Iron-based amorphous alloy strip and preparation method and application thereof

Abstract

The present invention provides an iron-based amorphous alloy strip having a composition substantially represented by formula (I): FeaBbCcSid (I); wherein 82.0 < = a < = 86.0, 8.5 < = b < = 15.0, 1.6 < = c < = 6.0, 0.4 < = d < = 2.5, a, b, c and d respectively represent the atomic percentage contents of Fe, B, C and Si, a + b + c + d = 100, and basically, the iron-based amorphous alloy does not exclude trace impurities from raw materials or brought in in the processing process. The invention further relates to a method for preparing the iron-based amorphous alloy strip, an iron core comprising the iron-based amorphous alloy strip and application of the iron-based amorphous alloy strip. The combination of high saturation flux density and amorphous forming ability is realized by increasing the Fe element and balancing the content of non-metallic elements, so that the amorphous strip with high saturation flux density and soft magnetic performance is obtained.

Description

Technical Field

[0001] This invention relates to the field of magnetic functional materials, specifically to an iron-based amorphous alloy strip, its preparation method, and its applications. Background Technology

[0002] Energy is a major challenge facing society today, and transformers, as core infrastructure for power transmission, are crucial for energy conservation. Against the backdrop of continuously growing global energy demand and increasingly stringent environmental requirements, the development of low-loss transformer materials and the optimization of transformer design have become research hotspots. Compared to traditional silicon steel, amorphous alloy strips have lower losses and excitation power, and are widely used in transformer cores. In recent years, the design requirements for miniaturization, low cost, and high capacity transformers have urgently necessitated increasing the saturation magnetic induction intensity (Bs) of the amorphous materials used. Increasing the saturation magnetic induction intensity enables high-capacity transformer designs while reducing core volume and lowering other material costs, thereby reducing the overall cost of the transformer. Therefore, amorphous components with high saturation magnetic induction intensity have remained a research focus for researchers in this field.

[0003] The saturation magnetic induction intensity of amorphous materials is mainly determined by the concentration of the average atomic magnetic moment and the strength of interatomic exchange coupling. Increasing the content of ferromagnetic elements (Fe, Co, Ni) is the most effective means to improve the saturation magnetic induction intensity of iron-based amorphous alloys. Although cobalt (Co) has a low atomic magnetic moment, the atomic exchange coupling between Fe and Co is the strongest. Although doping a certain amount of Co into iron-based alloys reduces the average atomic magnetic moment, it increases the overall exchange integral, which can effectively improve the material's Bs. Replacing Fe with Co does not reduce the content of non-metallic elements, therefore it is the best way to improve the Bs of iron-based amorphous alloys. Patent CN100582281C discloses an Fe-B-Si amorphous alloy strip containing an appropriate amount of N, and consequently, appropriate amounts of C and P. Fe content below 15% can be replaced with one or more elements selected from Co, Ni, or Cr below 5%. In Example 4 of this patent, replacing 2 at.% Fe with Co increased Bs from 1.55T to 1.78T. However, Co is an expensive metallic element, and its high material cost severely restricts the mass production of Co-containing alloys. Therefore, the use of Fe-Co amorphous alloys is limited to some applications requiring high quality and small quantities.

[0004] Increasing the Fe content in iron-based amorphous alloys is also a common method to enhance amorphous boron (Bs). Unlike replacing Fe with Co, increasing the Fe content means reducing the content of non-metallic elements. Non-metallic elements play a major role in enhancing the amorphous forming ability of alloys; reducing their content weakens the amorphous forming ability to the point that fully amorphous alloys cannot be formed, and the soft magnetic properties will be severely deteriorated. Improving the amorphous forming ability of alloys without increasing the non-metallic element content seems to be the only solution, one approach being to find stronger amorphous forming elements. In this regard, Japanese Patent JPS57-185957 proposes a method of replacing B in traditional amorphous alloys with P at an atomic percentage of 1-10%; it is believed that increasing the P content can enhance the ability to form an amorphous state. CN1124362C also mentions adding a certain amount of phosphorus (P) to FeSiBC alloy to prepare amorphous materials, thereby improving the alloy's amorphous forming ability. The amorphous alloy in this patent, by atomic percentage, comprises: 82≤Fe≤90, 2≤Si≤4, 5≤B≤16, 0.02≤C≤4, 0.2≤P≤12, and the Bs value of the alloy after annealing is as high as 1.74T. The P-containing alloy in its examples has annealing advantages; the addition of P can effectively improve the annealing window of the amorphous core. However, neither patent mentions an effective method for adding P or the requirements for raw materials. Low-quality P alloys are inexpensive but contain various high-melting-point alloying elements, such as V, Ti, and Al. These substances form high-melting-point oxides during smelting, inducing crystallization on the strip surface, which is detrimental to the smooth production of the strip. High-quality P alloys, on the other hand, have a very complex smelting process, making industrial production difficult. These two patents demonstrate the possibility of adding P to highly saturated amorphous materials based on compositional experiments, but they do not provide a reasonable explanation for industrial production. Furthermore... Neither of these two patents specifically mentions the annealing process for phosphorus-containing amorphous materials. P-containing amorphous ribbons are highly susceptible to oxidation, requiring stringent oxygen content control during annealing. Experimental studies show that under unprotected atmospheres, with a phosphorus atomic percentage exceeding 1% and an annealing temperature of 200℃, the annealed ribbon surface exhibits a light blue oxide color. The higher the phosphorus content and the higher the annealing temperature, the more severe the oxidation. Normal annealing temperatures exceed 200℃, at which point severely oxidized ribbon surfaces exhibit a deep blue or purple surface morphology, resulting in abnormally high core losses. In conclusion, the stringent annealing requirements severely restrict the industrial production of this type of alloy.

[0005] In summary, researchers have been dedicated to improving amorphous Bs and have achieved remarkable results, but very few researchers have been able to balance the cost of materials with the process issues in industrial production.

[0006] All patent and non-patent literature listed in this article is incorporated herein in its entirety for reference.

[0007] It should be noted that the information disclosed in the foregoing background section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0008] One object of the present invention is to provide an iron-based amorphous alloy strip that simultaneously possesses high saturation magnetic induction intensity and excellent soft magnetic properties (low core loss and excitation).

[0009] Another object of the present invention is to provide a method for preparing iron-based amorphous alloy strips, wherein the above-mentioned iron-based amorphous alloy strips can be prepared with low complexity and low raw material cost.

[0010] To achieve the above objectives, the technical solution adopted by the present invention includes: A first aspect of the present invention provides an iron-based amorphous alloy strip having essentially a composition represented by formula (I). Fe a B b C c Si d (I); Wherein, 82.0≤a≤86.0, 8.5≤b≤15.0, 1.6≤c≤6.0, 0.4≤d≤2.5, where a, b, c, and d represent the atomic percentage content of Fe, B, C, and Si, respectively, and a+b+c+d=100. The phrase “basically” indicates that the iron-based amorphous alloy does not exclude trace impurities introduced from the raw materials or processing.

[0011] Surprisingly, by appropriately selecting the above-mentioned components, it has been found that iron-based amorphous alloys possessing both high saturation magnetic induction and excellent soft magnetic properties can be prepared. These iron-based amorphous alloys are four-component alloys with a simple composition, do not use expensive or scarce metallic or non-metallic elements, and are cost-effective. The simple composition also avoids complex batching procedures and potential inhomogeneity problems, making them suitable for large-scale industrial applications. These iron-based amorphous alloys can be manufactured using a simple preparation process, can be easily produced as strips under unprotected production conditions, and can be used to manufacture cores, such as transformer cores.

[0012] The second aspect of the present invention provides a method for preparing the above-mentioned iron-based amorphous alloy strip, comprising the following steps: S1, batching the raw materials according to the atomic percentage of the composition represented by formula (I); S2, melting the batched raw materials; and S3, subjecting the melted material to single-roll rapid quenching to obtain the iron-based amorphous alloy strip.

[0013] A third aspect of the present invention provides an iron core made by winding and annealing the aforementioned iron-based amorphous alloy strip.

[0014] A fourth aspect of the present invention provides the use of the above-mentioned iron-based amorphous alloy strip for the preparation of iron cores.

[0015] This invention balances the elemental proportions of FeSiBC alloys to successfully prepare amorphous alloys with high saturation magnetic induction intensity while maintaining excellent amorphous formation capability. It can be successfully fabricated into strips and used to manufacture transformer cores under unprotected production conditions. This material exhibits high saturation magnetic induction intensity, excellent soft magnetic properties, mass production capability, and excellent product processability. Attached Figure Description

[0016] Figure 1 A VSM test diagram of an iron-based amorphous alloy strip according to an embodiment of the present invention is shown.

[0017] Figure 2 XRD patterns of several iron-based amorphous alloy strips according to embodiments of the present invention are shown.

[0018] Figure 3 The unit mass loss of iron cores prepared from iron-based amorphous alloy strips according to Embodiments 1, 2 and Comparative Example 4 of the present invention is shown under different magnetic flux densities at 50 Hz.

[0019] Figure 4 The excitation of iron cores prepared from iron-based amorphous alloy strips according to Embodiments 1, 2 and Comparative Example 4 under different magnetic flux densities at 50 Hz is shown. Detailed Implementation

[0020] Exemplary embodiments are provided to make this disclosure thorough and to fully communicate its scope to those skilled in the art. Numerous specific details, such as examples of specific compositions, components, apparatuses, and methods, are set forth to provide a full understanding of embodiments of this disclosure. It will be apparent to those skilled in the art that the specific details are not required, and that exemplary embodiments may be embodied in many different forms, none of which should be considered as limiting the scope of this disclosure. In some exemplary embodiments, well-known methods, well-known apparatus structures, and well-known techniques are not described in detail.

[0021] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "a," "an," and "the" as used herein are intended to include the plural forms as well. The terms "comprising," "including," "containing," and "having" are inclusive and thus describe the presence of the stated features, elements, compositions, steps, integers, operations, and / or components, but do not exclude the presence or inclusion of one or more other features, integers, steps, operations, elements, components, and / or sets thereof. Although the open-ended term "comprising" should be understood as a non-limiting term used to describe and claim the various embodiments described herein, in some respects it may instead be understood as a more restrictive and limiting term, such as "consisting of" or "essentially composed of." Thus, for any given embodiment describing a composition, material, component, element, feature, integer, operation, and / or process step, this disclosure also particularly includes embodiments consisting of or substantially consisting of such compositions, materials, components, elements, features, integers, operations, and / or process steps. In the case of "consisting of," the alternative embodiments exclude any additional compositions, materials, components, elements, features, integers, operations, and / or process steps. In the case of "essentially composed of," any additional compositions, materials, components, elements, features, integers, operations, and / or process steps that substantially affect the essential and novel characteristics are excluded from such embodiments. However, any compositions, materials, components, elements, features, integers, operations, and / or process steps that do not substantially affect the essential and novel characteristics may be included in the embodiments.

[0022] Any methods, procedures, and operations described herein should not be construed as necessarily requiring them to be performed in the specific order discussed or shown, unless explicitly stated otherwise. It should also be understood that additional or alternative steps may be used unless otherwise stated.

[0023] Any specific numerical values ​​disclosed herein (including the endpoints of numerical ranges) are not limited to their exact values, but should be understood to also include values ​​close to the exact value, such as all possible values ​​within ±5% of the exact value. Furthermore, with respect to the disclosed numerical ranges, one or more new numerical ranges can be obtained by arbitrarily combining the endpoint values ​​of the range, the endpoint values ​​with specific point values ​​within the range, and the specific point values ​​themselves; these new numerical ranges should also be considered as specifically disclosed herein.

[0024] Unless otherwise stated, the technical solutions, technical features or numerical ranges disclosed in one aspect of this document for one or more elements shall also apply to the same or corresponding elements in other aspects, unless those skilled in the art recognize that this is obviously unreasonable.

[0025] In this application, except where expressly stated, any matters or issues not mentioned herein shall be directly applicable to those known in the art without any modification. Furthermore, any implementation described herein may be freely combined with one or more other implementations described herein, and the resulting technical solutions or concepts shall be considered part of the original disclosure or original record of this application, and should not be regarded as new content not disclosed or anticipated herein, unless those skilled in the art consider the combination to be clearly unreasonable.

[0026] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. A technical feature described as preferred in one embodiment can be combined with a technical feature described as preferred or broader in another embodiment. The technical solutions obtained after various combinations should be considered as specifically disclosed herein. To avoid unnecessary repetition, this application will not describe the various possible combinations separately.

[0027] Unless otherwise stated, the terms used herein have the same meaning as commonly understood by those skilled in the art, and if a term is defined herein and its definition differs from the common understanding in the art, the definition herein shall prevail.

[0028] First aspect A first aspect of the present invention provides an iron-based amorphous alloy strip having essentially a composition represented by formula (I). Fe a B b C c Si d (I); Wherein, 82.0≤a≤86.0, 8.5≤b≤15.0, 1.6≤c≤6.0, 0.4≤d≤2.5, where a, b, c, and d represent the atomic percentage content of Fe, B, C, and Si, respectively, and a+b+c+d=100. The phrase “basically” indicates that the iron-based amorphous alloy does not exclude trace impurities introduced from the raw materials or processing.

[0029] In this disclosure, "substantially" is intended to mean excluding from the modified alloy composition any additional components or elements that substantially affect the basic and novel properties, but any components or elements that do not substantially affect the basic and novel properties may be included in the alloy composition.

[0030] Surprisingly, by appropriately selecting the above composition, it has been found that iron-based amorphous alloys possessing both high saturation magnetic induction and excellent soft magnetic properties can be prepared. These iron-based amorphous alloys are four-component alloys with a simple composition, do not use expensive and scarce alloying elements, and are cost-effective. Furthermore, the simple component mixing avoids complex batching procedures and potential inhomogeneity problems, making them suitable for large-scale industrial applications. The aforementioned iron-based amorphous alloys can be prepared using simple processes, can be easily fabricated into strips under unprotected production conditions, and can be used to manufacture cores, such as transformer cores.

[0031] According to a preferred aspect, the composition of the iron-based amorphous alloy of the present invention satisfies formula (II): 0.12c - 0.1 ≤ d ≤ 0.5c + 0.7 (II).

[0032] It has been found that when the composition of the iron-based amorphous alloy further satisfies formula (II), the prepared iron-based amorphous alloy exhibits higher saturation magnetic induction and excellent soft magnetic properties. On the other hand, the iron-based amorphous alloy possesses high mechanical ductility and improved amorphous forming ability, which is beneficial for successful ribbon formation and the preparation of wide iron-based amorphous alloy ribbons.

[0033] According to a preferred aspect, the composition of the iron-based amorphous alloy of the present invention satisfies formula (III): 13≤b+c≤16 (III).

[0034] It has been found that when the composition of the iron-based amorphous alloy further satisfies formula (III), the prepared iron-based amorphous alloy has a higher saturation magnetic induction intensity.

[0035] According to a preferred aspect of the invention, the saturation magnetic induction intensity of the iron-based amorphous alloy strip is ≥1.62T. According to some embodiments of the invention, the saturation magnetic induction intensity of the iron-based amorphous alloy strip is 1.62-1.70T, for example, 1.62, 1.63, 1.64, 1.65, 1.66, 1.67, 1.68, 1.69, and 1.70T, and any two of these values, preferably 1.64-1.70T, or even 1.66-1.70T.

[0036] As a ferromagnetic element, Fe's atomic magnetic moments and magnetic interactions are the source of high saturation magnetic induction. Increasing the Fe content increases the sum of atomic magnetic moments, with the maximum saturation magnetic induction achieved at approximately 86 atomic percent Fe. However, increasing Fe weakens the material's amorphous forming ability and thermal stability, leading to crystallization of the amorphous ribbon during ribbon fabrication or subsequent processing. The chosen atomic percentage of Fe is 82.0 ≤ a ≤ 86.0. According to a preferred aspect of the invention, the atomic percentage of Fe in formula (I) is, for example, 82.0, 82.5, 83.0, 83.5, 84.0, 84.5, 85.0, 85.5, or 86.0, preferably satisfying 82.5 ≤ a ≤ 85.0, and more preferably satisfying 83.0 ≤ a ≤ 85.0.

[0037] Metalloids are important elements for improving the amorphous forming ability of Fe-based amorphous materials, but their addition weakens Bs, so their content needs to be controlled. Metalloids include boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te).

[0038] Boron (B) is one of the most effective amorphous forming elements in iron-based amorphous alloys. Within a certain range, the higher the B content, the stronger the amorphous forming ability. If the B content is too low, it becomes more difficult to stably form amorphous materials. Based on actual production conditions and the basic requirement of high Fe content for highly saturated materials, the atomic percentage content of B in iron-based amorphous alloys is, for example, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, and any two of these values. Preferably, the atomic percentage content of B in formula (I) satisfies 11.0 ≤ b ≤ 14.0.

[0039] Carbon (C) is also an effective amorphous forming element, and increasing the C content can improve the amorphous forming ability of the material. In industrial production, it is extremely difficult to add a large amount of C without introducing impurities such as O, Mn, P, and S. Increased B and C content also reduces the viscosity and activity of molten steel, posing a significant challenge to impurity removal and strip forming during the smelting process. In this disclosure, strip forming smoothness refers to the stable and continuous strip forming state during single-roll rapid quenching, from melt injection, stable formation of the molten pool, continuous solidification, to the smooth peeling of the strip from the roll surface without interruption or fatal defects. It is an important indicator for measuring process stability and strip quality. The atomic percentage content of C in iron-based amorphous alloys is, for example, 1.6, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, and any two of these values ​​within a range. According to a preferred aspect of the present invention, the atomic percentage content of C in formula (I) satisfies 2.0≤c≤5.0, more preferably 3.0≤c≤5.0, and even more preferably 3.5≤c≤5.0.

[0040] Si is an amorphous forming element that improves the formability and thermal stability of amorphous ribbons. Si has a relatively large atomic radius and substitutes for Fe, which reduces the Fe-Fe atomic spacing, decreasing the exchange integral between Fe atoms and weakening Bs. To obtain high Bs and amorphous forming ability, the Si content should be low, with an atomic percentage of Si of 0.4 ≤ d ≤ 2.5, for example, 0.4, 0.5, 1.0, 1.5, 2.0, 2.5, and any two of these values. A lower Si content reduces the viscosity of the alloy melt, improves its fluidity, and reduces the surface tension of the molten pool, making it difficult to form a stable molten pool and resulting in poor ribbon production. Conversely, an excessively high Si content makes it impossible to obtain amorphous ribbons with higher Fe content and higher Bs. According to a preferred aspect of the invention, the atomic percentage of Si in formula (I) satisfies 0.5 ≤ d ≤ 1.5.

[0041] According to a preferred embodiment, the atomic percentage content in formula (I) satisfies: 82.5≤a≤85.0; 11.0≤b≤14.0; 2.0≤c≤5.0; 0.5≤d≤1.5. According to another preferred embodiment, the atomic percentage content in formula (I) satisfies: 83.0≤a≤85.0; 11.0≤b≤14.0; 3.5≤c≤5.0; 0.5≤d≤1.5.

[0042] When the composition of the iron-based amorphous alloy of the present invention is within the above-mentioned preferred range, its amorphous forming ability is improved, and the prepared iron-based amorphous alloy strip has high saturation magnetic induction intensity and excellent soft magnetic properties.

[0043] The iron-based amorphous alloy according to the present invention advantageously does not contain intentionally added cobalt. Cobalt, as a strategic metal, is expensive, costing 50-80 times more than iron, and its price fluctuates significantly, driven by demand from new energy vehicle batteries and aerospace applications. Furthermore, global cobalt reserves are concentrated (the Democratic Republic of Congo accounts for 70%), making the supply chain vulnerable to disruptions. By eliminating cobalt from the iron-based amorphous alloy, raw material costs are advantageously reduced by 20%-40%, the supply chain is stabilized, and the risk of price fluctuations in scarce resources is mitigated. Advantageously, the atomic percentage content of cobalt in the iron-based amorphous alloy of the present invention is ≤0.5%, i.e., 0-0.5%, preferably ≤0.2%, and more advantageously less than ≤0.1%.

[0044] The iron-based amorphous alloy according to the invention advantageously does not contain intentionally added copper (Cu). Copper costs approximately 10 times more than iron, and avoiding its addition advantageously reduces the cost of the iron-based amorphous alloy. Avoiding copper addition also prevents the possibility of copper segregation in the iron-based amorphous alloy, improving structural uniformity and machinability. Advantageously, the atomic percentage content of copper in the iron-based amorphous alloy of the invention is ≤0.3, i.e., 0-0.3, preferably ≤0.2, and more advantageously less than ≤0.1.

[0045] The iron-based amorphous alloy according to the invention advantageously does not contain intentionally added phosphorus. The introduction of low-quality phosphorus introduces more difficult-to-handle impurities, while the purification cost of high-quality phosphorus is high. Although phosphorus has a relatively high amorphous forming ability, it is difficult to process. Phosphorus in iron-based amorphous alloys containing about 1 at% phosphorus is easily oxidized during processing; severely oxidized bands exhibit a deep blue or purple surface morphology, resulting in abnormally high core losses. Therefore, the use of phosphorus necessitates stringent requirements on the oxygen content of the atmosphere used during annealing. Advantageously, the atomic percentage content of phosphorus in the iron-based amorphous alloy of the invention is ≤0.3, i.e., 0-0.3, preferably ≤0.2, and more advantageously less than ≤0.1.

[0046] The iron-based amorphous alloy according to the invention advantageously does not contain intentionally added rare earth elements (Re). Rare earth elements are expensive, and since there is no need to add rare earth elements, the cost of the iron-based amorphous alloy according to the invention is further reduced, and the deterioration of ductility caused by the introduction of rare earth elements is avoided, thus reducing the scrap rate.

[0047] The iron-based amorphous alloy according to the present invention has a simple composition, making it easy to produce industrially. Furthermore, the simplicity of the composition reduces recycling difficulty and improves resource recycling efficiency. During recycling, too many components will necessitate additional purification processes. Moreover, some high-melting-point components will increase the melting temperature, making recycling difficult.

[0048] According to a preferred aspect of the invention, the amorphous alloy in the iron-based amorphous alloy strip is in a completely amorphous state. In the context of this invention, a completely amorphous state indicates a crystal content of less than 1 wt%, i.e., 0-1 wt%, preferably less than 0.5 wt%, and more preferably less than 0.1 wt%. In the context of this invention, amorphism is determined by XRD. Amorphous alloy strips in a completely amorphous state result in lower losses and excitation power.

[0049] According to a preferred aspect of the invention, the iron-based amorphous alloy strip has a maximum amorphous thickness of at least 30 μm, for example, 30 μm, 32 μm, 34 μm, 35 μm, 36 μm, 38 μm, 40 μm, 43 μm, 45 μm, 48 μm, 50 μm, 53 μm, 55 μm, and any two of these values, for example, 30-50 μm. In this disclosure, the maximum amorphous thickness (also referred to as the critical thickness in some cases) refers to the maximum thickness at which the strip can just achieve a completely amorphous structure under a given alloy composition and process conditions (in this invention, melt spin quenching, preferably single-roll rapid quenching)... A larger maximum amorphous thickness indicates a higher amorphous forming ability of the amorphous alloy, resulting in thicker strips and higher magnetic flux per unit volume of the core, which is beneficial for high energy density design. Finished product thickness refers to the thickness of the amorphous strip produced stably in industrial production. Typically, the finished product thickness of iron-based amorphous strips is 24-28 μm. The finished thickness of the iron-based amorphous alloy material according to the present invention can reach 30-35 μm, and more preferably 32±2 μm.

[0050] According to a preferred aspect of the invention, the iron-based amorphous alloy strip has a width of ≥30mm, preferably ≥60mm, and more preferably 100~300mm.

[0051] Second aspect A second aspect of the present invention provides a method for preparing the above-described iron-based amorphous alloy strip, comprising the following steps: S1. Prepare ingredients according to the atomic percentages expressed in formula (I). S2. Melt the batched raw materials. S3. The molten material is subjected to melt spin quenching, preferably single-roller rapid quenching, to obtain iron-based amorphous alloy strip.

[0052] The method of melting the alloy raw materials in step S2 is not particularly limited in this invention. It can be carried out in various ways known to those skilled in the art, such as induction furnace (preferably medium frequency induction furnace), electric arc furnace, resistance furnace, and induction crucible furnace.

[0053] The smelting in step S2 of this invention does not require a protective atmosphere (e.g., nitrogen, argon, etc.), significantly reducing the difficulty of industrial operation. In an advantageous embodiment, step S2 can be performed under atmospheric conditions.

[0054] According to a preferred aspect, step S2 of the method according to the invention includes the following steps: S21, heating and melting the batched raw materials; S22, holding at 1450-1500°C to remove impurities; and S23, quenching at 1350-1400°C.

[0055] The industrial raw materials required for smelting are pure Fe, pure Si, pure C, and Fe-B alloys. After weighing, the raw materials are added to a furnace (e.g., a medium-frequency induction furnace) according to their mass ratio and heated to melt. After complete melting, the mixture is held at 1450-1500℃ to remove impurities. The holding time is 30 min to 2 h, for example, 30 min, 40 min, 50 min, 60 min, 70 min, 1.5 h, 2 h, or any combination of these values. After holding, the slag on the surface of the molten steel is removed, and the holding temperature is lowered to 1350-1400℃ for killing. The killing time is not particularly limited; its purpose is to ensure a homogeneous composition and prevent segregation in the molten steel. The killing time is 30 min to 3 h, for example, 30 min, 40 min, 50 min, 60 min, 2 h, 3 h, or even longer, or any combination of these values.

[0056] According to a preferred aspect, in step S3 of the method according to the invention, a cooling roller is used for melt swirl quenching, wherein the cooling roller is selected from molybdenum cooling rollers, copper cooling rollers, molybdenum alloy cooling rollers, copper alloy cooling rollers, or combinations thereof, and the rotation speed is 300-900 rpm, preferably 600-900 rpm. Melt swirl quenching methods include single-roller rapid quenching, double-roller rapid quenching, and centrifugal swirl quenching, with single-roller rapid quenching being preferred.

[0057] In step S3, the melt from step S2 is poured at 1400-1500°C onto the surface of a high-speed rotating cooling roller, causing the melt to rapidly cool and solidify into an amorphous ribbon. The equipment used for spraying the melt is not particularly limited; for example, it can be a spray bag, nozzle, etc. The diameter of the cooling roller is, for example, 680-1500 mm, and the rotation speed is, for example, 300-900 rpm, preferably 600-900 rpm. The material of the cooling roller in step S3 is not particularly limited; for example, it can be molybdenum and molybdenum alloys, copper and copper alloys, or combinations thereof.

[0058] The preparation method according to the present invention allows for the successful preparation of iron-based amorphous alloy strips with low process complexity and low process severity.

[0059] Unless otherwise stated, the technical solutions, technical features, or numerical ranges disclosed in one aspect of this document with respect to one or more elements are also applicable to the same or corresponding elements in other aspects, unless those skilled in the art recognize that this is obviously unreasonable. For example, the parameters and ranges disclosed in the first aspect for iron-based amorphous alloy strips are correspondingly applicable to iron-based amorphous alloy strips prepared in the second aspect of this invention.

[0060] Third aspect According to a third aspect of the invention, a core is provided which is made by stacking / winding and annealing iron-based amorphous alloy strips as described above.

[0061] In the context of this disclosure, annealing includes, for example, annealing in a periodic furnace under appropriate magnetic field heat treatment conditions (300-360°C, holding for 30-150 min). The heat treatment process is carried out, for example, in an atmosphere protected by an inert gas (e.g., helium, argon).

[0062] According to a preferred aspect of the invention, the core has the following characteristics under 50Hz and 1.40T conditions: core loss ≤0.13W / kg, preferably ≤0.12W / kg, for example, 0.13W / kg, 0.12W / kg, 0.11W / kg, 0.10W / kg, 0.09W / kg, 0.08W / kg, 0.07W / kg, 0.06W / kg, 0.05W / kg, and any two of these values; and excitation ≤0.3VA / kg. Preferably ≤0.25VA / kg, more preferably ≤0.2VA / kg, for example 0.3VA / kg, 0.25VA / kg, 0.2VA / kg, 0.19VA / kg, 0.18VA / kg, 0.17VA / kg, 0.16VA / kg, 0.15VA / kg, 0.14VA / kg, 0.13VA / kg, 0.12VA / kg, 0.11VA / kg, 0.10VA / kg, and any two of these values.

[0063] According to a preferred aspect of the invention, the core has a core loss of ≤0.15W / kg, preferably ≤0.14W / kg, for example, 0.15W / kg, 0.14W / kg, 0.13W / kg, 0.12W / kg, 0.11W / kg, 0.10W / kg, 0.09W / kg, 0.08W / kg, 0.07W / kg, 0.06W / kg, 0.05W / kg, and these values, under conditions of 50Hz and 1.50T. The range formed by any two of these values, where excitation is ≤0.5VA / kg, preferably ≤0.4VA / kg, such as 0.5VA / kg, 0.45VA / kg, 0.4VA / kg, 0.39VA / kg, 0.38VA / kg, 0.37VA / kg, 0.36VA / kg, 0.35VA / kg, 0.32VA / kg, 0.30VA / kg, 0.25VA / kg, and any two of these values.

[0064] According to a preferred aspect of the invention, the core has a core loss of ≤0.19W / kg, preferably ≤0.17W / kg, for example 0.19W / kg, 0.17W / kg, 0.16W / kg, 0.15W / kg, 0.14W / kg, 0.13W / kg, 0.12W / kg, 0.11W / kg, 0.10W / kg, 0.09W / kg, 0.08W / kg, 0.07W / kg, 0.06W / kg, under conditions of 50Hz and 1.60T. The range of values ​​0.05W / kg and any two of these values, with excitation ≤1.1VA / kg, preferably ≤0.9VA / kg, for example ≤1.1VA / kg, 1.0VA / kg, 0.9VA / kg, 0.85VA / kg, 0.8VA / kg, 0.75VA / kg, 0.7VA / kg, 0.65VA / kg, 0.62VA / kg, 0.6VA / kg, 0.5VA / kg and any two of these values.

[0065] These magnetic materials possess high magnetic softness, meaning they are easily magnetized. This results in low magnetic losses in magnetic devices using these materials. Low iron losses mean less wasted electrical energy during operation, improving energy efficiency. Low excitation means less reactive power is required to establish the magnetic field, reducing reactive power losses. When applied to transformers, the synergistic reduction in iron losses and excitation significantly lowers no-load losses and no-load current, improving energy efficiency. When applied to motors, low iron losses reduce heat generation, and low excitation improves the power factor, synergistically enhancing motor efficiency.

[0066] Fourth aspect The fourth aspect of the present invention provides the use of the iron-based amorphous alloy strip described above for the preparation of iron cores, particularly for the cores of transformers, inductors, generators, motors, and inverters. Example

[0067] General preparation process The iron-based amorphous alloy strips in the embodiments and comparative examples (excluding commercially available products) of this invention are prepared using a melt spin-quenching method. Specifically, the alloy of the stated composition is melted in an atmospheric environment using a medium-frequency induction furnace. The solution is then sprayed onto the surface of a high-speed rotating cooling roller through a spraying ladle, nozzle, or other device, causing the melt to rapidly cool and solidify into an amorphous strip. To ensure cooling capacity, copper alloy cooling rollers with a diameter of 680-1500 mm are used, with a rotation speed of 300-900 rpm. All the resulting strips have a width of 30 mm, and their thicknesses are listed in Table 1 below.

[0068] Evaluation of saturation magnetic induction, soft magnetic properties, and amorphous forming ability The amorphism of the prepared strips of different thicknesses was measured by X-ray diffraction (XRD). The XRD used a graphite monochromator with an X-ray wavelength (Cu Kα), a tube voltage of 40 kV, a tube current of 30 mA, a test range of 30–70°, a step size of 0.02°, and a scan speed of 6° / min. In this application, the amorphous alloy strip can be determined by XRD spectra. If its characteristic spectrum shows a broad diffraction peak (also known as a "bun peak") at 2θ = 40–50°, without any sharp characteristic peaks, it can be determined that the strip has a completely amorphous structure.

[0069] The saturation magnetic induction intensity was measured using a vibrating sample magnetometer (VSM) at a magnetic field strength of 8000 Oe. The VSM was a Lake Shore 8604 model, with a sensitivity of 33 nemu and a magnetic field resolution of 1 mOe. The standard samples used for testing were either spheres with a diameter of 3.0 mm or discs with a diameter of 3.2 mm. Due to the thinness of the amorphous ribbon, discs were used for sample preparation. The amorphous ribbon was punched into discs with a diameter of 3.2 mm, ensuring no notches or wrinkles at the edges that could exert stress on the sample. The disc samples were weighed (using a weighing balance with a testing accuracy of not less than 0.01 mg), and the average value was taken as the sample mass after five consecutive measurements with a mass error of less than 1%. The VSM was first calibrated using a nickel sheet of the same size before testing the required samples. The M (emu / g) obtained after the test was calculated using the formula... The Bs of the sample were calculated.

[0070] The amorphous forming capability is expressed as the maximum thickness that prevents the alloy from crystallizing; the latter is also called the maximum amorphous thickness. The maximum amorphous thickness is the maximum thickness that does not cause crystallization peaks in the sample. Specifically, it is determined by randomly selecting 5 points on the sample for XRD testing, measuring their thickness, and taking the average value. The thickness range must be ≤2μm.

[0071] The amorphous ribbon samples prepared according to the examples and comparative examples were wound into sample rings with a thickness of 2 mm and an inner diameter of 51 mm. Stress-relief annealing was performed using an amorphous iron core annealing furnace for motors from Shanghai Zhendong Engineering Equipment Complete Set Research Institute under appropriate heat treatment conditions (300-360℃, holding for 30-150 min). The heat treatment process was carried out in an argon-protected atmosphere, with a magnetic field of 1200 A / m applied along the length of the ribbon. The unit mass loss and excitation power of the heat-treated sample rings were tested using a TS1300 AC / DC magnetic measurement system for electrical steel from Tianheng Measurement & Control, under test conditions of 1.35T and a frequency of 50Hz.

[0072] Table 1 summarizes the composition of the iron-based amorphous alloys in each embodiment and comparative example, as well as the saturation magnetic induction, maximum amorphous thickness, iron loss per unit mass, and excitation measured using the above methods. VSM test plots and XRD test results are shown in... Figure 1 Among them, Comparative Example 4 uses amorphous ribbon with a high Bs content of 1.60T or higher, which is the mainstream material on the market.

[0073] Table 1. Compositions within the scope of this invention, their Bs, soft magnetic properties, and maximum amorphous thickness.

[0074] Comparative Example 1, without any added Si, exhibited high steel activity during smelting, generating significant amounts of smoke and dust, with sparks splashing from the steel surface. Due to the low B content, stable amorphous ribbon could not be formed under the current experimental conditions. Comparative Example 2, by reducing the Fe content, successfully produced an amorphous ribbon. The Bs content was slightly higher than in the commercial comparative example, at 1.64T. The maximum amorphous thickness of the ribbon was only 28 μm. Furthermore, even with inert gas protection during heat treatment, strong surface oxidation (blue-purple) still occurred. This was attributed to two factors: firstly, the high Fe content facilitated oxidation; and secondly, the inventors discovered that the lack of Si further contributed to the ribbon's susceptibility to oxidation. Surface oxidation resulted in poor soft magnetic properties, with iron loss > 0.8 W / kg and excitation > 2 VA / kg at 1.35 T / 50 Hz. Comparative Example 3 was similar to Example 1, successfully producing a ribbon after reducing the Fe content. However, the ribbon had already crystallized, leading to severe deterioration of soft magnetic properties, making it impossible to detect actual losses and excitation data. The maximum amorphous thickness in Comparative Example 3 did not exceed 23 μm, further indicating relatively poor amorphous formation capability. Example 1 contains 0.9% Si, 11.6% B, and 4.1% C. By balancing the proportions of non-metallic elements, Example 1 exhibits both good amorphous forming ability (maximum amorphous thickness of 49 μm) and high saturation magnetic induction (Bs = 1.67 T). No significant strip oxidation was observed in the sample of Example 1 during heat treatment. After heat treatment, the iron loss of the ring at 1.35 T / 50 Hz was 0.125 W / kg, and the excitation was 0.153 VA / kg, lower than that of the commercially available comparative example 4.

[0075] Compared to Example 1, Example 2 reduced the proportion of boron (B) and increased the content of carbon (C) and silicon (Si), while maintaining the same Fe content as in Example 1. The maximum amorphous thickness was 37 μm, and the Bs content was slightly reduced to 1.66 T. No process problems or abnormalities were found during the ribbon fabrication and heat treatment. After appropriate magnetic field heat treatment, the iron loss of the ring was 0.173 W / kg and the excitation was 0.213 VA / kg under conditions of 1.35 T / 50 Hz. In Examples 3-10, the Si content was gradually increased to 3%. The increased amorphous forming ability balanced the content of other elements, such as Fe (83.5-84.5%), B (11-12%), and C (1-3.2%), but no superior results were achieved. The Bs content was 1.62-1.67 T.

[0076] Comparative Example 5, containing 3% phosphorus, showed no obvious abnormalities in the tape-making process, successfully producing a high-quality tape which was then wound into a sample ring. During heat treatment, the furnace was filled with argon gas at a pressure of 0.4 MPa. After heat treatment under micro-oxygen conditions, the surface of Comparative Example 5 turned bluish-purple, and tests revealed abnormally high losses and excitation. Therefore, phosphorus-containing materials require stringent heat treatment conditions, which is unfavorable for engineering applications.

[0077] Analysis of the above results shows that in the FeBCSi system, reducing the Si content to below 1.5% and containing more than 3.5% C helps to further improve Bs while maintaining excellent soft magnetic properties. To obtain good amorphous forming ability, the B content is preferably above 10%; the Fe content is preferably not less than 82.5% to maintain a high total atomic magnetic moment.

[0078] Iron core preparation and product performance evaluation Based on the saturation magnetic flux density and magnetic properties of the samples, two components, Example 1 and Example 2, were selected. Under actual production conditions, amorphous ribbons with a width of 170 mm were produced and fabricated into planar cores. The core fabrication process is as follows: The finished ribbons were cut transversely into different lengths according to the core's dimensions. With the template in place, the lengths of each group of ribbons were matched and shaped to the required planar core shape. A steel strip was used to fix the shape. After fabrication, stress-relief annealing was performed in an annealing furnace at 280-360℃ for 120-360 min. After annealing, the stress generated during annealing was removed, and the core shape was cured with epoxy resin. The template and steel strip were then removed. The planar core fabrication was complete.

[0079] Table 2 shows the magnetic properties of the planar iron core measured at a frequency of 50 Hz and under different magnetic flux densities. Compared to the commercial comparative example, Examples 1 and 2 exhibit higher losses at low magnetic flux densities. For instance, at 1.3 T / 50 Hz, the losses of Examples 1 and 2 are increased by 5% and 12%, respectively, compared to Comparative Example 4. With increasing magnetic flux density, the loss growth rate of the examples is lower. Example 1 has a loss of 0.109 W / kg at 1.5 T / 50 Hz, which is 8% lower than that of the commercial comparative example 4; Example 2 is comparable to the commercial comparative example 4, at 0.118 W / kg. Examples 1 and 2 have lower excitation power, at 1.5 T / 50 Hz, which are 0.296 and 0.370 VA / kg, respectively, which are 46% and 32% lower than that of Comparative Example 4, respectively. At a higher frequency of 1.6 T / 50 Hz, Example 1 achieves a low loss of 0.141 W / kg and a low excitation of 0.633 VA / kg.

[0080] Table 2. Unit mass loss of planar iron core under different magnetic flux densities at 50Hz Magnetic flux density (T) 1.2 1.3 1.35 1.4 1.45 1.5 1.55 1.6 1.65 Example 1 0.067 0.078 0.084 0.091 0.099 0.109 0.123 0.141 0.168 Example 2 0.070 0.083 0.090 0.095 0.106 0.118 0.133 0.153 0.188 Comparative Example 4 0.061 0.074 0.081 0.089 0.102 0.118 0.139 0.177 ×

[0081] Table 3. Unit mass excitation of planar iron cores under different magnetic flux densities at 50Hz Magnetic flux density (T) 1.2 1.3 1.35 1.4 1.45 1.5 1.55 1.6 1.65 Example 1 0.087 0.116 0.141 0.170 0.214 0.296 0.426 0.633 0.927 Example 2 0.104 0.129 0.158 0.199 0.268 0.370 0.524 0.777 1.172 Comparative Example 4 0.122 0.181 0.215 0.288 0.390 0.547 0.769 1.166 ×

[0082] In summary, by adjusting the content of non-metallic elements in the iron-based amorphous alloy, an amorphous alloy with a saturation magnetic induction intensity as high as 1.67T was successfully prepared. The planar iron core made using the above amorphous material can achieve low losses of ≤0.14W / kg at 1.5T / 50Hz and excitation of ≤0.4VA / kg.

[0083] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. An iron-based amorphous alloy ribbon characterized by, which has a composition represented by formula (I) essentially Fe a B b C c Si d (I); wherein 82.0≤a≤86.0, 8.5≤b≤15.0, 1.6≤c≤6.0, 0.4≤d≤2.5, wherein a, b, c, d represent atomic percentage content of Fe, B, C and Si respectively, and a+b+c+d=100, wherein "essentially" means that the iron-based amorphous alloy does not exclude trace impurities brought from raw materials or processing process.

2. The ferrous-based amorphous alloy ribbon of claim 1, wherein, which has a composition satisfying formula (II): 0.12c - 0.1 ≤ d ≤ 0.5c + 0.7 (II).

3. The ferrous-based amorphous alloy ribbon of claim 1, wherein, which has a composition satisfying formula (III): 13≤b+c≤16 (III).

4. The ferrous-based amorphous alloy ribbon of any one of claims 1-3, wherein, which has a saturation magnetic induction ≥1.62T.

5. The ferrous-based amorphous alloy ribbon of any one of claims 1-4, wherein, The atomic percentage content in formula (I) satisfies at least one of the following conditions: 83.0≤a≤85.0； 11.0≤b≤14.0； 2.0≤c≤5.0； 0.5≤d≤1.5。 6. The ferrous-based amorphous alloy ribbon of any one of claims 1-5, wherein, The iron-based amorphous alloy is in a completely amorphous state.

7. The ferrous-based amorphous alloy ribbon of any of claims 1-6, wherein, The iron-based amorphous alloy strip has at least one of the following characteristics: The maximum amorphous thickness is at least 30μm, preferably ≥32μm, more preferably ≥35μm; The finished thickness of the iron-based amorphous alloy material can be 30-35μm, further preferably 32±2μm; The width is ≥30mm, preferably ≥60mm, more preferably 100-300mm.

8. A method for preparing the iron-based amorphous alloy strip according to any one of claims 1-7, comprising the following steps: S1, atomic percentage batching according to the composition represented by formula (I), S2, melting the batched raw materials, S3, melt-spinning the melted melt, preferably single-roll rapid quenching, to obtain an iron-based amorphous alloy strip.

9. The method of claim 8, wherein, In step S2, the following steps are included: S21, heating and melting the batched raw materials, S22, holding at 1450-1500℃ to remove impurities, and S23, at 1350-1400℃, staticizing.

10. The method of claim 8, wherein, In step S3, melt-spinning is performed using a cooling roll, wherein the cooling roll is selected from a molybdenum cooling roll, a copper cooling roll, a molybdenum alloy cooling roll, a copper alloy cooling roll, or a combination thereof, and the rotation speed is 300-900 rpm, preferably 600-900 rpm.

11. An iron core made by stacking / winding and annealing the iron-based amorphous alloy strip according to any one of claims 1-10.

12. The core of claim 11, characterized in that The iron core has at least one of the following characteristics: Under the condition of 50Hz, 1.40T, the core loss is ≤0.13W / kg, preferably ≤0.12W / kg, and the excitation is ≤0.3VA / kg, preferably ≤0.25VA / kg; Under the condition of 50Hz, 1.50T, the core loss is ≤0.15W / kg, preferably ≤0.14W / kg, and the excitation is ≤0.5VA / kg, preferably ≤0.4VA / kg; Under the condition of 50Hz, 1.60T, the core loss is ≤0.19W / kg, preferably ≤0.17W / kg, and the excitation is ≤1.1VA / kg, preferably ≤0.9VA / kg.

13. Use of the iron-based amorphous alloy ribbon according to any one of claims 1 to 7 or produced according to the method of any one of claims 8 to 10 for the production of an iron core, in particular of a transformer, an inductor, a generator, an electric motor, an inverter.

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