Nanocrystalline magnetically soft alloy strip as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of magnetic functional materials, and particularly relates to a nanocrystalline magnetically soft alloy strip and a preparation method and application thereof. The invention provides a nanocrystalline soft magnetic alloy strip, the chemical formula of the nanocrystalline soft magnetic alloy strip is Fe Si B < c > Cu < d > CeW < f > Mg, and M is selected from at least one of Hf, Zr and In; wherein according to atomic percent, 73% < = a < = 79%, 2.5% < = b < = 5%, 6% < = c < = 9.3%, 4.6% < = d < = 6.7%, 2.2% < = e < = 5.5%, 0.5% < = f < = 2%, 3% < = g < = 6%, and a + b + c + d + e + f + g = 100%. Compared with an existing nanocrystalline magnetically soft alloy strip, the nanocrystalline magnetically soft alloy strip is thinner and wider, has higher amorphous forming ability, higher saturation flux density and lower coercive force and loss, and has important significance on development of nanocrystalline magnetically soft alloy.

Description

Technical Field

[0001] The invention belongs to the technical field of magnetic functional materials, and in particular relates to a nanocrystalline soft magnetic alloy strip and a preparation method and application thereof. Background Art

[0002] Magnetic materials are an important basic functional material, which are widely used in various fields of the electronic power energy conversion industry, such as power transmission, energy conversion and new energy. In a broad sense, magnetic materials can be divided into two main categories: soft magnetic and permanent magnetic. Among them, soft magnetic materials are widely used and of many types. They have high saturation magnetization and low coercive force, and they play an important role in the entire family of magnetic materials. Nanocrystalline soft magnetic alloy is a soft magnetic material with excellent performance. It has high saturation magnetic induction intensity, magnetic permeability and low loss value, which can meet the needs of power electronic devices towards miniaturization and high efficiency. As electronic components continue to develop in the direction of high efficiency, energy saving and large capacity, the requirements for the soft magnetic properties of nanocrystalline soft magnetic alloys are getting higher and higher. Moreover, the current nanocrystalline strips are narrow and thick, which is difficult to meet actual needs.

[0003] The Chinese patent application number 202010920606.2 discloses an iron-based nanocrystalline ribbon and a preparation method thereof, wherein the chemical composition expression of the iron-based nanocrystalline ribbon is: Fe a Si b B c Cu d Nb e M f , M is selected from at least one of Mo and V. This patent obtains an alloy strip with good amorphous forming ability and good thermal stability by optimizing the composition content of the alloy. By adding Mo and V, the disadvantages of low high-frequency magnetic permeability and rapid attenuation of the alloy are significantly improved. At the same time, the resistivity of the material is improved, but its saturation magnetic induction intensity is still low. The Chinese patent with application number 202310220629.6 discloses a nanocrystalline soft magnetic alloy strip and a preparation method thereof. By limiting specific element components and adopting double-roller rapid quenching and foil rolling methods in the preparation method, an ultra-thin and ultra-wide nanocrystalline soft magnetic alloy strip with a thickness of 10 to 16 μm and a width of 200 to 300 mm with high saturation magnetic induction intensity, high magnetic permeability and low loss is obtained, but the strip needs to be obtained through multiple rolling, and the preparation process is relatively cumbersome. A Chinese patent with application number 202311216847.9 discloses an iron-based nanocrystalline ribbon. By specifically selecting the components and limiting the content of each component, the amorphous forming ability of the material is improved, and a nanocrystalline ribbon with refined grains is obtained by controlling the subsequent crystallization process, thereby obtaining a thinner and wider iron-based nanocrystalline ribbon. However, the coercive force of the soft magnetic alloy is relatively high, and its saturation magnetic induction intensity still has room for improvement. Summary of the invention

[0004] In view of this, the present invention provides a nanocrystalline soft magnetic alloy strip and a preparation method and application thereof. The nanocrystalline soft magnetic alloy strip not only has the advantages of being thinner and wider, but also has stronger amorphous forming ability, higher saturation magnetic induction intensity and lower coercive force, which is of great significance to the development of nanocrystalline soft magnetic alloys.

[0005] In order to solve the above technical problems, the first aspect of the present invention provides a nanocrystalline soft magnetic alloy strip, the chemical formula of the nanocrystalline soft magnetic alloy strip is Fe a Si b B c Cu d C e W f M g , M is selected from at least one of Hf, Zr, and In; wherein, in terms of atomic percentage, 73%≤a≤79%, 2.5%≤b≤5%, 6%≤c≤9.3%, 4.6%≤d≤6.7%, 2.2%≤e≤5.5%, 0.5%≤f≤2%, 3%≤g≤6%, and a+b+c+d+e+f+g=100%.

[0006] The present invention controls the element composition of the nanocrystalline soft magnetic alloy and the proportion of each element, thereby obtaining a thinner and wider nanocrystalline soft magnetic alloy strip with strong amorphous forming ability, high saturation magnetic induction intensity and low coercive force without using expensive niobium elements. Among them, Fe is an essential element of nanocrystalline soft magnetic alloy, and controlling its proportion within 73% to 79% will not reduce the saturation magnetic induction intensity of the nanocrystalline soft magnetic alloy, and at the same time, it can also avoid the decrease of amorphous forming ability due to excessive content; Si, B and C are all essential elements for the formation of amorphous phase, which can not only reduce the crystallinity of nanocrystalline soft magnetic alloy, ensure that disordered phase amorphous precursor can be obtained, but also stabilize the formed nanocrystals during alloy crystallization; Cu can form heterogeneous nucleation sites during amorphous crystallization, promote the formation of nanocrystalline grains, and reduce the loss value; the addition of W can not only promote the formation of amorphous phase in nanocrystalline soft magnetic alloy, but also improve the saturation magnetic induction intensity together with Fe; Hf, Zr and In can be enriched on the grain boundaries of nanocrystalline grains during the crystallization process, thereby inhibiting the excessive growth of grains, keeping the nanocrystalline grains at a smaller size, and increasing the number of nanocrystalline grains in the exchange length volume, thereby averaging the anisotropy of the grains, while enhancing the magnetic exchange coupling between the grains, reducing the coercive force and the loss value, and making the alloy have excellent comprehensive soft magnetic properties.

[0007] In combination with the first aspect, the nanocrystalline soft magnetic alloy strip consists of a disordered phase and an ordered phase, the ordered phase is an α-Fe nanocrystalline phase, and the grain size is 8 to 15 nm.

[0008] In combination with the first aspect, the nanocrystalline soft magnetic alloy strip has a thickness of 10 to 15 μm and a width of 180 to 270 mm.

[0009] In combination with the first aspect, the transverse thickness deviation of the nanocrystalline soft magnetic alloy strip does not exceed 1 μm.

[0010] The second aspect of the present invention provides a method for preparing the above-mentioned nanocrystalline soft magnetic alloy strip, the steps comprising: weighing and mixing the raw materials according to the stoichiometric ratio, obtaining a disordered phase precursor strip through vacuum melting and single-roller rapid quenching, and then heat treating the precursor strip under an external magnetic field to obtain a nanocrystalline soft magnetic alloy strip with ordered phase and disordered phase alternately distributed.

[0011] In combination with the second aspect, the raw materials are vacuum melted and then a disordered phase precursor strip is obtained by a single-roller rapid quenching method.

[0012] In combination with the second aspect, the temperature of the vacuum melting is 1680-1800°C.

[0013] In combination with the second aspect, the strength of the external magnetic field is 0.1~0.2T, and the direction of the external magnetic field is consistent with the width direction of the disordered phase precursor strip. Setting the external magnetic field during heat treatment can make the alloy strip produce induced anisotropy, so that the magnetic domain wall is consistent with the direction of the magnetic field, thereby reducing the high-frequency loss value of the strip.

[0014] In combination with the second aspect, the heat treatment is specifically to apply a tensile force in the length direction of the disordered phase precursor strip, and the tensile force is 60-150 MPa. By applying a tensile force of a specific strength in the length direction of the disordered phase precursor strip, an induced anisotropy is generated in the strip, so that the hysteresis loop of the alloy tends to be flat, thereby reducing the loss value of the strip.

[0015] In combination with the second aspect, the heat treatment temperature is 590-650° C. Under the action of an external magnetic field and stress, heat treatment of the precursor strip can make the alloy strip thinner and wider while having higher saturation magnetic induction intensity and excellent soft magnetic properties.

[0016] Preferably, the heating rate of the heat treatment is 5 to 20° C. / min.

[0017] A third aspect of the present invention provides an application of the above-mentioned nanocrystalline soft magnetic alloy strip or the nanocrystalline soft magnetic alloy strip prepared according to the above-mentioned preparation method in a high-frequency transformer, a common-mode inductor or wireless charging.

[0018] The beneficial effects obtained by the present invention are as follows: compared with the existing nanocrystalline soft magnetic alloy strips, the nanocrystalline soft magnetic alloy strip provided by the present invention has a width of 180 to 270 mm and a thickness of 10 to 15 μm, and is thinner and wider; in addition, the strip also has a stronger amorphous forming ability, the saturation magnetic induction intensity can reach up to 1.73 T, and the coercive force is as low as 0.25 A / m. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] Those skilled in the art will appreciate that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined.

[0021] Magnetic materials are basic functional materials that play a key role in modern science and industry. They play a vital role in many fields of the electronic power energy conversion industry, including but not limited to power transmission, energy conversion, and the development and utilization of new energy. Broadly speaking, magnetic materials can be further divided into two main categories: soft magnetic materials and permanent magnetic materials. Soft magnetic materials have attracted much attention due to their wide range of applications and variety. They usually have the characteristics of high saturation magnetization and low coercivity, which makes them occupy a pivotal position in the entire family of magnetic materials. Among many soft magnetic materials, nanocrystalline soft magnetic alloys stand out due to their excellent performance. They have high saturation magnetic induction, excellent magnetic permeability and extremely low loss value. These characteristics enable them to meet the growing development needs of miniaturization and high efficiency of power electronic devices. As electronic components continue to develop towards high efficiency, energy saving and large capacity, the soft magnetic properties of nanocrystalline soft magnetic alloys are also increasing. However, the nanocrystalline ribbons on the market are generally narrower and thicker, which to a certain extent limits their performance in practical applications and makes it difficult to fully meet the growing industrial needs.

[0022] To solve the above problems, Chinese patent application number 202010920606.2 discloses an iron-based nanocrystalline ribbon and a preparation method thereof, wherein the chemical composition expression of the iron-based nanocrystalline ribbon is: Fe a Si b B c Cud Nb e M f , M is selected from at least one of Mo and V. By optimizing the composition content of the alloy, the obtained alloy strip has good amorphous forming ability and good thermal stability. This patent improves the disadvantages of low high-frequency magnetic permeability and fast attenuation of the alloy by introducing Mo and V elements, and at the same time improves the resistivity of the material, but its saturation magnetic induction intensity is still low.

[0023] Chinese patent application number 202310220629.6 discloses a nanocrystalline soft magnetic alloy strip and a method for preparing the same. By limiting specific elemental components and adopting double-roller rapid quenching and foil rolling methods in the preparation method, an ultra-thin and ultra-wide nanocrystalline soft magnetic alloy strip with a thickness of 10 to 16 μm and a width of 200 to 300 mm having high saturation magnetic induction intensity, high magnetic permeability and low loss is obtained. However, the strip needs to be obtained through multiple rolling processes, and the preparation process is relatively complicated.

[0024] A Chinese patent with application number 202311216847.9 discloses an iron-based nanocrystalline ribbon. By specifically selecting the components and limiting the content of each component, the amorphous forming ability of the material is improved, and a nanocrystalline ribbon with refined grains is obtained by controlling the subsequent crystallization process, thereby obtaining a thinner and wider iron-based nanocrystalline ribbon. However, the coercive force of the soft magnetic alloy is relatively high, and its saturation magnetic induction intensity still has room for improvement.

[0025] In view of this, the present invention provides a nanocrystalline soft magnetic alloy strip, the chemical formula of the nanocrystalline soft magnetic alloy strip is Fe a Si b B c Cu d C e W f M g , M is selected from at least one of Hf, Zr, and In; wherein, in terms of atomic percentage, 73%≤a≤79%, 2.5%≤b≤5%, 6%≤c≤9.3%, 4.6%≤d≤6.7%, 2.2%≤e≤5.5%, 0.5%≤f≤2%, 3%≤g≤6%, and a+b+c+d+e+f+g=100%.

[0026] The present invention successfully prepared a new alloy strip that does not rely on expensive niobium elements by precisely controlling the chemical composition and proportion of nanocrystalline soft magnetic alloys. The alloy strip not only has excellent amorphous forming ability, but also exhibits the characteristics of high saturation magnetic induction intensity and low coercivity, while achieving thinner and wider sizes.

[0027] In the nanocrystalline soft magnetic alloy provided by the present invention, iron (Fe) is an indispensable element, and its content is controlled within the range of 73% to 79%, which not only ensures high saturation magnetic induction intensity, but also avoids the weakening of amorphous forming ability caused by excessive iron. Silicon (Si), boron (B) and carbon (C) are key elements for forming amorphous phases, which not only reduce the crystallinity of nanocrystalline soft magnetic alloys, ensure the formation of disordered phase amorphous precursors, but also stabilize the structure of nanocrystalline soft magnetic nanocrystals during the crystallization process. Copper (Cu) can act as a heterogeneous nucleation site in the crystallization stage to promote the formation of nanocrystalline grains, thereby reducing energy loss. The addition of tungsten (W) contributes to the formation of amorphous phases, and together with iron (Fe), improves the saturation magnetic induction intensity of the alloy. In addition, zirconium (Zr), hafnium (Hf) and indium (In) are enriched at grain boundaries during the crystallization process, which inhibits the excessive growth of grains, maintains the tiny size of nanograins, increases the number of grains within the exchange length volume, averages the anisotropy of the grains, and strengthens the magnetic exchange coupling between grains, effectively reducing the coercive force and energy loss, and giving the alloy excellent comprehensive soft magnetic properties.

[0028] For the following examples and comparative examples, the parts without specific experimental steps or conditions can be carried out according to the conventional experimental steps or conditions in the relevant technical field, and the raw materials, reagents or instruments used can be commercially available conventional products.

[0029] Example 1

[0030] This embodiment provides a nanocrystalline soft magnetic alloy strip, whose chemical formula is Fe 75.2 Si 3.1 B 7.6 Cu 5.5 C 3.6 W 1.2 Hf 3.8 The preparation steps of the nanocrystalline soft magnetic alloy strip include:

[0031] Industrial pure iron, pure silicon, ferroboron alloy, pure copper, graphite, ferrotungsten alloy and pure hafnium (the purity of each raw material is greater than 99.95%) are weighed and mixed according to the designed proportion, and then smelted in a vacuum melting furnace at 1750°C for 50 minutes. During the smelting process, the vacuum degree of the melting furnace is maintained below 1 Pa. Then, the liquid metal melt is sprayed through a nozzle onto the surface of a copper roller with a rotation speed of 55m / s using a single-roll rapid quenching method. The distance between the nozzle and the copper roller is 0.5mm. After the melt is rapidly cooled, a 12μm thick and 220mm wide disordered phase precursor strip is obtained (the maximum thickness deviation in the width direction is 0.8μm).

[0032] The obtained disordered phase precursor strip is heated to 620°C in a heat treatment furnace at a speed of 15°C / min for heat treatment to obtain a nanocrystalline soft magnetic alloy strip. The heat treatment furnace used is provided with a strip inlet and a strip outlet, the disordered phase precursor strip is wound on an unwinding winder at the strip inlet, and then the disordered phase precursor strip on the unwinding winder is unwound from the strip inlet into the heat treatment furnace, and then wound by a winding winder at the strip outlet, and the heat treatment time of the disordered phase precursor strip in the heat treatment furnace is controlled by the rotation speed of the unwinding winder and the winding winder to be 5 minutes, and the tension along the length direction of the strip is 90MPa, and a transverse magnetic field parallel to the width of the disordered phase precursor strip and having an intensity of 0.14T is provided in the heat treatment furnace.

[0033] Example 2

[0034] This embodiment provides a nanocrystalline soft magnetic alloy strip, whose chemical formula is Fe 73.1 Si 2.5 B 8.2 Cu 6.2 C 2.2 W 1.8 Zr6, the preparation steps of the nanocrystalline soft magnetic alloy strip include:

[0035] Industrial pure iron, pure silicon, ferroboron alloy, pure copper, graphite, ferrotungsten alloy and pure zirconium (the purity of each raw material is greater than 99.95%) are weighed and mixed according to the designed proportion, and smelted in a vacuum melting furnace at 1680°C for 65 minutes. During the smelting process, the vacuum degree of the melting furnace is maintained below 1 Pa. Then, the liquid metal melt is sprayed through a nozzle onto the surface of a copper roller with a rotation speed of 50m / s using a single-roller rapid quenching method. The distance between the nozzle and the copper roller is 0.7mm. After the melt is rapidly cooled, a disordered phase precursor strip with a thickness of 11μm and a width of 265mm is obtained (the maximum thickness deviation in the width direction is 0.6μm).

[0036] The obtained disordered phase precursor strip is heated to 650°C in a heat treatment furnace at a rate of 20°C / min for heat treatment to obtain a nanocrystalline soft magnetic alloy strip. The heat treatment furnace used is provided with a strip inlet and a strip outlet, the disordered phase precursor strip is wound on an unwinding winder at the strip inlet, and then the disordered phase precursor strip on the unwinding winder is unwound from the strip inlet into the heat treatment furnace, and then wound by a winding winder at the strip outlet, and the heat treatment time of the disordered phase precursor strip in the heat treatment furnace is controlled by the rotation speed of the unwinding winder and the winding winder to be 3 minutes, and the tension along the length direction of the strip is 140MPa, and a transverse magnetic field parallel to the width of the disordered phase precursor strip and having an intensity of 0.1T is provided in the heat treatment furnace.

[0037] Example 3

[0038] This embodiment provides a nanocrystalline soft magnetic alloy strip, whose chemical formula is Fe 77.6 Si 4.6 B 6.1 Cu 4.8 C 3.2 W 0.6 In 3.1 The preparation steps of the nanocrystalline soft magnetic alloy strip include:

[0039] Industrial pure iron, pure silicon, boron iron alloy, pure copper, graphite, tungsten iron alloy and pure indium (the purity of each raw material is greater than 99.95%) are weighed and mixed according to the designed proportion, and smelted in a vacuum melting furnace at 1800°C for 45 minutes. During the smelting process, the vacuum degree of the melting furnace is maintained below 1 Pa. Then, the liquid metal melt is sprayed through a nozzle onto the surface of a copper roller with a rotation speed of 50m / s using a single-roll rapid quenching method. The distance between the nozzle and the copper roller is 0.7mm. After the melt is rapidly cooled, a 15μm thick and 192mm wide disordered phase precursor strip is obtained (the maximum thickness deviation in the width direction is 1μm).

[0040] The obtained disordered phase precursor strip is heated to 590°C in a heat treatment furnace at a rate of 5°C / min for heat treatment to obtain a nanocrystalline soft magnetic alloy strip. The heat treatment furnace used is provided with a strip inlet and a strip outlet, the disordered phase precursor strip is wound on an unwinding winder at the strip inlet, and then the disordered phase precursor strip on the unwinding winder is unwound from the strip inlet into the heat treatment furnace, and then wound by a winding winder at the strip outlet, and the heat treatment time of the disordered phase precursor strip in the heat treatment furnace is controlled by the rotation speed of the unwinding winder and the winding winder to be 8 minutes, and the tension along the length direction of the strip is 65MPa, and a transverse magnetic field parallel to the width of the disordered phase precursor strip and having an intensity of 0.2T is provided in the heat treatment furnace.

[0041] Example 4

[0042] This embodiment provides a nanocrystalline soft magnetic alloy strip, whose chemical formula is Fe 73.2 Si 3.1 B 7.6 Cu 5.5 C 2.6 W 1.2 Hf 3.8 Zr3, the preparation steps of the nanocrystalline soft magnetic alloy strip include:

[0043] Industrial pure iron, pure silicon, ferroboron alloy, pure copper, graphite, ferrotungsten alloy, pure zirconium and pure hafnium (the purity of each raw material is greater than 99.95%) are weighed and mixed according to the designed proportion, and the subsequent preparation steps are the same as those of Example 1, which will not be repeated. The obtained strip has a thickness of 14 μm and a width of 215 mm.

[0044] Example 5

[0045] This embodiment provides a nanocrystalline soft magnetic alloy strip, whose chemical formula is Fe 73.2 Si 2.5 B 6.2 C5V 2.6 W 0.7 Hf 3. 2Zr 3.3 In 3.3 The preparation steps of the nanocrystalline soft magnetic alloy strip include:

[0046] Industrial pure iron, pure silicon, ferroboron alloy, pure copper, graphite, ferrotungsten alloy, pure zirconium, pure hafnium and pure indium (the purity of each raw material is greater than 99.95%) are weighed and mixed according to the designed proportion, and the subsequent preparation steps are the same as those of Example 1, which will not be repeated. The obtained strip has a thickness of 11 μm and a width of 210 mm.

[0047] Comparative Example 1

[0048] This comparative example provides a nanocrystalline soft magnetic alloy strip, whose chemical composition expression is Fe 75.2 Si 3.1 B 7.6 Cu 5.5 C 3.6 Hf5, the preparation steps of the nanocrystalline soft magnetic alloy strip are similar to the strip preparation steps in Example 1, the only difference is that no tungsten-iron alloy is added to the alloy raw material.

[0049] Comparative Example 2

[0050] This comparative example provides a nanocrystalline soft magnetic alloy strip, whose chemical composition expression is Fe 78.2 Si 3.1 B 7.6 Cu 5.5 C 3.6 W2, the preparation steps of the nanocrystalline soft magnetic alloy strip are the same as those of Example 3, the only difference being that pure indium is not added to the alloy raw material.

[0051] Comparative Example 3

[0052] This comparative example provides a nanocrystalline soft magnetic alloy strip, whose chemical composition expression is Fe 77.2 Si 3.1 B 7.6 Cu 5. 5C 3.6 W 1.2 In 1.8 The preparation steps of the nanocrystalline soft magnetic alloy strip are the same as those of Example 3, except that the amount of pure indium added to the alloy raw material is only 1.8%.

[0053] Comparative Example 4

[0054] This comparative example provides a nanocrystalline soft magnetic alloy strip, whose chemical composition expression is Fe 77.2 Si 3.1 B 7.6 Cu 5. 5C 3.6 W 1.2 Ag 1.8 The preparation steps of the nanocrystalline soft magnetic alloy strip are the same as those of Example 3, except that the pure indium in the alloy raw material is replaced by pure silver.

[0055] Comparative Example 5

[0056] This comparative example provides a nanocrystalline soft magnetic alloy strip, whose chemical composition expression is the same as that of Example 1, but the preparation steps of the nanocrystalline soft magnetic alloy strip are different from the strip preparation steps in Example 1. The difference is that in this comparative example, no additional magnetic field is applied when heat treating the disordered phase precursor strip.

[0057] Comparative Example 6

[0058] This comparative example provides a nanocrystalline soft magnetic alloy strip, whose chemical composition expression is the same as that of Example 1, but the preparation steps of the nanocrystalline soft magnetic alloy strip are different from the strip preparation steps in Example 1. The difference is that this comparative example does not apply additional tensile force of appropriate strength when heat treating the disordered phase precursor strip.

[0059] Test example

[0060] The performance tests were carried out on the nanocrystalline soft magnetic alloy strips obtained in Examples 1 to 5 and Comparative Examples 1 to 6 respectively: a transmission electron microscope was used to test the grain size of the nanocrystalline formed after the strip was heat treated; a vibrating sample magnetometer (VSM) was used to measure the saturation magnetic induction intensity and coercive force of the nanocrystalline soft magnetic alloy, and an AC BH meter was used to measure the loss value of the nanocrystalline soft magnetic alloy. The test results are shown in Table 1.

[0061] Table 1

[0062]

[0063] From the results in Table 1, it can be seen that compared with Example 1, Comparative Example 1 does not contain tungsten, resulting in a significant decrease in the saturation magnetic flux density of the obtained soft magnetic alloy strip, indicating that the addition of W in the present invention is conducive to increasing the saturation magnetic flux density, and high saturation magnetic permeability can be obtained even when the Fe content is relatively low. Comparative Example 5 replaces the tungsten iron alloy with the vanadium iron alloy. Compared with Example 3, the average size of the nanocrystalline grains increases when Comparative Examples 2 to 4 do not add In, the In content is lower than the specified range, or In is replaced by Ag, indicating that the addition of In, Hf or Zr can refine the nanocrystalline grains, which helps to reduce the coercive force and the loss value. Compared with Example 1, Comparative Examples 5 to 6 do not apply an external magnetic field or an external tensile force at the same time during the heat treatment, and the coercive force and loss value both increase, indicating that the additional application of a magnetic field or a tensile force during the heat treatment plays an important role in reducing the coercive force or loss value of the strip.

[0064] In summary, the nanocrystalline soft magnetic alloy strip provided by the present invention has a width of 180 to 270 mm and a thickness of 10 to 15 μm, and is thinner and wider; the strip also has a stronger amorphous forming ability, with a saturation magnetic induction intensity of up to 1.73 T and a coercive force of at least 0.25 A / m, and has broad application prospects.

[0065] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A nanocrystalline soft magnetic alloy strip, characterized in that: The chemical formula of the nanocrystalline soft magnetic alloy strip is Fe a Si b B c Cu d C e W f M g , M is selected from at least one of Hf, Zr, and In; Among them, according to atomic percentage, 73%≤a≤79%, 2.5%≤b≤5%, 6%≤c≤9.3%, 4.6%≤d≤6.7%, 2.2%≤e≤5.5%, 0.5%≤f≤2%, 3%≤g≤6%, a+b+c+d+e+f+g=100%.

2. The nanocrystalline soft magnetic alloy strip according to claim 1, characterized in that: The nanocrystalline soft magnetic alloy strip consists of a disordered phase and an ordered phase, wherein the ordered phase is an alpha-Fe nanocrystalline phase, and the grain size is 8-15 nm.

3. The nanocrystalline soft magnetic alloy strip according to claim 1 or 2, characterized in that: The nanocrystalline soft magnetic alloy strip has a thickness of 10 to 15 μm and a width of 180 to 270 mm.

4. The nanocrystalline soft magnetic alloy strip according to claim 3, characterized in that: The transverse thickness deviation of the nanocrystalline soft magnetic alloy strip does not exceed 1 μm.

5. The method for preparing a nanocrystalline soft magnetic alloy strip according to any one of claims 1 to 4, characterized in that the steps include: The raw materials are weighed and mixed according to the stoichiometric ratio, and a disordered phase precursor strip is obtained by vacuum melting. The disordered phase precursor strip is then heat treated under an external magnetic field to obtain a nanocrystalline soft magnetic alloy strip with ordered and disordered phases distributed alternately.

6. The method for preparing a nanocrystalline soft magnetic alloy strip according to claim 5, characterized in that: The raw materials are subjected to vacuum melting and then a disordered phase precursor strip is obtained by a single-roller rapid quenching method. The vacuum melting temperature is 1680-1800°C.

7. The method for preparing a nanocrystalline soft magnetic alloy strip according to claim 6, characterized in that: The strength of the external magnetic field is 0.1-0.2 T, and the direction of the external magnetic field is consistent with the width direction of the disordered phase precursor strip.

8. The method for preparing a nanocrystalline soft magnetic alloy strip according to claim 5, characterized in that: The heat treatment specifically includes applying tension in the length direction of the disordered phase precursor strip.

9. The method for preparing a nanocrystalline soft magnetic alloy strip according to claim 5, characterized in that: The temperature of the heat treatment is 590-650°C.

10. Use of the nanocrystalline soft magnetic alloy strip according to any one of claims 1 to 4 or the nanocrystalline soft magnetic alloy strip prepared by the method for preparing the nanocrystalline soft magnetic alloy strip according to any one of claims 5 to 9 in high-frequency transformers, common-mode inductors or wireless charging.

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