Method for reducing coercive force of iron-based nanocrystalline alloy with high iron content through tin doping

Abstract

The invention relates to the field of nanocrystalline soft magnetic materials, in particular to a method for reducing coercive force of iron-based nanocrystalline alloy with high iron content through tin doping, the component expression of the iron-based nanocrystalline alloy is FeaSibBcPdCeCufSng, a, b, c, d, e, f and g respectively represent the atomic percentage content of corresponding elements, and a is larger than or equal to 81.3 and smaller than or equal to 85.6, b is larger than or equal to 0 and smaller than or equal to 5, c is larger than or equal to 7 and smaller than or equal to 15, d is larger than or equal to 0 and smaller than or equal to 6, e is larger than or equal to 0 and smaller than or equal to 2, f is larger than or equal to 1 and smaller than or equal to 1.5, g is larger than or equal to 0.1 and smaller than or equal A first crystallization peak of the amorphous precursor of the iron-based nanocrystalline alloy is in an overlapped double-peak shape and has a wide heat treatment temperature window not lower than 130K; the average grain size of the iron-based nanocrystalline alloy ranges from 18 nm to 24 nm, the saturation flux density ranges from 1.75 T to 1.87 T, and the coercive force is not higher than 13.5 A / m. According to the method, the first crystallization peak of the amorphous precursor of the iron-based nanocrystalline alloy is in an overlapped double-peak shape, the heat treatment temperature window is widened, a fine and uniform nanocrystalline structure can be formed under the conventional heat treatment condition, and then low coercive force is obtained.

Description

Technical Field

[0001] This invention relates to the field of nanocrystalline soft magnetic materials, and more particularly to a method for reducing the coercivity of high-iron-content iron-based nanocrystalline alloys by tin doping. Background Technology

[0002] Iron-based nanocrystalline alloys are nanoscale multiphase structures composed of nanoscale α-Fe phase and amorphous phase. When the α-Fe grain size is within the ferromagnetic exchange correlation length range (30-40 nm), the exchange coupling effect between grains significantly reduces the average magnetocrystalline anisotropy of the alloy, giving it excellent soft magnetic properties such as high permeability and low coercivity (H). c It exhibits advantages such as low magnetostriction coefficient and low high-frequency loss. In 1988, Yoshizawa et al. added Cu and Nb elements to the Fe-Si-B alloy system and, after appropriate heat treatment of its rapidly quenched precursor, successfully developed the FINEMET nanocrystalline soft magnetic alloy (Fe-Si-B-Nb-Cu system). This alloy system has been applied in devices such as high-frequency transformers, inductors, and current transformers [Chinese Invention Patent CN101796207B]. Subsequently, researchers successively developed NANOPERM (Fe-MB-Cu system, M = Zr, Hf, Nb, etc.) and HITPERM ((Fe,Co)-MB-Cu system, M = Zr, Hf, Nb, etc.) nanocrystalline alloys. These alloys often contain large-sized pre-transition metal elements (ETM) to hinder the long-range diffusion of Fe atoms during heat treatment, suppress excessive grain growth, form a fine nanocrystalline structure, and thus obtain excellent soft magnetic properties. However, the high ETM content (up to 7 at.%) in NANOPERM and HITPERM alloys increases raw material costs and, coupled with demanding manufacturing processes, hinders large-scale production. While FINEMET, with its superior processability, has been industrialized, its low saturation magnetic induction limits its applications and makes it difficult to meet the increasingly miniaturized demands of power and electronic components.

[0003] Since 2007, Fe-B-Cu, Fe-Si-B-Cu [M Ohta et al, Appl Phys Lett, 2007(91): 2517], NANOMET (Fe-Si-BP-Cu) [A Makino et al, Mater Trans, 2009(50):204], and Fe-Si-BPC-Cu [T Liu et al, J Mater Res Technol, 2020(9): 3558-3565] nanocrystalline alloys have been reported. These nanocrystalline alloys contain over 80 at.% Fe and are free of ETM, exhibiting a B content higher than 1.8T. s Its high α-Fe content and excellent soft magnetic properties make it a promising candidate for applications in the power and electronics industries. However, due to the lack of ETM (extra-metallic mineralization) in the alloy to inhibit α-Fe grain growth, α-Fe grows very rapidly under traditional heat treatment processes, easily leading to coarsening of the nanocrystalline structure and affecting Hg. c Increase. Therefore, the formation of uniform and fine nanocrystalline structures usually requires a high heating rate (H). r ≥150℃ / min) and short holding time (t) a ≤10min, but this is difficult to implement under operating conditions (large fluctuations in heat treatment temperature, low heating rate, and long holding time).

[0004] In summary, there is a need to invent a mild yet effective method for controlling the composition of nanocrystalline alloys, capable of forming uniform and fine nanocrystalline structures under conventional heat treatment conditions, while ensuring that the nanocrystalline alloys possess high boron content. s While achieving high magnetic value, it also obtains excellent soft magnetic properties, which is of great significance for realizing the industrial application of high-iron-content iron-based nanocrystalline soft magnetic alloys. Summary of the Invention

[0005] To address the aforementioned technical problem, a method for reducing the coercivity of high-iron-content iron-based nanocrystalline alloys is provided through tin doping. This invention causes the first crystallization peak of the amorphous precursor of the iron-based nanocrystalline alloy to exhibit an overlapping double-peak shape and widens the heat treatment temperature window, enabling the formation of a fine and uniform nanocrystalline structure under conventional heat treatment conditions, thereby achieving low coercivity.

[0006] The technical means employed in this invention are as follows: A method for reducing the coercivity of high-iron-content iron-based nanocrystalline alloys by tin doping, wherein the composition formula of the iron-based nanocrystalline alloy is Fe a Si b B c P d C e Cu f Sn gWhere a, b, c, d, e, f, and g represent the atomic percentage content of each corresponding element, and satisfy 81.3≤a≤85.6, 0≤b≤5, 7≤c≤15, 0≤d≤6, 0≤e≤2, 1≤f≤1.5, 0.1≤g≤0.4, and a+b+c+d+e+f=100; the first crystallization peak of the amorphous precursor of the iron-based nanocrystalline alloy exhibits an overlapping double peak shape and has a wide heat treatment temperature window of not less than 130K; the iron-based nanocrystalline alloy is prepared from the amorphous precursor under the conditions of a heating rate of 20-30℃ / min, a holding temperature of 380-440℃, and a holding time of 60min; the average grain size of the iron-based nanocrystalline alloy is 18-24nm, the saturation magnetic induction intensity is 1.75-1.87T, and the coercivity is not higher than 13.5A / m.

[0007] Furthermore, doping with tin broadens the heat treatment temperature window of the amorphous precursor of the iron-based nanocrystalline alloy, refines the nanocrystalline structure under conventional heat treatment conditions, and reduces coercivity.

[0008] Furthermore, in the iron-based nanocrystalline alloy, when 2≤b≤5, 12≤c≤15, d=0, e=0, 1≤f≤1.5, and 0.1≤g≤0.4, the first crystallization initiation temperature of the amorphous precursor is 369-398℃, and the heat treatment temperature window is 132-159℃; the average grain size of the α-Fe phase in the nanocrystalline alloy is 18-22nm, the saturation magnetic induction intensity is 1.75-1.78T, and the coercivity is 7.7-13A / m.

[0009] Furthermore, in the iron-based nanocrystalline alloy, when b=0, 13≤c≤15, d=0, e=0, 1≤f≤1.3, and 0.1≤g≤0.4, the first crystallization initiation temperature of the amorphous precursor is 335-354℃, and the heat treatment temperature window is 130-149℃; the average grain size of the α-Fe phase in the nanocrystalline alloy is 20-24nm, the saturation magnetic induction intensity is 1.80-1.87T, and the coercivity is 10.1-13.5A / m.

[0010] Furthermore, in the iron-based nanocrystalline alloy, when b=4, 7≤c≤11, 2≤d≤6, e=0, 1.3≤f≤1.5, and 0.2≤g≤0.4, the first crystallization initiation temperature of the amorphous precursor is 379-387℃, and the heat treatment temperature window is 157-159℃; the average grain size of the α-Fe phase in the nanocrystalline alloy is 20-21nm, the saturation magnetic induction intensity is 1.75-1.76T, and the coercivity is 11.2-12A / m.

[0011] Furthermore, in the iron-based nanocrystalline alloy, when b=4, 11≤c≤12, d=0, 1≤e≤2, f=1.5, and g=0.2, the first crystallization initiation temperature of the amorphous precursor is 369-374℃, and the heat treatment temperature window is 153-165℃; the average grain size of the α-Fe phase in the nanocrystalline alloy is 20-22nm, the saturation magnetic induction intensity is 1.77-1.78T, and the coercivity is 10.3-12.8A / m.

[0012] Furthermore, in the iron-based nanocrystalline alloy, when 2≤b≤5, 12≤c≤15, d=0, e=0, f=1.5, and g=0.1, the first crystallization initiation temperature of the amorphous precursor is 369-380℃, and the heat treatment temperature window is 148-155℃; the average grain size of the α-Fe phase in the nanocrystalline alloy is 18-20nm, the saturation magnetic induction intensity is 1.78T, and the coercivity is 7.7-8.9A / m.

[0013] Furthermore, when the composition of the iron-based nanocrystalline alloy is Fe... 81.4 Si4B 13 Cu 1.5 Sn 0.1 At that time, the first crystallization initiation temperature of the amorphous precursor was 373℃, and the heat treatment temperature window was 155℃; the average grain size of the α-Fe phase in the nanocrystalline alloy was 18nm, the saturation magnetic induction intensity was 1.78T, and the coercivity was 7.7A / m.

[0014] Furthermore, when the composition of the iron-based nanocrystalline alloy is Fe... 83.7 B 15 Cu 1.2 Sn 0.1 At that time, the first crystallization initiation temperature of the amorphous precursor was 354℃, and the heat treatment temperature window was 130℃; the average grain size of the α-Fe phase in the nanocrystalline alloy was 20nm, the saturation magnetic induction intensity was 1.84T, and the coercivity was 10.1A / m.

[0015] Furthermore, when the composition of the iron-based nanocrystalline alloy is Fe... 81.3 Si4B 11 P2Cu 1.5 Sn 0.2 At that time, the first crystallization initiation temperature of the amorphous precursor was 387℃, and the heat treatment temperature window was 157℃; the average grain size of the α-Fe phase in the nanocrystalline alloy was 20nm, the saturation magnetic induction intensity was 1.76T, and the coercivity was 11.2A / m; When the iron-based nanocrystalline alloy composition is Fe 81.3 Si4B 11 C2Cu 1.5 Sn 0.2The first crystallization initiation temperature of the amorphous precursor is 369℃, and the heat treatment temperature window is 165℃. The average grain size of the α-Fe phase in the nanocrystalline alloy is 20nm, the saturation magnetic induction intensity is 1.77T, and the coercivity is 10.3A / m.

[0016] Compared with the prior art, the present invention has the following advantages: The iron-based nanocrystalline soft magnetic alloy provided by this invention has excellent comprehensive soft magnetic properties, and its B s The value is 1.75-1.87T, H c It ranges from 7.7 to 13.5 A / m.

[0017] The iron-based nanocrystalline soft magnetic alloy provided by this invention can be obtained through conventional heat treatment processes. The heating rate under the corresponding process conditions is 20-30℃ / min, the suitable heat treatment temperature is 380-440℃, and the holding time is 60min. Its preparation conditions are relatively broad, which reduces the requirements for heat treatment equipment.

[0018] The iron-based nanocrystalline soft magnetic alloy provided by this invention has an Fe content higher than 81 at.% and does not contain pre-transition metal elements such as Nb, Zr, and Hf. The raw material and preparation costs of the alloy are low; furthermore, the addition of trace amounts of non-magnetic Sn does not affect the B content of the nanocrystalline alloy. s This has had a significant impact.

[0019] The method for reducing the coercivity of high-iron-content iron-based nanocrystalline alloys by tin doping provided by this invention is applicable to multiple nanocrystalline alloy systems and has a certain degree of universality. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 The DSC curves are those of the precursor strips in Comparative Example 1 and Example 1 of this invention.

[0022] Figure 2 The XRD spectra of the precursor bands in Comparative Example 1 and Example 1 of this invention are shown.

[0023] Figure 3 The XRD spectra of the nanocrystalline strips obtained after heat treatment for 60 minutes on the precursor strips of Comparative Example 1 and Example 1 in this invention are shown.

[0024] Figure 4The images show TEM bright-field images, SAED images, and corresponding particle size distribution histograms of nanocrystalline strips obtained after 60 min of heat treatment on the precursor strips of Comparative Example 1(a) and Example 1(b) in this invention.

[0025] Figure 5 The hysteresis loops of nanocrystalline strips obtained after 60 min heat treatment of the precursor strips in Comparative Example 1 and Example 1 of the present invention are shown. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0029] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0030] This invention provides a method for reducing the coercivity of high-iron-content iron-based nanocrystalline alloys through tin doping. The composition formula of the iron-based nanocrystalline alloy is Fe. a Si b B c P d C e Cu f Sn g Where a, b, c, d, e, f, and g represent the atomic percentage content of each corresponding element, and satisfy 81.3≤a≤85.6, 0≤b≤5, 7≤c≤15, 0≤d≤6, 0≤e≤2, 1≤f≤1.5, 0.1≤g≤0.4, and a+b+c+d+e+f=100; The first crystallization peak of the amorphous precursor of the iron-based nanocrystalline alloy is an overlapping double peak, and has a wide heat treatment temperature window of not less than 130K. The iron-based nanocrystalline alloy is prepared from an amorphous precursor under the conditions of a heating rate of 20-30℃ / min, a holding temperature of 380-440℃, and a holding time of 60min. The iron-based nanocrystalline alloy has an average grain size of 18-24 nm, a saturation magnetic induction intensity of 1.75-1.87 T, and a coercivity not higher than 13.5 A / m.

[0031] In a specific implementation, as a preferred embodiment of the present invention, doping with tin element widens the heat treatment temperature window of the amorphous precursor of the iron-based nanocrystalline alloy, refines the nanocrystalline structure under conventional heat treatment conditions, and reduces coercivity.

[0032] In a specific implementation, as a preferred embodiment of the present invention, in the iron-based nanocrystalline alloy, when 2≤b≤5, 12≤c≤15, d=0, e=0, 1≤f≤1.5, and 0.1≤g≤0.4, the first crystallization initiation temperature of the amorphous precursor is 369-398℃, and the heat treatment temperature window is 132-159℃; the average grain size of the α-Fe phase in the nanocrystalline alloy is 18-22nm, the saturation magnetic induction intensity is 1.75-1.78T, and the coercivity is 7.7-13A / m.

[0033] In a specific implementation, as a preferred embodiment of the present invention, in the iron-based nanocrystalline alloy, when b=0, 13≤c≤15, d=0, e=0, 1≤f≤1.3, and 0.1≤g≤0.4, the first crystallization initiation temperature of the amorphous precursor is 335-354℃, and the heat treatment temperature window is 130-149℃; the average grain size of the α-Fe phase in the nanocrystalline alloy is 20-24nm, the saturation magnetic induction intensity is 1.80-1.87T, and the coercivity is 10.1-13.5A / m.

[0034] In a specific implementation, as a preferred embodiment of the present invention, in the iron-based nanocrystalline alloy, when b=4, 7≤c≤11, 2≤d≤6, e=0, 1.3≤f≤1.5, and 0.2≤g≤0.4, the first crystallization initiation temperature of the amorphous precursor is 379-387℃, and the heat treatment temperature window is 157-159℃; the average grain size of the α-Fe phase in the nanocrystalline alloy is 20-21nm, the saturation magnetic induction intensity is 1.75-1.76T, and the coercivity is 11.2-12A / m.

[0035] In a specific implementation, as a preferred embodiment of the present invention, in the iron-based nanocrystalline alloy, when b=4, 11≤c≤12, d=0, 1≤e≤2, f=1.5, and g=0.2, the first crystallization initiation temperature of the amorphous precursor is 369-374℃, and the heat treatment temperature window is 153-165℃; the average grain size of the α-Fe phase in the nanocrystalline alloy is 20-22nm, the saturation magnetic induction intensity is 1.77-1.78T, and the coercivity is 10.3-12.8A / m.

[0036] In a specific implementation, as a preferred embodiment of the present invention, in the iron-based nanocrystalline alloy, when 2≤b≤5, 12≤c≤15, d=0, e=0, f=1.5, and g=0.1, the first crystallization initiation temperature of the amorphous precursor is 369-380℃, and the heat treatment temperature window is 148-155℃; the average grain size of the α-Fe phase in the nanocrystalline alloy is 18-20nm, the saturation magnetic induction intensity is 1.78T, and the coercivity is 7.7-8.9A / m.

[0037] In a specific implementation, as a preferred embodiment of the present invention, when the iron-based nanocrystalline alloy composition is Fe... 81.4 Si4B 13 Cu 1.5 Sn 0.1 At that time, the first crystallization initiation temperature of the amorphous precursor was 373℃, and the heat treatment temperature window was 155℃; the average grain size of the α-Fe phase in the nanocrystalline alloy was 18nm, the saturation magnetic induction intensity was 1.78T, and the coercivity was 7.7A / m.

[0038] In a specific implementation, as a preferred embodiment of the present invention, when the iron-based nanocrystalline alloy composition is Fe... 83.7 B 15 Cu 1.2 Sn 0.1 At that time, the first crystallization initiation temperature of the amorphous precursor was 354℃, and the heat treatment temperature window was 130℃; the average grain size of the α-Fe phase in the nanocrystalline alloy was 20nm, the saturation magnetic induction intensity was 1.84T, and the coercivity was 10.1A / m.

[0039] In a specific implementation, as a preferred embodiment of the present invention, when the iron-based nanocrystalline alloy composition is Fe... 81.3 Si4B 11 P2Cu 1.5 Sn 0.2 At that time, the first crystallization initiation temperature of the amorphous precursor was 387℃, and the heat treatment temperature window was 157℃; the average grain size of the α-Fe phase in the nanocrystalline alloy was 20nm, the saturation magnetic induction intensity was 1.76T, and the coercivity was 11.2A / m; When the iron-based nanocrystalline alloy composition is Fe 81.3 Si4B 11 C2Cu 1.5 Sn 0.2 The first crystallization initiation temperature of the amorphous precursor is 369℃, and the heat treatment temperature window is 165℃. The average grain size of the α-Fe phase in the nanocrystalline alloy is 20nm, the saturation magnetic induction intensity is 1.77T, and the coercivity is 10.3A / m.

[0040] The method for reducing the coercivity of high-iron-content iron-based nanocrystalline alloys by tin doping provided by this invention specifically includes the following steps: Step 1: Weigh and batch raw materials of Fe, Si, B, P, C, Cu, and Sn with a purity greater than 99 wt.% according to the designed alloy composition; Step 2: Prepare a master alloy ingot with uniform chemical composition by using an electric arc furnace or induction furnace under an Ar atmosphere; Step 3: After cutting the master alloy ingot into appropriate sizes, it is placed into a quartz tube and a single-roller spinning process is used to spin the strip at a speed of 40-45m / s to obtain an amorphous precursor strip with a width of 1-2mm and a thickness of 17-22μm. Step 4: Vacuum-encapsulate the precursor alloy strip and then heat-treat it in a muffle furnace to prepare a nanocrystalline alloy. The specific heat treatment parameters are as follows: heat the sample to the set temperature at a heating rate of 20-30℃ / min, hold for 60 minutes, remove and water-cool to room temperature. The holding temperature of the equipment is 380-440℃.

[0041] The final Fe-based nanocrystalline alloy has an α-Fe grain size of 18-24 nm, B s For 1.75-1.87T, H c It ranges from 7.7 to 13.5 A / m.

[0042] Example The alloy composition of Example 1 has the chemical formula Fe. 81.4 Si4B 13 Cu 1.5 Sn 0.1 .

[0043] The alloy composition of Example 2 has the chemical formula Fe. 81.35 Si4B 13 Cu 1.5 Sn 0.15 .

[0044] The alloy composition of Example 3 has the chemical formula Fe. 81.3 Si4B 13 Cu 1.5 Sn 0.2 .

[0045] The alloy composition of Example 4 has the chemical formula Fe. 81.3 Si4B 13 Cu 1.3 Sn 0.4 .

[0046] The alloy composition of Comparative Example 1 has the chemical formula Fe. 81.5 Si4B 13 Cu 1.5 .

[0047] The alloy composition of Comparative Example 2 has the chemical formula Fe. 81.7 Si4B 13 Cu 1.3 .

[0048] In Examples 1-4 and Comparative Examples 1-2, the preparation methods of the nanocrystalline alloy strips are the same, mainly including the following steps: Step 1: Weigh and batch Fe, Si, B, Cu, and Sn raw materials with a purity greater than 99 wt.% according to the designed alloy composition; Step 2: Prepare a master alloy ingot with uniform chemical composition by using an electric arc furnace or induction furnace under an Ar atmosphere; Step 3: After cutting the master alloy ingot into appropriate sizes, it is placed into a quartz tube and a single-roller spinning process is used to spin the strip at a speed of 40-45m / s to obtain an amorphous precursor strip with a width of 1-2mm and a thickness of 17-22μm. Step 4: Cut the precursor strip into 60-70mm pieces and vacuum seal the tubes to a vacuum level of approximately 1.5 × 10⁻⁶. -3 Pa.

[0049] Step 5: Perform conventional isothermal heat treatment on multiple batches of vacuum-sealed precursor strips. The specific parameters and steps are as follows: In the temperature range of 380-470℃, every 15℃ is a heat preservation node. Heat to each node at a heating rate of 20-30℃ / min and hold for 60 minutes. Then take it out and cool it to room temperature with water.

[0050] The thermal properties of the precursor strips prepared in step three were determined using differential scanning calorimetry (DSC) at a heating rate of 40 °C / min to obtain the first crystallization initiation temperature (T). x1 ) and second crystallization initiation temperature (T x2 ), and determined two crystallization temperature intervals, namely the heat treatment temperature window ( T x = T x2 -T x1 (See attached table in the instruction manual for details.) Figure 1 DSC curves for the precursor strips of Comparative Example 1 and Example 1 are presented. T values ​​for Examples 1-4 are also provided. x1 and T x The temperatures were 373-398℃ and 132-155℃, respectively; the temperatures of Comparative Examples 1-2 were... x1 and T x The temperatures were 413-425℃ and 107-120℃, respectively. It is noted that the first crystallization peak in Example 1 was formed by the superposition of two peaks, exhibiting a bimodal shape. This indicates that the precursor strips contain a certain amount of fine α-Fe phase. The low-temperature side reflects the exothermic growth of the pre-existing α-Fe phase, while the high-temperature side reflects the nucleation and exothermic growth of the newly formed α-Fe phase. Thermal analysis results show that when the Cu content is 1.3-1.5 at.%, doping with 0.1-0.4 at.% Sn will cause the first crystallization peak of the precursor alloy to change from a single peak to a bimodal peak, reducing the temperature at T. x1 and obtain a wider T x This helps promote the precipitation of the α-Fe phase while avoiding the formation of Fe-type metal compounds.

[0051] X-ray diffractometer (XRD) (Cu Kα, The structure of the alloy strips in steps three and five was determined using a microscope with a wavelength of 0.15406 nm and a transmission electron microscope (TEM). Figure 2 The XRD spectra of the precursor strips of Comparative Example 1 and Example 1 are presented, indicating that both alloys have an amorphous structure. Figure 3 The XRD patterns of the precursor strips from Comparative Example 1 and Example 1 after 60 min heat treatment are presented, indicating that a single α-Fe phase precipitated in both alloys. The average grain size (Dg) of the nanocrystalline strips from Examples 1-4 and Comparative Examples 1-2 was calculated using the Scherrer formula. α-Fe The wavelengths are 18-22nm and 47-49nm respectively, as shown in Table 1.

[0052] Table 1. Alloy composition of Examples 1-16 and Comparative Examples 1-6, peak shape of the first crystallization peak of the precursor strip, and first crystallization initiation temperature (T).x1 ), heat treatment temperature window ( T x ), the saturation magnetic induction intensity of nanocrystalline strips (B s ), coercivity (H) c ), α-Fe average grain size (D α-Fe ), and suitable heat treatment temperature range

[0053] Figure 4 TEM results of the precursor strips from Comparative Example 1 and Example 1 after 60 min of heat treatment are presented, showing that α-Fe nanocrystals precipitated in the amorphous matrix. α-Fe The nanometer diameters were 49.1 nm and 18.4 nm, respectively, which are not significantly different from the results calculated by the Scherrer formula. According to the attached table, when the Cu content is 1.3-1.5 at.%, doping with 0.1-0.4 at.% Sn can lower the required heat treatment temperature and broaden the suitable heat treatment temperature range, significantly refine the microstructure of the FeSiBCu nanocrystalline alloy, and improve its soft magnetic properties. Analysis of the reasons for the differences in the nanocrystalline alloy structure reveals that under conventional annealing conditions, Sn-doped Examples 1-4 can induce a competitive growth effect between the high number density pre-existing and newly formed α-Fe phases, inhibiting the uneven and rapid growth of α-Fe grains and forming a uniform and fine nanocrystalline structure; while Comparative Examples 1-2 lack effective inhibition of grain growth, easily leading to coarsening of the nanocrystalline structure.

[0054] The B0 of the nanocrystalline strips was measured using a vibrating sample magnetometer (VSM) and a DC hysteresis loop tracer (BH loop tracer). s and H c . Figure 5 The hysteresis loop results of the precursor strips of Comparative Example 1 and Example 1 after 60 min of heat treatment are given. The B of Examples 1-5 is measured. s For 1.76-1.78T, H c It is 7.7-13 A / m; B in Comparative Example 1-2 s For 1.76-1.78T, H c The Hm ranges from 213.6 to 256.2. According to the attached table, when the Cu content is 1.3-1.5 at.%, doping with 0.1-0.4 at.% Sn can significantly reduce the Hm of FeSiBCu nanocrystalline alloys. c and maintain a high B s .

[0055] The alloy composition of Example 5 has the chemical formula Fe. 81.4 Si2B15 Cu 1.5 Sn 0.1 .

[0056] The alloy composition of Example 6 has the chemical formula Fe. 81.4 Si5B 12 Cu 1.5 Sn 0.1 .

[0057] This series of examples is based on the alloy composition of Comparative Example 1, with the Si content changed to 2-5 at.%, the B content changed to 12-15 at.%, and 0.1 at.% Sn element doped. The steps for batching, preparation of the master alloy ingot, preparation of the alloy strip, and testing of the alloy structure and properties are the same as in Examples 1-4. The difference between this series of examples and Examples 1-4 is that the suitable heat treatment temperature range is 395-440℃. The first crystallization peak shape of the precursor strip, T... x1 , T x B corresponding to nanocrystalline strips s H c With D α-Fe See the appendix to the instruction manual for details. In Examples 5-6, the first crystallization peak of the precursor bands exhibits a bimodal shape, and its measured T... x1 The temperature is 369-380℃. T x The temperature was 148-151℃. After a 60-minute heat treatment, the D of the nanocrystalline strips... α-Fe For 19-20nm, B s It is 1.78T, H c The value is 8.1-8.9 A / m. According to the attached table, when the Si content is 2-5 at.% and the B content is 12-15 at.%, 0.1 at.% Sn doping can still significantly refine the nanocrystalline structure and reduce the H content of the FeSiBCu nanocrystalline alloy. c and maintain a high B s .

[0058] The alloy composition of Example 7 has the chemical formula Fe. 81.6 Si2B 15 Cu1Sn 0.4 .

[0059] The alloy composition of Example 8 has the chemical formula Fe. 81.6 Si5B 12 Cu1Sn 0.4 .

[0060] This series of examples is based on the alloy composition of Comparative Example 1, with the Cu content reduced to 1 at.%, the Si content changed to 2-5 at.%, the B content changed to 12-15 at.%, and 0.4 at.% Sn doped. The steps for batching, master alloy ingot preparation, alloy strip preparation, and alloy structure and property testing are the same as in Examples 1-5. The difference between this series and Examples 1-4 is that the suitable heat treatment temperature range is 425-440℃. The first crystallization peak shape of the precursor strip, T... x1 , T x B corresponding to nanocrystalline strips s H c With D α-Fe See the appendix to the instruction manual for details. In Examples 7-8, the first crystallization peak of the precursor bands exhibits a bimodal shape, and its measured T... x1 The temperature ranges from 371 to 385℃. T x The temperature was 155-159℃. After a 60-minute heat treatment, the D of the nanocrystalline strips... α-Fe For 21-22nm, B s For 1.75-1.76T, H c The value is 11.8-12.7 A / m. According to the attached table, when the Cu content is 1 at.%, the Si content is 2-5 at.%, and the B content is 12-15 at.%, 0.4 at.% Sn doping can still significantly refine the nanocrystalline structure and reduce the H content of the FeSiBCu nanocrystalline alloy. c and maintain a high B s .

[0061] The alloy composition of Example 9 has the chemical formula Fe. 83.6 B 15 Cu 1.3 Sn 0.1 .

[0062] The alloy composition of Example 10 has the chemical formula Fe. 83.7 B 15 Cu 1.2 Sn 0.1 .

[0063] The alloy composition of Example 11 has the chemical formula Fe. 83.6 B 15 Cu1Sn 0.4 .

[0064] The alloy composition of Example 12 has the chemical formula Fe. 85.6 B 13 Cu1Sn 0.4 .

[0065] The alloy composition of Comparative Example 3 has the chemical formula Fe.84 B 15 Cu1.

[0066] The examples and comparative examples in this series use the FeBCu nanocrystalline alloy system. In these examples, the Cu content is 1-1.3 at.%, the B content is 13-15 at.%, and the Sn doping amount is 0.1-0.4 at.%. The steps for batching, preparation of the master alloy ingot, preparation of the alloy strip, and testing of the alloy structure and properties are the same as in Examples 1-4. The difference between these examples and Examples 1-4 is that the suitable heat treatment temperature range is 395-425℃. The peak shape of the first crystallization peak of the precursor strip, T... x1 , T x B corresponding to nanocrystalline strips s H c With D α-Fe See the appendix to the instruction manual for details. The first crystallization peak of the precursor bands in Examples 9-12 exhibits a bimodal shape, indicating the presence of a certain amount of fine α-Fe phase. The Tg of Examples 9-12 was determined to be... x1 and T x The temperatures were 335-354℃ and 130-149℃, respectively; the temperature of Comparative Example 3 was T. x1 and T x The temperatures were 410℃ and 86℃, respectively. Thermal analysis results show that when the Cu content is 1-1.3 at.% and the B content is 13-15 at.%, doping with 0.1-0.4 at.% Sn causes the first crystallization peak of the precursor alloy to change from a single peak to a double peak, reducing the temperature (T). x1 and obtain a wider T x After a 60-minute heat treatment, the D-values ​​of the nanocrystalline strips in Examples 9-12 and Comparative Example 3 were compared. α-Fe The wavelengths were 20-24 nm and 51 nm, respectively. The B in Examples 9-12 was determined to be... s For 1.80-1.87T, H c The value is 10.1-13.5 A / m; Comparative Example 3, B s It is 1.81T, H c The value is 276.9 A / m. According to the attached table, when the Cu content is 1-1.3 at.% and the B content is 13-15 at.%, 0.1-0.4 at.% Sn doping can still significantly refine the nanocrystalline structure and reduce the H content of the FeBCu nanocrystalline alloy. c and maintain a high B s .

[0067] The alloy composition of Example 13 has the chemical formula Fe. 81.3 Si4B7P6Cu 1.3Sn 0.4 .

[0068] The alloy composition of Example 14 has the chemical formula Fe. 81.3 Si4B 11 P2Cu 1.5 Sn 0.2 .

[0069] The alloy composition of Example 15 has the chemical formula Fe. 81.3 Si4B 12 C1Cu 1.5 Sn 0.2 .

[0070] The alloy composition of Example 16 has the chemical formula Fe. 81.3 Si4B 11 C2Cu 1.5 Sn 0.2 .

[0071] The alloy composition of Comparative Example 4 has the chemical formula Fe. 81.7 Si4B9P4Cu 1.3 .

[0072] The alloy composition of Comparative Example 5 has the chemical formula Fe. 81.5 Si4B 11 P2Cu 1.5 .

[0073] The alloy composition of Comparative Example 6 has the chemical formula Fe. 81.5 Si4B 12.5 C 0.5 Cu 1.5 .

[0074] This series of examples and comparative examples uses FeSiBPCu and FeSiBCCu nanocrystalline alloy systems. In these examples, the Cu content is 1.3-1.5 at.%, the B content is 7-12 at.%, the P content is 2-6 at.%, the C content is 1-2 at.%, and the Sn doping amount is 0.2-0.4 at.%. The steps for batching, master alloy ingot preparation, alloy strip preparation, and alloy structure and property testing are the same as in Examples 1-4. The difference between these examples and Examples 1-4 is that the suitable heat treatment temperature range is 410-440℃. The first crystallization peak shape of the precursor strip, T... x1 , T x B corresponding to nanocrystalline strips s H c With D α-Fe See the appendix to the instruction manual for details. The first crystallization peak of the precursor bands in Examples 13-16 exhibits a bimodal shape, indicating the presence of a certain amount of α-Fe phase. The Tg of Examples 13-16 was determined to be... x1and T x The temperatures were 369-387℃ and 153-165℃, respectively; the temperatures of Comparative Examples 4-6 were... x1 and T x The temperatures were 394-416℃ and 136-142℃, respectively. Thermal analysis results show that when the Cu content is 1.3-1.5 at.%, the B content is 7-12 at.%, the P content is 2-6 at.%, and the C content is 1-2 at.%, doping with 0.2-0.4 at.% Sn causes the first crystallization peak of the precursor alloy to change from a single peak to a double peak, reducing the temperature (T). x1 and obtain a wider T x After a 60-minute heat treatment, the D-type nanocrystalline strips of Examples 13-16 and Comparative Examples 4-6 were compared. α-Fe The wavelengths are 20-22 nm and 32-42 nm, respectively. The B wavelengths in Examples 13-16 were determined to be... s For 1.75-1.78T, H c The value is 10.3-12.8 A / m; B in Comparative Examples 4-6 s For 1.75-1.77T, H c The value ranges from 32.2 to 135.2 A / m. According to the attached table, when the Cu content is 1.3-1.5 at.%, the B content is 7-12 at.%, the P content is 2-6 at.%, and the C content is 1-2 at.%, 0.2-0.4 at.% Sn doping can still significantly refine the nanocrystalline structure and reduce the Hg of FeSiBPCu and FeSiBCCu nanocrystalline alloys. c and maintain a high B s .

[0075] In summary, based on the analysis of Examples 1-16 and Comparative Examples 1-6, it can be seen that by employing the technical solution provided by this invention, namely, by doping 0.1-0.4 at.% Sn element into a high-Fe-content Fe-based nanocrystalline alloy, the first crystallization peak of its amorphous precursor exhibits an overlapping double-peak shape and has a wide heat treatment temperature window (130-165K). This allows for the formation of a fine and uniform nanocrystalline structure under conventional heat treatment conditions, thereby obtaining a low-H... c (7.7-13.5A / m), and maintain high B s (1.75-1.87T).

[0076] This invention optimizes the alloy composition and proportions through extensive experiments, significantly broadening the heat treatment temperature window of amorphous precursors. Furthermore, it significantly improves the structure and soft magnetic properties of high-Fe-content Fe-based nanocrystalline alloys under conventional heat treatment conditions. This is significant for novel high-B... sThe development and practical application of nanocrystalline soft magnetic alloys are inspiring.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for reducing the coercivity of high-iron-content iron-based nanocrystalline alloys by tin doping, characterized in that, The composition formula for iron-based nanocrystalline alloys is Fe a Si b B c P d C e Cu f Sn g Where a, b, c, d, e, f, and g represent the atomic percentage content of each corresponding element, and satisfy 81.3≤a≤85.6, 0≤b≤5, 7≤c≤15, 0≤d≤6, 0≤e≤2, 1≤f≤1.5, 0.1≤g≤0.4, and a+b+c+d+e+f=100; The first crystallization peak of the amorphous precursor of the iron-based nanocrystalline alloy is an overlapping double peak, and has a wide heat treatment temperature window of not less than 130K. The iron-based nanocrystalline alloy is prepared from an amorphous precursor under the conditions of a heating rate of 20-30℃ / min, a holding temperature of 380-440℃, and a holding time of 60min. The iron-based nanocrystalline alloy has an average grain size of 18-24 nm, a saturation magnetic induction of 1.75-1.87 T, and a coercivity not exceeding 13.5 A / m.

2. The method for reducing the coercivity of high-iron-content iron-based nanocrystalline alloys by tin doping according to claim 1, characterized in that, Doping with tin broadens the heat treatment temperature window of the amorphous precursor of the iron-based nanocrystalline alloy, refines the nanocrystalline structure under conventional heat treatment conditions, and reduces coercivity.

3. The method for reducing the coercivity of high-iron-content iron-based nanocrystalline alloys by tin doping according to claim 1, characterized in that, In the iron-based nanocrystalline alloy, when 2≤b≤5, 12≤c≤15, d=0, e=0, 1≤f≤1.5, and 0.1≤g≤0.4, the first crystallization initiation temperature of the amorphous precursor is 369-398℃, and the heat treatment temperature window is 132-159℃; the average grain size of the α-Fe phase in the nanocrystalline alloy is 18-22nm, the saturation magnetic induction intensity is 1.75-1.78T, and the coercivity is 7.7-13A / m.

4. The method for reducing the coercivity of high-iron-content iron-based nanocrystalline alloys by tin doping according to claim 1, characterized in that, In the iron-based nanocrystalline alloy, when b=0, 13≤c≤15, d=0, e=0, 1≤f≤1.3, and 0.1≤g≤0.4, the first crystallization initiation temperature of the amorphous precursor is 335-354℃, and the heat treatment temperature window is 130-149℃; the average grain size of the α-Fe phase in the nanocrystalline alloy is 20-24nm, the saturation magnetic induction intensity is 1.80-1.87T, and the coercivity is 10.1-13.5A / m.

5. The method for reducing the coercivity of high-iron-content iron-based nanocrystalline alloys by tin doping according to claim 1, characterized in that, In the iron-based nanocrystalline alloy, when b=4, 7≤c≤11, 2≤d≤6, e=0, 1.3≤f≤1.5, and 0.2≤g≤0.4, the first crystallization initiation temperature of the amorphous precursor is 379-387℃, and the heat treatment temperature window is 157-159℃; the average grain size of the α-Fe phase in the nanocrystalline alloy is 20-21nm, the saturation magnetic induction intensity is 1.75-1.76T, and the coercivity is 11.2-12A / m.

6. The method for reducing the coercivity of high-iron-content iron-based nanocrystalline alloys by tin doping according to claim 1, characterized in that, In the iron-based nanocrystalline alloy, when b=4, 11≤c≤12, d=0, 1≤e≤2, f=1.5, and g=0.2, the first crystallization initiation temperature of the amorphous precursor is 369-374℃, and the heat treatment temperature window is 153-165℃; the average grain size of the α-Fe phase in the nanocrystalline alloy is 20-22nm, the saturation magnetic induction intensity is 1.77-1.78T, and the coercivity is 10.3-12.8A / m.

7. The method for reducing the coercivity of high-iron-content iron-based nanocrystalline alloys by tin doping according to claim 1, characterized in that, In the iron-based nanocrystalline alloy, when 2≤b≤5, 12≤c≤15, d=0, e=0, f=1.5, and g=0.1, the first crystallization initiation temperature of the amorphous precursor is 369-380℃, and the heat treatment temperature window is 148-155℃; the average grain size of the α-Fe phase in the nanocrystalline alloy is 18-20nm, the saturation magnetic induction intensity is 1.78T, and the coercivity is 7.7-8.9A / m.

8. The method for reducing the coercivity of high-iron-content iron-based nanocrystalline alloys by tin doping according to claim 1, characterized in that, When the iron-based nanocrystalline alloy composition is Fe 81.4 Si4B 13 Cu 1.5 Sn 0.1 At that time, the first crystallization initiation temperature of the amorphous precursor was 373℃, and the heat treatment temperature window was 155℃; the average grain size of the α-Fe phase in the nanocrystalline alloy was 18nm, the saturation magnetic induction intensity was 1.78T, and the coercivity was 7.7A / m.

9. The method for reducing the coercivity of high-iron-content iron-based nanocrystalline alloys by tin doping according to claim 1, characterized in that, When the iron-based nanocrystalline alloy composition is Fe 83.7 B 15 Cu 1.2 Sn 0.1 At that time, the first crystallization initiation temperature of the amorphous precursor was 354℃, and the heat treatment temperature window was 130℃; the average grain size of the α-Fe phase in the nanocrystalline alloy was 20nm, the saturation magnetic induction intensity was 1.84T, and the coercivity was 10.1A / m.

10. The method for reducing the coercivity of high-iron-content iron-based nanocrystalline alloys by tin doping according to claim 1, characterized in that, When the iron-based nanocrystalline alloy composition is Fe 81.3 Si4B 11 P2Cu 1.5 Sn 0.2 At that time, the first crystallization initiation temperature of the amorphous precursor was 387℃, and the heat treatment temperature window was 157℃; the average grain size of the α-Fe phase in the nanocrystalline alloy was 20nm, the saturation magnetic induction intensity was 1.76T, and the coercivity was 11.2A / m; When the iron-based nanocrystalline alloy composition is Fe 81.3 Si4B 11 C2Cu 1.5 Sn 0.2 The first crystallization initiation temperature of the amorphous precursor is 369℃, and the heat treatment temperature window is 165℃. The average grain size of the α-Fe phase in the nanocrystalline alloy is 20nm, the saturation magnetic induction intensity is 1.77T, and the coercivity is 10.3A / m.

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