Low-cost high saturation magnetic flux density iron-based amorphous nanocrystalline soft magnetic alloy and preparation and application thereof

Abstract

The application relates to a low-cost high-saturation-flux-density iron-based amorphous nanocrystalline soft magnetic alloy and preparation and application thereof, and aims to solve the technical problems of high cost, difficult consideration of high saturation magnetic induction and low coercivity, and narrow heat treatment process window of existing iron-based nanocrystalline soft magnetic alloys. 82 Si a B b P c Mo 0.5 Cu x , wherein 2.79<=a<=2.87, 12.07<=b<=12.44, 1.39<=c<=1.44, 0.75<=x<=1.25, and a+b+c=17.5-x. The alloy can optimize the soft magnetic performance by adjusting the Cu content and the annealing process. Under the optimal test condition, the saturation magnetic flux density of the typical component alloy can reach 1.82 T, and the coercivity is as low as 1.4 A / m, thereby forming an excellent combination of high magnetic energy storage and low magnetic hysteresis loss, and being suitable for the scene of high magnetic flux and low loss of a soft magnetic device.

Description

Technical Field

[0001] This invention relates to the fields of materials science and magnetic materials technology, specifically to a low-cost, high-saturation magnetic flux density iron-based amorphous nanocrystalline soft magnetic alloy and its preparation and application. Background Technology

[0002] Soft magnetic materials, as the core functional carriers for energy generation and conversion in electromagnetic equipment and motor power devices, are key supporting materials for the stable operation of an electrified society and are widely used in many cutting-edge fields such as new energy power generation, smart grids, high-efficiency motors, and power electronics. Against the backdrop of an increasingly severe global energy crisis and the continuous advancement of low-carbon emission reduction goals, modern power equipment, represented by motors and generators, is accelerating its iterative upgrade towards higher frequencies, smaller sizes, and higher efficiency, placing more stringent requirements on the comprehensive performance of soft magnetic materials. Ideal soft magnetic materials must simultaneously possess high saturation magnetic flux density (…). B S Low coercivity H C and low magnetostriction coefficient ( λ S ):high B S It can effectively reduce device size and increase power density; low H C It can significantly reduce hysteresis loss; low λ S It is a key indicator to ensure the stable operation of materials under high-frequency conditions.

[0003] Iron-based amorphous / nanocrystalline soft magnetic alloys, with their excellent comprehensive magnetic properties, can not only reduce energy loss in power equipment by 30% to 50% but also improve system power density and operational reliability, making them one of the core materials for building a green and low-carbon energy structure. However, existing commercially available iron-based nanocrystalline soft magnetic alloys all have significant performance or cost shortcomings, making it difficult to meet the dual requirements of high performance and low cost for modern power equipment. 1. Finemet type alloys (such as Fe) 73.5 Cu1Nb3Si 13.5 B9), although it has extremely low H c (0.53 A / m), high permeability ( μ e ), close to 0 λ S It has good thermal stability and corrosion resistance, but due to its high Nb content and low Fe content, the saturation magnetic flux density is only about 1.24T, which limits its application in high power density and miniaturized devices. In addition, the high Nb content significantly increases the cost of raw materials. 2. Nanoperm type alloys (such as Fe)90 Zr7B), B S Upgraded to 1.5~1.7T, and λs Smaller, but H C The concentration is relatively high, and the Zr element in the composition is easily oxidized and difficult to preserve, requiring stringent environmental conditions for industrial preparation, which increases the difficulty and cost of production. 3. Hitperm type alloys (such as (Fe) 1-x Co x ) 88 Zr7B4Cu1), developed based on the Nanoperm alloy. B s Further increasing the temperature to 1.6~2.1T, it exhibits good thermal stability, but the addition of Co significantly increases the alloy cost, hindering large-scale production. H C Approximately 20 A / m, 1 kHz μ e With a strength of only 1800, the magnetic properties are not very uniform. 4. Nanomet alloys (such as Fe) 83.3 Si4B8P4Cu 0.7 Fe 84.3 Si4B8P3Cu 0.7 ),That B s They reached 1.88T and 1.94T respectively, approaching the level of silicon steel. H c The values ​​are 7 A / m and 10 A / m, respectively, but the amorphous forming ability (AFA) is extremely low, the crystallization conditions are harsh, surface crystallization is prone to occur during melt spin quenching, and subsequent heat treatment is difficult to control. The grains are very easy to grow, which leads to the deterioration of soft magnetic properties, seriously hindering its widespread industrial application.

[0004] In recent years, researchers have attempted to improve performance through compositional manipulation, such as adjusting elements like Cu and C in the Fe-Si-BP-Cu system. Although... B s and H cWhile improvements have been made, problems such as poor process adaptability, high cost, or insufficient overall magnetic properties still exist. The article "Refining nanocrystalline-amorphous composite structure for superior soft magnetics in FeBSiPMoCu alloys via localized dynamic high-entropy effect enhanced by Mo micro-alloying" (Fe-B-Si-P-Mo-Cu alloy system) proposes optimizing Fe through Mo micro-alloying. 83-x B8Si4P4Mo x The scheme for improving the properties of Cu1 (x=0~4) alloys involves introducing a local dynamic high-entropy effect through the element Mo, thereby enhancing the alloy's properties. B s Reaching 1.48~1.76T, H c The strength ranges from 6.7 to 11.4 A / m, while simultaneously improving amorphous forming ability and the heat treatment process window. However, this alloy system still has limitations. H c High B s There are issues that need further improvement, and its performance has not yet reached "high" levels. B s With ultra-low H c The ideal state of "balancing all aspects" is difficult to meet the extreme requirements of high power density devices for magnetic performance.

[0005] In summary, existing iron-based nanocrystalline soft magnetic alloys generally exhibit... B s and H c Problems such as difficulty in coordinated optimization and significant contradictions between cost and processability exist. Therefore, developing a method that combines high efficiency with low cost is crucial. B s 、 ultra-low H c The development of novel iron-based amorphous / nanocrystalline soft magnetic alloys with low cost and excellent industrial processability has become a pressing technical challenge in this field.

[0006] The information disclosed in this background section is intended only to enhance the understanding of the background technology of this disclosure and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] This invention addresses the technical problems of high cost, difficulty in achieving both high saturation magnetic flux density and low coercivity, and narrow heat treatment process window of existing iron-based nanocrystalline soft magnetic alloys. By introducing trace amounts of Cu (0.75 at.% ~ 1.25 at.%) into Fe-Si-BP-Mo based amorphous alloys and combining it with an ultra-high heating rate rapid annealing process, a controllable transformation of the amorphous matrix into a uniform nanocrystalline structure is achieved. Ultimately, this results in a comprehensive technical effect that maintains high saturation magnetic flux density (~1.82 T) while significantly reducing coercivity (as low as 1.4 A / m), significantly widening the heat treatment process window, and substantially reducing raw material costs.

[0008] According to one aspect of this disclosure, an iron-based amorphous nanocrystalline soft magnetic alloy is provided, the alloy composition of which is expressed as Fe. 82 Si a B b P c Mo 0.5 Cu x The atomic percentages satisfy the following: 2.79≤a≤2.87, 12.07≤b≤12.44, 1.39≤c≤1.44, 0.75≤x≤1.25, a+b+c=17.5-x; the alloy has a nanocrystalline phase after annealing.

[0009] In some embodiments of this disclosure, the alloy composition is expressed as Fe. 82 Si 2.87 B 12.44 P 1.44 Mo 0.5 Cu 0.75 .

[0010] In some embodiments of this disclosure, the alloy composition is expressed as Fe. 82 Si 2.83 B 12.26 P 1.41 Mo 0.5 Cu1.

[0011] In some embodiments of this disclosure, the alloy composition is expressed as Fe. 82 Si 2.79 B 12.07 P 1.39 Mo 0.5 Cu 1.25 .

[0012] According to another aspect of this disclosure, a method for preparing the iron-based amorphous nanocrystalline soft magnetic alloy is provided, comprising the following steps: S1. Prepare the raw materials according to the alloy composition formula; S2. Mix the prepared raw materials and then perform vacuum induction melting to obtain a master alloy ingot; S3. The master alloy ingot is processed into amorphous alloy strips by vacuum rapid quenching process; S4. The amorphous alloy strip is subjected to rapid annealing heat treatment, wherein the heating rate of the rapid annealing heat treatment is ≥ 500 K / s, the annealing temperature is 500~540℃, and the holding time is 2~10 seconds.

[0013] In some embodiments of this disclosure, in step S3, the vacuum rapid quenching process parameters are: cooling roller speed of 40 m / s, spray temperature of 1250°C, spray pressure of 0.035 MPa, and tube-roller spacing of 0.75 mm. In some embodiments of this disclosure, in step S4, the annealing temperature is 500~520℃, the holding time is 2~6s, and the annealing is followed by air cooling.

[0014] According to another aspect of this disclosure, the iron-based amorphous nanocrystalline soft magnetic alloy is used in the preparation of at least one of the following products: (1) Medium and high frequency transformer core; (2) Inductor core; (3) Core magnetic circuit components of on-board chargers for new energy vehicles; (4) Photovoltaic inverter magnetic core; (5) Electromagnetic sensor sensitive magnetic core; (6) Core of medium and low voltage distribution transformer; (7) Core components of the magnetic circuit of industrial relays; (8) Anti-interference inductor core for precision electronic equipment.

[0015] According to another aspect of this disclosure, a magnetic core for a soft magnetic device is provided, which is made of the above-mentioned iron-based amorphous nanocrystalline soft magnetic alloy, or is made of an iron-based amorphous nanocrystalline soft magnetic alloy obtained by the preparation method described above.

[0016] According to another aspect of this disclosure, a transformer, inductor, or motor core is provided, comprising the aforementioned soft magnetic device core.

[0017] One or more technical solutions provided in the embodiments of this application have at least any of the following technical effects or advantages: 1. Excellent comprehensive magnetic properties: Under optimal annealing process, the saturation magnetic flux density of typical alloy compositions ( B s The coercivity reached 1.82 T, and the coercivity was ( H c With a magnetic energy storage capacity as low as 1.4 A / m, it forms an excellent combination of "high magnetic energy storage + low hysteresis loss". This performance is significantly better than Fe.83-x B8Si4P4Mo x Cu1 (x=0~4) alloy system B s = 1.48~1.76 T, H c = 6.7~1.4 A / m), B S Approaching silicon steel B S Horizontal, simultaneously achieving ultra-low H c It fully meets the performance requirements of high-frequency, high-power-density soft magnetic devices. B S The core breakthrough in increasing the temperature to 1.82T lies in: avoiding the runaway crystallization problem in high-Fe content alloys, while simultaneously solving the problem of "grain refinement elements diluting the Fe content, leading to..." B s The contradiction of "decline" is resolved by adjusting the amount of Cu to achieve a performance balance.

[0018] 2. Controllable nanocrystallization process: By combining trace Cu addition (0.75 at.%~1.25 at.%) with rapid annealing at ultra-high heating rates, the controllable transformation of the amorphous matrix into a uniform nanocrystalline structure was achieved, effectively suppressing excessive grain growth and precipitation of harmful hard magnetic phases (such as Fe3(B,P)).

[0019] 3. Good process compatibility: The introduction of Cu optimizes nucleation without significantly impairing the amorphous forming ability of the alloy, allowing the alloy to still be prepared into fully amorphous ribbons through conventional melt rapid quenching, providing a good foundation for industrial preparation.

[0020] 4. Structural refinement and improved stability: In the final obtained nanocrystalline-amorphous composite structure, α The small and uniform size of Fe(Si) grains, along with the high stability of the residual amorphous phase, together ensure the stability of the magnetic properties of the material at high temperatures and high frequencies.

[0021] In summary, this invention, through the synergistic effect of sophisticated composition control (low Mo content, Cu addition within a specific range) and rapid annealing process, has successfully developed an iron-based amorphous nanocrystalline soft magnetic alloy that combines the advantages of high saturation magnetism, low coercivity, high permeability, good process stability, and low cost, providing an excellent material solution for the manufacture of high-performance, low-cost soft magnetic components. Attached Figure Description

[0022] Figure 1 Fe in the embodiments of the present invention 82 Si a B bP c Mo 0.5 Cu x The X-ray diffraction (XRD) patterns of the series of alloys (2.79≤a≤2.87, 12.07≤b≤12.44, 1.39≤c≤1.44, 0.75≤x≤1.25, a+b+c=17.5-x) in the quenched amorphous structure show typical amorphous diffuse scattering peak characteristics.

[0023] Figure 2 Fe in the embodiments of the present invention 82 Si a B b P c Mo 0.5 Cu x The XRD patterns of the series of alloys after holding at different annealing temperatures for 2 seconds demonstrate the phase transformation behavior during the nanocrystallization process.

[0024] Figure 3 Fe in the embodiments of the present invention 82 Si a B b P c Mo 0.5 Cu x The effect of Cu content on the crystal volume fraction of a series of alloys at an annealing temperature of 500℃ is shown in the figure.

[0025] Figure 4 Fe in the embodiments of the present invention 82 Si a B b P c Mo 0.5 Cu x The coercivity of a series of alloys after holding at different annealing temperatures for 2 seconds ( H c The variation curve reflects the characteristics of the process window.

[0026] Figure 5 Fe in the embodiments of the present invention 82 Si a B b P c Mo 0.5 Cu x The coercivity of a series of alloys after holding at the optimal annealing temperature of 500℃ for different times ( H c ) Change curve.

[0027] Figure 6 Fe in the embodiments of the present invention 82 Si a B b P c Mo 0.5Cu x The effective magnetic permeability of a series of alloys after holding at different annealing temperatures for 2 seconds ( μ e ) Change curve.

[0028] Figure 7 Fe in the embodiments of the present invention 82 Si a B b P c Mo 0.5 Cu x The Cu content in the series alloys affects B S The influence relationship diagram.

[0029] Figure 8 Fe in the embodiments of the present invention 82 Si 2.79 B 12.07 P 1.39 Mo 0.5 Cu 1.25 Transmission electron microscopy (TEM) characterization results of the alloy after annealing at 500℃ for 2s show a uniform and fine nanocrystalline structure. Figure a: Cu1.25 bright-field TEM image, a-1 is the SAED pattern, a-2 is the average grain size; b: HAADF-STEM, b(1-6) are the surface scan patterns of elemental distributions; c: line scan of the area indicated by the yellow arrow in Figure b. To avoid ambiguity caused by blurring of some text in the images due to image compression, Figures a-1, a-2, and c have been enlarged, and corresponding appendices are provided. Figure 8-1 Appendix Figure 8-2 Appendix Figure 8-3 . Detailed Implementation

[0030] To better understand the technical solution of this application, the above technical solution will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Unless otherwise specified, all instruments and equipment used in the following embodiments are conventional instruments and equipment; all industrial raw materials used are commercially available conventional industrial raw materials; and all processing and manufacturing methods used are conventional methods. The models of the experimental instruments used are as follows: X-ray diffractometer (XRD): Empyrean type, used for phase analysis of alloy strips; DC BH measuring instrument: MATS-2010SD model, used for coercivity. H C Measurement; Impedance analyzer: Model E4990A, used for effective permeability μe Characterization; Magnetic Measurement System (SQUID): Quantum Design MPMS3 model, used for saturation magnetization (Ms) and saturation magnetic flux density (Ms). B S )Measurement.

[0032] Transmission electron microscope (TEM): Thermo Fisher Talos F200X, for microstructure characterization.

[0033] 1. Alloy Preparation (1) Batching and Melting: Based on the designed composition (atomic percentage), high-purity raw materials (purity ≥ 99.9wt%) are weighed, with the mass error controlled within ± 0.2%. The prepared raw materials are placed in a high-purity quartz crucible thoroughly cleaned with anhydrous ethanol, and melted using a vacuum induction melting furnace (NMS-GYI type). The furnace cavity is evacuated to 5×10⁻⁶. -3 After Pa, 0.05 MPa of high-purity argon gas (99.999%) was introduced as a protective atmosphere. A gradient heating program was adopted: first, the temperature was raised to 800 °C at a rate of 50 A / min and held for 2 minutes, then raised to 1550-1600 °C at a rate of 100 A / min. After the alloy was completely melted, it was held for 120 seconds, and then cooled to room temperature under argon protection to obtain a master alloy ingot with uniform composition.

[0034] (2) Preparation of amorphous ribbons: The master alloy ingot is crushed into particles with a diameter of 5-8 mm. A vacuum rapid quenching device (NMS-GRIV type) is used, with a vacuum degree better than 5×10⁻⁶. -1 Under conditions of Pa, argon injection pressure of 0.035 MPa, copper roller linear speed of 40 m / s, and melt temperature of 1250±10 ℃, the alloy melt is sprayed onto the surface of a high-speed rotating copper roller and rapidly cooled to obtain a continuous, bright amorphous alloy strip. Typical strip dimensions are: thickness 25±2 μm and width 0.9±0.1 mm.

[0035] (3) Nanocrystallization heat treatment: The amorphous strip is cut into segments of about 70 mm in length, wrapped with high-purity copper foil with a thickness of 0.02 mm, and placed in an annealing device capable of rapid heating. The heating rate of the device is ≥500 K / s, and the temperature control accuracy is ±1℃. Rapid annealing is carried out in a temperature range of 500-540℃, with a holding time of 2-10 seconds. After the annealing is completed, the strip is quickly removed and cooled in air.

[0036] 2. Performance and structural characterization (1) Phase analysis: XRD was used to test the quenched and annealed samples. A Cu target was used. KAlpha rays (λ = 1.54056 Å) were used, with a scanning range of 30-90° and a scanning speed of 10° / min. The amorphous structure was confirmed by the diffuse scattering peaks of the quenched sample, and the type and crystallinity of the nanocrystalline phase were confirmed by the diffraction peaks of the annealed sample.

[0037] (2) Magnetic property test: - Saturation magnetic flux density ( B s ): Measurement was performed using an MPMS3 SQUID system. The sample was cut to 5-6 mm, accurately weighed, and placed on the sample rod. The saturation magnetization was measured under an external magnetic field of 800 kA / m. M s ), then convert to B s .

[0038] - Coercivity ( H c The measurement was performed using a MATS-2010SD DC BH measuring instrument. The sample's geometric and mass parameters were input, and the hysteresis loop was measured in 0.8 A / m steps under an 800 A / m magnetic field. The average of at least three measurements was taken as the result. H c value.

[0039] - Effective permeability ( μ e ): Using an E4990A impedance analyzer, in inductance-resistance combined mode, the test was conducted in a magnetic field range of 0.7-70 A / m. The inductance was calculated by measuring the solenoid inductance containing the sample and the no-load reference value.

[0040] (3) Microstructure observation: For the selected annealed sample, TEM thin film samples were prepared by focused ion beam (FIB) technology. Bright field image observation, selected area electron diffraction (SAED) and energy dispersive spectroscopy (EDS) were performed using a Talos F200X TEM to determine the morphology, size distribution and phase composition of the nanocrystals. Example

[0041] The following embodiments are intended to illustrate the implementation process and the technical effects obtained by the present invention. All embodiments were prepared and tested according to the above-described general methods. The main differences lie in the different Cu element content (x value) in the alloy composition and the fine-tuning of the annealing process to optimize performance.

[0042] .

[0043] Results analysis: 1. Synergistic effects of ingredient design: like Figure 1As shown, samples with different Cu contents (0.75, 1, 1.25) all exhibited diffuse scattering peaks at 2θ≈45°, displaying typical XRD characteristics of an amorphous structure. Examples 1-3 systematically varied the Cu content (x increased from 0.75 to 1.25), maintaining the total metalloid content balance by adjusting the contents of Si, B, and P, while keeping the iron content fixed at 82 at.%. Figure 2 The XRD pattern shows sharp edges after heat treatment. α -Fe(Si) diffraction peaks indicate that Fe(Si) crystal phases precipitated in the amorphous matrix after heat treatment. α -Fe(Si) nanocrystalline phase; with increasing heat treatment temperature α The intensity of the -Fe(Si) peak gradually increases and the peak shape becomes sharper, indicating that the higher the temperature, α The more Fe(Si) nanocrystals precipitated, the higher the degree of crystallization; the higher the Cu content, the better at the same temperature. α The more prominent the Fe(Si) peak signal, the more likely Cu can promote [the development of the product]. α - The precipitation of Fe(Si) nanocrystals can be achieved, but it should be noted that if the Cu content exceeds 1.25 at.%, the AFA (amorphous forming ability) will decrease significantly, making it difficult to prepare alloy strips.

[0044] By utilizing the signal difference between the "sharp diffraction peaks of the crystalline phase" and the "diffuse scattering background of the amorphous phase" in the XRD pattern, and combining the Rietveld refinement method (fitting the structural parameters of the crystalline phase and the scattering characteristics of the amorphous phase), the volume fraction of the crystalline phase was quantitatively calculated, thus obtaining the crystal volume fraction of the alloy. The results are shown in [Figure number missing]. Figure 3 At the optimal annealing temperature (500℃), when the Cu content increased from 0.75 at.% to 1 at.%, the crystal volume fraction showed a decreasing trend, indicating that the increase in Cu content within this range did not promote the precipitation of crystalline phases, but rather inhibited crystallization to some extent. However, when the Cu content further increased to 1.25 at.%, the crystal volume fraction increased significantly, demonstrating that an appropriate amount of Cu can act as a nucleating agent, effectively promoting the precipitation of crystalline phases and improving the degree of crystallinity. This change is directly related to the soft magnetic properties of the alloy (the magnetic properties of iron-based nanocrystalline alloys are highly correlated with the degree of crystallization and grain uniformity), providing experimental basis for subsequent optimization of the soft magnetic properties of the alloy by controlling the Cu content.

[0045] 2. Optimization and balancing of magnetic properties: Figure 4 It can be seen that the annealing temperature has an effect on H C Influence pattern: T A ≤400℃, H CThe overall level is relatively high, but it decreases with increasing temperature. This is due to the relaxation process of the amorphous matrix, where internal stress is gradually released, reducing the resistance to magnetic domain wall movement. H C reduce; T A Within the range of 400℃ to 520℃, H C Continued decrease (especially Cu) 1.25 (The sample reduction was more significant), combined with the XRD results, fine precipitates formed in the amorphous matrix during this stage. α -Fe(Si) nanocrystals, with refined and uniformly distributed grains, further reduce the resistance to magnetic domain wall movement, making... H C Reduced to a lower level; TA≥520℃, H C The temperature rose sharply, indicating that the annealing temperature was too high. α Excessive growth of Fe(Si) nanocrystals leads to a significant increase in grain size, resulting in a sharp increase in the resistance to magnetic domain wall movement and a deterioration in soft magnetic properties. At the same annealing temperature, Cu... 1.25 The sample H C The overall lower Cu content indicates that the nanocrystals precipitated after annealing are finer and more uniform, resulting in superior soft magnetic properties; while Cu 0.75 Cu1 sample H C The relatively higher level is directly related to the degree of crystallization and the difference in grain size regulated by different Cu contents.

[0046] From the perspective of the control effect of annealing temperature ( Figure 6 Within the range of 360–440℃, each sample μ e The temperature gradually increases, which is due to the sufficient relaxation of the amorphous matrix and the precipitation of fine and uniform α-Fe(Si) nanocrystals, resulting in a decrease in the resistance to magnetic domain wall movement; when the temperature is in the range of 440~500℃, μ e Reaching the peak temperature corresponds to the structural state of "optimal amorphous relaxation + optimal amount and size of nanocrystalline precipitation," resulting in the best soft magnetic properties; however, when the temperature exceeds 500℃... μ e The decline in drama stems from α Excessive growth of Fe(Si) nanocrystals leads to a sharp increase in magnetic domain wall resistance, resulting in a deterioration of soft magnetic properties. From the perspective of the influence of Cu content, Cu... 1.25 The sample μ e The peak value is significantly higher than other samples, demonstrating superior soft magnetic properties. This is related to the nucleating effect of Cu, which promotes the precipitation of finer and more uniform nanocrystals. However, the peak value is lower in the high-temperature range (≥540℃). μe The largest decrease was observed, indicating higher temperature sensitivity; Cu 0.75 The sample μ e The peak value and overall level are in the middle, the decrease in the high-temperature range is relatively gradual, and the temperature stability of the soft magnetic properties is slightly better; Cu1 sample μ e Peak value lower than Cu 1.25 Furthermore, the temperature drops to a lower level after the high-temperature range, indicating that the uniformity and dimensional stability of its nanocrystals are slightly poor, and the temperature adaptation range of its soft magnetic properties is relatively narrow.

[0047] Figure 7 The results show that under optimal annealing conditions (500℃, holding time 2s), Cu 0.75 Cu1, Cu 1.25 The alloy exhibits a saturation magnetic flux density of 1.7–1.9 T, demonstrating strong magnetic flux carrying capacity; it also possesses a narrow hysteresis loop and low coercivity. For Cu under optimal experimental conditions… 1.25 Microstructural characterization was performed, see Figure 8 The figure, characterized by TEM, SAED, and HAADF-STEM, further clarifies that the Fe-based alloy is... α -Fe(Si) nanocrystalline / amorphous matrix composite structure: α -Fe(Si) nanocrystals are uniform in size (~14.4 nm) and diffusely distributed, with SAED rings corresponding to their (110), (200), and (211) crystal planes; the elements exhibit heterogeneous distribution: Fe is enriched in α -Fe(Si) nanocrystals, with uniform distribution of Si, Cu, P, and Mo (since B is relatively light, the EDS results do not reflect the true distribution of B, so it is not discussed). According to Herzer's theory, the nanocrystal size is much smaller than the exchange interaction length of iron-based alloys, significantly reducing the magnetic anisotropy dispersion and corresponding to the low coercivity of the alloy. H c ); α The enrichment of Fe in the Fe(Si) crystal phase, relying on the high saturation magnetization of this phase, ensures the high saturation magnetic flux density of the alloy. B S Meanwhile, the rapid annealing process has a short annealing time, resulting in insufficient diffusion of Si, Cu, P, and Mo elements, thus leading to uniform distribution. Furthermore, the extremely short annealing time results in fine grains. This uniform and fine crystal-matrix composite structure effectively reduces magnetic loss, thereby supporting the alloy's high effective magnetic permeability. μ e ).

[0048] 3. Expanding the process window: Figure 5 The alloy of Example 3 was shown at the optimal annealing temperature (500°C). H cVariation with heat preservation time (2-10 s). H c The magnetic flux density remained at a low level of 1.4-1.7 A / m for 2-6 s, only slightly increasing to around 2.1 A / m after 10 s. This demonstrates that the alloy of this invention, with its preferred composition, can maintain excellent soft magnetic properties over a wide holding time range (2-10 s), significantly improving upon the problems of existing alloys (such as Nanomet) being extremely sensitive to heat treatment conditions and having a narrow process window. Figure 4 Example 3: Annealing temperature range of 500-540℃ H c The results, all below 2.1 A / m, fully demonstrate that the technical solution provided by this invention has excellent process stability and robustness.

[0049] 4. A balance between low cost and high performance: As shown in Table 1, all examples are free of expensive elements such as Co and Ni, and the Mo content is only 0.5 at.%, resulting in significantly lower raw material costs compared to Nb-containing Finemet alloys and Co-containing Hitperm alloys. Particularly noteworthy is that the alloy in Example 3, while reducing the iron content from approximately 83.3 at.% in Nanomet alloys to 82 at.%, not only... H c The flow rate decreased significantly from the typical 7-10 A / m in Nanomet to 1.4 A / m, and B s The magnetic flux density was reduced only slightly from about 1.88 T to 1.82 T, with a very small sacrifice in magnetic induction in exchange for an improvement in soft magnetic properties.

[0050] In summary, the embodiments of the present invention fully verify the effectiveness of using Fe as the component. 82 Si a B b P c Mo 0.5 Cu x A design with a range of 0.75 ≤ x ≤ 1.25, combined with an ultra-high heating rate rapid annealing process, successfully prepared a low-cost, iron-based amorphous nanocrystalline soft magnetic alloy with excellent comprehensive magnetic properties and good process stability. This technical solution effectively solves the problems of high cost, narrow heat treatment window, and high temperature sensitivity associated with existing high-performance nanocrystalline alloys. B s With low H c Despite technical challenges such as difficulty in achieving both goals, it possesses outstanding value for industrial applications.

Claims

1. A type of iron-based amorphous nanocrystalline soft magnetic alloy, characterized in that, Its alloy composition formula is Fe 82 Si a B b P c Mo 0.5 Cu x The atomic percentages satisfy the following: 2.79≤a≤2.87, 12.07≤b≤12.44, 1.39≤c≤1.44, 0.75≤x≤1.25, a+b+c=17.5-x; the alloy has a nanocrystalline phase after annealing.

2. The iron-based amorphous nanocrystalline soft magnetic alloy according to claim 1, characterized in that, Its alloy composition formula is Fe 82 Si 2.87 B 12.44 P 1.44 Mo 0.5 Cu 0.75 .

3. The iron-based amorphous nanocrystalline soft magnetic alloy according to claim 1, characterized in that, Its alloy composition formula is Fe 82 Si 2.83 B 12.26 P 1.41 Mo 0.5 Cu1.

4. The iron-based amorphous nanocrystalline soft magnetic alloy according to claim 1, characterized in that, Its alloy composition formula is Fe 82 Si 2.79 B 12.07 P 1.39 Mo 0.5 Cu 1.25 .

5. A method for preparing the iron-based amorphous nanocrystalline soft magnetic alloy according to claim 1, characterized in that, Includes the following steps: S1. Prepare the raw materials according to the alloy composition formula; S2. Mix the prepared raw materials and then perform vacuum induction melting to obtain a master alloy ingot; S3. The master alloy ingot is processed into amorphous alloy strips by vacuum rapid quenching process; S4. The amorphous alloy strip is subjected to rapid annealing heat treatment, wherein the heating rate of the rapid annealing heat treatment is ≥500 K / s, the annealing temperature is 500~540℃, and the holding time is 2~10 seconds.

6. The preparation method according to claim 5, characterized in that, In step S3, the vacuum rapid quenching process parameters are: cooling roller speed of 40 m / s, spray temperature of 1250℃, spray pressure of 0.035 MPa, and tube-roller spacing of 0.75 mm.

7. The preparation method according to claim 5, characterized in that, In step S4, the annealing temperature is 500~520℃, and the holding time is 2~6s; after annealing, air cooling is performed.

8. The use of the iron-based amorphous nanocrystalline soft magnetic alloy according to claim 1 in the preparation of at least one of the following products: (1) Medium and high frequency transformer core; (2) Inductor core; (3) Core magnetic circuit components of on-board chargers for new energy vehicles; (4) Photovoltaic inverter magnetic core; (5) Electromagnetic sensor sensitive magnetic core; (6) Core of medium and low voltage distribution transformer; (7) Core components of the magnetic circuit of industrial relays; (8) Anti-interference inductor core for precision electronic equipment.

9. A magnetic core for soft magnetic devices, characterized in that, It is made of the iron-based amorphous nanocrystalline soft magnetic alloy according to any one of claims 1-4, or the iron-based amorphous nanocrystalline soft magnetic alloy obtained by the preparation method according to any one of claims 5-7.

10. A transformer, inductor, or motor core, characterized in that, It includes the magnetic core for soft magnetic devices as described in claim 9.

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