Nanocrystalline strip, method of manufacture and use

Abstract

The application belongs to the technical field of nanocrystalline materials, and particularly relates to a nanocrystalline strip with high saturation magnetic induction and low coercivity, and further discloses a preparation method and application thereof. a Co b Ni c Si d B e R f Sr j Cu h (MCl) x . The nanocrystalline strip has a strip thickness of 14-22 mu m, a strip width of 1-100 mm, a saturation magnetic induction of 1.85-1.99 T, a coercivity of 0.2-6 A / m, and a loss of 4.6-5.2 W / kg. B s H c P 1kHz / 1T The nanocrystalline strip has high saturation magnetic induction, low coercivity, low loss and high amorphous forming ability, and effectively solves the problem that the current nanocrystalline strip is difficult to have high saturation magnetic induction, low coercivity, low loss and high amorphous forming ability.​​

Description

Technical Field

[0001] This invention belongs to the field of nanocrystalline materials technology, specifically relating to a nanocrystalline ribbon with high saturation magnetic induction intensity and low coercivity, and further disclosing its preparation method and application. Background Technology

[0002] In recent years, wireless charging technology has gradually become a standard feature of smartphones. The wireless charging receiver for mobile phones mainly consists of two parts: a coil and a magnetic sheet. The coil primarily generates the excitation magnetic field at the receiving and transmitting end, which is then converted into alternating current. The magnetic sheet mainly serves to isolate and guide the magnetic field, thereby improving the charging efficiency of the entire system and preventing magnetic field leakage. Currently, the main materials for the magnetic sheet in the receiver are ferrite and nanocrystalline alloys. Nanocrystalline magnetic sheets are gradually becoming the mainstream material due to their high saturation magnetization and high permeability.

[0003] Nanocrystalline soft magnetic alloys are currently a research hotspot and core development direction in the field of soft magnetic materials. Based primarily on iron, they are produced by rapidly solidifying amorphous precursors followed by precise crystallization heat treatment to form ultrafine grain structures of approximately 10 nm. Performance breakthroughs are achieved through the regulation of trace elements such as Cu and Nb, and ferromagnetic exchange coupling. Currently, mainstream products achieve saturation magnetic induction of over 1.2 T and coercivity as low as 0.5-10 A / m, while also exhibiting high permeability and low high-frequency loss characteristics. In terms of technological development, domestic enterprises have achieved industrial-scale production of wide-width ultra-thin strips through breakthroughs in processes such as single-roll rapid quenching, with some products reaching internationally advanced levels. However, the highest saturation magnetic induction of industrially produced nanocrystalline strips is only 1.4 T, far lower than that of amorphous alloys and silicon steel, which cannot meet application requirements and restricts the development and application of nanocrystalline materials in low-loss, high-capacity high-frequency transformers and other devices. Therefore, the development of nanocrystalline strips with high saturation magnetic induction and low coercivity is urgently needed.

[0004] For example, Chinese patent CN103060691A discloses an iron-based nanocrystalline ribbon and its preparation method, wherein the chemical formula of the iron-based nanocrystalline ribbon is Fe. a Cu b Nb c Si d B e A high-performance nanocrystalline soft magnetic tape was prepared through a process involving raw material mixing, smelting to form steel ingots, single-roll ultra-cold strip forming, and heat treatment. Based on the composition of FINEMET soft magnetic alloys, this method details the preparation process of domestically produced iron-based nanocrystalline tapes, producing tapes with a thickness of 30-40 μm and a width of 3-10 mm. However, given the current pace of development in power electronic devices, this specification of nanocrystalline tape can no longer meet more advanced requirements.

[0005] For example, Chinese patent CN112176249A discloses an iron-based nanocrystalline thin strip and its preparation method, wherein the chemical composition of the iron-based nanocrystalline thin strip is Fe. a Si b B c Cu d Nb e M f M is selected from at least one of Mo and V. The strip prepared by optimizing the alloy composition has good amorphous forming ability and good thermal stability. The addition of Mo and V elements effectively improves the shortcomings of soft magnetic alloys, such as rapid decay of high-frequency magnetic permeability and low value, and improves the resistivity of the material. However, the disadvantage of this alloy is its low saturation magnetic induction.

[0006] For example, Chinese patent CN106086714A discloses an iron-based soft magnetic alloy with a width greater than 63.5 mm, a thickness between 13-20 μm, and a composition expressed by the following formula: (Fe 1-a M a ) 100-x-y-z-p-q-r Cu x Si y B z M' p M" q X r In this alloy, M is Co and / or Ni; M' is at least one element selected from the combination of Nb, W, Ta, Zr, Hf, Ti, and Mo; M" is at least one element selected from the combination of V, Cr, Mn, Al, platinum group elements, Sc, Y, rare earth elements, Au, Zn, Sn, and Re; and X is at least one element selected from the combination of C, Ge, P, Ga, Sb, In, Be, and As. The alloy is at least 50% crystalline and has an average particle size of less than 100 nm. This alloy exhibits good soft magnetic properties, but the patent does not provide a detailed analysis of the alloy composition or examples illustrating the influence of different element contents on the alloy's soft magnetic properties. Furthermore, while the alloy was successfully processed into ultra-thin and ultra-wide strips using advanced techniques, it exhibits low saturation magnetic induction and fails to simultaneously achieve high saturation magnetic induction and low coercivity.

[0007] It is evident that the fabrication of nanocrystalline ribbons with high saturation magnetic induction and low coercivity requires consideration of two key aspects. Firstly, the relationship between saturation magnetic induction and low coercivity must be considered, as increasing saturation magnetic induction leads to increased coercivity. Secondly, improving the amorphous forming capability of the ribbon is crucial, as wide, ultra-thin amorphous precursor ribbons are difficult to form during the fabrication process with high saturation magnetic induction. Therefore, the field seeks to develop a nanocrystalline ribbon that simultaneously possesses high saturation magnetic induction and low coercivity, enabling further advancements in areas such as mid-to-high frequency transformers and wireless charging. Summary of the Invention

[0008] The first objective of this invention is to provide a nanocrystalline ribbon with high saturation magnetic induction intensity, low coercivity and high amorphous formation capability. The nanocrystalline ribbon effectively solves the problem that current nanocrystalline ribbons are difficult to achieve simultaneously with high saturation magnetic induction intensity, low coercivity and high amorphous formation capability, and is suitable for applications such as medium and high frequency transformers and wireless charging. The second objective of this invention is to provide a method for preparing and applying the above-mentioned nanocrystalline ribbon with high saturation magnetic induction, low coercivity and high amorphous forming ability.

[0009] To address the aforementioned technical problems, this invention provides a nanocrystalline ribbon, wherein the chemical elemental composition of the nanocrystalline ribbon is such as Fe. a Co b Ni c Si d B e R f Sr j Cu h (MCl) x As shown; where, R is a rare earth element, selected from at least one of Tb, Ho, or Er; M is an alkali metal element, selected from at least one of Na or K; a, b, c, d, e, f, j, h, and x represent the atomic percentages of their respective elements; where 70 ≤ a ≤ 85, 10 ≤ b ≤ 20, 1 ≤ c ≤ 2, 1 ≤ d ≤ 2, 1 ≤ e ≤ 6, 0.5 ≤ f ≤ 1, 0.5 ≤ j ≤ 1, 0.5 ≤ h ≤ 2, and 0.5 ≤ x ≤ 1, and the sum of the atomic percentages of all components is 100.

[0010] In the nanocrystalline ribbon, MClx is an alkali metal chloride alloy, which is introduced as a reactive substance during the smelting process.

[0011] Specifically, the nanocrystalline ribbon material: The saturation magnetic induction intensity of the nanocrystalline ribbon B s For 1.85-1.99T; and / or, The coercivity of the nanocrystalline ribbon H c 0.2-6 A / m; and / or, The loss of the nanocrystalline ribbon P 1kHz / 1T It is 4.6-5.2 W / kg; and / or, The thickness of the nanocrystalline ribbon is 14-22 μm; and / or, The width of the nanocrystalline ribbon is 1-100 mm.

[0012] The present invention also provides a method for preparing the nanocrystalline ribbon as described above, comprising the following steps: (1) According to the elemental composition of the nanocrystalline ribbon, weigh out iron, cobalt, nickel, silicon, boron, rare earth elements, Sr, copper and alkali metal chloride alloy and mix them to obtain a mixture; (2) The mixture is subjected to plasma melting under an inert atmosphere to obtain a molten alloy liquid; (3) The molten alloy liquid is dispersed to form micron-sized amorphous droplets, and then solidified and rolled to obtain amorphous precursor strip; (4) The amorphous precursor tape is subjected to ultrasonic-magnetic field composite heat treatment to obtain the desired nanocrystalline tape.

[0013] Specifically, in the preparation method of the nanocrystalline ribbon, in step (2), the heating method of the plasma melting step includes a composite heating method combining electromagnetic induction heating and plasma arc heating; wherein, The heating temperature of the electromagnetic induction heating is 1300-1400℃, and the heating time is 5-15 minutes; The plasma arc heating temperature is 1500-1600℃, and the heating time is 5-15 min; The vibration current of the composite heating is 50-100A.

[0014] In the plasma melting step, the mixture is placed in a plasma melting furnace and melted using a composite melting process combining induction heating and plasma arc heating. Induction heating generates electromagnetic induction, raising the temperature to 1300-1400℃ for 5-15 minutes, causing the alloy material to melt through eddy current heating. Simultaneously, the plasma arc provides an ultra-high temperature heat source, adjusting the plasma temperature to 1500-1600℃ for another 5-15 minutes. Throughout the plasma melting process, a vibration current of 50-100A is applied from start to finish in the composite heating method formed by induction heating and plasma arc heating, causing the solution to vibrate and resulting in a more uniform composition distribution.

[0015] Specifically, in the preparation method of the nanocrystalline ribbon, in step (2), the inert atmosphere includes argon gas with a purity greater than 99.99%.

[0016] Specifically, in the preparation method of the nanocrystalline ribbon, the dispersion treatment step in step (3) includes the step of forming 20-200μm amorphous droplets by high-speed rotating spraying of the molten alloy liquid.

[0017] Specifically, in the preparation method of the nanocrystalline ribbon, in step (3), the solidification-rolling process includes the step of spraying the amorphous molten droplets onto the surface of a rotating roll at high speed; The linear velocity of the rolls is 20-40 m / s, the rolling pressure is 50-200 MPa, and the cooling rate is 10. 4 -10 6 K / s; The thickness of the amorphous precursor strip is 14-22 μm and the width is 1-100 mm.

[0018] Specifically, in the preparation method of the nanocrystalline ribbon, in step (4), the ultrasonic-magnetic field composite heat treatment step controls the ultrasonic frequency to be 20-50kHz, the power to be 200-1100W, and the ultrasonic amplitude to be 10-20μm.

[0019] Specifically, in the preparation method of the nanocrystalline ribbon, in step (4), the ultrasonic-magnetic field composite heat treatment step uses a longitudinal magnetic field, controls the magnetic field strength to be 20-100mT, and uses high-purity nitrogen for protection.

[0020] Specifically, in the preparation method of the nanocrystalline ribbon, in step (4), the temperature of the ultrasonic-magnetic field composite heat treatment step is 350-480℃, the heating rate is controlled at 100-500℃ / s, and the cooling rate is 10℃ / s. 3 -10 4 ℃ / s, heat preservation time 1-10 minutes.

[0021] The present invention also provides the application of the nanocrystalline ribbon or the nanocrystalline ribbon prepared by the method in the fields of medium and high frequency transformers and wireless charging.

[0022] The nanocrystalline ribbon described in this invention is designed with an elemental composition such as Fe. a Co b Ni c Si d B e R f Sr j Cu h (MCl) xAs shown, Fe, Co, and Ni elements, as ferromagnetic elements, play a role in maintaining the saturation magnetic induction intensity. At the same time, the coupling of Fe, Co, and Ni can achieve extremely strong magnetic exchange interaction, thereby significantly improving the saturation magnetic induction intensity of the alloy. The appropriate ratio of Si and B-type metal elements is the key to improving the amorphous forming ability. Sr element can combine with oxygen and sulfur in the melt to form high-melting-point SrO and SrS, effectively removing harmful impurities in steel, reducing the impact of oxide inclusions on the mechanical properties of steel, and also effectively hindering the growth of nanocrystal grains and reducing the diffusion coefficient. Cu element, as a nucleating element, can form Cu clusters, which is beneficial to the precipitation and refinement of micro-grains. However, if added in excess, it will lead to the deterioration of the strip performance. In addition to these typical elements, small amounts of alkali metals, chloride (Cl), and rare earth elements were also added. The combination of alkali metals and Cl creates a chloride-alkali metal alloy. During smelting, alkali metals react strongly with oxygen, nitrogen, and sulfur, acting as deoxidizers and desulfurizers to improve solution purity. Furthermore, the addition of alkali metals lowers atomic transition energies during subsequent heat treatment, promoting heterogeneous nucleation of nanocrystals, increasing the nucleation ratio, and reducing coercivity. Cl is used to complement the alkali metals in the alloy; a small amount of Cl improves solution homogeneity during smelting and also promotes [further development] during heat treatment. Nanocrystalline heterogeneous nucleation refines grains, but excessive addition of alkali metals and Cl can reduce the amorphous formation ability of nanocrystals, leading to deterioration of material properties. Compared with other rare earth elements, Tb, Ho, and Er have strong magnetic moments and magnetic anisotropy. Through subsequent magnetic field heat treatment, the magnetocrystalline anisotropy field can be effectively adjusted, increasing the Curie temperature of the alloy, widening the heat treatment temperature range, and making it more conducive to the adjustment of magnetic properties. In addition, as large-sized rare earth elements, Tb, Ho, and Er are conducive to the precipitation and refinement of α-Fe grains, increasing the saturation magnetic induction of the alloy and reducing coercivity. However, if added in excess, it will lead to a decrease in saturation magnetic induction.

[0023] The nanocrystalline ribbon of this invention has a thickness of 14-22 μm, a width of 1-100 mm, and a saturation magnetic induction intensity of [missing information]. B s The coercivity is 1.85-1.99T. H c The loss is 0.2-6 A / m. P 1kHz / 1T With a strength of 4.6-5.2 W / kg, it exhibits high saturation magnetic induction, low coercivity, low loss, and high amorphous formation capability, effectively solving the problem that current nanocrystalline ribbons struggle to simultaneously achieve these characteristics. This nanocrystalline soft magnetic material is suitable for applications such as medium- and high-frequency transformers and wireless charging.

[0024] The method for preparing nanocrystalline ribbons according to the present invention firstly involves melting prepared alloy materials into a uniform and pure master alloy through plasma induction melting. Then, an amorphous precursor ribbon with a thickness of 14-22 μm and a width of 1-100 mm is prepared by high-pressure rotary jetting combined with rolling process. Finally, the magnetic properties are controlled by ultrasonic-magnetic field composite heat treatment to form a nanocrystalline ribbon with excellent soft magnetic properties.

[0025] The method for preparing nanocrystalline ribbons according to this invention involves adding the alloy material to a plasma induction melting furnace after determining the alloy composition. A composite melting process combining induction heating and plasma arc heating is used. Electromagnetic induction heating raises the temperature to 1300-1400℃ for 5-15 minutes, inducing eddy current heating and melting of the alloy material. Simultaneously, the plasma arc provides an ultra-high temperature heat source, adjusting the plasma temperature to 1500-1600℃ for another 5-15 minutes. Throughout the plasma melting process, a vibration current of 50-100A is applied from start to finish to vibrate the solution. Argon gas (with a purity greater than 99.99%) is introduced into the furnace to create an inert atmosphere. The two heat sources work synergistically, using electromagnetic stirring to homogenize the melt composition and leveraging the high temperature of the plasma and the active slag to remove impurities and refine the alloy, resulting in the preparation of a high-purity master alloy.

[0026] The method for preparing nanocrystalline ribbons according to this invention involves using a high-pressure rotary jetting process combined with rolling to prepare the master alloy. First, the molten alloy is dispersed into micron-sized droplets using a high-speed rotary jetting device. By controlling the jetting pressure, amorphous droplets of 20-200 μm are formed. These droplets are then jetted at high speed onto the surface of rotating rolls, where they rapidly solidify upon impact. Simultaneously, rolling is performed, with rolling parameters adjusted to achieve a roll linear speed of 20-40 m / s, a rolling pressure of 50-200 MPa, and a cooling rate of 10... 4 -10 6 At a speed of K / s, densification is achieved to form amorphous precursor strips with a thickness of 14-22 μm and a width of 1-100 mm. The preparation method described in this invention employs a high-pressure rotary jetting process combined with a rolling process. Under high-pressure rapid cooling, a uniform and refined preliminary microstructure can be obtained. Furthermore, under high-speed cooling conditions, the atoms in the alloy melt do not have sufficient time to complete orderly arrangement and directly solidify into an amorphous alloy, providing an amorphous precursor strip structure for subsequent nanocrystalline structures. Moreover, rapid cooling also inhibits grain boundary growth and reduces coercivity.

[0027] The method for preparing the nanocrystalline ribbon of the present invention involves placing the amorphous alloy ribbon in an ultrasonic-magnetic field heat treatment furnace. The magnetic properties are controlled by ultrasonic-magnetic field composite heat treatment. The ultrasonic field parameters are as follows: frequency 20-50kHz, power 200-1100W, and ultrasonic amplitude 10-20μm. The magnetic field heat treatment parameters are as follows: heat treatment temperature 350-480℃, heating rate 100-500℃ / s, cooling rate 103-104℃ / s, holding time 1-10 minutes, using a longitudinal magnetic field with a magnetic field strength of 20-100mT, and high-purity nitrogen protection. The nanocrystalline alloy utilizes ultrasonic vibration to generate microbubbles, which break up and release internal stress and localized high temperatures, promoting nucleation and refining grains, reducing coercivity and loss. Simultaneously, a longitudinal magnetic field is applied, further inducing anisotropy in the longitudinal direction, moving domain walls to align with the magnetic field, and improving the magnetic domain structure. The mechanical vibration effect of ultrasound promotes dislocation movement and recrystallization, improving the material's plasticity and toughness, thus comprehensively enhancing the mid-to-high frequency performance of the strip. The addition of alkali metals and Cl promotes the precipitation and refinement of nanocrystalline grains during heat treatment. The addition of rare earth elements Tb, Ho, and Er effectively regulates the magnetocrystalline anisotropy field, increasing the alloy's Curie temperature and widening the heat treatment temperature range. Considering the high heat treatment temperature and duration of nanocrystalline strips, resulting in high brittleness, the annealing time is controlled to ensure the strip possesses excellent soft magnetic properties while maintaining good toughness. Detailed Implementation

[0028] In the following embodiments of the present invention, in order to solve the problem that current nanocrystalline ribbons are difficult to simultaneously achieve high saturation magnetic induction, low coercivity, and high amorphous formation capability, a nanocrystalline ribbon with high saturation magnetic induction, low coercivity, and high amorphous formation capability is provided. The chemical elemental composition of the nanocrystalline ribbon is as follows: Fe a Co b Ni c Si d B e R f Sr j Cu h (MCl) x As shown; where, R is a rare earth element, selected from at least one of Tb, Ho, or Er; M is an alkali metal element, selected from at least one of Na or K; a, b, c, d, e, f, j, h, and x represent the atomic percentages of their respective elements; where 70 ≤ a ≤ 85, 10 ≤ b ≤ 20, 1 ≤ c ≤ 2, 1 ≤ d ≤ 2, 1 ≤ e ≤ 6, 0.5 ≤ f ≤ 1, 0.5 ≤ j ≤ 1, 0.5 ≤ h ≤ 2, and 0.5 ≤ x ≤ 1, and the sum of the atomic percentages of all components is 100.

[0029] In the nanocrystalline ribbon, MClx is an alkali metal chloride alloy, which is introduced as a reactive substance during the smelting process.

[0030] Specifically, the nanocrystalline ribbon material: The saturation magnetic induction intensity of the nanocrystalline ribbon B s For 1.85-1.99T; and / or, The coercivity of the nanocrystalline ribbon H c 0.2-6 A / m; and / or, The loss of the nanocrystalline ribbon P 1kHz / 1T The content is 4.6-5.2 W / kg; and / or, the thickness of the nanocrystalline ribbon is 14-22 μm; and / or, The width of the nanocrystalline ribbon is 1-100 mm.

[0031] In the following embodiments of the present invention, a method for preparing the nanocrystalline ribbon as described above is also provided, comprising the following steps: (1) According to the elemental composition of the nanocrystalline ribbon, weigh out iron, cobalt, nickel, silicon, boron, rare earth elements, Sr, copper and alkali metal chloride alloy and mix them to obtain a mixture; (2) The mixture is subjected to plasma melting under an inert atmosphere to obtain a molten alloy liquid; (3) The molten alloy liquid is dispersed to form micron-sized amorphous droplets, and then solidified and rolled to obtain amorphous precursor strip; (4) The amorphous precursor tape is subjected to ultrasonic-magnetic field composite heat treatment to obtain the desired nanocrystalline tape.

[0032] In some specific embodiments, in step (2), the heating method of the plasma melting step includes a composite heating method combining electromagnetic induction heating and plasma arc heating; wherein, In some specific embodiments, the heating temperature of the electromagnetic induction heating is 1300-1400℃, and the heating time is 5-15 minutes; In some specific embodiments, the heating temperature of the plasma arc heating is 1500-1600℃, and the heating time is 5-15min; The vibration current of the composite heating is 50-100A.

[0033] In some specific embodiments, in step (2), the inert atmosphere includes argon gas with a purity greater than 99.99%.

[0034] In some specific embodiments, the dispersion treatment step in step (3) includes the step of forming 20-200μm amorphous droplets by high-speed rotating spraying of the molten alloy liquid.

[0035] In some specific embodiments, in step (3), the solidification-rolling process includes the step of spraying the amorphous molten droplets at high speed onto the surface of a rotating roll; In some specific embodiments, the linear speed of the roll is 20-40 m / s, the rolling pressure is 50-200 MPa, and the cooling rate is 10 m / s. 4 -10 6 K / s; In some specific embodiments, the thickness of the amorphous precursor strip is 14-22 μm and the width is 1-100 mm.

[0036] In some specific embodiments, in step (4), the ultrasonic-magnetic field composite heat treatment step is controlled with an ultrasonic frequency of 20-50kHz, a power of 200-1100W, and an ultrasonic amplitude of 10-20μm.

[0037] In some specific embodiments, in step (4), the ultrasonic-magnetic field composite heat treatment step uses a longitudinal magnetic field, controls the magnetic field strength to be 20-100mT, and uses high-purity nitrogen for protection.

[0038] In some specific embodiments, in step (4), the temperature of the ultrasonic-magnetic field composite heat treatment step is 350-480℃, the heating rate is controlled at 100-500℃ / s, and the cooling rate is 10℃ / s. 3 -10 4 ℃ / s, heat preservation time 1-10 minutes.

[0039] Example 1 The nanocrystalline ribbon described in this embodiment is characterized by its Fe content. 70 Co 20 Ni2Si2B1R1Sr1Cu2(MCl)1, where R is Tb and M is Na.

[0040] The preparation method of the nanocrystalline ribbon described in this embodiment includes the following steps: (1) Raw material preparation According to the above elemental chemical composition formula, weigh iron, cobalt, nickel, silicon, boron, Tb, Sr, copper, and NaCl with a purity greater than 99%, and weigh them accurately according to the preset proportions of the above chemical formula to ensure that all raw materials are mixed evenly to obtain a mixture. Place it in a dry environment to prevent the influence of impurities and moisture. (2) Plasma induction melting The mixture was placed in a plasma melting furnace and heated in an argon atmosphere (argon purity ≥ 99.99%). The electromagnetic induction melting temperature was set at 1300℃ for 7 minutes, and the plasma temperature was set at 1500℃ for 8 minutes. Throughout the composite heating process, the vibration current was set to 70A to ensure that the alloy raw materials were completely melted and fully mixed to obtain a molten alloy liquid. (3) High-pressure rotary jetting process combined with rolling process for strip production The molten alloy liquid is dispersed into 200 μm micron-sized droplets using a high-pressure rotary jetting device, and then sprayed at high speed onto the surface of rotating rolls for cooling. The roll linear speed is 40 m / s, the rolling pressure is 200 MPa, and the cooling rate reaches 10. 6 K / s, to achieve densification and form an amorphous precursor strip with a thickness of 22μm and a width of 100mm; (4) Ultrasonic-magnetic field composite heat treatment The rolled strip was placed in an ultrasonic-magnetic field composite heat treatment process. The ultrasonic field parameters were as follows: frequency 50kHz, power 1100W, and ultrasonic amplitude 20μm. The magnetic field heat treatment parameters were as follows: heat treatment temperature 480℃, heating rate 500℃ / s, and cooling rate 10℃ / s. 4 The temperature was set at ℃ / s, and the holding time was 10 minutes. A longitudinal magnetic field with a magnetic field strength of 100mT was used, and high-purity nitrogen was used for protection. The annealed strip was obtained, which is the nanocrystalline ribbon material.

[0041] Examples 2-5 In the following Examples 2-5 of the present invention, the preparation method of the nanocrystalline ribbon is carried out in accordance with Example 1. The specific elemental composition of the nanocrystalline ribbon is shown in Table 1 below, and the parameter differences of the preparation method are shown in Table 2 below.

[0042] Table 1. Composition of nanocrystalline ribbons in Examples 1-5

[0043] Table 2. Preparation process conditions of nanocrystalline ribbons in Examples 1-5

[0044] Comparative Examples 1-3 In the following comparative examples 1-3 of this invention, three comparative products from the market were used for relevant comparisons. The preparation method of the nanocrystalline ribbon was carried out in accordance with Example 1. The specific differences in the elemental composition of the nanocrystalline ribbon are shown in Table 3 below.

[0045] Table 3. Components of Comparative Examples 1-3

[0046] Comparative Example 4 The raw material composition of the nanocrystalline ribbon described in this comparative example has a similar alloy composition to that of the nanocrystalline ribbon described in Example 1, which is Fe. 70 Co 20 The only difference between Ni2Si2B2Sr1Cu2(MCl)1 and Ni2Si2B2Sr1Cu2(MCl)1 is that rare earth elements are not added, but the content of element B is increased accordingly.

[0047] The preparation process of the nanocrystalline ribbon described in this comparative example is the same as that in Example 1.

[0048] Comparative Example 5 The raw material composition of the nanocrystalline ribbon described in this comparative example has a similar alloy composition to that of the nanocrystalline ribbon described in Example 1, which is Fe. 70 Co 20 The difference is that Ni2Si3B1R1Cu2(MCl)1 does not add Sr, but increases the Si content accordingly.

[0049] The preparation process of the nanocrystalline ribbon described in this comparative example is the same as that in Example 1.

[0050] Comparative Example 6 The raw material composition of the nanocrystalline ribbon described in this comparative example has a similar alloy composition to that of the nanocrystalline ribbon described in Example 1, which is Fe. 70 Co 20 The difference between Ni2Si2B2R1Sr1Cu2 and Ni2Si2B2R1Sr1Cu2 is that no alkali metal chloride alloy is added, but the content of element B is increased accordingly.

[0051] The preparation process of the nanocrystalline ribbon described in this comparative example is the same as that in Example 1.

[0052] Comparative Example 7 The raw material composition of the nanocrystalline ribbon described in this comparative example has the same alloy composition as that of the nanocrystalline ribbon in Example 1, which is Fe. 70 Co 20 The only difference between this comparative example and Example 1 is that the preparation process uses electromagnetic induction heating, while the rest of the preparation process is the same.

[0053] Comparative Example 8 The raw material composition of the nanocrystalline ribbon described in this comparative example has the same alloy composition as that of the nanocrystalline ribbon in Example 1, which is Fe. 70 Co 20 The only difference between this comparative example and Example 1 is that the amorphous precursor strip is prepared by copper roller spinning, while the rest of the preparation process is the same.

[0054] Comparative Example 9 The raw material composition of the nanocrystalline ribbon described in this comparative example has the same alloy composition as that of the nanocrystalline ribbon in Example 1, which is Fe. 70 Co 20 The only difference between this comparative example and Example 1 is that the heat treatment used in this example is magnetic field heat treatment, while the rest of the preparation process is the same.

[0055] Test case The performance of the nanocrystalline soft magnetic alloy strips prepared under the above-mentioned Examples 1-5 and Comparative Examples 1-9 was tested respectively, and the test results are shown in Table 4 below.

[0056] The saturation magnetic flux density of the nanocrystalline ribbon was measured using a vibrating sample magnetometer (VSM), the coercivity of the nanocrystalline ribbon was measured using a DC BH meter, and the loss of the nanocrystalline ribbon was measured using an AC BH meter.

[0057] Table 4 Performance test results of Examples 1-5 and Comparative Examples 1-9

[0058] As can be seen, the nanocrystalline ribbons prepared under the schemes of Examples 1-3 of the present invention have a ribbon thickness of 14-22 μm, a ribbon width of less than 100 mm, and a saturation magnetic induction intensity of... B s The coercivity is 1.85-1.99T. H c The loss is 0.2-6 A / m. P 1kHz / 1T It has a strength of 4.6-5.2 W / kg and features high saturation magnetic induction, low coercivity, low loss, and high amorphous formation capability.

[0059] As can be seen from the data in Comparative Examples 1-3, for the conventional commercially available nanocrystalline ribbon products, there is a contradictory relationship between their saturation magnetic induction intensity, coercivity, and loss performance. That is, if the saturation magnetic induction intensity is increased, the coercivity and loss will also increase, making it difficult to achieve a synergistic improvement; it is impossible to achieve a balance between saturation magnetic induction intensity and coercivity and loss performance.

[0060] As can be seen from the data in Comparative Example 4, compared with the product of Example 1, the addition of rare earth elements can effectively regulate the anisotropic field of magnetocrystalline, promote the precipitation and refinement of nanocrystals, and improve the soft magnetic properties of nanocrystalline iron core.

[0061] As can be seen from the data in Comparative Example 5, the addition of Sr can effectively remove harmful impurities in molten steel, reduce the impact of oxide inclusions on the mechanical properties of steel, and effectively inhibit the growth of nanocrystal grains.

[0062] As can be seen from the data in Comparative Example 6, the addition of alkali metal elements and Cl can effectively improve the purity of the solution and effectively stabilize the magnetic properties of the iron core.

[0063] As can be seen from the data in Comparative Example 7, the composite heating method combining electromagnetic induction heating and plasma arc heating can make the solution more uniform, which is beneficial to the formation of amorphous precursor structures.

[0064] As can be seen from the data in Comparative Example 8, the high-pressure rotary jetting process combined with the rolling process can obtain a uniform and refined preliminary microstructure, while suppressing grain boundary growth and reducing coercivity.

[0065] As can be seen from the data in Comparative Example 9, ultrasonic-magnetic field composite heat treatment can release internal stress and local high temperature in the material on the one hand, and improve the magnetic domain structure on the other hand. Applying a magnetic field and controlling the stress during the heat treatment process can induce anisotropy in the strip, improve the magnetic domain structure, and further enhance the soft magnetic properties of the material.

[0066] In summary, the nanocrystalline ribbon obtained by the method of this invention has a saturation magnetic induction intensity of not less than 1.85T and also possesses ultra-low coercivity, with adjustable thickness and width. It is evident that the Fe, Co, Ni, Si, B, Sr, Cu, rare earth elements, and alkali metal chloride alloys in the nanocrystalline ribbon of this invention interact with each other, synergistically improving the saturation magnetic induction intensity and reducing coercivity. The composite melting process combining induction heating and plasma arc heating enables the preparation of a high-purity master alloy. The high-pressure rotary jetting process combined with rolling technology yields a uniform amorphous precursor ribbon structure with adjustable thickness and width, while reducing coercivity and loss. Ultrasonic-magnetic field composite heat treatment effectively eliminates ribbon stress, refines magnetic domains, promotes uniform grain precipitation and refinement, and the application of a magnetic field further refines magnetic domains, enhancing the alloy's magnetic properties.

[0067] The embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A nanocrystalline ribbon, characterized in that, The chemical elemental composition of the nanocrystalline ribbon is such as Fe a Co b Ni c Si d B e R f Sr j Cu h (MCl) x As shown; where, R is a rare earth element, selected from at least one of Tb, Ho, or Er; M is an alkali metal element, selected from at least one of Na or K; a, b, c, d, e, f, j, h, and x represent the atomic percentages of their respective elements; where 70 ≤ a ≤ 85, 10 ≤ b ≤ 20, 1 ≤ c ≤ 2, 1 ≤ d ≤ 2, 1 ≤ e ≤ 6, 0.5 ≤ f ≤ 1, 0.5 ≤ j ≤ 1, 0.5 ≤ h ≤ 2, and 0.5 ≤ x ≤ 1, and the sum of the atomic percentages of all components is 100.

2. The nanocrystalline ribbon according to claim 1, characterized in that: The saturation magnetic induction intensity of the nanocrystalline ribbon B s For 1.85-1.99T; and / or, The coercivity of the nanocrystalline ribbon H c 0.2-6 A / m; and / or, The loss of the nanocrystalline ribbon P 1kHz / 1T It is 4.6-5.2 W / kg; and / or, The thickness of the nanocrystalline ribbon is 14-22 μm; and / or, The width of the nanocrystalline ribbon is 1-100 mm.

3. A method for preparing the nanocrystalline ribbon as described in claim 1 or 2, characterized in that, Includes the following steps: (1) According to the elemental composition of the nanocrystalline ribbon, weigh out iron, cobalt, nickel, silicon, boron, rare earth elements, Sr, copper and alkali metal chloride alloy and mix them to obtain a mixture; (2) The mixture is subjected to plasma melting under an inert atmosphere to obtain a molten alloy liquid; (3) The molten alloy liquid is dispersed to form micron-sized amorphous droplets, and then solidified and rolled to obtain amorphous precursor strip; (4) The amorphous precursor tape is subjected to ultrasonic-magnetic field composite heat treatment to obtain the desired nanocrystalline tape.

4. The method for preparing the nanocrystalline ribbon according to claim 3, characterized in that, In step (2), the heating method of the plasma melting step includes a composite heating method combining electromagnetic induction heating and plasma arc heating; wherein, The heating temperature of the electromagnetic induction heating is 1300-1400℃, and the heating time is 5-15 minutes; The plasma arc heating temperature is 1500-1600℃, and the heating time is 5-15 min; The vibration current of the composite heating is 50-100A.

5. The method for preparing the nanocrystalline ribbon according to claim 3 or 4, characterized in that, In step (3), the dispersion treatment step includes the step of forming 20-200μm amorphous droplets by high-speed rotating spraying of the molten alloy liquid.

6. The method for preparing the nanocrystalline ribbon according to any one of claims 3-5, characterized in that, In step (3), the solidification-rolling process includes the step of spraying the amorphous molten droplets at high speed onto the surface of a rotating roll; The linear velocity of the rolls is 20-40 m / s, the rolling pressure is 50-200 MPa, and the cooling rate is 10. 4 -10 6 K / s; The thickness of the amorphous precursor strip is 14-22 μm and the width is 1-100 mm.

7. The method for preparing the nanocrystalline ribbon according to any one of claims 3-6, characterized in that, In step (4), the ultrasonic-magnetic field composite heat treatment step controls the ultrasonic frequency to be 20-50kHz, the power to be 200-1100W, and the ultrasonic amplitude to be 10-20μm.

8. The method for preparing the nanocrystalline ribbon according to any one of claims 3-7, characterized in that, In step (4), the ultrasonic-magnetic field composite heat treatment step uses a longitudinal magnetic field, controls the magnetic field strength to be 20-100mT, and uses high-purity nitrogen for protection.

9. The method for preparing the nanocrystalline ribbon according to any one of claims 3-8, characterized in that, In step (4), the temperature of the ultrasonic-magnetic field composite heat treatment step is 350-480℃, the heating rate is controlled at 100-500℃ / s, and the cooling rate is 10℃ / s. 3 -10 4 ℃ / s, heat preservation time 1-10 minutes.

10. The application of the nanocrystalline ribbon according to claim 1 or 2 or the nanocrystalline ribbon prepared by the method according to any one of claims 3-9 in the fields of medium and high frequency transformers and wireless charging.

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