for 20min, and then dropped to below 200℃. Pretreatment can produce structural relaxation inside the material, remove internal stress, and enhance the structural stability of the material. Then, rapid cyclic magnetic field heat treatment is performed, the temperature is rapidly raised to 400℃ at a rate of 150℃/min, which is the temperature between the primary and secondary crystallization temperatures, kept at this temperature for 15min, and a transverse magnetic field with a magnetic field strength of 55mT is applied to the material at the same time. After the heat treatment, the strip is cooled to 200℃ with the furnace without closing the magnetic field and the same heat treatment steps are continued. The cycle is repeated 4 times, and the strip is cooled to 200℃ with the furnace and the magnetic field is taken out and closed. After heat treatment, the nanocrystalline strip is micro-scored, and the free surface of the precursor strip is scored with a low-power YAG laser. By adjusting the pulse frequency, scoring speed and other parameters, uniform parallel grooves are formed, the groove width is 40nm, the depth is 40nm, and the spacing between two adjacent grooves is 5mm.

Embodiment 15:

This embodiment provides a high saturation magnetic induction nanocrystalline soft magnetic alloy, whose chemical formula is (Fe _0.9 Ni _0.1 ) _80.2 Si ₄ B ₁₁ Nb ₃ Cu ₁ Yb _0.8 . The specific preparation method is as follows: after the raw material components are proportioned, a master alloy with uniform composition is prepared by an induction melting furnace, and then the liquid molten alloy is uniformly sprayed onto a high-speed rotating copper roller by a non-uniform crystallization method. The cooling rate of the molten alloy is lower than 10 ⁵ ℃/s by controlling the copper roller speed and the spraying pressure, and a strip with a thickness of 14μm, a width of 150mm, and a transverse thickness deviation of less than ±0.001mm is obtained, so that the roller-attached surface of the strip is amorphous, and the free surface is crystallized, forming non-uniform crystallization. Then, the foil rolling method is used to roll 5 times to form an ultra-thin and ultra-wide amorphous precursor strip with a thickness of 10μm, a width of 250mm, and a transverse thickness deviation of the strip less than ±0.001mm. The prepared precursor strip is then wound into an iron core with an outer diameter of 40mm, an inner diameter of 30mm, and a height of 250mm using an automatic winding machine. The nanocrystalline iron core is then placed in a magnetic field heat treatment furnace in a nitrogen atmosphere for pretreatment and rapid cycle magnetic field heat treatment. First, the iron core needs to be inserted into a copper tube with an outer diameter of 42mm and an inner diameter of 41mm, and the good thermal conductivity of copper is used to make the temperature inside and outside the iron core uniform. Then, pretreatment is performed, the temperature is rapidly raised to 300℃ at a rate of 50℃/min, kept for 15min, and then dropped to below 200℃. Pretreatment can produce structural relaxation inside the material, remove internal stress, and enhance the structural stability of the material. Then, rapid cyclic magnetic field heat treatment is performed, the temperature is rapidly raised to 410℃ at a rate of 100℃/min, which is the temperature between the primary and secondary crystallization temperatures, kept for 10min, and a transverse magnetic field with a magnetic field strength of 55mT is applied to the material at the same time. After the heat preservation, the strip is cooled to 200℃ with the furnace without turning off the magnetic field and the same heat treatment steps are continued. The cycle is repeated 4 times. After the strip is cooled to 200℃ with the furnace, the magnetic field is taken out and turned off. After heat treatment, the nanocrystalline strip is micro-scored. The free surface of the precursor strip is scored with a low-power YAG laser. By adjusting the pulse frequency, scoring speed and other parameters, uniform parallel grooves are formed. The groove width is 30nm, the depth is 30nm, and the spacing between two adjacent grooves is 4mm.

Comparative Example 11:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses an alloy composition similar to that used in Example 11, and has a chemical formula of Fe ₈₀ Si ₁₀ B ₆ Nb ₁ Cu ₁ Ce ₂ . The difference is that the comparative example does not add Al element, and the preparation method is the same.

Comparative Example 12:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses an alloy composition similar to that used in Example 11, and has a chemical formula of Fe ₇₉ Si ₁₀ B ₆ Nb ₁ Cu ₁ Al ₁ . The difference is that no rare earth element is added in the comparative example, and the preparation method is the same.

Comparative Example 13:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses the same alloy composition as that used in Example 11, and has a chemical formula of Fe ₇₉ Si ₁₀ B ₆ Nb ₁ Cu ₁ Al ₁ Ce ₂ . The difference is that the preparation method does not use the inhomogeneous crystallization method, and the rest of the preparation methods are the same.

Comparative Example 14:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses the same alloy composition as Example 11. The scientific formula is Fe ₇₉ Si ₁₀ B ₆ Nb ₁ Cu ₁ Al ₁ Ce ₂ . The difference is that the foil rolling method is not used in the preparation method, and the other preparation methods are the same.

Comparative Example 15:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses the same alloy composition as that used in Example 11, and has a chemical formula of Fe ₇₉ Si ₁₀ B ₆ Nb ₁ Cu ₁ Al ₁ Ce ₂ . The difference is that a common heat treatment method is used in the preparation method, and the rest of the preparation methods are the same.

Comparative Example 16:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses the same alloy composition as that used in Example 1, and has a chemical formula of Fe ₇₉ Si ₁₀ B ₆ Nb ₁ Cu ₁ Al ₁ Ce ₂ . The difference is that micro-scratching is not used in the preparation method, and the rest of the preparation methods are the same.

Test Example 1:

The nanocrystalline soft magnetic alloy strips obtained in Examples 11 to 15 and Comparative Examples 11 to 16 were measured for saturation magnetic induction intensity using a vibrating sample magnetometer (VSM), and the loss of the nanocrystalline soft magnetic alloy was measured using an AC BH instrument. The relative fracture strain εf of the strips was tested by a flat plate bending test to evaluate their toughness and brittleness, as shown in Table 1. The flat plate bending test device disclosed in the present invention is shown in FIG1. The strip is bent into a U shape and placed between two flat plates, and then the distance between the two flat plates is slowly reduced at a constant rate until the strip breaks or bends to 180°. The equation is: The εf value can be calculated. In the formula: d is the thickness of the strip, and D is the distance between the two plates when the strip breaks. If the strip is bent 180° without breaking, then εf = 1, indicating that the strip is tough; if the strip breaks before bending 180°, then εf < 1, that is, the strip is brittle, and the smaller εf is, the greater the brittleness of the strip is.

Table 1

As can be seen from Table 1, compared with Example 11, the addition of Al element in Comparative Example 11 makes the prepared precursor strip less likely to crystallize, improves the amorphous forming ability, and is helpful for thermal regulation; compared with Example 11, the strip in Comparative Example 12 does not contain rare earth elements, and the performance is poor after heat treatment, and it is brittle when bent. This is because the rare earth element Er is beneficial to the precipitation and refinement of grains, delays the tough-brittle transition, and maintains high soft magnetic properties. At the same time, uneven crystallization helps to obtain uniform and fine nanocrystalline particles as a whole, thereby inhibiting its annealing brittleness and improving soft magnetic properties; compared with Example 11, Comparative Example 13 adopts the traditional rapid quenching method, and there is a temperature gradient in the strip. The formation of uneven grains during the subsequent heat treatment is not conducive to the soft magnetic properties of the strip; compared with Example 11, Comparative Example 14 does not add foil rolling, and the strip performance is poor; compared with Example 11, the strip performance deteriorates in Comparative Example 15, because the magnetic field heat treatment method used in the present disclosure can Obtaining uniform, fine nanocrystalline particles is more helpful for inhibiting annealing brittleness and improving soft magnetic properties. Compared with Example 11, the soft magnetic properties of the strip without micro-scratching treatment in Comparative Example 16 are not as good as the performance of the strip after micro-scratching treatment. This is because micro-scratching can further refine the magnetic domains on the basis of heat treatment, reduce iron loss, and improve strip performance.

Embodiment 21:

This embodiment provides a nanocrystalline soft magnetic alloy, whose chemical formula is Fe ₇₉ Si ₁₀ B ₆ Nb ₁ Cu ₁ Al ₁ Ce ₂ , and the specific preparation method is: after the raw material components are proportioned, a master alloy with uniform composition is prepared by induction melting furnace, and then an amorphous precursor strip with a thickness of 14 μm, a width of 130 mm, and a transverse thickness deviation of less than ±0.001 mm is prepared by single-roll rapid quenching method. Whether the precursor strip is crystallized is observed by X-ray diffractometer (XRD), and the phase can be analyzed by comparing with the standard powder diffraction card (PDF). As shown in FIG2-1, it can be seen that the precursor strip is completely amorphous. The thermodynamic analysis of the precursor strip is performed by differential scanning calorimeter (DSC). As shown in FIG2-2, the microstructure of the precursor strip is observed by transmission electron microscope, showing a randomly oriented disordered structure, which is consistent with the XRD result. Then, the amorphous precursor strip is placed in a magnetic field heat treatment furnace, and after vacuuming, nitrogen protection is injected. The annealing is divided into two stages. First, the temperature is rapidly raised to 450℃ at a speed of 50℃/min and kept for 30min. At the beginning of the heat preservation, a transverse magnetic field is applied to make the easy magnetization direction of the precursor strip consistent with the direction of the magnetic field. The magnetic field intensity is 50mT. This is the stress relief stage. Then, the temperature is rapidly raised to 550℃ at 100℃/min and kept for 20min. This is the nanocrystallization stage. After the heat preservation, the temperature is lowered to 200℃ and the magnetic field is turned off to take out the strip. After heat treatment, the nanocrystalline strip is micro-scored. The free surface of the precursor strip is scored with a low-power YAG laser. By adjusting the pulse frequency, scoring speed and other parameters, uniform parallel grooves are formed. The groove width is 30nm, the depth is 40nm, and the spacing between two adjacent grooves is 3mm.

Figures 2-3 and 2-4 are respectively photographs of magnetic domains of the precursor strip obtained after rapid quenching and the nanocrystalline soft magnetic alloy after micro-scratching in Example 21. It can be seen that the magnetic domains in Figure 2-3 exhibit an irregular, multi-branched magnetic domain structure, while after transverse magnetic heat treatment and micro-scratching treatment, the magnetic domains in Figure 2-4 appear flat and smooth, reducing the main magnetic domain width by 180°, and exhibiting good soft magnetic properties.

Embodiment 22:

The present embodiment provides a nanocrystalline soft magnetic alloy, whose chemical formula is Fe ₈₀ Si ₁₁ B ₄ Nb ₂ Cu ₁ Al ₁ Ce ₁ , and the specific preparation method is: after the raw material components are proportioned, a master alloy with uniform composition is prepared by induction melting furnace, and then an amorphous precursor strip with a thickness of 14 μm, a width of 130 mm, and a transverse thickness deviation of less than ±0.001 mm is prepared by single-roll rapid quenching method. Then, the amorphous precursor strip is placed in a magnetic field heat treatment furnace, and after vacuuming, nitrogen protection is injected. The annealing is divided into two stages. First, the temperature is rapidly increased to 460°C at a speed of 50°C/min, and the temperature is kept for 30 minutes. At the beginning of the temperature keeping, a transverse magnetic field is applied to make the easy magnetization direction of the precursor strip consistent with the magnetic field direction, and the magnetic field strength is 50mT, which is the stress relief stage, and then the temperature is rapidly increased to 560°C at 100°C/min, and the temperature is kept for 30 minutes, which is the nanocrystallization stage. After the temperature is kept, the temperature is lowered to 200°C, the magnetic field is turned off, and the strip is taken out. After heat treatment, the nanocrystalline strip is micro-scored. The free surface of the precursor strip is scored using a low-power YAG laser. By adjusting parameters such as pulse frequency and scoring speed, uniform parallel grooves are formed. The groove width is 40nm, the depth is 50nm, and the spacing between two adjacent grooves is 3mm.

Embodiment 23:

This embodiment provides a nanocrystalline soft magnetic alloy, whose chemical formula is Fe ₇₈ Si ₁₁ B ₅ Nb ₂ Cu ₁ Al ₂ Ce ₁ , and the specific preparation method is: after the raw material components are proportioned, a master alloy with uniform composition is prepared by induction melting furnace, and then an amorphous precursor strip with a thickness of 14 μm, a width of 130 mm, and a transverse thickness deviation of less than ±0.001 mm is prepared by single-roll rapid quenching method. Then, the amorphous precursor strip is placed in a magnetic field heat treatment furnace, and after vacuuming, nitrogen protection is injected. The annealing is divided into two stages. First, the temperature is rapidly increased to 440°C at a speed of 50°C/min, and the temperature is kept for 40 minutes. At the beginning of the temperature keeping, a transverse magnetic field is applied to make the easy magnetization direction of the precursor strip consistent with the magnetic field direction. The magnetic field strength is 50mT, which is the stress relief stage. Then, the temperature is rapidly increased to 540°C at 100°C/min, and the temperature is kept for 20 minutes. This is the nanocrystallization stage. After the temperature is kept, the temperature is lowered to 200°C, the magnetic field is turned off, and the strip is taken out. After heat treatment, the nanocrystalline ribbon is micro-scored. The free surface of the precursor strip is scored with a low-power YAG laser. By adjusting parameters such as pulse frequency and scoring speed, uniform parallel grooves are formed. The groove width is 20nm, the depth is 30nm, and the distance between two adjacent grooves is 4mm.

Embodiment 24:

This embodiment provides a nanocrystalline soft magnetic alloy, whose chemical formula is Fe ₇₆ Si ₁₂ B ₆ Nb ₁ Cu ₁ Al ₂ Gd ₂ . The specific preparation method is as follows: after the raw material components are proportioned, a master alloy with uniform composition is prepared by induction melting furnace, and then an amorphous precursor strip with a thickness of 14 μm, a width of 130 mm, and a transverse thickness deviation of less than ±0.001 mm is prepared by single-roll rapid quenching method. Then, the amorphous precursor strip is placed in a magnetic field heat treatment furnace, and after vacuuming, nitrogen protection is injected. The annealing is divided into two stages. First, the temperature is rapidly increased to 460°C at a speed of 50°C/min, and the temperature is kept for 40 minutes. At the beginning of the temperature keeping, a transverse magnetic field is applied to make the easy magnetization direction of the strip consistent with the magnetic field direction. The magnetic field strength is 50mT, which is the stress relief stage. Then, the temperature is rapidly increased to 560°C at 100°C/min, and the temperature is kept for 30 minutes. This is the nanocrystallization stage. After the temperature is kept, the temperature is lowered to 200°C, the magnetic field is turned off, and the strip is taken out. After heat treatment, the nanocrystalline strip is micro-scored. The free surface of the precursor strip is scored using a low-power YAG laser. By adjusting parameters such as pulse frequency and scoring speed, uniform parallel grooves are formed. The groove width is 40nm, the depth is 40nm, and the spacing between two adjacent grooves is 5mm.

Embodiment 25:

This embodiment provides a nanocrystalline soft magnetic alloy, whose chemical formula is Fe ₇₇ Si ₁₁ B ₅ Nb ₃ Cu ₁ Al ₂ Gd ₁ , and the specific preparation method is: after the raw material components are proportioned, an induction melting furnace is used to prepare a master alloy with uniform composition, and then a single-roller rapid quenching method is used to prepare an amorphous precursor strip with a thickness of 14 μm, a width of 130 mm, and a transverse thickness deviation of less than ±0.001 mm. Then, the amorphous precursor strip is placed in a magnetic field heat treatment furnace, and after vacuuming, nitrogen protection is injected. The annealing is divided into two stages. First, the temperature is rapidly increased to 440°C at a speed of 50°C/min, and the temperature is kept for 20 minutes. At the beginning of the temperature keeping, a transverse magnetic field is applied to make the easy magnetization direction of the strip consistent with the magnetic field direction. The magnetic field strength is 50mT, which is the stress relief stage, and then the temperature is rapidly increased to 540°C at 100°C/min, and the temperature is kept for 20 minutes. This is the nanocrystallization stage. After the temperature is kept, the temperature is lowered to 200°C, the magnetic field is turned off, and the strip is taken out. After heat treatment, the nanocrystalline strip is micro-scored. The free surface of the precursor strip is scored using a low-power YAG laser. By adjusting parameters such as pulse frequency and scoring speed, uniform parallel grooves are formed. The groove width is 30nm, the depth is 30nm, and the spacing between two adjacent grooves is 4mm.

Comparative Example 21:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses the same alloy composition as that used in Example 21, and has a chemical formula of Fe ₇₉ Si ₁₀ B ₆ Nb ₁ Cu ₁ Al ₁ Ce ₂ . The difference is that micro-scratching is not used in the preparation method, and the rest of the preparation methods are the same.

Comparative Example 22:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses the same alloy composition as Example 22, and has a chemical formula of Fe ₈₀ Si ₁₁ B ₄ Nb ₂ Cu ₁ Al ₁ Ce ₁ . The difference is that micro-scratching is not used in the preparation method, and the rest of the preparation method is the same.

Comparative Example 23:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses a rare earth element different from that of Example 21, and has a chemical formula of Fe ₇₉ Si ₁₀ B ₆ Nb ₁ Cu ₁ Al ₁ Nd ₂ . The rest of the preparation method is the same.

Comparative Example 24:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses the same alloy composition as that used in Example 21, and has a chemical formula of Fe ₇₉ Si ₁₀ B ₆ Nb ₁ Cu ₁ Al ₁ Ce ₂ . The difference is that the micro-scratching parameters are modified in the preparation method to make the scratches too small, and the rest of the preparation method is the same.

Comparative Example 25:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses the same alloy composition as that used in Example 21, and has a chemical formula of Fe ₇₉ Si ₁₀ B ₆ Nb ₁ Cu ₁ Al ₁ Ce ₂ . The difference is that the micro-scratching parameters are modified in the preparation method to make the scratches too large, and the rest of the preparation method is the same.

Comparative Example 26:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses the same alloy composition as that used in Example 21, except that the ratio of elements is different. Its chemical formula is Fe ₈₁ Si ₇ B ₃ Nb ₁ Cu ₂ Al ₃ Ce ₃ , and its preparation method is the same.

Comparative Example 27:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses the same alloy composition as Example 21, and its chemical formula is Fe ₇₉ Si ₁₀ B ₆ Nb ₁ Cu ₁ Al ₁ Ce _2. The difference is that the heat treatment method is different, specifically, the amorphous precursor strip is placed in a magnetic field heat treatment furnace, evacuated and flushed with nitrogen protection, and the temperature is slowly raised to 550°C at a rate of 10°C/min, and kept warm for 30 minutes. At the beginning of the heat preservation, a transverse magnetic field is applied to make the easy magnetization direction of the strip consistent with the magnetic field direction, and the magnetic field intensity is 50mT. After the heat preservation is completed, the temperature is lowered to 200°C, the magnetic field is turned off, and the strip is taken out. The rest of the preparation method is the same.

Test Example 2:

The saturation magnetic induction intensity of the nanocrystalline soft magnetic alloy strips obtained in Examples 21 to 25 and Comparative Examples 21 to 27 was measured using a vibrating sample magnetometer, and the coercive force and loss of the strips were measured using an AC/DC B-H meter, as shown in Table 2.

Table 2

As shown in Table 2, compared with Examples 21 and 22, the soft magnetic properties of the strips without micro-scratching treatment in Comparative Examples 21 and 22 are not as good as those after micro-scratching treatment. This is because micro-scratching can further refine the magnetic domains on the basis of heat treatment, reduce iron loss, and improve the performance of the strip. Compared with Example 21, in terms of soft magnetic properties, the strip with Nd element added in Comparative Example 23 is slightly weaker than the strip with Ce element. This is because Ce or Gd rare earth elements are more likely to form a dense oxide film on the surface of the material than other rare earth elements, thereby improving the corrosion resistance of the alloy and ensuring that the structure is not damaged by the laser. Compared with Example 21, the micro-scratching treatment in Comparative Example 24 is too small, and it can be seen that If it is too small, the soft magnetic properties are close to those of Example 21, without much change, and its performance is not as good as Example 21; Compared with Example 21, the micro-scratching treatment in Example 25 is too large, which will deteriorate the nanocrystalline matrix structure, and the strip is brittle and easy to break, and the performance is significantly lower than that of Example 21; Compared with Example 21, the different element proportions in Example 26 lead to poor strip performance, indicating that the overall performance of the alloy can be in the optimal state only when the element dosage is within the appropriate range proposed in the present disclosure; Compared with Example 21, the heat treatment in Example 27 adopts the traditional heat treatment method, but its improvement on the internal stress and magnetic domain of the material is not as good as Example 21, which further affects the soft magnetic properties of the strip after subsequent micro-scratching treatment.

Embodiment 31:

This embodiment provides a nanocrystalline soft magnetic alloy, whose chemical formula is Fe _78.5 Si ₅ B ₁₁ Nb ₁ Cu ₁ Ge _1.5 Tb ₂ . The specific preparation method is as follows: fully melt the material, use the rapid quenching method to uniformly spray the liquid molten alloy from a quartz nozzle into the gap between the high-speed rotating double rollers, and quickly cool the molten alloy to form an amorphous alloy with a thickness of 0.5 mm and a width of 40 mm. The alloy strip is rolled into an ultra-thin and ultra-wide amorphous precursor strip with a thickness of 11μm and a width of 260mm by the foil rolling method for 5 times. The transverse thickness deviation of the strip is less than ±0.001mm. The crystallization of the precursor strip is observed by X-ray diffractometer, and the physical phase can be analyzed by comparing with the standard PDF card. As can be seen from Figure 3-1, the strip is completely amorphous. The thermodynamic analysis of the strip uses a differential scanning calorimeter. Subsequently, the prepared amorphous strip is placed in a magnetic field heat treatment furnace under the protection of a nitrogen atmosphere, and the amorphous strip is subjected to transverse magnetic field heat treatment. The magnetic field heat treatment rapidly raises the temperature to about 260℃ at a rate of 50℃/min, which is the temperature between the primary and secondary crystallization temperatures, and is kept warm for 45min. At the beginning of the heat preservation, a transverse magnetic field with a magnetic field strength of 55mT is applied to the material. After the heat preservation is completed, the strip is cooled to 150℃ with the furnace and the magnetic field is turned off after it is taken out.

Embodiment 32:

This embodiment provides a nanocrystalline soft magnetic alloy, whose chemical formula is Fe _81.5 Si ₄ B ₁₀ Nb _1.5 Cu ₁ Ge ₁ Tb ₁ , and the specific preparation method is: fully melt the material, use the rapid quenching method to uniformly spray the liquid molten alloy from the quartz nozzle into the high-speed rotating double roller gap, and the molten alloy is quickly cooled to form an amorphous alloy strip with a thickness of 0.5 mm and a width of 40 mm, and then the foil rolling method is used to roll 5 times to form an ultra-thin and ultra-wide amorphous precursor strip with a thickness of 14 μm and a width of 250 mm, and the transverse thickness deviation of the strip is less than ±0.001 mm. Subsequently, the prepared amorphous strip is placed in a magnetic field heat treatment furnace under the protection of a nitrogen atmosphere, and the amorphous strip is subjected to transverse magnetic field heat treatment. The temperature of the magnetic field heat treatment is rapidly raised to about 255°C at a rate of 50°C/min, which is the temperature between the primary and secondary crystallization temperatures. The temperature is kept for 60 minutes. At the beginning of the heat preservation, a transverse magnetic field with a magnetic field strength of 55mT is applied to the material. After the heat preservation is completed, the strip is cooled to 150°C in the furnace and the magnetic field is turned off after it is taken out.

Embodiment 33:

This embodiment provides a nanocrystalline soft magnetic alloy, whose chemical formula is Fe ₈₀ Si ₄ B ₁₀ Nb ₁ Cu ₁ Ge _1.5 Tb _1.5 , and the specific preparation method is: fully melt the material, use the rapid quenching method to uniformly spray the liquid molten alloy from the quartz nozzle into the gap between the high-speed rotating double rollers, and quickly cool the molten alloy to form an amorphous alloy strip with a thickness of 0.5 mm and a width of 40 mm, and then use the foil rolling method to roll 5 times to form an ultra-thin and ultra-wide amorphous precursor strip with a thickness of 13 μm and a width of 270 mm, and the transverse thickness deviation of the strip is less than ±0.001 mm. Subsequently, the prepared amorphous strip is placed in a magnetic field heat treatment furnace under the protection of a nitrogen atmosphere, and the amorphous strip is subjected to transverse magnetic field heat treatment. The temperature of the magnetic field heat treatment is rapidly raised to about 260°C at a rate of 50°C/min, which is the temperature between the primary and secondary crystallization temperatures. The temperature is kept for 75 minutes. At the beginning of the heat preservation, a transverse magnetic field with a magnetic field strength of 55mT is applied to the material. After the heat preservation is completed, the strip is cooled to 150°C in the furnace and the magnetic field is turned off after it is taken out.

Embodiment 34:

This embodiment provides a nanocrystalline soft magnetic alloy, whose chemical formula is Fe ₇₉ Si _5.5 B ₁₀ Nb _1.5 Cu ₁ Ge ₁ Tb ₂ , and the specific preparation method is: fully melt the material, use the rapid quenching method to uniformly spray the liquid molten alloy from the quartz nozzle into the gap of the high-speed rotating double rollers, and quickly cool the molten alloy to form an amorphous alloy strip with a thickness of 0.5 mm and a width of 40 mm, and then use the foil rolling method to roll 5 times to form an ultra-thin and ultra-wide amorphous precursor strip with a thickness of 11 μm and a width of 260 mm, and the transverse thickness deviation of the strip is less than ±0.001 mm. Subsequently, the prepared amorphous strip is placed in a magnetic field heat treatment furnace under the protection of a nitrogen atmosphere, and the amorphous strip is subjected to transverse magnetic field heat treatment. The temperature of the magnetic field heat treatment is rapidly raised to about 260°C at a rate of 50°C/min, which is the temperature between the primary and secondary crystallization temperatures. The temperature is kept for 60 minutes. At the beginning of the heat preservation, a transverse magnetic field with a magnetic field strength of 55mT is applied to the material. After the heat preservation is completed, the strip is cooled to 150°C in the furnace and the magnetic field is turned off after it is taken out.

Embodiment 35:

This embodiment provides a nanocrystalline soft magnetic alloy, whose chemical formula is Fe _77.5 Si ₆ B ₁₁ Nb ₂ Cu ₁ Ge _1.5 Gd ₁ , and the specific preparation method is: fully melt the material, use the rapid quenching method to uniformly spray the liquid molten alloy from the quartz nozzle into the gap between the high-speed rotating double rollers, and quickly cool the molten alloy to form an amorphous alloy strip with a thickness of 0.5 mm and a width of 40 mm, and then use the foil rolling method to roll 5 times to form an ultra-thin and ultra-wide amorphous precursor strip with a thickness of 10 μm and a width of 270 mm, and the transverse thickness deviation of the strip is less than ±0.001 mm. Then, the prepared amorphous strip is placed The amorphous strip is placed in a magnetic field heat treatment furnace under the protection of nitrogen atmosphere, and the amorphous strip is subjected to transverse magnetic field heat treatment. The magnetic field heat treatment rapidly raises the temperature to about 250°C at a rate of 50°C/min, which is the temperature between the primary and secondary crystallization temperatures, and is kept warm for 30 minutes. At the beginning of the heat preservation, a transverse magnetic field with a magnetic field strength of 55mT is applied to the material. After the heat preservation is completed, the strip is cooled to 150°C with the furnace, taken out, and the magnetic field is turned off.

Embodiment 36:

The embodiment of the present disclosure provides a nanocrystalline soft magnetic alloy, whose chemical formula is Fe ₇₈ Si _6.5 B ₁₀ Nb ₁ Cu ₁ Ge ₂ Gd _1.5 , and the specific preparation method is: fully melt the material, use the rapid quenching method to uniformly spray the liquid molten alloy from the quartz nozzle into the high-speed rotating double roller gap, and the molten alloy is quickly cooled to form an amorphous alloy strip with a thickness of 0.5 mm and a width of 40 mm, and then rolled by a foil rolling method for 5 times to form an ultra-thin and ultra-wide amorphous precursor strip with a thickness of 12 μm and a width of 255 mm, and the transverse thickness deviation of the strip is less than ±0.001 mm. Subsequently, the prepared amorphous strip is placed in a magnetic field heat treatment furnace under the protection of a nitrogen atmosphere, and the amorphous strip is subjected to transverse magnetic field heat treatment. The temperature of the magnetic field heat treatment is rapidly raised to about 250°C at a rate of 50°C/min, which is the temperature between the primary and secondary crystallization temperatures. The temperature is kept for 45 minutes. At the beginning of the heat preservation, a transverse magnetic field with a magnetic field strength of 55mT is applied to the material. After the heat preservation is completed, the strip is cooled to 150°C in the furnace and the magnetic field is turned off after it is taken out.

Comparative Example 31:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses an alloy composition similar to that of Example 31, and has a chemical formula of Fe _78.5 Si ₆ B ₁₂ Nb ₁ Cu ₁ Ge _1.5 , except that no Tb element is added, but Si and B-type metal elements are added. The specific preparation method is: fully melt the material, and use a rapid quenching method to uniformly spray the liquid molten alloy from a quartz nozzle into a high-speed rotating double-roll gap, and the molten alloy is quickly cooled to form an amorphous alloy strip with a thickness of 0.5 mm and a width of 40 mm, and then rolled by a foil rolling method for 5 times to form an ultra-thin and ultra-wide amorphous precursor strip with a thickness of 12 μm and a width of 260 mm, and a transverse thickness deviation of the strip is less than ±0.001 mm. Whether the precursor strip is crystallized is observed by X-ray diffractometer. As can be seen from Figure 3-2, the precursor strip has an obvious sharp peak near 2θ=65°, indicating that compared with Example 31, there is no Tb element, and the precursor strip after rolling has crystallized, which will affect the soft magnetic properties. The prepared amorphous strip is then placed in a magnetic field heat treatment furnace under the protection of a nitrogen atmosphere, and the amorphous strip is subjected to transverse magnetic field heat treatment. The magnetic field heat treatment quickly raises the temperature to about 260°C at a rate of 50°C/min, which is the temperature between the primary and secondary crystallization temperatures. The temperature is kept for 45 minutes. At the beginning of the heat preservation, a transverse magnetic field with a magnetic field strength of 55mT is applied to the material. After the heat preservation is completed, the strip is cooled to 150°C with the furnace and the magnetic field is turned off after it is taken out. Figures 3-3 and 3-4 are respectively the magnetic permeability and frequency variation curves of the nanocrystalline soft magnetic alloys finally obtained in Example 31 and Comparative Example 31. The magnetic permeability of Example 31 under the test condition of a frequency of 1kHz is 77900, and the magnetic permeability under the test condition of a frequency of 100kHz is 28500. The magnetic permeability of Comparative Example 31 under the test condition of a frequency of 1kHz is 25600, and the magnetic permeability under the test condition of a frequency of 100kHz is 11200. At the same time, the curve of Example 31 is smoother than that of Comparative Example 31, indicating that the strip structure is stable and the performance is good.

Comparative Example 32:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses an alloy composition similar to that of Example 31, and has a chemical formula of Fe ₇₅ Si ₅ B ₁₀ Nb ₁ Cu ₁ Ge ₄ Tb ₄ . The difference is that Ge and Tb elements are added in excess, and Fe element is reduced. The preparation method is the same.

Comparative Example 33:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses the same alloy composition as Example 32, and its chemical formula is Fe _81.5 Si ₄ B ₁₀ Nb _1.5 Cu ₁ Ge ₁ Tb _1. The difference is that the thickness of the precursor strip produced by rolling is different, and the preparation method is the same.

Comparative Example 34:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses a rare earth element different from that of Example 31, has a chemical formula of Fe _78.5 Si ₅ B ₁₁ Nb ₁ Cu ₁ Ge _1.5 Nd ₂ , and is prepared by the same method.

Comparative Example 35:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses the same alloy composition as Example 31, and its chemical formula is Fe _78.5 Si ₅ B ₁₁ Nb ₁ Cu ₁ Ge _1.5 Tb ₂ . The difference is that double-roller rapid quenching and foil rolling are not used during preparation, and the rest of the preparation methods are the same.

Test Example 3:

The nanocrystalline soft magnetic alloys obtained from Examples 31 to 36 and Comparative Examples 31 to 35 were tested. The saturation magnetic induction intensity of the nanocrystalline soft magnetic alloys was measured using a vibrating sample magnetometer, the magnetic permeability versus frequency curve of the nanocrystalline soft magnetic alloy was measured using an impedance analyzer, and the loss of the nanocrystalline soft magnetic alloy was measured using an AC B-H meter, as shown in Table 3.

Table 3

It can be seen from Table 3 that, compared with Example 31, the addition of Tb element in Comparative Example 31 makes the prepared precursor strip less likely to crystallize, improves the amorphous forming ability, and is helpful for thermal regulation; it can be seen from Comparative Example 32 that, compared with Example 31, excessive addition of Ge and Tb elements reduces Fe element, resulting in a decrease in the saturation magnetic induction of the alloy, while the magnetic permeability and loss are deteriorated, indicating that excessive addition of Ge and Tb elements is not conducive to the nanocrystallization of the strip. Similarly, reducing the content of other elements will also lead to poor strip performance, indicating that the overall performance of the alloy can be in the optimal state only when the element dosage is within the appropriate range proposed in the present disclosure; it can be seen from Comparative Example 33 that, compared with Example 32, the rolling thickness is further increased. However, it leads to surface crystallization of the precursor strip, indicating that rolling to a certain thickness will cause the strip to crystallize, and at the same time produce shear bands that damage the structure and deteriorate the soft magnetic properties of the material; Compared with Example 31, in terms of soft magnetic properties, the strip with added Nd element is slightly weaker than the strip with Tb element. This is because compared with other rare earth elements, Tb and Gd elements have better amorphous forming ability and thermal stability, and are easier to improve the soft magnetic properties of the alloy; Compared with Example 31, Comparative Example 35 adopts the traditional single-roll rapid quenching technology, and the prepared strip is difficult to achieve lateral thickness consistency as the thickness decreases. Therefore, the thickness is thicker, and the crystallization temperature is above 400°C, and the comprehensive magnetic properties are not as good as Example 31.

Embodiment 41:

The present embodiment provides a nanocrystalline soft magnetic alloy, whose chemical formula is (Fe _0.9 Ni _0.1 ) _80.5 Si ₅ B ₁₀ Nb ₃ Cu ₁ Er _0.5 . The specific preparation method is as follows: the raw materials are fully melted 4 times at a melting temperature of 2000°C by vacuum induction melting, the liquid molten alloy is evenly sprayed onto a high-speed rotating copper roller by using a non-uniform crystallization method, and the cooling rate of the molten alloy is lower than 10 ⁵ ℃/s by controlling the rotation speed of the copper roller and the spraying pressure, so as to obtain a strip with a thickness of 13μm, a width of 150mm, and a lateral thickness deviation of less than ±0.001mm, as shown in FIG4-1. It is found by using an XRD diffractometer that the roller-attached surface of the strip is amorphous and the free surface is crystallized, forming non-uniform crystallization. Figures 4-2 and 4-3 are transmission electron microscope images of the roller surface and free surface of the nanocrystalline precursor in Example 41. It can be seen from Figures 4-2 and 4-3 that the roller surface has no obvious contrast and is a completely amorphous structure, while grains are observed on the free surface, which is consistent with the XRD result and is caused by the temperature gradient caused by uneven crystallization. The prepared precursor strip is then wound using an automatic winder. The core is made into an iron core with an outer diameter of 40mm, an inner diameter of 30mm and a height of 150mm. Then the nanocrystalline iron core is placed in a magnetic field heat treatment furnace in a nitrogen atmosphere for pretreatment and rapid cycle magnetic field heat treatment. First, the iron core needs to be inserted into a copper tube with an outer diameter of 42mm and an inner diameter of 41mm, and the good thermal conductivity of copper is used to make the temperature inside and outside the iron core uniform. Then comes the pretreatment, where the temperature is rapidly raised to 300°C at a rate of 50°C/min, kept at this temperature for 10 minutes, and then dropped to below 200°C. The pretreatment can produce structural relaxation inside the material, remove internal stress, and enhance the structural stability of the material. This is followed by rapid cyclic magnetic field heat treatment, where the temperature is rapidly raised to 430°C at a rate of 150°C/min (this temperature is between the primary and secondary crystallization temperatures), and kept at this temperature for 10 minutes. While keeping this temperature, a transverse magnetic field with a magnetic field strength of 55mT is applied to the material. After the insulation is completed, the strip is cooled to 200°C in the furnace, and the magnetic field is not turned off, and the same heat treatment steps are continued. This cycle is repeated 4 times. After the end, the strip is cooled to 200°C in the furnace, and the magnetic field is taken out and the magnetic field is turned off.

Embodiment 42:

This embodiment provides a nanocrystalline soft magnetic alloy, whose chemical formula is (Fe _0.9 Ni _0.1 ) _80.3 Si ₄ B ₁₁ Nb ₃ Cu ₁ Er _0.7 , and the specific preparation method is: the raw material is fully melted 4 times at a melting temperature of 2000°C by vacuum induction melting, and the liquid molten alloy is uniformly sprayed onto a high-speed rotating copper roller by a non-uniform crystallization method, and the cooling rate of the molten alloy is controlled to be lower than 10 ⁵ ℃/s by controlling the rotation speed of the copper roller and the pressure of the spray belt, so as to obtain a strip with a thickness of 12μm, a width of 150mm, and a transverse thickness deviation of less than ±0.001mm. Then, the prepared precursor strip is wound into an iron core with an outer diameter of 40mm, an inner diameter of 30mm, and a height of 150mm by an automatic winding machine. Subsequently, the nanocrystalline iron core is placed in a magnetic field heat treatment furnace in a nitrogen atmosphere for pretreatment and rapid cycle magnetic field heat treatment. First, the core needs to be inserted into a copper tube with an outer diameter of 42mm and an inner diameter of 41mm, and the good thermal conductivity of copper is used to make the temperature inside and outside the core uniform. Then, pretreatment is performed, and the temperature is quickly raised to 300℃ at a rate of 50℃/min, kept warm for 15 minutes, and then dropped to below 200℃. Pretreatment can produce structural relaxation inside the material, remove internal stress, and enhance the structural stability of the material. Then, rapid cyclic magnetic field heat treatment is performed, and the temperature is quickly raised to 420℃ at a rate of 100℃/min. This temperature is between the primary and secondary crystallization temperatures. Keep warm for 15 minutes. While keeping warm, a transverse magnetic field with a magnetic field strength of 55mT is applied to the material. After the insulation is completed, the strip is cooled to 200℃ with the furnace, and the magnetic field is not turned off to continue the same heat treatment steps. The cycle is repeated 4 times. After the strip is cooled to 200℃ with the furnace, the magnetic field is taken out and the magnetic field is turned off.

Embodiment 43:

This embodiment provides a nanocrystalline soft magnetic alloy, whose chemical formula is (Fe _0.9 Ni _0.1 ) _80.8 Si ₅ B ₁₁ Nb ₂ Cu ₁ Er _0.2 , and the specific preparation method is: the raw material is fully melted 4 times at a melting temperature of 2000°C by vacuum induction melting, and the liquid molten alloy is uniformly sprayed onto a high-speed rotating copper roller by a non-uniform crystallization method, and the cooling rate of the molten alloy is controlled to be lower than 10 ⁵ ℃/s by controlling the rotation speed of the copper roller and the pressure of the spray belt, so as to obtain a strip with a thickness of 14μm, a width of 150mm, and a transverse thickness deviation of less than ±0.001mm. Then, the prepared precursor strip is wound into an iron core with an outer diameter of 40mm, an inner diameter of 30mm, and a height of 150mm by an automatic winding machine. Subsequently, the nanocrystalline iron core is placed in a magnetic field heat treatment furnace in a nitrogen atmosphere for pretreatment and rapid cycle magnetic field heat treatment. First, the core needs to be inserted into a copper tube with an outer diameter of 42mm and an inner diameter of 41mm to make the temperature inside and outside the core uniform by using the good thermal conductivity of copper. Then, pretreatment is performed first, and the temperature is quickly raised to 300℃ at a rate of 50℃/min, kept warm for 10 minutes, and then dropped to below 200℃. Pretreatment can produce structural relaxation inside the material, remove internal stress, and enhance the structural stability of the material. Then, rapid cyclic magnetic field heat treatment is performed, and the temperature is quickly raised to 450℃ at a rate of 200℃/min. This temperature is between the primary and secondary crystallization temperatures. Keep warm for 20 minutes. While keeping warm, a transverse magnetic field with a magnetic field strength of 55mT is applied to the material. After the insulation is completed, the strip is cooled to 200℃ with the furnace, and the magnetic field is not turned off to continue the same heat treatment steps. The cycle is repeated 4 times. After the strip is cooled to 200℃ with the furnace, the magnetic field is taken out and the magnetic field is turned off.

Embodiment 44:

The present embodiment provides a nanocrystalline soft magnetic alloy, whose chemical formula is (Fe _0.9 Ni _0.1 ) _80.7 Si ₅ B ₁₀ Nb ₃ Cu ₁ Yb _0.3 . The specific preparation method is as follows: the raw materials are fully melted 4 times at a melting temperature of 2000°C by vacuum induction melting, and the liquid molten alloy is uniformly sprayed onto a high-speed rotating copper roller by a non-uniform crystallization method, and the cooling rate of the molten alloy is controlled to be lower than 10 ⁵ ℃/s by controlling the rotation speed of the copper roller and the pressure of the spray belt, so as to obtain a nanocrystalline soft magnetic alloy with a thickness of 13μm, a width of 150mm, and a transverse width of 100mm. For strips with a thickness deviation of less than ±0.001mm, the XRD diffractometer was used to find that the roller surface of the strip was amorphous, and the free surface was crystallized, forming uneven crystallization. The prepared precursor strip was then wound into an iron core with an outer diameter of 40mm, an inner diameter of 30mm, and a height of 150mm using an automatic winding machine. The nanocrystalline iron core was then placed in a magnetic field heat treatment furnace in a nitrogen atmosphere for pretreatment and rapid cycle magnetic field heat treatment. First, the iron core needs to be inserted into a copper tube with an outer diameter of 42mm and an inner diameter of 41mm, and the good thermal conductivity of copper is used to make the temperature inside and outside the iron core uniform. Then comes the pretreatment, where the temperature is rapidly raised to 300°C at a rate of 50°C/min, kept at that temperature for 20 minutes, and then dropped to below 200°C. The pretreatment can produce structural relaxation inside the material, remove internal stress, and enhance the structural stability of the material. This is followed by rapid cyclic magnetic field heat treatment, where the temperature is rapidly raised to 400°C at a rate of 150°C/min (this temperature is between the primary and secondary crystallization temperatures), and kept at that temperature for 15 minutes. While keeping at that temperature, a transverse magnetic field with a magnetic field strength of 55mT is applied to the material. After the insulation is completed, the strip is cooled to 200°C in the furnace, and the magnetic field is not turned off and the same heat treatment steps are continued. This cycle is repeated 4 times. After the end, the strip is cooled to 200°C in the furnace and the magnetic field is taken out and the magnetic field is turned off.

Embodiment 45:

This embodiment provides a nanocrystalline soft magnetic alloy, whose chemical formula is (Fe _0.9 Ni _0.1 ) _80.2 Si ₄ B ₁₁ Nb ₃ Cu ₁ Yb _0.8 , and the specific preparation method is: the raw material is fully melted 4 times at a melting temperature of 2000°C by vacuum induction melting, and the liquid molten alloy is uniformly sprayed onto a high-speed rotating copper roller by a non-uniform crystallization method, and the cooling rate of the molten alloy is controlled to be lower than 10 ⁵ ℃/s by controlling the rotation speed of the copper roller and the pressure of the spray belt, so as to obtain a strip with a thickness of 14μm, a width of 150mm, and a transverse thickness deviation of less than ±0.001mm. Then, the prepared precursor strip is wound into an iron core with an outer diameter of 40mm, an inner diameter of 30mm, and a height of 150mm by an automatic winding machine. Subsequently, the nanocrystalline iron core is placed in a magnetic field heat treatment furnace in a nitrogen atmosphere for pretreatment and rapid cycle magnetic field heat treatment. First, the core needs to be inserted into a copper tube with an outer diameter of 42mm and an inner diameter of 41mm, and the good thermal conductivity of copper is used to make the temperature inside and outside the core uniform. Then, pretreatment is performed, and the temperature is quickly raised to 300℃ at a rate of 50℃/min, kept warm for 15 minutes, and then dropped to below 200℃. Pretreatment can produce structural relaxation inside the material, remove internal stress, and enhance the structural stability of the material. Then, rapid cyclic magnetic field heat treatment is performed, and the temperature is quickly raised to 410℃ at a rate of 100℃/min. This temperature is between the primary and secondary crystallization temperatures, and kept warm for 10 minutes. While keeping warm, a transverse magnetic field with a magnetic field strength of 55mT is applied to the material. After the insulation is completed, the strip is cooled to 200℃ with the furnace, and the magnetic field is not turned off to continue the same heat treatment steps. The cycle is repeated 4 times. After the strip is cooled to 200℃ with the furnace, the magnetic field is taken out and the magnetic field is turned off.

Comparative Example 41:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses an alloy composition similar to that of Example 41, and has a chemical formula of (Fe _0.9 Ni _0.1 ) ₈₁ Si ₅ B ₁₀ Nb ₃ Cu ₁ . The difference is that Er element is not added, but Fe and Ni metal elements are added. The preparation method is the same.

Comparative Example 42:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses a rare earth element different from that of Example 41, has a chemical formula of (Fe _0.9 Ni _0.1 ) _80.5 Si ₅ B ₁₀ Nb ₃ Cu ₁ Nd _0.5 , and is prepared by the same method.

Comparative Example 43:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses the same alloy composition as that used in Example 41, except that the element ratios are different. Its chemical formula is (Fe _0.8 Ni _0.2 ) ₇₇ Si ₅ B ₁₀ Nb ₄ Cu ₁ Er ₃ , and its preparation method is the same.

Comparative Example 44:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses the same alloy composition as that of Example 41, except that it uses a traditional rapid quenching method. Its chemical formula is (Fe _0.9 Ni _0.1 ) _80.5 Si ₅ B ₁₀ Nb ₃ Cu ₁ Er _0.5 , and the rest of the preparation method is the same.

Comparative Example 45:

This comparative example provides a nanocrystalline soft magnetic alloy, which uses the same alloy composition as that of Example 41, except that a traditional heat treatment method is used. Its chemical formula is (Fe _0.9 Ni _0.1 ) _80.5 Si ₅ B ₁₀ Nb ₃ Cu ₁ Er _0.5 , and the rest of the preparation method is the same.

Test example 4:

The saturation magnetic induction intensity of the nanocrystalline soft magnetic alloy was measured using a vibrating sample magnetometer, the loss of the nanocrystalline soft magnetic alloy was measured using an AC B-H instrument, and the relative fracture strain εf of the strip after heat treatment was tested by a flat plate bending test to evaluate its toughness and brittleness. The specific test results are shown in Table 4.

Table 4

As shown in Table 4, compared with Example 41, the strip of Comparative Example 41 does not contain the Er element and the precursor strip is amorphous, the performance after heat treatment is poor, and it is brittle when bent. This is because the rare earth element Er is beneficial to the precipitation and refinement of grains, delays the tough-brittle transition, and maintains high soft magnetic properties. At the same time, uneven crystallization helps to obtain uniform and fine nanocrystalline particles as a whole, thereby suppressing its annealing brittleness and improving soft magnetic properties. Compared with Example 41, in terms of soft magnetic properties, the strip with the added Nd element in Comparative Example 42 is slightly weaker than the strip with the Er element. This is because compared with other rare earth elements, Er and Yb elements have better effects on the precipitation and refinement of grains and can maintain high soft magnetic properties. Compared with Example 41, Comparative Example 43 has different element ratios resulting in poor strip performance, and the precursor strip is extremely brittle after crystallization heat treatment, indicating that the overall performance of the alloy can be optimal only when the element dosage is within the appropriate range proposed in the present disclosure; Comparative Example 44 compared with Example 41 adopts the traditional rapid quenching method, and there is a temperature gradient in the strip. The formation of uneven grains during the subsequent heat treatment is not conducive to the soft magnetic properties of the strip; Comparative Example 45 compared with Example 41, the strip performance deteriorates. This is because the magnetic field heat treatment method used in the present application can obtain uniform and fine nanocrystalline particles, which is more helpful for suppressing annealing brittleness and improving soft magnetic properties.

Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims (13)

A high saturation magnetic induction nanocrystalline soft magnetic alloy, _wherein the chemical formula of the high saturation magnetic _induction nanocrystalline _{soft magnetic} alloy _{is FeaSibBcNbdCueMfNg} , M is one of Ge, Al and Ni, and N is one of the rare earth elements Ce, _Gd , Tb, Er and Yb; Among them, a, b, c, d, e, f and g are the atomic percentages of the corresponding elements respectively, and a+b+c+d+e+f+g=100. The high saturation magnetic induction nanocrystalline soft magnetic alloy according to claim 1, wherein 74≤a≤80, 3≤b≤12, 4≤c≤12, 1≤d≤4, 0.5≤e≤1.5, 0.1≤f≤2.5, and 0.01≤g≤2.5. The high saturation magnetic induction nanocrystalline soft magnetic alloy according to claim 1, wherein the high saturation magnetic induction nanocrystalline soft magnetic alloy has a thickness of 10 to 16 μm, a width of 200 to 300 mm, and a lateral thickness deviation of less than ±0.001 mm. Application of the high saturation magnetic induction nanocrystalline soft magnetic alloy according to any one of claims 1 to 3 in high frequency transformers or wireless charging. A method for preparing a high saturation magnetic induction nanocrystalline soft magnetic alloy, the preparation method comprising: smelting, cooling treatment, foil rolling, core winding, magnetic field heat treatment and micro-scratching; The smelting comprises: using an induction melting furnace to melt the material after the component matching ratio to obtain a molten alloy; the material after the component matching ratio comprises: elements for preparing the high saturation magnetic induction nanocrystalline soft magnetic alloy and the atomic percentages corresponding to the elements; The cooling process includes: spraying the molten alloy onto a high-speed rotating copper roller, and controlling the copper roller to cool the molten alloy at a preset speed to obtain a first alloy; The foil rolling comprises: rolling the first alloy for a preset number of passes to obtain a second alloy; The core winding comprises: using an automatic winding machine to wind the second alloy to obtain a third alloy; The magnetic field heat treatment comprises: performing magnetic field heat treatment on the third alloy using a magnetic field heat treatment furnace to obtain a fourth alloy; The micro-scratching comprises: performing micro-scratching treatment on the fourth alloy by using a laser to obtain the high saturation magnetic induction nanocrystalline soft magnetic alloy. The preparation method according to claim 5, wherein the step of melting the materials after the component matching ratio is carried out by an induction melting furnace to obtain a molten alloy comprises: The material with the matched composition ratio is dissolved four times in an induction melting furnace at a melting temperature of 2000° C. to obtain the molten alloy. The preparation method according to claim 5, wherein the cooling treatment includes single-roller rapid quenching, double-roller rapid quenching and inhomogeneous crystallization method, wherein the molten alloy is sprayed onto a high-speed rotating copper roller, and the copper roller is controlled to cool the molten alloy at a preset speed to obtain a first alloy, including but not limited to: The single-roller rapid quenching includes: spraying the molten alloy uniformly from a quartz nozzle into a rotating single-roll gap, cooling the molten alloy at a cooling rate of 10 ⁵ to 10 ⁷ °C/s, and obtaining the first alloy with a thickness of 12 to 16 μm, a width of 150 mm, and a transverse thickness deviation of less than ±0.001 mm; The double-roller rapid quenching includes: spraying the molten alloy uniformly from the quartz nozzle into the gap between the rotating double rolls, cooling the molten alloy at a cooling rate of 10 ⁵ to 10 ⁷ °C/s, and obtaining the first alloy with a thickness of 0.5 mm and a width of 40 mm; The inhomogeneous crystallization method comprises: in an argon atmosphere, uniformly spraying the molten alloy from the quartz nozzle onto a rotating single roller, cooling the molten alloy at a cooling rate lower than 10 ⁵ ℃/s, and obtaining the first alloy with a thickness of 12 to 16 μm, a width of 150 mm, and a lateral thickness deviation of less than ±0.001 mm. The preparation method according to claim 5, wherein the first alloy is subjected to a preset number of passes. Rolling to obtain a second alloy comprising: The first alloy is rolled 4 to 6 times with a total reduction ratio of 60% to 70% to obtain the second alloy with a thickness of 8 to 12 μm and a width of 200 to 300 mm. The preparation method according to claim 5, wherein the second alloy is coiled using an automatic coiler to obtain the third alloy, comprising: The second alloy is wound into the third alloy with an outer diameter of 40 mm, an inner diameter of 30 mm, and a height of 200-300 mm by an automatic winding machine; the third alloy is a nanocrystalline iron core; when winding, the roller surface of the second alloy is inside and the free surface of the second alloy is outside. The preparation method according to claim 5, wherein the magnetic field heat treatment includes ordinary magnetic field heat treatment and rapid cycle magnetic field heat treatment, and the magnetic field heat treatment of the third alloy using a magnetic field heat treatment furnace to obtain a fourth alloy includes but is not limited to: Placing the third alloy in a magnetic field heat treatment furnace in a nitrogen atmosphere to perform pretreatment and the ordinary magnetic field heat treatment to obtain the fourth alloy; The third alloy is placed in a magnetic field heat treatment furnace in a nitrogen atmosphere to undergo pretreatment and the rapid cycle magnetic field heat treatment to obtain the fourth alloy. The preparation method according to claim 10, wherein Placing the third alloy into a magnetic field heat treatment furnace in a nitrogen atmosphere comprises: inserting the third alloy into a copper tube with an outer diameter of 42 mm and an inner diameter of 41 mm, so that a gap of 0.9 to 1.1 mm is maintained between the outer diameter of the third alloy and the inner diameter of the copper tube; The pretreatment comprises: raising the temperature of the third alloy to 270-330° C. at a rate of 40-60° C./min, keeping the temperature for 10-20 minutes, and then lowering the temperature to below 200° C. to obtain a pretreated alloy; The conventional magnetic field heat treatment comprises: a stress relief stage and a nano-crystallization stage, wherein the stress relief stage comprises: heating the pre-treated alloy to 350-460°C at a rate of 40-60°C/min, keeping the temperature for 20-40min, and applying a transverse magnetic field with a magnetic field strength of 40-60mT to the pre-treated alloy while keeping the temperature; the nano-crystallization stage comprises: heating the alloy after the stress relief stage to 520-580°C at a rate of 80-120°C/min, keeping the temperature for 10-30min, and then cooling the alloy to 200°C in the magnetic field heat treatment furnace and taking it out, and adding a transverse magnetic field with a magnetic field strength of 40-60mT throughout the nano-crystallization stage; The rapid cycle magnetic field heat treatment includes: a first stage and a second stage, wherein the first stage includes: heating the pretreated alloy to 400-450°C at a rate of 100-200°C/min, keeping the temperature for 10-20 minutes, applying a transverse magnetic field with a magnetic field strength of 30-60mT to the pretreated alloy while keeping the temperature, and cooling the alloy to 200°C in the magnetic field heat treatment furnace after the insulation is completed; the second stage includes: heating the alloy cooled to 200°C to 400-450°C at a rate of 100-200°C/min, keeping the temperature for 10-20 minutes, applying a transverse magnetic field with a magnetic field strength of 30-60mT to the alloy while heating and keeping the temperature, and cooling the alloy to 200°C in the magnetic field heat treatment furnace after the insulation is completed; and cooling the alloy after the second stage is cycled 2-4 times to 200°C in the magnetic field heat treatment furnace, taking it out and closing the magnetic field to obtain the fourth alloy, wherein the fourth alloy is an iron-based high saturation magnetic induction nanocrystalline soft magnetic alloy. The preparation method according to claim 5, wherein the step of performing micro-scratching treatment on the fourth alloy using a laser to obtain the high saturation magnetic induction nanocrystalline soft magnetic alloy comprises: The fourth alloy is scored by a laser magnetic domain refinement system to obtain the high saturation magnetic induction nanocrystalline soft magnetic alloy with a scoring groove width of 10 to 50 nm, a scoring groove depth of 20 to 50 nm, and a spacing of 1 to 10 mm between two adjacent scoring grooves. The preparation method according to claim 12, wherein the width of the notch groove is 20 to 30 nm, the depth of the notch groove is 30 to 50 nm, and the interval between two adjacent notch grooves is 3 to 5 mm.