A flexible papered nanocrystalline magnetic material

Abstract

A flexible paperized nanocrystalline magnetic material, taking Fe 78 Si9B 13 Amorphous strip as the core raw material, after annealing cooling, pre-cutting, nitrogen protection ball milling, drying, passivation, coating → dry pretreatment to obtain modified Fe 78 Si9B 13 Nanocrystalline powder; and then through the continuous process of "slurry preparation → R2R coating → magnetic field orientation → drying → online detection → winding → slitting". It has excellent soft magnetic properties and paperized flexibility, can be bent and cut, effectively solves the technical defects of traditional Fe 78 Si9B 13 Amorphous strip, such as poor flexibility, easy oxidation, unstable magnetic properties and low production efficiency. Low cost, high cost performance; The preparation process is continuous and controllable, green and environmentally friendly, high production efficiency, can realize mass production, suitable for new energy, wireless charging, electromagnetic shielding, flexible electronic devices and other application scenarios.

Description

Technical Field

[0001] This invention relates to the field of nanocrystalline magnetic materials technology, and in particular to a flexible paper-like nanocrystalline magnetic material. Background Technology

[0002] Fe 78 Si9B 13 Nanocrystalline magnetic materials, with their excellent soft magnetic properties such as high permeability, low eddy current loss, and high saturation magnetic induction, have broad application prospects in fields such as electronic information, new energy, and electromagnetic protection. However, existing Fe... 78 Si9B 13 There are many core technological conflicts in the processing and application of amorphous ribbons, specifically reflected in: 1. Performance synergy conflict: First, there is a conflict between flexibility and magnetic properties, traditional Fe... 78 Si9B 13 Amorphous ribbons are brittle and hard with a bend radius of ≥15mm, making it difficult to process them into thin and flexible paper-like structures. Simply adding flexible binders will lead to a decrease in the material's magnetic permeability and an increase in eddy current losses. Secondly, there is a conflict between oxidation resistance and magnetic properties. The surface of amorphous ribbons is prone to oxidation, which leads to a decrease in magnetic properties. The thick coating formed by conventional passivation / coating treatments will hinder the conduction of magnetic flux, further reducing the material's magnetic properties.

[0003] 2. Conflicts in process implementation: First, there is a conflict between continuous production and product quality. Existing intermittent processing is cumbersome, inefficient, and environmentally unfriendly, while R2R continuous coating processes are prone to uneven coating, wrinkling, and delamination of the preform. Second, there is a conflict between ball milling efficiency and powder quality. Increasing ball milling intensity can cause powder agglomeration and oxidation, while decreasing ball milling intensity results in excessively large powder particles, making it impossible to achieve paper-like forming. Third, there is a conflict between drying efficiency and preform integrity. Rapid drying can easily lead to cracking and wrinkling of the preform, while slow drying contradicts the production efficiency requirements of continuous processes.

[0004] 3. Conflict between raw material processing and application requirements: Although annealing and cooling can improve the magnetic properties of materials, it will increase the brittleness of amorphous zones and affect the uniformity of paper-forming; the smaller the particle size of nanocrystalline powder, the better the material flexibility but the faster the oxidation rate. If the particle size is too large, the powder dispersion will be poor and the material flexibility will be insufficient; the comprehensive requirements of "lightweight, thin, flexible, high magnetic properties and long life" for magnetic materials in flexible electronics, wireless charging and other scenarios cannot be achieved by existing technologies.

[0005] Furthermore, some improved processes lack effective powder protection and surface modification methods, and have not formed a complete continuous production system. This makes it impossible to prepare products that combine paper-like morphology and excellent magnetic properties, thus failing to meet the needs of industrial mass production and applications in flexible electronics. Therefore, developing a flexible paper-like nanocrystalline magnetic material and its preparation method that can effectively solve all the above-mentioned technical conflicts, possessing paper-like flexibility, excellent magnetic properties, and oxidation resistance, while also being highly efficient, cost-controllable, and environmentally friendly, has become an urgent technical challenge in this field. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention discloses a flexible paper-like nanocrystalline magnetic material.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: A flexible paper-like nanocrystalline magnetic material, the components of which, by mass percentage, are: modified Fe 78 Si9B 13 The modified Fe alloy comprises 65%–85% nanocrystalline powder, 10%–30% flexible binder, 1%–4% dispersant, 0.5%–2% KH-550 silane coupling agent, and 0.1%–1.5% hindered phenolic antioxidant; 78 Si9B 13 Nanocrystalline powder is based on Fe 78 Si9B 13 Amorphous ribbons are obtained from raw materials through pretreatment; The preparation method is as follows: (1) Raw material pretreatment: using Fe 78 Si9B 13 Modified Fe was obtained by sequentially processing amorphous ribbons as raw material, followed by annealing and cooling, pre-cutting, nitrogen-protected ball milling, drying, passivation, coating, and drying. 78 Si9B 13 Nanocrystalline powder; (2) Slurry preparation: Weigh each component according to the mass percentage, add 25% to 40% of the total mass of deionized water, and control the solid-liquid ratio to 1:1.5 to 2; stir at a speed of 2000 to 3000 r / min for 30 to 60 min, and then disperse at an ultrasonic power of 250 to 350 W for 25 to 35 min to obtain a uniformly dispersed, non-agglomerated cast slurry with a viscosity of 5000 to 8000 mPa·s; (3) R2R coating: The pulp obtained in step (2) is made into a wet paper blank; (4) Magnetic field orientation: The wet paper blank obtained in step (3) is fed into a magnetic field orientation device and a DC magnetic field of 0.1 to 0.3T is applied for 10 to 20 minutes. (5) Gradient heating and drying: The wet paper blank obtained after magnetic field orientation in step (4) is sent into a continuous drying oven and dried by segmented gradient heating: 80-100℃ for 1-2 hours, and then dried at 120-150℃ for 2-3 hours. (6) Online monitoring: The dried paper blanks obtained after step (5) are subjected to comprehensive performance testing by online testing equipment. Unqualified products are recycled and reprocessed, while qualified products enter the next process. (7) Winding: The blank that has passed the inspection in step (6) is continuously wound up through the winding device. The winding speed is controlled to be synchronized with the coating speed. The winding tension is 50-100N to avoid wrinkles and stretching deformation of the blank and to ensure that the roll is flat and undamaged. (8) Slitting: The roll material after step (7) is fed into the slitting machine, the slitting speed is adjusted to 0.4~0.7m / min, the slitting accuracy is ±0.02mm, the edge burrs are removed, and the flexible paper-like nanocrystalline magnetic material product that can be directly cut and bent is obtained.

[0008] Preferably, the modified Fe 78 Si9B 13 The magnetic permeability (1kHz) of the nanocrystalline powder material is ≥1500, and the eddy current loss (50kHz) is ≤30mW / cm³.

[0009] Preferably, the flexible adhesive is one or a mixture of several of waterborne polyurethane, waterborne epoxy resin, and waterborne silane resin.

[0010] Preferably, the dispersant is one of polyethylene glycol 400 and sodium polyacrylate.

[0011] Preferably, the specific steps of the raw material pretreatment are: 1.1 Annealing and cooling: Fe 78 Si9B 13 The amorphous ribbon was placed in an annealing furnace and heated to 480–550°C at a rate of 5–10°C / min under a nitrogen protective atmosphere, held for 2–3 hours, and then cooled to room temperature at a rate of 3–5°C / min; 1.2 Pre-cutting: The annealed and cooled Fe 78 Si9B 131.3 Nitrogen-protected ball milling: Place the pre-cut amorphous ribbon fragments into a ball mill, add zirconia balls as the milling medium, and purge with nitrogen as the protective gas. Control the ball-to-material ratio at 10–15:1, the milling speed at 200–300 r / min, and the milling time at 4–6 h. 1.4 Drying: Place the milled nanocrystalline powder into a drying oven and dry at 80–100℃ for 2–3 h to remove moisture from the powder. 1.5 Passivation: After drying... 1.6 Soaking: Place the nanocrystalline powder in a 1%–3% (w / w) phosphoric acid passivation solution at room temperature for 30–60 min; 1.7 Coating: Remove the passivated nanocrystalline powder and dry it. Add an aqueous silane resin coating agent and stir in a high-speed stirrer at a speed of 500–800 r / min for 1–2 h to ensure that the coating agent is evenly coated on the powder surface and forms a complete passivation coating layer; 1.8 Drying: Place the coated nanocrystalline powder in a drying oven at 80–100℃ and dry for 1–2 h.

[0012] Preferably, the R2R coating in step (3) specifically involves: continuously coating the slurry obtained in step (2) using an R2R coating machine at a coating speed of 1 to 3 m / min and a coating thickness of 0.1 to 0.5 mm, with a flexible substrate being a polyimide film, to obtain a wet paper blank; or using a wet paper forming process, uniformly spreading the slurry obtained in step (1) onto a forming mesh belt, and obtaining a wet paper blank through vacuum dewatering and pressing dewatering.

[0013] Preferably, the qualified product requirements in step (6) are: no obvious scratches, bubbles, or cracks on the surface; thickness deviation ≤ ±0.01mm; magnetic permeability (1kHz) ≥1500; and magnetic loss (10kHz) ≤50mW / cm³.

[0014] Core process Fe 78 Si9B 13 Amorphous ribbon → Annealing and cooling → Pre-cutting → Nitrogen-protected ball milling → Drying → Passivation → Coating → Drying → Slurry preparation → R2R coating / wet papermaking → Magnetic field orientation → Gradient temperature drying → Online inspection → Winding → Slitting → Finished product. The core functions of each step are: Annealing and cooling eliminate internal stress, promote nanocrystal precipitation, and optimize magnetic properties and thermal stability; Nitrogen-protected ball milling prepares uniform-sized nanocrystal powder, avoiding agglomeration and oxidation; Passivation and coating improve oxidation resistance and reduce eddy current losses; Magnetic field orientation ensures orderly powder arrangement and improves the consistency of magnetic properties; Continuous processing enables large-scale mass production, and online inspection ensures product quality throughout the process.

[0015] By employing the technical solution described above, the present invention has the following beneficial effects: Low raw material cost and excellent overall performance: It uses Fe that does not contain precious metals. 78 Si9B 13Using amorphous ribbons as raw materials, compared to traditional high-performance soft magnetic materials containing precious metals, this material can maintain excellent magnetic properties and thermal stability without the need for added precious metals, significantly reducing raw material costs. After annealing, the material exhibits a higher degree of nanocrystallization and can be used for extended periods within a temperature range of -40℃ to 120℃. Magnetic performance decay is ≤5%, permeability (1kHz) ≥1600, saturation magnetic induction ≥1.2T, and eddy current loss at 50kHz ≤35mW / cm³, achieving the dual advantages of "low cost and high performance." Standardized pretreatment yields modified nanocrystalline powder with uniform particle size, good oxidation resistance, and stable magnetic properties, resolving the technical conflicts between ball milling efficiency and powder quality, and between annealing brittleness and processability, laying a core raw material foundation for subsequent continuous molding.

[0016] Achieving large-scale continuous production with high efficiency: The continuous production process of "slurry preparation → R2R coating → magnetic field orientation → drying → online detection → winding → slitting" realizes integrated mass production from raw materials to finished products, greatly improving production efficiency; the R2R coating process ensures uniform material thickness, the magnetic field orientation enables the nanocrystalline powder to be arranged in an orderly manner, further improving magnetic properties and reducing eddy current losses, and online detection controls product quality in real time, completely resolving the technical conflict between continuous mass production and product quality.

[0017] The process is green and environmentally friendly, with controllable energy consumption and cost: the entire preparation process uses an aqueous system with no harmful solvent emissions. Nitrogen-protected ball milling and environmentally friendly reagent passivation coating all meet green and environmental protection requirements. The process steps are simple and easy to operate, requiring no high-temperature sintering, resulting in low energy consumption. Furthermore, all raw materials and additives are conventional low-cost materials, effectively controlling the overall cost of industrial production.

[0018] The product boasts excellent flexibility and a wide range of applications: the prepared material has a bending radius of ≤3mm and can withstand 1000 bends without damage, exhibiting excellent flexibility and cutability, and can be directly adapted to curved surface applications such as flexible electronics and foldable devices; at the same time, the material also has the advantages of good thermal stability, oxidation resistance, and low eddy current loss, and can adapt to the application requirements of high temperature, high frequency, and harsh environments, with significant cost advantages, and has extremely strong market competitiveness and industrialization value.

[0019] The preparation process of this invention is simple and controllable, the raw materials are readily available and do not contain precious metals, and the entire process emits no harmful gases, meeting the environmental protection requirements of industrial production. Combining the excellent comprehensive performance and low cost of the materials, it can significantly improve the economic and social benefits of the products and promote the widespread application of flexible nanocrystalline magnetic materials in various fields. Detailed Implementation Example 1

[0020] A flexible paper-like nanocrystalline magnetic material and its preparation method are described below: (1) Raw material pretreatment: using Fe78 Si9B 13 Amorphous ribbons are used as raw materials; 1.1 Annealing and Cooling: Take Fe 78 Si9B 13 The amorphous ribbon was placed in an annealing furnace, protected by nitrogen, heated to 500°C at a heating rate of 8°C / min, held at that temperature for 2.5 hours, and then cooled to room temperature at a rate of 8°C / min to optimize the thermal stability of the raw material. 1.2 Pre-cutting: Cut the annealed amorphous ribbon into 8mm segments; 1.3 Nitrogen-protected ball milling: The cut amorphous ribbon segments were placed into a ball mill, and zirconia balls were added as the milling medium at a ball-to-material ratio of 12:1. Nitrogen gas was introduced, and the milling speed was 250 r / min for 5 h to obtain Fe particles with a particle size of 100-150 nm. 78 Si9B 13 Nanocrystalline powder; 1.4 Drying: Place the nanocrystalline powder in a drying oven and dry at 90℃ for 2.5 hours to remove moisture; 1.5 Passivation: The dried powder is placed in a 2% phosphoric acid solution and soaked at room temperature for 45 minutes to form a dense passivation layer; 1.6 Coating: After drying the powder, add water-based silane resin coating agent and stir at a high speed of 600 r / min for 1.5 h to form a complete passivation coating layer; 1.7 Drying: The coated nanocrystalline powder was placed in a drying oven at 90℃ and dried for 1.5 h to obtain modified Fe. 78 Si9B 13 Nanocrystalline powder; (2) Slurry preparation: According to the mass percentage, take 75% of modified nanocrystalline powder, 19.5% of waterborne epoxy resin, 1% of polyethylene glycol 400, 2% of KH-550 silane coupling agent, and 1.5% of hindered phenolic antioxidant, add them to the mixing tank and add deionized water, with a solid-liquid ratio of 1:1.8, stir at 2500 r / min for 45 min, and disperse at 300 W ultrasonic power for 30 min to obtain a magnetic slurry with a viscosity of 6500 mPa·s; (3) R2R coating: The magnetic paste is passed through an R2R coating machine at a coating speed of 2m / min and a coating thickness of 0.35mm; (4) Magnetic field orientation: The coated wet paper blank is fed into the magnetic field orientation device, a DC magnetic field of 0.2T is applied, and the orientation time is 15min to make the powder arrange in an orderly manner; (5) Gradient heating and drying: The oriented green body is sent into a continuous drying oven. The first stage is dried at 85℃ for 1.5h, and the second stage is dried at 135℃ for 2.5h. The moisture content after drying is 0.3%, which ensures the integrity of the material structure and thermal stability. (6) Online testing: The dried paper blank was subjected to comprehensive performance testing using online testing equipment. The test results showed that there were no obvious scratches, bubbles, or cracks on the surface, the thickness was 0.3 mm, the magnetic permeability (1 kHz) was 1700, the bending radius was 2.5 mm, the oxidation resistance at room temperature met the standard, there was no obvious oxidation after 72 hours of storage at 100℃, the magnetic performance decayed by 3% at -40℃~120℃, and the eddy current loss (50 kHz) was 30 mW / cm. 3 It is a qualified product; (7) Winding: The qualified blank is continuously wound up by a winding device at a winding speed of 2m / min and a winding tension of 80N. (8) Slitting: Feed the rolled material into the slitting machine, adjust the slitting speed to 0.5m / min, slitting it into finished products of 300mm×200mm with a slitting accuracy of ±0.01mm, and then package and store it.

[0021] The flexible paper-like nanocrystalline magnetic material prepared in this embodiment has a bending radius of 2.5 mm, can be bent 1000 times without breakage, has a magnetic permeability of 1700, a coercivity of 7 A / m, a saturation magnetic induction of 1.25 T, and an eddy current loss (50 kHz) of 30 mW / cm. 3 It is suitable for high-frequency applications of tens of kHz; it has excellent thermal stability, with magnetic properties decaying by 3% within the range of -40℃ to 120℃, and no oxidation phenomenon after 12 months of storage at room temperature, and no obvious oxidation after 72 hours of storage at 100℃; while ensuring high performance, the cost is reduced by more than 30% compared with traditional soft magnetic materials containing precious metals, which meets the usage requirements of flexible electronics and wireless charging scenarios, especially suitable for medium and high temperature and high-frequency applications of tens of kHz, and is suitable for industrial mass production. Example 2

[0022] A flexible paper-like nanocrystalline magnetic material and its preparation method are described below: (1) Raw material pretreatment: using Fe 78 Si9B 13 Amorphous ribbons are used as raw materials; 1.1 Annealing and Cooling: Take Fe 78 Si9B 13 The amorphous ribbon was placed in an annealing furnace, protected by nitrogen, heated to 480°C at a heating rate of 5°C / min, held for 3 hours, and cooled to room temperature at a rate of 5°C / min to optimize the thermal stability of the raw material. 1.2 Pre-cutting: Cut the annealed amorphous ribbon into 5mm segments; 1.3 Nitrogen-protected ball milling: The cut amorphous ribbon segments were placed into a ball mill, and zirconia balls were added as the milling medium at a ball-to-material ratio of 10:1. Nitrogen gas was introduced, and the milling speed was 200 r / min for 6 hours to obtain Fe particles with a particle size of 50–100 nm. 78 Si9B13 Nanocrystalline powder; 1.4 Drying: Place the nanocrystalline powder in a drying oven and dry at 80℃ for 3 hours to remove moisture; 1.5 Passivation: The dried powder is placed in a 1% phosphoric acid solution and soaked at room temperature for 60 minutes to form a dense passivation layer; 1.6 Coating: After drying the powder, add water-based silane resin coating agent and stir at a high speed of 500 r / min for 1 h to form a complete passivation coating layer; 1.7 Drying: The coated nanocrystalline powder was placed in an 80℃ drying oven and dried for 2 hours to obtain modified Fe. 78 Si9B 13 Nanocrystalline powder (2) Slurry preparation: According to the mass percentage, take 70% of modified nanocrystalline powder, 25% of waterborne silane resin, 3% of sodium polyacrylate, 0.5% of KH-550 silane coupling agent, and 1.5% of hindered phenolic antioxidant, add them to the mixing tank and add deionized water, with a solid-liquid ratio of 1:1.5, stir at 2000 r / min for 60 min, and disperse at 250 W ultrasonic power for 25 min to obtain a magnetic slurry with a viscosity of 5000 mPa·s; (3) R2R coating: The magnetic paste is passed through an R2R coating machine at a coating speed of 1m / min and a coating thickness of 0.1mm; (4) Magnetic field orientation: The coated wet paper blank is fed into the magnetic field orientation device, a DC magnetic field of 0.1T is applied, and the orientation time is 20min to make the powder arrange in an orderly manner; (5) Gradient heating and drying: The oriented wet paper blank is sent into a continuous drying oven. The first stage is dried at 80℃ for 2 hours, and the second stage is dried at 120℃ for 3 hours. The moisture content after drying is 0.4%, which ensures the integrity of the material structure and thermal stability. (6) Online testing: The dried paper blank was subjected to comprehensive performance testing using online testing equipment. The test results showed that there were no obvious scratches, bubbles, or cracks on the surface, the thickness was 0.1 mm, the magnetic permeability (1 kHz) was 1600, the bending radius was 3 mm, the oxidation resistance at room temperature met the standard, there was no obvious oxidation after 72 hours of storage at 100℃, the magnetic performance decay was 4.5% at -40℃ to 120℃, and the eddy current loss (50 kHz) was 35 mW / cm. 3 It is a qualified product; (7) Winding: The qualified blank is continuously wound up by a winding device at a winding speed of 1m / min and a winding tension of 50N. (8) Slitting: Send the rolled material into the slitting machine, adjust the slitting speed to 0.7m / min, slitting it into 100mm×100mm finished products with a slitting accuracy of ±0.01mm, and package it into the warehouse.

[0023] The flexible paper-like nanocrystalline magnetic material prepared in this embodiment has a bending radius of 3 mm, can be bent 1000 times without breakage, has a magnetic permeability of 1600, a coercivity of 8 A / m, a saturation magnetic induction of 1.2 T, and an eddy current loss (50 kHz) of 35 mW / cm. 3 It is suitable for high-frequency applications of tens of kHz; it has excellent thermal stability, with magnetic properties decaying by 4.5% in the range of -40℃ to 120℃, and no oxidation phenomenon after 12 months of storage at room temperature and no obvious oxidation after 72 hours of storage at 100℃; it has low production cost, is suitable for small flexible electronic devices, and can be used stably in medium and low temperature and high frequency scenarios of tens of kHz, making it suitable for industrial mass production. Example 3

[0024] (1) Raw material pretreatment: using Fe 78 Si9B 13 Amorphous ribbons are used as raw materials; 1.1 Annealing and Cooling: Take Fe 78 Si9B 13 The amorphous ribbon was placed in an annealing furnace, protected by nitrogen, and heated to 550°C at a rate of 10°C / min. It was held at that temperature for 2 hours and then cooled to room temperature at a rate of 10°C / min to optimize the thermal stability of the raw material. 1.2 Pre-cutting: Cut the annealed amorphous ribbon into 10mm segments; 1.3 Nitrogen-protected ball milling: The cut amorphous ribbon segments were placed into a ball mill, and zirconia balls were added as the milling medium at a ball-to-material ratio of 15:1. Nitrogen gas was introduced, and the milling speed was 300 r / min for 4 hours to obtain Fe particles with a particle size of 150–200 nm. 78 Si9B 13 Nanocrystalline powder; 1.4. Drying: Place the nanocrystalline powder in a drying oven and dry at 100℃ for 2 hours to remove moisture; 1.5 Passivation: The dried powder is placed in a 3% phosphoric acid solution and soaked at room temperature for 30 minutes to form a dense passivation layer; 1.6 Coating: After drying the powder, add water-based silane resin coating agent and stir at 800 r / min for 2 h to form a complete passivation coating layer; 1.7 Drying: The coated nanocrystalline powder was placed in a drying oven at 100℃ and dried for 2 hours to obtain modified Fe. 78 Si9B 13 Nanocrystalline powder; (2) Slurry preparation: Take 85% of modified nanocrystalline powder, 10% of waterborne polyurethane resin, 3.9% of polyethylene glycol 400, 1% of silane coupling agent KH-550, and 0.1% of hindered phenolic antioxidant by mass percentage, add them to the mixing tank and add deionized water, with a solid-liquid ratio of 1:2, stir at 3000 r / min for 30 min, and disperse at 350 W ultrasonic power for 35 min to obtain a magnetic slurry with a viscosity of 8000 mPa·s; (3) R2R coating: The magnetic paste is passed through an R2R coating machine at a coating speed of 3m / min and a coating thickness of 0.5mm; (4) Magnetic field orientation: The coated wet paper blank is fed into the magnetic field orientation device, a DC magnetic field of 0.3T is applied, and the orientation time is 10min to make the powder arrange in an orderly manner; (5) Gradient heating and drying: The oriented wet paper blank is sent into a continuous drying oven. The first stage is dried at 100℃ for 1 hour, and the second stage is dried at 150℃ for 2 hours. The moisture content after drying is 0.2%, which ensures the integrity of the material structure and thermal stability. (6) Online testing: The dried paper blank was subjected to comprehensive performance testing using online testing equipment. The test results showed that there were no obvious scratches, bubbles, or cracks on the surface, the thickness was 0.5 mm, the magnetic permeability (1kHz) was 1800, the bending radius was 2 mm, the oxidation resistance at room temperature met the standard, there was no obvious oxidation after 72 hours of storage at 100℃, the magnetic performance decayed by 2% at -40℃~120℃, and the eddy current loss (50kHz) was 25 mW / cm. 3 It is a qualified product; (7) Winding: The qualified blank is continuously wound up by a winding device at a winding speed of 2m / min and a winding tension of 100N. (8) Slitting: Send the rolled material into the slitting machine, adjust the slitting speed to 0.4m / min, slitting it into finished products of 500mm×300mm with a slitting accuracy of ±0.01mm, and then package and store it.

[0025] The flexible paper-like nanocrystalline magnetic material prepared in this embodiment has a bending radius of 2 mm, can be bent 1000 times without breakage, has a magnetic permeability of 1800, a coercivity of 6 A / m, a saturation magnetic induction of 1.3 T, and an eddy current loss (50 kHz) of 25 mW / cm. 3 It is suitable for high-frequency applications of tens of kHz; it has excellent thermal stability, with magnetic properties decaying by 2% within the range of -40℃ to 120℃, and no oxidation phenomenon after 12 months of storage at room temperature, and no obvious oxidation after 72 hours of storage at 100℃; it combines high performance and low cost, and is suitable for large electromagnetic shielding and wireless charging equipment. It can be used stably for a long time in high-temperature and high-frequency scenarios of tens of kHz, and is suitable for industrial mass production.

[0026] Comparative test The flexible paper-like nanocrystalline magnetic materials prepared in Examples 1-3 of this invention are compared with existing unmodified Fe... 78 Si9B 13 Amorphous zone, traditional Fe 78 Si9B 13 The performance of nanocrystalline bulk materials was compared, and the results are shown in the table below:

[0027] The comparative test results above show that the flexible paper-like nanocrystalline magnetic material prepared by this invention, through synergistic optimization of each process step and component ratio, successfully solves a series of core technical conflicts in the prior art, such as flexibility versus magnetic properties, oxidation resistance versus magnetic properties, and continuous production versus product quality. It is significantly superior to existing unmodified Fe in terms of morphology, flexibility, magnetic properties, oxidation resistance, preparation process, and production efficiency. 78 Si9B 13 Amorphous ribbons and traditional nanocrystalline bulk materials have been successfully transformed into paper-like and flexible materials, overcoming the core defects of existing technologies and possessing significant technological advantages and application value.

[0028] The parts of this invention not described in detail are prior art. It will be apparent to those skilled in the art that this invention is not limited to the details of the above exemplary embodiments, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all changes falling within the meaning and scope of the equivalents of the claims be included within the invention.

Claims

1. A flexible paper-like nanocrystalline magnetic material, characterized in that: The components, by mass percentage, are: modified Fe 78 Si9B 13 The modified Fe alloy comprises 65%–85% nanocrystalline powder, 10%–30% flexible binder, 1%–4% dispersant, 0.5%–2% KH-550 silane coupling agent, and 0.1%–1.5% hindered phenolic antioxidant. 78 Si9B 13 Nanocrystalline powder is based on Fe 78 Si9B 13 Amorphous ribbons are obtained from raw materials through pretreatment; The preparation method is as follows: (1) Raw material pretreatment: using Fe 78 Si9B 13 Modified Fe was obtained by sequentially processing amorphous ribbons as raw material, followed by annealing and cooling, pre-cutting, nitrogen-protected ball milling, drying, passivation, coating, and drying. 78 Si9B 13 Nanocrystalline powder; (2) Slurry preparation: Weigh each component according to the mass percentage, add 25% to 40% of the total mass of deionized water, and control the solid-liquid ratio to 1:1.5 to 2; stir at a speed of 2000 to 3000 r / min for 30 to 60 min, and then disperse at an ultrasonic power of 250 to 350 W for 25 to 35 min to obtain a uniformly dispersed, non-agglomerated cast slurry with a viscosity of 5000 to 8000 mPa·s; (3) R2R coating: The pulp obtained in step (2) is made into a wet paper blank; (4) Magnetic field orientation: The wet paper blank obtained in step (3) is fed into a magnetic field orientation device and a DC magnetic field of 0.1 to 0.3T is applied for 10 to 20 minutes. (5) Gradient heating and drying: The wet paper blank obtained after magnetic field orientation in step (4) is sent into a continuous drying oven and dried by segmented gradient heating: 80-100℃ for 1-2 hours, and then dried at 120-150℃ for 2-3 hours. (6) Online monitoring: The dried paper blanks obtained after step (5) are subjected to comprehensive performance testing by online testing equipment. Unqualified products are recycled and reprocessed, while qualified products enter the next process. (7) Winding: The blank that has passed the inspection in step (6) is continuously wound up through the winding device. The winding speed is controlled to be synchronized with the coating speed. The winding tension is 50-100N to avoid wrinkles and stretching deformation of the blank and to ensure that the roll is flat and undamaged. (8) Slitting: The roll material after step (7) is fed into the slitting machine, the slitting speed is adjusted to 0.4~0.7m / min, the slitting accuracy is ±0.02mm, the edge burrs are removed, and the flexible paper-like nanocrystalline magnetic material product that can be directly cut and bent is obtained.

2. The flexible paper-like nanocrystalline magnetic material as described in claim 1, characterized in that: The modified Fe 78 Si9B 13 The magnetic permeability (1kHz) of the nanocrystalline powder material is ≥1500, and the eddy current loss (50kHz) is ≤30mW / cm³.

3. The flexible paper-like nanocrystalline magnetic material as described in claim 1, characterized in that: The flexible adhesive is one or a mixture of several of the following: waterborne polyurethane resin, waterborne epoxy resin, and waterborne silane resin.

4. The flexible paper-like nanocrystalline magnetic material as described in claim 1, characterized in that: The dispersant is one of polyethylene glycol 400 and sodium polyacrylate.

5. The flexible paper-like nanocrystalline magnetic material as described in claim 1, characterized in that: The specific steps of the raw material pretreatment are as follows: 1.1 Annealing and cooling: Fe 78 Si9B 13 The amorphous ribbon is placed in an annealing furnace and heated to 480-550°C at a rate of 5-10°C / min under a nitrogen protective atmosphere. It is held at this temperature for 2-3 hours and then cooled to room temperature at a rate of 3-5°C / min. 1.2 Pre-cutting: The annealed and cooled Fe... 78 Si9B 13 1.3 Nitrogen-protected ball milling: Place the pre-cut amorphous ribbon fragments into a ball mill, add zirconia balls as the milling medium, and purge with nitrogen as the protective gas. Control the ball-to-material ratio at 10–15:1, the milling speed at 200–300 r / min, and the milling time at 4–6 h. 1.4 Drying: Place the milled nanocrystalline powder into a drying oven and dry at 80–100℃ for 2–3 h to remove moisture from the powder. 1.5 Passivation: After drying... 1.6 Soaking: Place the nanocrystalline powder in a 1%–3% (w / w) phosphoric acid passivation solution at room temperature for 30–60 min; 1.7 Coating: Remove the passivated nanocrystalline powder and dry it. Add an aqueous silane resin coating agent and stir in a high-speed stirrer at a speed of 500–800 r / min for 1–2 h to ensure that the coating agent is evenly coated on the powder surface and forms a complete passivation coating layer; 1.8 Drying: Place the coated nanocrystalline powder in a drying oven at 80–100℃ and dry for 1–2 h.

6. The flexible paper-like nanocrystalline magnetic material as described in claim 1, characterized in that: The R2R coating in step (3) specifically involves continuously coating the slurry obtained in step (2) using an R2R coating machine at a coating speed of 1-3 m / min and a coating thickness of 0.1-0.5 mm. The flexible substrate is a polyimide film, resulting in a wet paper blank.

7. The flexible paper-like nanocrystalline magnetic material as described in claim 1, characterized in that: The qualified product requirements in step (6) are: no obvious scratches, bubbles, or cracks on the surface; thickness deviation ≤ ±0.01mm; magnetic permeability (1kHz) ≥1500; and magnetic loss (10kHz) ≤50mW / cm³.

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