Iron-based nanocrystalline strip and preparation method therefor, nanocrystalline iron core, and preparation method therefor and use thereof

Abstract

An iron-based nanocrystalline strip and a preparation method therefor, a nanocrystalline iron core, and a preparation method therefor and the use thereof. The chemical formula of the material of the iron-based nanocrystalline strip is FeaSibBcNbdCueTifTgEhMi, wherein T is selected from at least one of alkali metals; E is selected from at least one of halogen elements; M is selected from at least one of rare earth metals; and a, b, c, d, e, f, g, h and i are atomic percentages of corresponding elements, where a+b+c+d+e+f+g+h+i=100 at%, 76 at%≤a≤82 at%, 3 at%≤b≤6 at%, 8 at%≤c≤12 at%, 1 at%≤d≤3 at%, 0.5 at%≤e≤1.5 at%, 0.5 at%≤f≤2.5 at%, 0.5 at%≤g≤1.5 at%, 0.5 at%≤h≤1.5 at%, 0.5 at%≤i≤2.5 at%, and g=h.

Description

An iron-based nanocrystalline strip and its preparation method, a nanocrystalline iron core and its preparation method and application

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure is based on the Chinese patent application with application number 202311216847.9, application date September 20, 2023, and application name “A kind of iron-based nanocrystalline strip and its preparation method and application”, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into the present disclosure as a reference. Technical Field

[0003] The present disclosure relates to, but is not limited to, the field of magnetic functional materials, and in particular to an iron-based nanocrystalline strip and a preparation method thereof, a nanocrystalline core and a preparation method and application thereof. Background Art

[0004] Since the advent of iron-based nanocrystalline soft magnetic alloys in the 1980s, their excellent soft magnetic properties have opened a new chapter in the soft magnetic industry. Compared to traditional soft magnetic materials such as silicon steel and ferrite, nanocrystalline soft magnetic alloys combine high saturation magnetic induction and permeability with low losses, meeting the needs of power electronic devices for continuous miniaturization and efficiency. In related technologies, the Finemet nanocrystalline alloy, invented by Hitachi Metals, is widely used domestically and internationally due to its excellent soft magnetic properties. With the development trend of high-efficiency, energy-saving, and high-capacity power electronic components, there is a demand for wider and thinner nanocrystalline materials. In related technologies, the width (≤100mm) and thickness (≥18μm) of strip materials no longer meet application requirements. In addition, the difficulty in controlling the magnetic field annealing heat treatment of large-sized cores has restricted the development and application of nanocrystalline materials in devices such as low-loss, high-capacity, and high-frequency transformers. The development of wide, ultra-thin nanocrystalline strips and large-sized cores is urgently needed.

[0005] Chinese patent application CN103060691A discloses an iron-based nanocrystalline ribbon and a preparation method thereof, wherein the chemical formula of the iron-based nanocrystalline ribbon is: Fe a Cu b Nb c Si d B e The method, based on the composition of the FINEMET soft magnetic alloy, details the production process of domestically produced iron-based nanocrystalline ribbon. The resulting ribbon has a thickness of 30-40 μm and a width of 3-10 mm. However, given the current development speed of power electronics, nanocrystalline ribbons of this specification are no longer sufficient to meet the demands of more advanced devices.

[0006] Chinese patent application CN112176249A discloses an iron-based nanocrystalline ribbon and a preparation method thereof, wherein the chemical composition of the iron-based nanocrystalline ribbon is expressed as follows: Fe a Si b B c Cu d Nb e M f , wherein M is selected from at least one of Mo and V. The alloy, prepared by optimizing the alloy component content, has good amorphous forming ability and thermal stability. The addition of Mo and V effectively improves the shortcomings of the soft magnetic alloy, such as rapid attenuation of high-frequency magnetic permeability and low value, while also improving the resistivity of the material. However, the disadvantage of this alloy is its low saturation magnetic induction.

[0007] Patent CN106086714A discloses an iron-based soft magnetic alloy having a width greater than 63.5 mm, a thickness between 13 and 20 microns, and a composition represented by the following expression: (Fe 1-a M a )100-xyz- p-q-r Cu x Si y B z M' p M" q X r wherein M is Co and / or Ni, M' is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo; M" is at least one element selected from the group consisting of V, Cr, Mn, Al, platinum group elements, Sc, Y, rare earth elements, Au, Zn, Sn and Re; and a, x, y, z, p, q and r respectively satisfy 0≤a≤0.5, 0.1≤x≤3, 0≤y≤30, 1≤z≤25, 5≤y+z≤30, 0.1≤p≤30, q≤10 and r≤ 10. X is at least one element selected from the group consisting of C, Ge, P, Ga, Sb, In, Be, and As. The alloy is at least 50% crystalline with an average particle size of less than 100 nm. This alloy exhibits good soft magnetic properties, but the patent does not provide a detailed analysis of the alloy composition or examples illustrating the effects of different element contents on the alloy's soft magnetic properties. While the alloy is capable of producing ultra-thin and ultra-wide strips using a superior process, the saturation magnetic induction is low, failing to simultaneously achieve high saturation magnetic induction, high high-frequency permeability, and low losses.

[0008] The saturation magnetic induction intensity and high-frequency loss of nanocrystalline alloys are mutually constrained. Increasing the saturation magnetic induction intensity will lead to increased losses. Under high-frequency conditions, the losses will increase sharply with the increase of frequency. The development of a wide-width ultra-thin iron-based nanocrystalline strip with high saturation magnetic induction intensity, high frequency and low loss is of great significance for the preparation of larger-sized iron cores, thereby realizing larger-capacity high-frequency transformers, higher-power wireless charging and other fields.

[0009] Summary of the Invention

[0010] Therefore, in order to address the problems in the related art that iron-based nanocrystalline strips are difficult to have high saturation magnetic induction intensity, high frequency and low loss, and the strips have wide and ultra-thin dimensions, the embodiments of the present disclosure provide an iron-based nanocrystalline strip and a preparation method thereof, a nanocrystalline iron core and a preparation method and application thereof.

[0011] The present disclosure provides an iron-based nanocrystalline ribbon. The chemical formula of the iron-based nanocrystalline ribbon material is Fe a Si b B c Nb d Cu e Ti f T g E h M i ;

[0012] Wherein, T is selected from at least one of alkali metals; E is selected from at least one of halogen elements; M is selected from at least one of rare earth metals;

[0013] a, b, c, d, e, f, g, h, i are the atomic percentages of the corresponding elements, a+b+c+d+e+f+g+h+i=100at%, 76at%≤a≤82at%, 3at%≤b≤6, 8at%≤c≤12at%, 1at%≤d≤3at%, 0.5at%≤e≤1.5at%, 0.5at%≤f≤2.5at%, 0.5at%≤g≤1.5at%, 0.5at%≤h≤1.5at%, 0.5at%≤i≤2.at%5, g=h.

[0014] In some embodiments, the T is selected from at least one of Li (lithium), Na (sodium), and K (potassium); and / or

[0015] The E is selected from Cl (chlorine); and / or,

[0016] The M is selected from at least one of Tb (terbium), Nd (neodymium), and Pm (praseodymium).

[0017] In some embodiments, the strip has a thickness of 12 to 16 μm (micrometers), a width of 150 to 250 mm (millimeters), and a thickness deviation in the width direction of the strip is less than 0.001 mm.

[0018] An embodiment of the present disclosure provides a method for preparing the above-mentioned iron-based nanocrystalline ribbon, comprising the following steps: weighing raw materials according to a stoichiometric ratio, then mixing and smelting the raw materials, forming the melt obtained by smelting into an amorphous precursor ribbon, and then subjecting the formed amorphous precursor ribbon to a magnetic field stress heat treatment to obtain the iron-based nanocrystalline ribbon.

[0019] In some embodiments, the raw material is selected from: industrial pure iron, pure silicon, ferroboron alloy, ferroniobium alloy, pure copper, pure titanium, sodium chloride, pure neodymium, lithium chloride, pure cerium, potassium chloride, pure terbium, pure promethium, and rubidium chloride.

[0020] In some embodiments, the smelting process is carried out in a vacuum induction furnace under the action of electromagnetic force; the smelting temperature is 1300-1500° C. (Celsius).

[0021] In some embodiments, the process of forming the amorphous precursor ribbon is to form the amorphous precursor ribbon by subjecting the melt obtained by smelting to a single-roller rapid quenching method;

[0022] In some embodiments, the process of forming the amorphous precursor ribbon by the single-roll rapid quenching method is to use inert gas pressurization to spray the melt obtained by smelting from a quartz nozzle onto a high-speed rotating copper roller;

[0023] In some embodiments, the inert gas comprises argon;

[0024] Wherein, in the single-roller rapid quenching method, the cooling rate of the melt is 10 5 ~10 7 ℃ / s;

[0025] The thickness of the formed amorphous precursor strip is 12 to 16 μm, and the width of the strip is 150 to 250 mm.

[0026] In some embodiments, the process of subjecting the formed amorphous precursor ribbon to magnetic field stress heat treatment is to apply tension in the length direction of the amorphous precursor ribbon;

[0027] The temperature of the magnetic field stress heat treatment is 520-580°C, the magnetic field intensity of the magnetic field stress heat treatment is 30-70mT, the magnetic field direction is perpendicular to the longitudinal section of the amorphous precursor strip; the time of the magnetic field stress heat treatment is 10s-10min, and the tension is 1-100MPa.

[0028] The present disclosure also provides a nanocrystalline core, which is obtained by winding an iron-based nanocrystalline ribbon to form a precursor core material, varnishing the precursor core material, and then curing it in a chlorine atmosphere. The iron-based nanocrystalline ribbon is the iron-based nanocrystalline ribbon described above or the iron-based nanocrystalline ribbon prepared by the preparation method described above.

[0029] Among them, the impregnating agent used in the dipping paint includes epoxy resin and curing agent.

[0030] In some embodiments, the cross-section of the winding needle used for winding the iron-based nanocrystalline ribbon is rectangular, circular, or triangular.

[0031] In some embodiments, the iron-based nanocrystalline ribbon is wound using a winding needle with a rectangular cross section to form a precursor core material with a window height of 100-400 mm, a width of 100-300 mm, a window chamfer radius of 10-100 mm, and a winding thickness of 40-80 mm.

[0032] In some embodiments, the iron-based nanocrystalline ribbon is wound using a winding needle with a triangular cross section to form a window of a precursor core material, the side length of which is 100-400 mm, the radius of the window chamfer arc is 10-100 mm, and the winding thickness is 40-80 mm.

[0033] In some embodiments, the time for dipping the formed precursor core material into the paint is 1-5 hours; and / or,

[0034] The curing temperature is 60-180° C., and the curing time is 3-10 hours.

[0035] In some embodiments, the dipping paint further includes a toughening agent;

[0036] The mass ratio of epoxy resin, curing agent and toughening agent in the impregnating agent is (8-12): (3-6): (0.8-1.2); and / or,

[0037] The epoxy resin is selected from epoxy resin E-51; the curing agent is selected from polyetheramine D400; and the toughening agent is selected from carboxyl-terminated nitrile rubber.

[0038] The embodiments of the present disclosure also provide applications of the aforementioned nanocrystalline core in high-frequency transformers or wireless charging.

[0039] The embodiment of the present disclosure also provides a method for preparing a nanocrystalline iron core, comprising the following steps: winding the iron-based nanocrystalline strip prepared by the preparation method described above to form a precursor core material, varnishing the precursor core material, and then curing it in a chlorine atmosphere to obtain the nanocrystalline iron core; wherein the impregnating agent used in the varnishing includes epoxy resin and curing agent.

[0040] The technical solution of the disclosed embodiment has the following advantages:

[0041] 1. An iron-based nanocrystalline ribbon provided in an embodiment of the present disclosure has a chemical formula of Fe a Si b B c Nb d Cu e Ti f T g E h M i ; Wherein, T is selected from at least one of the alkali metals; E is selected from at least one of the halogen elements; M is selected from at least one of the rare earth metals; a+b+c+d+e+f+g+h+i=100, 76at%≤a≤82at%, 3at%≤b≤6at%, 8at%≤c≤12at%, 1at%≤d≤3at%, 0.5at%≤e≤1.5at%, 0.5at%≤f≤2.5at%, 0.5at%≤g≤1.5at%, 0.5at%≤h≤1.5at%, 0.5at%≤i≤2.5at%, g=h.

[0042] The iron-based nanocrystalline ribbon of the embodiment of the present disclosure uses specific components and limits the content of each component. Among them, the Fe (iron) element in the iron-based nanocrystalline ribbon plays a role in maintaining the saturation magnetic induction intensity as a ferromagnetic element, and the appropriate ratio of Si (silicon) and B (boron) metal elements is the key to obtaining an amorphous precursor; large-sized Nb (niobium) elements and Ti (titanium) elements can effectively hinder the growth of nanocrystalline grains and reduce the diffusion coefficient. At the same time, Ti has the effect of corrosion resistance and oxidation resistance, reducing the reduction of saturation magnetic induction intensity caused by oxidation of the material; Cu (copper) element as a nucleation element is conducive to the precipitation and refinement of nanocrystalline grains; alkali metal elements are added in combination with halogen elements. Alkali metal elements can strongly react with substances such as oxygen, nitrogen, and sulfur during the smelting process, acting as deoxidizers and desulfurizers, thereby improving the purity of the solution. At the same time, the addition of alkali metal elements can reduce the atomic transition energy during the subsequent heat treatment process, promote the heterogeneous nucleation of nanocrystalline grains, increase the nucleation ratio, thereby refining the grains and reducing losses; halogen elements are used to be added to the alloy in combination with alkali metals. Halogen elements can The uniformity of the solution is improved during the smelting process, and the heterogeneous nucleation of nanocrystalline grains and the refinement of grains can be promoted during the heat treatment process. The combined addition of alkali metal elements and halogen elements can reduce the thickness deviation in the width direction of the finally prepared iron-based nanocrystalline ribbon, smooth the surface, and produce thinner and wider iron-based nanocrystalline ribbons. It can also improve the saturation magnetic induction intensity of the finally prepared iron core and reduce its high-frequency loss. However, the addition of excessive alkali metal elements and halogen elements will reduce the material's ability to form amorphous during the preparation process, thereby reducing the performance of the finally obtained ribbon. The addition of rare earth elements can improve the amorphous forming ability and thermal stability of the bulk amorphous alloy, and can produce thinner and wider iron-based nanocrystalline ribbons. In summary, by selecting specific components and limiting the content of each component, the amorphous forming ability of the material can be improved, and the subsequent crystallization process can be controlled to obtain a nanocrystalline ribbon with refined grains, thereby making the material produce thinner and wider iron-based nanocrystalline ribbons, and the prepared iron-based nanocrystalline ribbons have high saturation magnetic induction intensity and low high-frequency loss.

[0043] 2. In some embodiments, the rare earth metals provided in the embodiments of the present disclosure are selected from Tb, Nd, and Pm. Compared with other rare earth elements, they are more likely to react with impurity elements such as sulfur and oxygen in the alloy to the surface of the solution during the smelting process, and at the same time, a dense oxide film can be formed on the surface of the alloy, making the mother alloy purer. In addition, Tb, Nd, and Pm can further improve the amorphous forming ability and thermal stability of the alloy, which is conducive to the preparation of thinner and wider iron-based nanocrystalline strips. At the same time, as larger-sized rare earth elements, they are conducive to the precipitation and refinement of α-Fe grains, thereby improving the saturation magnetic induction intensity of the final iron core and reducing its high-frequency loss.

[0044] 3. The preparation method of the iron-based nanocrystalline strip provided in the embodiment of the present disclosure includes the following steps: weighing raw materials according to the stoichiometric ratio, then mixing and smelting the raw materials, forming the melt obtained by smelting into an amorphous precursor strip, and then subjecting the formed amorphous precursor strip to magnetic field stress heat treatment to obtain the iron-based nanocrystalline strip.

[0045] Press Fe a Si b B c Nb d Cu e Ti f T g E h M i Prepare raw materials, mix and smelt the raw materials, and then form the melt obtained by smelting into an amorphous precursor strip. In the process of crystallizing the formed amorphous precursor strip, magnetic field stress heat treatment is adopted. In the process of magnetic field stress heat treatment, uniform and fine nanocrystalline grains will first be precipitated, reducing coercive force and loss. By applying appropriate stress, a large induced anisotropy will be generated in the width direction of the strip, making the hysteresis loop of the alloy tend to be flat, and improving the saturation magnetic induction intensity of the material. At the same time, a transverse magnetic field is applied. Compared with the process of stress heat treatment first and then magnetic field heat treatment, induced anisotropy can be further generated in the width direction, the domain wall is moved to be consistent with the direction of the magnetic field, the magnetic domain structure is improved, and the high-frequency loss of the strip is reduced; Fe a Si b B c Nb d Cu e Ti f T g E h M i Alkali metal elements and halogen elements are added to the alloy. The addition of alkali metal elements can reduce the atomic transition energy during the subsequent heat treatment, promote the heterogeneous nucleation of nano-grains, and increase the nucleation ratio, thereby refining the grains and reducing losses. Halogen elements are used to match alkali metals and are added to the alloy. Halogen elements can improve the uniformity of the solution during the smelting process, and can also promote the heterogeneous nucleation of nano-grains and refine the grains during the heat treatment process. The combined addition of alkali metal elements and halogen elements can reduce the thickness deviation in the width direction of the finally prepared iron-based nanocrystalline ribbon, smooth the surface, and prepare thinner and wider iron-based nanocrystalline ribbons. It can also increase the saturation magnetic induction intensity of the finally prepared iron core and reduce its high-frequency loss. Specific raw materials are mixed and smelted to form an amorphous precursor ribbon, and then subjected to magnetic field stress heat treatment to obtain thinner and wider iron-based nanocrystalline ribbons with high saturation magnetic induction intensity, high frequency and low loss.

[0046] 4. A nanocrystalline core provided by an embodiment of the present disclosure is obtained by winding the iron-based nanocrystalline strip obtained by the preparation method described above to form a precursor core material, and the precursor core material is dipped in varnish and then cured in a chlorine atmosphere to obtain the nanocrystalline core; wherein the impregnating agent used in the dipping in varnish includes epoxy resin, curing agent, and toughening agent.

[0047] After the iron-based nanocrystalline strip is wound to form a precursor core material, the precursor core material is then dipped in a specific impregnating agent. The toughening agent in the impregnating agent can make the precursor core material have better toughness, and the iron-based nanocrystalline strip is not easy to break. It is then cured in a chlorine atmosphere. The chlorine can cooperate with the halogen elements in the iron-based nanocrystalline strip to further prevent the iron core from oxidation. On the other hand, the chlorine can be integrated into the impregnating agent to improve the adhesion and curing rate of the impregnating agent, thereby reducing the high-frequency loss of the final nanocrystalline core.

[0048] 5. In some embodiments, the mass ratio of the epoxy resin, curing agent, and toughening agent in the impregnating agent provided by the embodiments of the present disclosure is (8-12): (3-6): (0.8-1.2); the epoxy resin is selected from epoxy resin E-51; the curing agent is selected from polyetheramine D400; and the toughening agent is selected from carboxyl-terminated nitrile rubber. By selecting specific epoxy resins, curing agents, and toughening agents and limiting their relative mass ratios, the impregnating agent can have better fluidity, higher bonding strength, and lower cure shrinkage, thereby resulting in high-capacity nanocrystalline cores with improved high-frequency loss performance, and core capacities exceeding 1MVA. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the specific embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0050] The accompanying drawings herein are incorporated into and constitute a part of the specification. These drawings illustrate embodiments consistent with the present disclosure and, together with the specification, are used to explain the technical solutions of the present disclosure.

[0051] Figure 1 is a schematic diagram of the structure of the strip in the embodiment of the present disclosure, wherein OX, OY, and OZ are mutually perpendicular coordinate axes, wherein OY is parallel to the length direction of the strip, OZ is parallel to the thickness direction of the strip, OX is parallel to the width direction of the strip, and the longitudinal section of the strip is a section parallel to the OYZ plane. DETAILED DESCRIPTION

[0052] The following examples are provided to further better understand the present disclosure, but are not limited to the best mode of implementation and do not limit the content and protection scope of the present disclosure. Any product identical or similar to the present disclosure obtained by anyone under the guidance of the present disclosure or by combining the features of the present disclosure with other prior arts shall fall within the protection scope of the present disclosure.

[0053] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0054] Example 1

[0055] The present disclosure provides an iron-based nanocrystalline ribbon, the chemical formula of which is:

[0056] Fe 80 Si4B 10 Nb1Cu1Ti1Na1Cl1Nd1. It can be understood that taking 80 as an example, it represents the atomic percentage of Fe is 80at%.

[0057] This embodiment provides a method for preparing a nanocrystalline core, comprising the following steps:

[0058] 1) Industrial pure iron, pure silicon, ferroboron alloy, ferroniobium alloy, pure copper, pure titanium, sodium chloride, and pure neodymium are proportioned and mixed according to the above chemical formula. The mixed raw materials are then placed in a vacuum induction furnace and smelted under electromagnetic force (melting temperature is 1350°C) to obtain a melt with uniform composition. The melt is uniformly sprayed from a quartz nozzle onto a high-speed rotating copper roller using pressurized argon gas. The melt is heated at a speed of 10 6 ~10 7 The amorphous precursor strip with a thickness of 14 μm (the thickness deviation in the width direction of the strip is less than 0.001 mm) and a width of 200 mm was formed by cooling at a cooling rate of 100 °C / s. The structure of the strip is shown in Figure 1. OX, OY, and OZ are mutually perpendicular coordinate axes, where OY is parallel to the length direction of the strip, OZ is parallel to the thickness direction of the strip, OX is parallel to the width direction of the strip, and the longitudinal section of the strip is the section parallel to the OYZ plane.

[0059] 2) the amorphous precursor strip obtained in step 1) is subjected to magnetic field stress heat treatment at 560° C. in a heat treatment furnace to obtain the iron-based nanocrystalline strip, wherein a strip inlet and a strip outlet are provided at both ends of the heat treatment furnace, and the specific process of the magnetic field stress heat treatment is as follows: the amorphous precursor strip is wound on an unwinding winder at the strip inlet, and then the amorphous precursor strip on the unwinding winder is sent from the strip inlet into the heat treatment furnace and wound up by a winding winder at the strip outlet, the tension of the amorphous precursor strip along the length direction is controlled to be 60 MPa when the amorphous precursor strip passes through the heat treatment furnace by the unwinding winder and the winding winder, and the travel time of the amorphous precursor strip from the strip inlet to the strip outlet at the same position is 2 min, and during the heat treatment process, a transverse magnetic field with a strength of 50 mT perpendicular to the longitudinal section of the amorphous precursor strip is provided in the section from the strip inlet to the strip outlet;

[0060] 3) The iron-based nanocrystalline ribbon obtained in step 2) is wound into a precursor core material with a window height of 320 mm, a width of 180 mm, a window chamfer radius of 60 mm, and a winding thickness of 170 mm using a winding machine with a winding needle with a rectangular cross-section. The capacity can reach 1 MVA, and the precursor core material is then dipped in an impregnating agent for 2 hours, wherein the impregnating agent includes epoxy resin E-51, polyetheramine D400, and end-carboxyl nitrile rubber, wherein the mass ratio of epoxy resin E-51, polyetheramine D400, and end-carboxyl nitrile rubber is 10:5:1; Subsequently, the dipped precursor core material is placed in an oven in a chlorine atmosphere and cured at 90° C. for 6 hours to obtain the nanocrystalline iron core.

[0061] Example 2

[0062] The present disclosure provides an iron-based nanocrystalline ribbon, the chemical formula of which is:

[0063] Fe 81 Si3B9Nb2Cu1Ti1Li1Cl1Pm1.

[0064] The present disclosure provides a method for preparing the above-mentioned iron-based nanocrystalline ribbon, comprising the following steps:

[0065] 1) Industrial pure iron, pure silicon, ferroboron alloy, ferroniobium alloy, pure copper, pure titanium, lithium chloride, and pure promethium are proportioned and mixed according to the above chemical formula. The mixed raw materials are then placed in a vacuum induction furnace and smelted under electromagnetic force (smelting temperature is 1350°C) to obtain a melt with uniform composition. The melt is uniformly sprayed from a quartz nozzle onto a high-speed rotating copper roller using pressurized argon gas. The melt is heated at a speed of 10 6 ~10 7The amorphous precursor strip with a thickness of 15 μm (the thickness deviation in the width direction of the strip is less than 0.001 mm) and a width of 200 mm was formed by cooling at a cooling rate of 100 °C / s. The structure of the strip is shown in Figure 1. OX, OY, and OZ are mutually perpendicular coordinate axes, where OY is parallel to the length direction of the strip, OZ is parallel to the thickness direction of the strip, OX is parallel to the width direction of the strip, and the longitudinal section of the strip is the section parallel to the OYZ plane.

[0066] 2) the amorphous precursor strip obtained in step 1) is subjected to magnetic field stress heat treatment at 550° C. in a heat treatment furnace to obtain the iron-based nanocrystalline strip, wherein a strip inlet and a strip outlet are provided at both ends of the heat treatment furnace, and the specific process of the magnetic field stress heat treatment is as follows: the amorphous precursor strip is wound on an unwinding winder at the strip inlet, and then the amorphous precursor strip on the unwinding winder is sent from the strip inlet into the heat treatment furnace and wound up by a winding winder at the strip outlet, the tension of the amorphous precursor strip along the length direction is controlled to be 70 MPa when the amorphous precursor strip passes through the heat treatment furnace by the unwinding winder and the winding winder, and the travel time of the amorphous precursor strip from the strip inlet to the strip outlet at the same position is 3 min, and during the heat treatment process, a transverse magnetic field with a strength of 50 mT perpendicular to the longitudinal section of the amorphous precursor strip is provided in the section from the strip inlet to the strip outlet;

[0067] 3) The iron-based nanocrystalline ribbon obtained in step 2) is wound into a precursor core material with a window height of 320 mm, a width of 180 mm, a window chamfer radius of 60 mm, and a winding thickness of 150 mm using a winding machine with a winding needle with a rectangular cross section, and the capacity can reach 900 kVA. The precursor core material is then dipped in an impregnating agent for 2.5 hours, wherein the impregnating agent includes epoxy resin E-51, polyetheramine D400, and end-carboxyl nitrile rubber, wherein the mass ratio of epoxy resin E-51, polyetheramine D400, and end-carboxyl nitrile rubber is 10:5:1; Subsequently, the dipped precursor core material is placed in an oven in a chlorine atmosphere and cured at 80°C for 7 hours to obtain the nanocrystalline iron core.

[0068] Example 3

[0069] The present disclosure provides an iron-based nanocrystalline ribbon, the chemical formula of which is:

[0070] Fe 78 Si4B 11 Nb2Cu1Ti1K1Cl1Tb1.

[0071] The present disclosure provides a method for preparing a nanocrystalline core, comprising the following steps:

[0072] 1) Commercially purchased industrial pure iron, pure silicon, ferroboron alloy, ferroniobium alloy, pure copper, pure titanium, potassium chloride, and pure terbium are proportioned and mixed according to the above chemical formula. The mixed raw materials are then placed in a vacuum induction furnace and smelted under electromagnetic force (smelting temperature is 1350°C) to obtain a melt with uniform composition; pressurized argon gas is used to evenly spray the melt from a quartz nozzle onto a high-speed rotating copper roller, and the melt is heated at a speed of 10 6 ~10 7 The amorphous precursor strip with a thickness of 13 μm (the thickness deviation in the width direction of the strip is less than 0.001 mm) and a width of 200 mm was formed by cooling at a cooling rate of 100 °C / s. The structure of the strip is shown in Figure 1. OX, OY, and OZ are mutually perpendicular coordinate axes, where OY is parallel to the length direction of the strip, OZ is parallel to the thickness direction of the strip, OX is parallel to the width direction of the strip, and the longitudinal section of the strip is the section parallel to the OYZ plane.

[0073] 2) the amorphous precursor strip obtained in step 1) is subjected to magnetic field stress heat treatment at 570° C. in a heat treatment furnace to obtain the iron-based nanocrystalline strip, wherein a strip inlet and a strip outlet are provided at both ends of the heat treatment furnace, and the specific process of the magnetic field stress heat treatment is as follows: the amorphous precursor strip is wound on an unwinding winder at the strip inlet, and then the amorphous precursor strip on the unwinding winder is fed from the strip inlet into the heat treatment furnace and wound up by a winding winder at the strip outlet, the tension of the amorphous precursor strip along the length direction is controlled to be 80 MPa when the amorphous precursor strip passes through the heat treatment furnace by the unwinding winder and the winding winder, and the travel time of the amorphous precursor strip from the strip inlet to the strip outlet at the same position is 4 min, and during the heat treatment process, a transverse magnetic field with a strength of 50 mT perpendicular to the longitudinal section of the amorphous precursor strip is provided in the section from the strip inlet to the strip outlet;

[0074] 3) The iron-based nanocrystalline strip obtained in step 2) is wound into a precursor core material with a window side length of 380 mm, a window chamfer arc radius of 60 mm, and a winding thickness of 90 mm using a winding machine with a triangular cross-section. The capacity can reach 540 kVA, and the precursor core material is then dipped in an impregnating agent for 2.5 hours, wherein the impregnating agent includes epoxy resin E-51, polyetheramine D400, and end-carboxyl nitrile rubber, wherein the mass ratio of epoxy resin E-51, polyetheramine D400, and end-carboxyl nitrile rubber is 10:5:1; Subsequently, the dipped precursor core material is placed in an oven in a chlorine atmosphere and cured at 100° C. for 5 hours to obtain the nanocrystalline iron core.

[0075] Example 4

[0076] The present disclosure provides an iron-based nanocrystalline ribbon, the chemical formula of which is:

[0077] Fe76 Si5B 11 Nb1Cu1Ti2Rb1Cl1Tb2.

[0078] The present disclosure provides a method for preparing a nanocrystalline core, comprising the following steps:

[0079] 1) Industrial pure iron, pure silicon, ferroboron alloy, ferroniobium alloy, pure copper, pure titanium, rubidium chloride, and pure terbium are proportioned and mixed according to the above chemical formula. The mixed raw materials are then placed in a vacuum induction furnace and smelted under electromagnetic force (smelting temperature is 1350°C) to obtain a melt with uniform composition. The melt is uniformly sprayed from a quartz nozzle onto a high-speed rotating copper roller using pressurized argon gas. The melt is heated at a speed of 10 6 ~10 7 The amorphous precursor strip with a thickness of 14 μm (the thickness deviation in the width direction of the strip is less than 0.001 mm) and a width of 200 mm was formed by cooling at a cooling rate of 100 °C / s. The structure of the strip is shown in Figure 1. OX, OY, and OZ are mutually perpendicular coordinate axes, where OY is parallel to the length direction of the strip, OZ is parallel to the thickness direction of the strip, OX is parallel to the width direction of the strip, and the longitudinal section of the strip is the section parallel to the OYZ plane.

[0080] 2) the amorphous precursor strip obtained in step 1) is subjected to magnetic field stress heat treatment at 570° C. in a heat treatment furnace to obtain the iron-based nanocrystalline strip, wherein a strip inlet and a strip outlet are provided at both ends of the heat treatment furnace, and the specific process of the magnetic field stress heat treatment is as follows: the amorphous precursor strip is wound on an unwinding winder at the strip inlet, and then the amorphous precursor strip on the unwinding winder is fed from the strip inlet into the heat treatment furnace and wound up by a winding winder at the strip outlet, the tension of the amorphous precursor strip along the length direction is controlled to be 70 MPa when the amorphous precursor strip passes through the heat treatment furnace by the unwinding winder and the winding winder, and the travel time of the amorphous precursor strip from the strip inlet to the strip outlet at the same position is 2 min, and during the heat treatment process, a transverse magnetic field with a strength of 50 mT perpendicular to the longitudinal section of the amorphous precursor strip is provided in the section from the strip inlet to the strip outlet;

[0081] 3) The iron-based nanocrystalline strip obtained in step 2) is wound into a precursor core material with a window side length of 380 mm, a window chamfer radius of 60 mm, and a winding thickness of 100 mm using a winding machine with a triangular cross-section needle, and the capacity can reach 600 kVA. The precursor core material is then dipped in an impregnating agent for 3 hours, wherein the impregnating agent includes epoxy resin E-51, polyetheramine D400, and end-carboxyl nitrile rubber, wherein the mass ratio of epoxy resin E-51, polyetheramine D400, and end-carboxyl nitrile rubber is 10:5:1; Subsequently, the dipped precursor core material is placed in an oven in a chlorine atmosphere and cured at 70°C for 8 hours to obtain the nanocrystalline iron core.

[0082] Example 5

[0083] The present disclosure provides an iron-based nanocrystalline ribbon, the chemical formula of which is:

[0084] Fe 80 Si4B 10 Nb1Cu1Ti1Na1Cl1Nd1.

[0085] The preparation method of the nanocrystalline core is similar to that in Example 1, except that step 2) is:

[0086] The amorphous precursor strip obtained in step 1) is subjected to stress heat treatment at 560°C in a heat treatment furnace to obtain the iron-based nanocrystalline strip. A strip inlet and a strip outlet are provided at both ends of the heat treatment furnace. The specific process of the stress heat treatment is to wind the amorphous precursor strip on a unwinding winder, and then send the amorphous precursor strip on the unwinding winder from the strip inlet into the heat treatment furnace and wind it up through the strip outlet. The tension of the amorphous precursor strip along the length direction is controlled to be 60MPa when the amorphous precursor strip passes through the heat treatment furnace by the unwinding winder and the winding winder, and the travel time from the strip inlet to the strip outlet at the same position on the amorphous precursor strip is made to be 2min.

[0087] Example 6

[0088] The present disclosure provides an iron-based nanocrystalline ribbon, the chemical formula of which is:

[0089] Fe 80 Si4B 10 Nb1Cu1Ti1Na1Cl1Nd1.

[0090] The preparation method of the nanocrystalline core is similar to the preparation method in Example 1, except that the impregnating agent in step 3) does not contain carboxyl-terminated nitrile rubber.

[0091] Example 7

[0092] This embodiment provides an iron-based nanocrystalline ribbon, the chemical formula of which is:

[0093] Fe 80 Si4B 10 Nb1Cu1Ti1Na1Cl1Nd1.

[0094] The preparation method of the nanocrystalline core is similar to that in Example 1, except that in step 3), the precursor core material after varnish dipping is placed in an oven with air atmosphere and cured at 90° C. for 6 hours.

[0095] Example 8

[0096] The present disclosure provides an iron-based nanocrystalline ribbon, the chemical formula of which is:

[0097] Fe 80 Si4B 10 Nb1Cu1Ti1Na1Cl1Nd1.

[0098] The preparation method of the nanocrystalline core is similar to that in Example 1, except that step 2) is:

[0099] 2) The amorphous precursor strip obtained in step 1) is subjected to heat treatment in a heat treatment furnace at 560° C. to obtain the iron-based nanocrystalline strip, wherein the heat treatment process comprises winding the amorphous precursor strip and placing the coil in a heat treatment furnace for heat treatment for 2 minutes.

[0100] Example 9

[0101] The present disclosure provides an iron-based nanocrystalline ribbon, the chemical formula of which is:

[0102] Fe 80 Si4B 10 Nb1Cu1Ti1Na1Cl1Nd1.

[0103] The preparation method of the nanocrystalline iron core is similar to the preparation method in Example 1, except that step 2) is: the amorphous precursor strip obtained in step 1) is subjected to magnetic field heat treatment at 560°C in a heat treatment furnace to obtain the iron-based nanocrystalline strip, wherein the heat treatment process is to coil the amorphous precursor strip and place the coil in a heat treatment furnace for 2 minutes under the action of a magnetic field, wherein the magnetic field is a transverse magnetic field perpendicular to the longitudinal section of the amorphous precursor strip and has an intensity of 50mT.

[0104] Comparative Example 1

[0105] This comparative example provides an iron-based nanocrystalline ribbon, the chemical formula of which is:

[0106] Fe 80 Si4B 10Nb1Cu1Ti1Na1Cl1;

[0107] The preparation method of the nanocrystalline core is similar to the preparation method in Example 1, except that the raw materials in step 1) do not include pure neodymium.

[0108] Comparative Example 2

[0109] This comparative example provides an iron-based nanocrystalline ribbon, the chemical formula of which is:

[0110] Fe 80 Si4B 10 Nb1Cu1Ti1Nd1.

[0111] The preparation method of the nanocrystalline core is similar to the preparation method in Example 1, except that the raw materials in step 1) do not include sodium chloride.

[0112] Comparative Example 3

[0113] This comparative example provides an iron-based nanocrystalline ribbon, the chemical formula of which is:

[0114] Fe 80 Si4B 10 Nb1Cu1Na1Cl1Nd1.

[0115] The preparation method of the nanocrystalline core is similar to the preparation method in Example 1, except that the raw materials in step 1) do not include pure titanium.

[0116] Comparative Example 4

[0117] The present disclosure provides an iron-based nanocrystalline ribbon, the chemical formula of which is:

[0118] Fe 80 Si4B 10 Nb1Cu1Ti1Na1Nd1.

[0119] The preparation method of the nanocrystalline core is similar to the preparation method in Example 1, except that the sodium chloride in the raw material of step 1) of Example 1 is replaced by Na.

[0120] Test Case

[0121] The nanocrystalline cores obtained in Examples 1 to 9 and Comparative Examples 1 to 4 of the present disclosure were tested. The saturation magnetic induction intensity of the nanocrystalline cores was measured using a vibrating sample magnetometer (VSM), and the loss of the nanocrystalline cores was measured using an AC BH meter. The test conditions were: 10 kHz, 0.5 T, 25°C; 20 kHz, 0.5 T, 25°C. The test results of saturation magnetic induction intensity and loss are shown in Table 1.

[0122] Table 1

[0123] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present disclosure. Industrial Applicability

[0124] The present disclosure provides an iron-based nanocrystalline strip and a preparation method thereof, a nanocrystalline core and a preparation method and application thereof, wherein the chemical formula of the iron-based nanocrystalline strip material is Fe a Si b B c Nb d Cu e Ti f T g E h M i ; Wherein, T is selected from at least one of the alkali metals; E is selected from at least one of the halogen elements; M is selected from at least one of the rare earth metals; a, b, c, d, e, f, g, h, i are the atomic percentages of the corresponding elements, a+b+c+d+e+f+g+h+i=100at%, 76at%≤a≤82at%, 3at%≤b≤6, 8at%≤c≤12at%, 1at%≤d≤3at%, 0.5at%≤e≤1.5at%, 0.5at%≤f≤2.5at%, 0.5at%≤g≤1.5at%, 0.5at%≤h≤1.5at%, 0.5at%≤i≤2.at%5, g=h. In the embodiments of the present disclosure, by selecting specific components and limiting the content of each component, the amorphous forming ability of the material can be improved, and the subsequent crystallization process can be controlled to obtain nanocrystalline ribbons with refined grains, thereby enabling the material to be prepared into thinner and wider iron-based nanocrystalline ribbons, and the prepared iron-based nanocrystalline ribbons have high saturation magnetic induction intensity and low high-frequency loss.

Claims

1. An iron-based nanocrystalline ribbon, wherein the chemical formula of the iron-based nanocrystalline ribbon material is Fe a Si b B c Nb d Cu e Ti f T g E h M i ; in, T is selected from at least one of alkali metals; E is selected from at least one of halogen elements; M is selected from at least one of rare earth metals; a, b, c, d, e, f, g, h, i are the atomic percentages of corresponding elements, a+b+c+d+e+f+g+h+i=100at%, 76at%≤a≤82at%, 3at%≤b≤6, 8at%≤c≤12at%, 1at%≤d≤3at%, 0.5at%≤e≤1.5at%, 0.5at%≤f≤2.5at%, 0.5at%≤g≤1.5at%, 0.5at%≤h≤1.5at%, 0.5at%≤i≤2.at%5, g=h.

2. The iron-based nanocrystalline ribbon according to claim 1, wherein: The T is selected from at least one of Li, Na, K and Rb; and / or, The E is selected from Cl; and / or, The M is selected from at least one of Tb, Nd, and Pm.

3. The iron-based nanocrystalline ribbon according to claim 1 or 2, wherein: The strip thickness is 12-16 μm, the strip width is 150-250 mm, and the thickness deviation in the strip width direction is less than 0.001 mm.

4. A method for preparing the iron-based nanocrystalline ribbon according to any one of claims 1 to 3, comprising the following steps: weighing raw materials according to a stoichiometric ratio, then mixing and smelting the raw materials, forming an amorphous precursor ribbon from the smelted melt, and then subjecting the formed amorphous precursor ribbon to a magnetic field stress heat treatment to obtain the iron-based nanocrystalline ribbon.

5. The preparation method according to claim 4, wherein The process of forming the amorphous precursor strip is to form the amorphous precursor strip by a single-roller rapid quenching method from the melt obtained by smelting; Wherein, in the single-roller rapid quenching method, the cooling rate of the melt is 10 5 ~10 7 °C / s; The thickness of the formed amorphous precursor strip is 12-16 μm, and the width of the strip is 150-250 mm.

6. The preparation method according to claim 4 or 5, wherein: The process of subjecting the formed amorphous precursor strip to magnetic field stress heat treatment is to apply tension in the length direction of the amorphous precursor strip; Among them, the temperature of the magnetic field stress heat treatment is 520-580°C, the magnetic field intensity of the magnetic field stress heat treatment is 30-70mT, the magnetic field direction is perpendicular to the longitudinal section of the amorphous precursor strip, the time of the magnetic field stress heat treatment is 10s-10min, and the tension is 1-100MPa.

7. A nanocrystalline iron core, which is obtained by winding an iron-based nanocrystalline ribbon to form a precursor core material, dipping the precursor core material in varnish, and then curing it in a chlorine atmosphere, wherein the iron-based nanocrystalline ribbon is the iron-based nanocrystalline ribbon according to any one of claims 1 to 3 or the iron-based nanocrystalline ribbon prepared by the preparation method according to any one of claims 4 to 6; in, The impregnating agents used in the varnishing include epoxy resin and curing agent.

8. The nanocrystalline core according to claim 7, wherein: The immersion time is 1-5 hours; and / or, The curing temperature is 60-180° C. and the curing time is 3-10 hours.

9. The nanocrystalline core according to claim 7, wherein: The varnish also includes a toughening agent; The mass ratio of epoxy resin, curing agent and toughening agent in the impregnating agent is (8-12): (3-6): (0.8-1.2); and / or, The epoxy resin is selected from epoxy resin E-51; the curing agent is selected from polyetheramine D400; and the toughening agent is selected from carboxyl-terminated nitrile rubber.

10. The nanocrystalline core according to claim 7, wherein: The capacity can reach 1MVA.

11. Application of the nanocrystalline core according to any one of claims 7 to 10 in high-frequency transformers or wireless charging.

12. A method for preparing a nanocrystalline iron core, comprising the following steps: winding the iron-based nanocrystalline ribbon prepared in any one of claims 4 to 6 to form a precursor core material, varnishing the precursor core material, and then curing it in a chlorine atmosphere to obtain the nanocrystalline iron core; wherein, The impregnating agents used in the varnishing include epoxy resin and curing agent.

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