A high-performance Fe-Si-BY iron-based amorphous alloy thin strip based on trace yttrium addition, its preparation method and application

Abstract

This invention belongs to the field of amorphous soft magnetic materials technology, specifically disclosing a high-performance Fe-Si-B-Y iron-based amorphous alloy thin strip based on trace yttrium addition, its preparation method, and applications. The alloy is based on the Fe-Si-B system, with a Fe mass fraction as high as 95% in its chemical composition, and contains 0.1%~0.5% trace rare earth element Y to partially replace the metalloid element B. This invention innovatively utilizes trace Y as a "melt purifier," removing impurities such as oxygen and sulfur from the melt through in-situ reaction, eliminating the core for α-Fe heterogeneous nucleation induced on the free surface of the thin strip during rapid quenching; simultaneously, it utilizes the atomic size effect to enhance the topological disorder of the melt. Combined with conventional industrial production conditions of 38-48 m / s, this method successfully increases the critical thickness of the limiting iron content amorphous alloy from approximately 20 μm to over 25 μm, and significantly optimizes the soft magnetic properties (Bs≥1.68T, Hc≤4.0 A / m). Furthermore, it allows the use of industrial-grade raw materials, possessing significant cost advantages and industrialization value.

Description

Technical Field

[0001] This invention belongs to the field of amorphous soft magnetic materials technology, specifically relating to a high-performance Fe-Si-BY iron-based amorphous alloy thin strip based on trace yttrium addition, its preparation method, and its application. Background Technology

[0002] As power electronic equipment evolves towards higher frequencies and smaller sizes, the industry's pursuit of saturation magnetic flux density (Bs) in soft magnetic materials has approached physical limits. Amorphous alloys, with their high permeability, high resistivity, high saturation magnetic flux density, and low coercivity, are widely used in distribution transformers and are increasingly becoming an important alternative to traditional silicon steel. However, the saturation magnetic flux density of the most widely used commercially available Fe-Si-B amorphous alloys (such as Fe78Si9B13 and Fe82Si4B13C1) is typically between 1.56T and 1.64T, far lower than that of silicon steel. This performance limitation results in a larger size for amorphous transformers, significantly restricting their widespread application in distribution transformers. To obtain higher saturation magnetic flux density, increasing the iron (Fe) content to 95wt% (approximately 82 at.%) has become an inevitable choice.

[0003] However, this extreme composition design introduces significant instability into industrial manufacturing. In single-roll melt quenching, due to the gradient difference in cooling rate across the roll surface, the free surface of the strip naturally cools at a lower rate compared to the roll-attached surface. For high-Fe alloys, their amorphous formation capability is already limited, and even minute amounts of impurities can disrupt the metastable equilibrium. In actual production, it has been found that elements such as oxygen (O) and sulfur (S), which inevitably remain in industrial raw materials, readily act as heterogeneous nucleation sites, inducing the preferential precipitation of α-Fe crystalline phases on the free surface of the strip. This surface crystallization phenomenon is a fatal flaw in obtaining high-performance amorphous strips: the microcrystals precipitated on the surface not only destroy the isotropy of the amorphous material but also form high-density magnetic domain pinning points, greatly restricting the movement of magnetic domain walls. As a result, while increasing the iron content achieves high saturation magnetization, it also leads to persistently high coercivity Hc, a surge in losses, and the strip becoming brittle and prone to breakage.

[0004] Faced with this challenge, most existing technologies adopt an "additive" strategy, but they have not fundamentally balanced the contradiction between surface crystallization and good soft magnetic properties. 1. Increased Compositional Complexity: Adding multiple elements such as Nb, Mo, and Cu to the Fe-Si-B base system in an attempt to improve amorphous formation capability through retarded diffusion. This not only significantly increases raw material costs but also makes melting control extremely difficult, often requiring specific heat treatment to precipitate nanocrystals to obtain good performance, making it impossible to achieve optimal performance in the as-cast state.

[0005] 2. Functional deviation: Although some patents (such as patent CN103187136A) also involve rare earth addition, their original intention is to use the large atomic radius of rare earth to improve corrosion resistance or oxidation resistance, and they do not use rare earth to inhibit crystallization from the perspective of nucleation kinetics; or the amount added is too high (used in magnetostrictive materials), which leads to the deterioration of soft magnetic properties.

[0006] Therefore, without introducing expensive refractory metals and maintaining the simple composition of the Fe-Si-B system, finding a technical means to clean impurities from the inside of the melt and cut off the surface nucleation path from the source is an urgent problem to be solved for the industrial mass production of high-iron-content amorphous ribbon. Summary of the Invention

[0007] To address the problems in existing technologies, this invention provides a high-performance Fe-Si-BY iron-based amorphous alloy thin strip based on trace yttrium addition, its preparation method, and its applications. This alloy has a simple composition design, a clear mechanism, and good process compatibility. By precisely controlling the content and proportion of Y element in the Fe-Si-BY quaternary system, a thin strip material with a fully amorphous structure, high Bs, and low Hc can be obtained under conventional industrial production conditions.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a high-performance Fe-Si-BY iron-based amorphous alloy thin strip based on trace amounts of yttrium addition, wherein the mass percentage composition expression of the amorphous alloy thin strip is Fe 95 Si1B (4-x) Y x Where x takes values ​​from 0.1 to 0.5. The preferred range is: 0.2 ≤ x ≤ 0.4.

[0009] Furthermore, the aforementioned amorphous alloy ribbon is completely amorphous, with no α-Fe crystalline phase precipitated on its free surface; its amorphous forming capability is characterized by a critical thickness of 25 μm to 35 μm.

[0010] As a further preferred embodiment of the technical solution of the present invention, the thickness of the amorphous alloy strip is 28-33 μm. This thickness range is the preferred result for achieving good amorphous state formation and soft magnetic property balance, and the optimal thickness is 30 μm.

[0011] This invention targets the common Fe-Si-B system of iron-based alloys by adding trace amounts of the rare earth element Y to partially replace the metalloid element B. It innovatively utilizes trace amounts of Y as a melt purifier to adsorb impurities, inhibit surface crystallization, and improve the amorphous formation capability. Simultaneously, it optimizes the soft magnetic properties of the amorphous alloy, reduces its coercivity, and obtains an Fe-based amorphous alloy with excellent soft magnetization performance.

[0012] This invention controls the appropriate amount of rare earth element Y added to amorphous materials. If too much Y is added, it will dilute the magnetic moment of Fe atoms, leading to the deterioration of soft magnetic properties.

[0013] In a preferred embodiment of the Fe-Si-BY amorphous alloy of the present invention, the amorphous alloy strip is composed of any of the following components: a) Fe 95 Si1B 3.8 Y 0.2 ; b) Fe 95 Si1B 3.7 Y 0.3 ; c) Fe 95 Si1B 3.6 Y 0.4 .

[0014] Secondly, the present invention provides a method for preparing the above-mentioned Fe-Si-BY iron-based amorphous alloy thin strip, comprising the following steps: S1. Alloy melting and ingot preparation: Weigh Fe, Si, B, and Y elemental raw materials with a purity of not less than 99.9% according to the designed composition, and place them in a crucible in the order of the lowest melting point at the bottom and the highest melting point at the top; after evacuating to below 3.5×10-3 Pa, fill the furnace with protective gas until the pressure inside the furnace is -0.06 MPa, melt all the raw materials, and obtain an alloy ingot after cooling; after turning the alloy ingot over, repeat the melting at least once under magnetic stirring to obtain an alloy ingot with uniform composition; S2. Melt surface treatment: Mechanical removal of oxide layer and impurities from the surface of alloy ingot; S3. Single-roll melt quenching forming: The alloy ingot obtained in step S2 is placed in a single-roll melt quenching device, and a protective gas is introduced into the vacuum environment to a pressure of 400mbar. After the alloy melts, the molten alloy is sprayed onto the surface of the rotating cooling roller and quickly solidified to form an amorphous alloy strip. S4. Annealing treatment: The amorphous alloy strip obtained in step S3 is annealed in a protective atmosphere at 360-400°C for 15 minutes.

[0015] In a preferred embodiment of the preparation method described in this invention, the protective gas is high-purity argon with a purity of not less than 99.95 wt%.

[0016] As a preferred embodiment of the preparation method described in this invention, the Fe, Si, B, and Y elemental raw materials are ultrasonically cleaned sequentially with petroleum ether and anhydrous ethanol before use.

[0017] In a preferred embodiment of the preparation method of the present invention, the melting under magnetic stirring in step S1 is performed 6 times.

[0018] In a preferred embodiment of the preparation method of the present invention, in step S2, a thickness of 0.5-1 mm is removed from the surface of the master alloy ingot by mechanical grinding or cutting.

[0019] In a preferred embodiment of the preparation method of the present invention, in step S3, the linear velocity of the copper roller is 38-48 m / s.

[0020] Thirdly, the present invention provides the application of the above-mentioned Fe-Si-BY iron-based amorphous alloy thin strip in the preparation of soft magnetic materials.

[0021] As a preferred embodiment of the application described in this invention, the soft magnetic material is used to manufacture high-efficiency distribution transformer cores, new energy vehicle drive motor cores, or high-frequency inductor cores.

[0022] As a preferred embodiment of the application described in this invention, the soft magnetic material is used to fabricate a magnetic sensor element.

[0023] Advantages and beneficial effects of the present invention: This invention creatively constructs a dual modification mechanism of "melt self-purification + structure modulation" in a near-eutectic Fe-Si-B system by substituting a portion of the metalloid B with trace amounts of rare earth Y and combining this with a high-speed rapid quenching process. Compared with existing technologies, this invention brings significant technological advancements and industrial value. 1. A "chemical scavenger" mechanism has been established to eliminate the potential for surface crystallization: This invention clarifies for the first time the role of rare earth element Y (Y) as a "purifier" in high-speed rail amorphous systems. Utilizing Y's extremely high chemical affinity for non-metallic impurities such as O and S, free impurities in the melt can be "captured" and fixed into stable compounds with high melting points and low densities (such as yttrium oxide) during the smelting stage. These inclusions are effectively separated during subsequent slag removal or rotary quenching, resulting in an alloy melt with extremely high purity. This deep purification directly eliminates the "seeds" that induce α-Fe nucleation on the free surface of the thin strip during rapid quenching, fundamentally solving the industry-wide problem of poor strip quality in high-speed rail amorphous alloys.

[0024] 2. Significant results were achieved, with a substantial increase in the critical thickness of amorphous materials: Building upon the solution to the nucleation source, this invention utilizes the size effect of Y atoms being significantly larger than Fe and B atoms to introduce strong topological disorder into the melt, increasing the resistance to atomic rearrangement. This structural "congestion effect," combined with the high purity of the melt, significantly enhances the alloy's intrinsic amorphous forming capability. Under the same cooling conditions, this invention increases the critical thickness of fully amorphous ribbons from the traditional approximately 20 μm to the 25-35 μm range. This means that a wider process window can be used in industrial production, greatly reducing the breakage rate and brittleness risk during high-speed production, and significantly improving the yield.

[0025] 3. Release of magnetic domain structure, resulting in a leapfrog improvement in soft magnetic properties: By completely eliminating the microcrystalline pinning layer on the surface and obtaining a more uniform amorphous matrix, the resistance to magnetic domain wall movement within the material is minimized, resulting in a wider and more regular magnetic domain structure. This optimization of the microstructure leads to a leap in macroscopic performance: while maintaining an ultra-high magnetic induction of Bs > 1.68T, the coercivity (Hc) of the material is also reduced to a low value of 4 A / m. This perfect coexistence of "high magnetic induction" and "low loss" is something that cannot be achieved by simply increasing the Fe content in traditional methods.

[0026] 4. The advantages of minimal ingredients and low-cost industrialization: Unlike other complex quaternary and pentagonal alloy systems, this invention adheres to a minimalist "Fe-Si-BY" quaternary composition, with Y primarily used to replace the more expensive B element, and contains no expensive metals such as Nb and Zr. This not only makes raw material costs highly controllable, but also ensures that the process is fully compatible with existing iron-based amorphous production lines. Mass production can be achieved simply by introducing a trace amount of Y in the smelting process and combining it with conventional strip spinning technology, without requiring expensive equipment upgrades, thus possessing extremely high industrial application value. Attached Figure Description

[0027] Figure 1 The X-ray diffraction patterns of the Fe-Si-BY amorphous alloys in Examples 1-5 of this invention are shown below. Figure 2 The X-ray diffraction patterns of the Fe-Si-BY amorphous alloys of Comparative Examples 1-3 of this invention are shown. Figure 3 The saturation magnetization curves of the Fe-Si-BY amorphous alloys in Examples 1-5 of this invention are shown. Figure 4 The saturation magnetization curves of the Fe-Si-BY amorphous alloys in Comparative Examples 1-3 of this invention are shown. Figure 5 This is a trend diagram showing the effect of different Y contents on the critical thickness of a series of alloys. Detailed Implementation

[0028] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to the accompanying drawings and specific embodiments. Unless otherwise specified, other materials and reagents used in the following embodiments are commercially available.

[0029] Example 1 This embodiment provides an Fe-Si-BY amorphous alloy thin strip, the mass percentage of which is expressed as Fe 95 Si1B 3.9 Y 0.1 Its preparation method includes the following steps: S1. Using Fe, Si, B, and Y elements with a purity of not less than 99.9% as raw materials, the elements are weighed according to the mass percentage of the alloy composition, and then placed in a copper crucible in the order of lowest melting point to highest melting point. The crucible is then evacuated to a vacuum of 3.5 × 10⁻⁶. -3 Pa, then introduce high-purity argon gas with a purity of 99.99wt% as a protective gas until the pressure inside the furnace reaches -0.06Mpa and stop the gas supply; melt all the raw materials, and after all the raw materials have melted to form an alloy ingot, cool and flip the alloy ingot, melt it again and turn on the magnetic stirring, with a melting current of 450A, repeat the melting 6 times to obtain the alloy ingot. S2. Remove the oxide layer impurities of 0.5-1mm from the surface of the alloy ingot obtained in step S1 by mechanical grinding; S3. Place the alloy ingot from step S2 in the quartz tube of the single-roller melt quenching system, evacuate the vacuum, and introduce argon gas to 400 mbar. After the alloy ingot is completely melted, drop it onto a copper roller with a linear velocity of 38-48 m / s, cool and form it to obtain a Fe-Si-BY amorphous alloy thin strip with a thickness of 25 μm.

[0030] S4. Anneal the alloy strip obtained in step S2 in a medium-frequency induction furnace at 400°C for 15 minutes under a protective atmosphere.

[0031] Example 2 This embodiment provides an Fe-Si-BY amorphous alloy, the mass percentage of which is expressed as Fe 95 Si1B 3.8 Y 0.2 The preparation method is basically the same as in Example 1, except that the thickness of the amorphous alloy strip obtained in step S3 is 28 μm and the annealing temperature in step S4 is 380 °C.

[0032] Example 3 This embodiment provides an Fe-Si-BY amorphous alloy, the mass percentage of which is expressed as Fe 95 Si1B 3.7 Y 0.3The preparation method is basically the same as in Example 1, except that the thickness of the amorphous alloy strip obtained in step S3 is 30 μm and the annealing temperature in step S4 is 370 °C.

[0033] Example 4 This embodiment provides an Fe-Si-BY amorphous alloy, the mass percentage of which is expressed as Fe 95 Si1B 3.6 Y 0.4 The preparation method is basically the same as in Example 1, except that the thickness of the amorphous alloy strip obtained in step S3 is 33 μm and the annealing temperature in step S4 is 360℃.

[0034] Example 5 This embodiment provides an Fe-Si-BY amorphous alloy, the mass percentage of which is expressed as Fe 95 Si1B 3.5 Y 0.5 The preparation method is basically the same as in Example 1, except that the thickness of the amorphous alloy strip obtained in step S3 is 35 μm and the annealing temperature in step S4 is 360 °C.

[0035] Comparative Example 1 This comparative example provides an Fe-Si-B amorphous alloy, whose mass percentage is expressed as Fe 95 The preparation method of Si1B4 is basically the same as that in Example 1, except that the thickness of the amorphous alloy strip obtained in step S3 is 22 μm.

[0036] Comparative Example 2 This embodiment provides an Fe-Si-BY amorphous alloy, the mass percentage of which is expressed as Fe 95 Si1B 3.3 Y 0.7 The preparation method is basically the same as in Example 1, except that the thickness of the amorphous alloy strip obtained in step S3 is 34 μm and the annealing temperature in step S4 is 350 °C.

[0037] Comparative Example 3 This embodiment provides an Fe-Si-BY amorphous alloy, the mass percentage of which is expressed as Fe 95 The preparation method of Si1B3Y1 is basically the same as that in Example 1, except that the thickness of the amorphous alloy strip obtained in step S3 is 37μm and the annealing temperature in step S4 is 330℃.

[0038] Next, the Fe-Si-BY amorphous alloy strips of Examples 1-5 and Comparative Examples 1-3 were tested: I. X-ray diffraction patterns of Fe-Si-BY amorphous alloy thin strips from Examples 1-5 and Comparative Examples 1-3 were measured.

[0039] Using an X-ray diffractometer (XRD), Kα rays (λ=0.15406 nm) generated by a copper target were used for scanning. The scanning range was 30°~90° and the scanning speed was 4° / min to obtain the 2θ-intensity spectrum.

[0040] The X-ray diffraction patterns of Fe-Si-BY amorphous alloy ribbons in Examples 1-5 are as follows: Figure 1 As shown, the results indicate that the diffraction peaks of the Fe-Si-BY amorphous alloy thin strip in the embodiment do not have obvious sharp crystallization peaks, but are typical amorphous structure “bun peak” characteristics, indicating that it is a completely amorphous structure.

[0041] The X-ray diffraction patterns of the Fe-Si-BY amorphous alloy thin strips in Comparative Examples 1-3 are as follows: Figure 2 As shown, the results indicate that the diffraction peaks of the Fe-Si-BY amorphous alloy thin strip in the embodiment do not have obvious sharp crystallization peaks, but are typical amorphous structure “bun peak” characteristics, indicating that it is a completely amorphous structure.

[0042] 2. The coercivity and saturation magnetization of the amorphous alloys of Examples 1-5 and Comparative Examples 1-3 were tested.

[0043] The vibration sample magnetometer (VSM) is used to test the sample in the coil. An alternating signal is induced in the detection coil by the vibration of the sample in the coil. The alternating voltage is proportional to the magnetic moment of the sample. The hysteresis loop measured by the VSM is analyzed and the JH curve, coercivity and saturation magnetization are obtained by combining the VSM software.

[0044] The JH curves of the Fe-Si-BY amorphous alloys in Examples 1-5 are as follows: Figure 3 As shown, the results indicate that the Fe-Si-BY amorphous alloy thin strip increases sharply with the increase of magnetic field under low magnetic field and then gradually reaches saturation, indicating that this amorphous alloy exhibits typical soft magnetic properties.

[0045] The JH curves of the amorphous alloys in Comparative Examples 1-3 are as follows: Figure 4 As shown.

[0046] The trend of the effect of different Y contents on the critical thickness of the series alloys is shown in the figure. Figure 5 As shown, the results indicate that in the amorphous alloy series with high iron content, the addition of trace rare earth element Y can significantly enhance the amorphous forming ability of the system, resulting in a significant increase in the critical thickness of the strip, which is conducive to mass production in industrial applications.

[0047] The coercivity and saturation magnetization results of the amorphous alloys in Examples 1-5 and Comparative Examples 1-3 are shown in Table 1: Table 1. Coercivity and saturation magnetization results of amorphous alloys in Examples 1-5 and Comparative Examples 1-3 Amorphous alloy Coercivity (Hc, A / m) Saturation magnetization (Ms, T) Example 1 <![CDATA[Fe 95 Si1B 3.9 AND 0.1 ]]> 4 1.70 Example 2 <![CDATA[Fe 95 Si1B 3.8 AND 0.2 ]]> 3.7 1.73 Example 3 <![CDATA[Fe 95 Si1B 3.7 AND 0.3 ]]> 3 1.71 Example 4 <![CDATA[Fe 95 Si1B 3.6 AND 0.4 ]]> 2.8 1.68 Example 5 <![CDATA[Fe 95 Si1B 3.5 AND 0.5 ]]> 3.2 1.68 Comparative Example 1 <![CDATA[Fe 95 Si1B4]]> 5 1.72 Comparative Example 2 <![CDATA[Fe 95 Si1B 3.3 AND 0.7 ]]> 4.5 1.64 Comparative Example 3 <![CDATA[Fe 95 Si1B3Y1]]> 5.7 1.62 Table 1 shows that the addition of trace amounts of rare earth element Y initially increases and then decreases the saturation magnetization, while significantly reducing the coercivity. Compared to traditional Fe-Si-B amorphous alloys, the Fe-Si-BY amorphous alloy of this invention exhibits higher saturation magnetization, lower coercivity, and superior overall soft magnetic properties. As shown in Comparative Examples 2-3, excessive addition of rare earth element Y can actually cause a dilution effect of the magnetic moment of Fe atoms, worsening the overall soft magnetic properties. Therefore, only trace amounts can provide significant improvement.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A high-performance Fe-Si-BY iron-based amorphous alloy thin strip based on trace yttrium addition, characterized in that, The mass percentage composition of the amorphous alloy ribbon is expressed as Fe. 95 Si1B (4-x) Y x , where x ranges from 0.1 to 0.

5.

2. The Fe-Si-BY iron-based amorphous alloy thin strip according to claim 1, characterized in that, The range of x is: 0.2 ≤ x ≤ 0.

4.

3. The Fe-Si-BY iron-based amorphous alloy thin strip according to any one of claims 1-2, characterized in that, The amorphous alloy ribbon is completely amorphous, and no α-Fe crystalline phase precipitates on its free surface.

4. The Fe-Si-BY iron-based amorphous alloy thin strip according to any one of claims 1-2, characterized in that, The amorphous alloy strip exhibits an amorphous forming capability with a critical thickness of 25 μm to 35 μm.

5. A method for preparing Fe-Si-BY iron-based amorphous alloy thin strips as described in any one of claims 1-2, characterized in that, Includes the following steps: S1. Alloy smelting and ingot preparation: Weigh Fe, Si, B and Y elemental raw materials with a purity of not less than 99.9% according to the designed composition, and place them in the crucible in the order of the lowest melting point at the bottom and the highest melting point at the top. Vacuum up to 3.5×10 -3 After the pressure drops below Pa, a protective gas is introduced until the furnace pressure reaches -0.06 MPa, all raw materials are melted, and after cooling, an alloy ingot is obtained. The alloy ingot is then turned over and melted at least once under magnetic stirring to obtain a uniform alloy ingot. S2. Melt surface treatment: Mechanical removal of oxide layer and impurities from the surface of alloy ingot; S3. Single-roll melt quenching forming: The alloy ingot obtained in step S2 is placed in a single-roll melt quenching device, and a protective gas is introduced into the vacuum environment to a pressure of 400mbar. After the alloy melts, the molten alloy is sprayed onto the surface of the rotating cooling roller and quickly solidified to form an amorphous alloy strip. S4. Annealing treatment: The amorphous alloy strip obtained in step S3 is annealed in a protective atmosphere at 360-400°C for 15 minutes.

6. The method according to claim 5, characterized in that, The Fe, Si, B, and Y elemental raw materials are ultrasonically cleaned sequentially with petroleum ether and anhydrous ethanol before use; the protective gas is high-purity argon with a purity of not less than 99.95 wt%.

7. The method according to claim 5, characterized in that, In step S1, the melting under magnetic stirring is performed 6 times; in step S2, 0.5-1 mm of thickness is removed from the surface of the alloy ingot by mechanical grinding or cutting; in step S3, the linear speed of the copper roller is 38-48 m / s.

8. The application of Fe-Si-BY iron-based amorphous alloy thin strips as described in any one of claims 1-2 in the preparation of soft magnetic materials.

9. The application according to claim 8, characterized in that, The soft magnetic material is used to manufacture magnetic sensor elements, high-efficiency power distribution transformer cores, new energy vehicle drive motor cores, or high-frequency inductor cores.

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