Iron-based amorphous nanocrystalline nanoparticles, their pressed magnetic cores, preparation methods, and applications
Iron-based amorphous nanocrystalline nanoparticles prepared by atomic manufacturing strategy have solved the problems of high high-frequency loss and difficulty in removing internal stress in traditional processes, and realized amorphous nanocrystalline magnetic powder cores with high frequency, low loss and high magnetization.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HOHAI UNIV
- Filing Date
- 2026-05-06
- Publication Date
- 2026-06-30
AI Technical Summary
Existing iron-based amorphous and nanocrystalline magnetic powder cores suffer from high high-frequency losses and difficulty in achieving both high saturation magnetization and low losses. Traditional preparation processes are cumbersome and internal stress is difficult to completely remove, resulting in unsatisfactory soft magnetic properties.
Iron-based amorphous nanocrystalline nanoparticles were prepared using an atomic manufacturing strategy. Nanoparticles with a particle size of 5-100 nm were prepared using laser inert gas condensation technology. They have an in-situ generated core-shell structure, avoiding the insulation coating process. They were formed under low pressure and did not require high-temperature heat treatment, thus preparing amorphous nanocrystalline magnetic powder cores.
It achieves extremely low high-frequency loss and high saturation magnetization. The high-frequency loss of the magnetic core is Pcv(0.05 T, 100 kHz) = 78-94 mW/cm3, Pcv(0.01 T, 1 MHz) = 11-53 mW/cm3, and the magnetization is 160-188 emu/g, which is significantly better than traditional magnetic powder cores.
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Figure CN122303759A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of soft magnetic materials technology, specifically relating to an iron-based amorphous nanocrystalline nanoparticle and its pressed magnetic core, preparation method and application; in particular, it relates to an iron-based amorphous nanocrystalline nanoparticle prepared by an atomic manufacturing strategy, its pressed magnetic core, preparation method and application. Background Technology
[0002] Energy conservation and emission reduction have become the core driving force for the development of new materials, especially with the rapid iteration in fields such as third-generation semiconductors, new energy, next-generation information technology, and artificial intelligence. Power electronic devices are gradually developing towards higher frequencies, lower power consumption, and integration, placing higher demands on matching soft magnetic materials. Soft magnetic composite materials, also known as magnetic powder cores, are magnetic powder cores formed by insulating and pressing magnetic powder into the desired shape using powder metallurgy. As a new generation of soft magnetic materials, their significant characteristic is the abundance of interfaces and distributed air gaps. Therefore, magnetic powder cores combine the performance characteristics of traditional metallic soft magnetic materials and soft magnetic ferrites, exhibiting high saturation magnetization and permeability, high cutoff frequency and low eddy current loss, as well as good formability, making them suitable for molding complex devices. They are widely used in photovoltaic inverters, switching power supplies, power inductors, and integrally molded inductors. Typical systems include pure iron powder cores, Sendust (FeSiAl) magnetic cores, permalloy powder cores, and amorphous nanocrystalline powder cores. Compared to traditional metallic magnetic powder cores, iron-based amorphous magnetic powder cores exhibit lower high-frequency eddy current losses due to their unique long-range disordered, short-range ordered atomic structure and higher resistivity. Furthermore, appropriate nanocrystallization can further improve the overall soft magnetic properties of iron-based amorphous magnetic powder cores. Therefore, iron-based amorphous nanocrystalline magnetic powder cores are considered ideal soft magnetic materials for mid-to-high frequency applications.
[0003] However, current research on iron-based amorphous and nanocrystalline magnetic powder cores focuses on micron-sized magnetic powders, and the following problems urgently need to be addressed: high-frequency losses need to be reduced; due to the introduction of non-magnetic insulating materials, it is difficult to simultaneously achieve high saturation magnetization and low losses; the insulation coating process is cumbersome; the forming pressure is too high, and the internal stress is difficult to completely remove during subsequent heat treatment, resulting in unsatisfactory overall soft magnetic properties. Chinese patent CN109273185A discloses a method for preparing magnetic powder cores using iron-based nanocrystalline alloy powder, achieving a core loss greater than 1000 mW / cm under conditions of 0.1 T and 100 kHz. 3 Chinese patent application CN110706912A discloses a method for preparing amorphous nanocrystalline soft magnetic powder cores, with a core loss greater than 800 mW / cm. 3 Chinese patent application CN117497278A discloses a high-permeability, low-loss iron-based amorphous composite magnetic powder core and its preparation method, with a core loss of 1000 mW / cm. 3 Around 100°C, the core loss is at a relatively high level.
[0004] Nanopowders possess the advantage of intrinsically low eddy current loss, and surface nanoengineering strategies hold promise for revolutionizing insulating coating processes. Traditional methods such as mechanical ball milling can only prepare submicron iron-based nanoparticles, and the sphericity needs improvement. Chemical synthesis methods can prepare iron-based nanoparticles with a particle size within 100 nm, but significant agglomeration occurs, making monodispersity impossible, and resulting in numerous chemical impurities. Therefore, the preparation technology for iron-based amorphous nanoparticles with a particle size within 100 nm and high sphericity, as well as the technology for their magnetic powder cores, is currently undisclosed and urgently needs breakthroughs. Summary of the Invention
[0005] Objective: There is an inverse relationship between magnetization and loss in iron-based amorphous nanocrystalline soft magnetic composite materials. Traditional manufacturing processes include powder preparation, insulating coating, pressing, and heat treatment, which are quite cumbersome. Due to the inherent high strength and hardness of amorphous alloys and their near-zero plastic deformation capacity, high forming pressure (typically above 1.5 GPa) is required, leading to large internal stresses that are difficult to completely remove during subsequent heat treatment, thus preventing optimal soft magnetic properties. To address these issues, this invention provides iron-based amorphous nanocrystalline nanoparticles and their pressed magnetic cores prepared using an atomic manufacturing strategy. Benefiting from the in-situ core-shell structure generated from the nanoparticles, no subsequent insulating coating process is required. Furthermore, molding can be performed under extremely low pressure, avoiding the introduction of large internal stresses and high-temperature heat treatment. This results in a novel amorphous nanocrystalline magnetic powder core, revolutionizing the magnetic powder core manufacturing process and breaking the inverse relationship between high magnetization and low loss.
[0006] Meanwhile, the present invention provides a method for preparing iron-based amorphous nanocrystalline nanoparticles.
[0007] Meanwhile, the present invention provides a method for preparing pressed powder magnetic cores.
[0008] Meanwhile, this invention provides an application of iron-based amorphous nanocrystalline magnetic cores.
[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: The present invention describes an iron-based amorphous nanocrystalline nanoparticle prepared using an atomic manufacturing strategy, wherein the chemical formula of the alloy is Fe, based on the molar percentage of each atom. a B b Si c P d Cu e TM fa+b+c+d+e+f = 100, where 72≤a≤85, 0<b≤10, 0≤c≤9, 0<d≤10, 0≤e≤1, 0≤f≤3, b+d = 15, TM is selected from one of Nb, Cr, V, Mo, Zr, Co, Ni; the atomic nanoparticle manufacturing technology used is laser inert gas condensation technology.
[0010] The magnetic powder core prepared based on the atomic manufacturing strategy described in this invention uses cold pressing as the magnetic powder core forming technology.
[0011] Preferably, the alloy composition is Fe. 79 Si6B 10 P5, the prepared nanoparticles have a particle size between 5-100 nm, good dispersibility, and high sphericity. The nanoparticles possess an in-situ generated core-shell structure, with a surface oxide layer thickness of approximately 2 nm, which can serve as an in-situ insulating coating, thus eliminating the need for subsequent insulating coating processes and allowing direct pressing into magnetic cores. Due to the excellent self-lubricating effect and abundant interfaces of the nanoparticles, high-strength magnetic powder cores can be prepared by cold pressing under extremely low pressure (less than 0.1 GPa), achieving a compressive strength of 50 MPa. Because of the low molding pressure, internal stress can be fully removed without subsequent high-temperature heat treatment. The saturation magnetization of the nanoparticle magnetic core of this invention is 160-188 emu / g, and the high-frequency loss of the magnetic core is low. P cv (0.05 T, 100kHz) Only 78-94 mW / cm 3 , P cv (0.01 T, 1 MHz) Only 11-53 mW / cm 3 Its overall soft magnetic properties are superior to those of previously reported amorphous and nanocrystalline soft magnetic composite materials.
[0012] The method for preparing iron-based amorphous nanocrystalline nanoparticles based on an atomic manufacturing strategy according to the present invention includes the following steps: Step 1: According to the molecular formula, the raw materials are prepared, with phosphorus (P) added in the form of an iron-phosphorus alloy, and all other components being elemental. The purity of the raw materials is >99.9%, and the batching accuracy is ±0.0005 g. The raw materials are placed into the alumina crucible of the induction melting furnace (melting temperature 1800-2000 ℃), the cavity is closed, and the cavity is evacuated to a vacuum of 3×10⁻⁶. -3 Below Pa, high-purity Ar gas is introduced for protection, and the alloy is melted for 15-20 minutes to ensure complete and uniform melting. The melt is then poured into a copper mold and cooled to obtain a master alloy ingot. The uniformly melted master alloy ingot is machined using wire cutting to prepare a target material with a diameter of 2-5 cm and a thickness of 2-3 mm. The surface of the target material is polished smooth using 1000-2000 grit sandpaper, and then cleaned with anhydrous ethanol and an ultrasonic cleaner. Step 2: Place the alloy target material prepared in Step 1 into the target position of the multifunctional laser inert gas condensation device developed by Shenyang Scientific Instruments Co., Ltd., Chinese Academy of Sciences, and evacuate the cavity to 10... -6 Below Pa, a high-purity inert gas (nitrogen, argon, or helium with a purity >99.99%) is filled into a vacuum-sealed chamber to maintain a constant pressure of 500-600 Pa within the chamber. Liquid nitrogen is then introduced into the cold trap within the powder preparation chamber. Once the rotating cold trap (0-100 r / min) is full of liquid nitrogen, a high-energy laser beam (LSZ-BN / Beijing Laize, 40-65 W laser, pulse frequency 1 kHz-500 kHz) bombards the target material. The sputtered atomic clusters collide with the inert gas molecules, lose energy, and condense into nanoscale amorphous nanocrystalline particles. These nanoparticles are deposited onto the liquid nitrogen cold trap in the center of the equipment under thermal convection. The particles are then scraped off the cold trap and collected using a scraper.
[0013] Step 3: Weigh a certain amount of the nanoparticles prepared in step 2 and place them into a cold press mold. Press them into shape using a hydraulic press with a pressing force of 0.05-0.5 GPa. The sample weighing process is carried out in a glove box.
[0014] Step 4: Place the magnetic powder core prepared in Step 3 into a high vacuum (10). -3 The heat treatment furnace was heated to 250 °C for 10 min.
[0015] The iron-based amorphous nanocrystalline nanoparticle magnetic core of the present invention P cv (0.05 T, 100 kHz) = 78-94 mW / cm 3 , P cv (0.01 T, 1 MHz) = 11-53 mW / cm 3 High saturation magnetization, reaching 160-188 emu / g, and high core compressive strength. σ f The pressure ranges from 43.5 to 55.6 MPa.
[0016] The application of the iron-based amorphous nanocrystalline soft magnetic powder core described in this invention is as a one-piece molded inductor soft magnetic material. This invention prepares iron-based amorphous nanocrystalline nanoparticles into one-piece molded inductors and other electronic devices.
[0017] Application of an iron-based amorphous nanocrystalline magnetic core in integrally molded inductive soft magnetic materials.
[0018] Beneficial effects: Compared with the prior art, the present invention has the following advantages: In existing technologies, the production of iron-based amorphous nanocrystalline magnetic powder cores is based on micron-sized powders (prepared by gas atomization or mechanical crushing). The process includes powder preparation, insulating coating (an essential step), pressing (requiring high forming pressure, approximately 2 GPa, due to the micron-sized powder), and stress-relief heat treatment (the aforementioned high forming pressure introduces significant internal stress, necessitating high-temperature, long-duration stress-relief heat treatment). Because the powder is at the micron level and internal stress is difficult to completely eliminate, this type of magnetic powder core exhibits high high-frequency losses (especially eddy current losses) and requires insulating coating, involving numerous process steps. In contrast, this invention utilizes atomic manufacturing technology to prepare iron-based amorphous nanocrystalline nanoparticles (possessing a core-shell structure with a thin layer of iron oxide acting as an insulating material). This eliminates the need for insulating coating, requires low forming pressure (approximately 0.1 GPa), and results in a higher core strength than micron-sized powder cores formed under high pressure. The low pressure introduced during forming eliminates the need for high-temperature stress-relief heat treatment, and the nanoparticles significantly reduce high-frequency eddy current losses. Therefore, the high-frequency performance of this magnetic core is far superior to that of magnetic powder cores prepared from traditional micron-sized powders.
[0019] This invention utilizes a laser inert gas condensation system to prepare iron-based amorphous nanocrystalline nanoparticles (with a particle size of less than 100 nm and high dispersibility; they are amorphous nanocrystals, not complete crystals). In the prior art, traditional amorphous nanocrystalline powder preparation methods (such as atomization, ball milling, and chemical synthesis) cannot produce the iron-based amorphous nanocrystalline nanoparticles of this invention. Simply using inert gas condensation may not be able to produce the iron-based amorphous nanocrystalline nanoparticles of this invention. Nanoparticles can be produced, but amorphous nanocrystals cannot necessarily be produced. The synergistic effect of component design is required to obtain the iron-based amorphous nanocrystalline nanoparticles of this invention.
[0020] Compared with existing iron-based amorphous soft magnetic composite materials, the advantages of this invention are: (1) The iron-based amorphous nanocrystalline nanoparticles prepared by this invention have a particle size distribution of 5-100 nm and an average particle size of about 25 nm. They have good particle dispersion and high sphericity. The powder prepared by the traditional atomization method has a particle size at the micron level and cannot prepare nanoparticles. The powder prepared by the traditional mechanical ball milling method has a minimum particle size of submicron. The nanoparticles synthesized by the chemical method have serious agglomeration and poor dispersion; (2) The laser inert gas condensation technology used in this invention is a bottom-up atomic manufacturing strategy, which is different from the traditional casting powder preparation method; (3) The nanoparticles prepared by this invention have an in-situ generated core-shell structure with an oxide layer thickness of about 2 nm, which can play an insulating role. Therefore, there is no need for a separate insulating coating process; (4) The molding pressure used by this invention to prepare magnetic powder cores based on nanoparticles is much lower than that of traditional amorphous soft magnetic composite materials, only 0.1 GPa; (5) The amorphous nanoparticle magnetic powder cores of this invention have a high saturation magnetization of 160-188 emu / g and extremely low high-frequency loss. P cv(0.01 T, 1 MHz) Only 11-53 mW / cm 3 It is nearly an order of magnitude lower than traditional iron-based amorphous and nanocrystalline soft magnetic composite materials, and its overall soft magnetic properties are significantly better than those of traditional magnetic powder core materials.
[0021] This invention discloses an iron-based amorphous nanocrystalline nanoparticle and its pressed magnetic core prepared by an atomic manufacturing strategy. The magnetic core exhibits extremely low high-frequency loss and high saturation magnetization. The preparation method includes: target material preparation, using an induction melting furnace to prepare a master alloy ingot, and then machining it into the desired alloy target material using wire cutting; atomic manufacturing of nanoparticles, using laser inert gas condensation technology to prepare iron-based amorphous nanocrystalline nanoparticles with a particle size distribution of 5-100 nm; pressing and molding, weighing an appropriate amount of powder and placing it into a mold, then using a hydraulic press to prepare a ring-shaped magnetic powder core with a minimum forming pressure of less than 0.1 GPa; and heat treatment, using a high-vacuum heat treatment furnace to complete the heat treatment, with a stress-relieving heat treatment temperature of less than 300 ℃. The iron-based amorphous nanocrystalline nanoparticle magnetic core of this invention has the following advantages: extremely low high-frequency loss, P cv (0.05 T, 100 kHz) = 78-94 mW / cm 3 , P cv (0.01 T, 1MHz) = 11-53 mW / cm 3 The loss value is far lower than that of traditional amorphous and nanocrystalline magnetic powder cores under the same conditions; the high saturation magnetization intensity can reach 160-188 emu / g, which is higher than that of most amorphous and nanocrystalline magnetic powder cores; the compressive strength of the magnetic core is also high. σ f The pressure is 43.5-55.6 MPa; the core cutoff frequency is above 10 MHz, comparable to traditional amorphous and nanocrystalline magnetic powder cores; the nanoparticles have an in-situ generated core-shell structure, eliminating the need for additional insulation coating processes; the pressure required for cold pressing of the core can be below 100 MPa, far less than the molding pressure required for traditional amorphous and nanocrystalline magnetic powder cores. The core can be used in high-frequency electronic devices depending on the specific application. Attached Figure Description
[0022] Figure 1 TEM image of FeSiBP amorphous nanocrystalline nanoparticles fabricated at the atomic level; inset is a selected area electron diffraction pattern. Figure 2 High-resolution TEM images of nanoparticles, corresponding high-angle annular dark-field images (HAADF), and energy dispersive spectroscopy (EDS) are shown. Figure 3 The particle size distribution diagram of the prepared nanoparticles; Figure 4 The image shows the XRD pattern of the prepared nanoparticles, with the inset showing a picture of the pressed magnetic core. Figure 5XRD pattern of FeSiBP amorphous powder prepared by gas atomization; Figure 6 The DSC curves for FeSiBP nanoparticles and atomized powder are shown, with a heating rate of 20 K / min. Figure 7 SEM morphology of atomized amorphous powder; Figure 8 Hysteresis loops for nanoparticles and atomized powders; Figure 9 The curves showing the effective permeability of nanoparticle and atomized powder magnetic cores as a function of frequency; Figure 10 The curves showing the change in loss of nanoparticle and atomized powder magnetic cores as a function of frequency; Figure 11 The curve of high-frequency loss of nanoparticle magnetic core as a function of frequency; Figure 12 The curve of high-frequency loss of atomized powder magnetic core as a function of frequency; Figure 13 Comparison of compressive strength of magnetic cores prepared from nanoparticles and atomized powder. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.
[0024] Unless otherwise specified, all other materials and raw materials used in this invention are conventional raw materials that can be purchased from the market. The equipment used in this invention is conventional equipment in the art. The technical means used are conventional means well known to those skilled in the art.
[0025] The testing methods used in this embodiment are as follows: (1) Alloy ingots are prepared using a high-vacuum induction melting furnace, and then the target material is prepared by wire cutting.
[0026] (2) Iron-based amorphous nanocrystalline nanoparticles were prepared using a laser inert gas condensation device.
[0027] (3) Use an ultrasonic cleaner, beaker, stirring rod, etc. to complete the powder insulation coating.
[0028] (4) Use the glove box to complete the nanopowder filling mold.
[0029] (5) Use a hydraulic press to press and shape the magnetic core.
[0030] (6) Use a high vacuum heat treatment furnace to complete the annealing heat treatment of the magnetic core.
[0031] (7) Use X-ray diffraction (XRD) to determine the phase structure of the sample.
[0032] (8) The morphology of the sample was characterized by scanning electron microscopy (SEM).
[0033] (9) The microstructure of the sample was characterized by transmission electron microscopy (TEM), selected area electron diffraction (SAED) and energy loss spectroscopy (EDS).
[0034] (10) The thermal properties of the amorphous powder were measured using a differential scanning calorimeter (DSC). The iron-based amorphous powder was heated to complete crystallization at a heating rate of 20 K / min, and the crystallization temperature of the sample was calibrated. T x This guides the setting of heat treatment parameters.
[0035] (11) The magnetic hysteresis loop of the sample was measured using a magnetic measurement system (MPMS) to obtain the saturation magnetization intensity; the effective permeability of the magnetic powder core was measured as a function of frequency using an impedance analyzer; and the loss of the magnetic powder core was measured as a function of frequency using an AC BH meter.
[0036] (12) Use a universal testing machine to test the compressive strength of the magnetic core. Example 1
[0037] The preferred composition of the iron-based amorphous nanocrystalline nanoparticles and their pressed magnetic cores prepared in this embodiment is Fe. 79 Si6B 10 P5, its preparation process is as follows: Step 1: Prepare the raw materials according to the alloy composition, where phosphorus (P) is added in the form of an iron-phosphorus alloy, and all other components are elemental. The purity of the raw materials is >99.9%, and the batching accuracy is ±0.0005 g. Place the raw materials into the alumina crucible of the induction melting furnace, melt at 1900 ℃, close the chamber, and evacuate the chamber to a vacuum of 3×10⁻⁶. -3 Pa, filled with high-purity Ar gas for protection, melted for 18 min to ensure the alloy liquid is fully melted and uniform, poured into a copper mold, and cooled to obtain the master alloy ingot.
[0038] Step 2: Use wire cutting to process the master alloy ingot prepared in step 1 into a circular target material with a diameter of about 20 mm and a thickness of about 2 mm. Use 2000-grit sandpaper to polish the surface of the target material, and then use anhydrous ethanol and an ultrasonic cleaner to clean the target material.
[0039] Step 3: Place the FeSiBP alloy target prepared in Step 2 into the target position of the laser inert gas condensation device, and evacuate the cavity to 10... -6In a vacuum-sealed chamber, high-purity helium (purity > 99.99%) is introduced to maintain a constant pressure of 500 Pa. Liquid nitrogen is then introduced into the cold trap within the powder-making chamber. Once the rotating cold trap (60 r / min) is full of liquid nitrogen, a high-energy laser beam (50 W laser power, 1 kHz pulse frequency) bombards the target material. The sputtered atomic clusters lose energy upon collision with inert gas molecules, condensing into nanoscale amorphous nanocrystalline particles. These nanoparticles are deposited onto the liquid nitrogen cold trap in the center of the equipment under thermal convection. The particles are then scraped off the cold trap and collected using a scraper.
[0040] Step 4: The nanoparticles prepared in Step 3 are transferred to a molding die in the sample preparation chamber and pressed into discs with a diameter of 10 mm and a thickness of 0.2 mm under a pressure of 500 MPa. The remaining nanoparticle powder is collected in a sample vial. The microstructure of the prepared nanoparticles is as follows: Figure 1 As shown, the particles are dispersed among each other and have high sphericity. Notably, the nanoparticles exhibit a core-shell structure, with an approximately 2 nm thick oxide layer formed in situ on their surface, as shown... Figure 2 As shown. Powder particle size distribution is as follows. Figure 3 As shown, the overall particle size exhibits a bimodal distribution with an average particle size of approximately 25 nm. XRD analysis of the aforementioned pressed wafers revealed a typical amorphous nanocrystalline structure, with the precipitated phase containing only α-Fe, consistent with high-resolution TEM results (see [link to XRD analysis]). Figure 2 a). Using DSC to test the thermal properties of the sample, a broad exothermic peak appears at around 277 °C, followed by a sharp exothermic peak at around 483 °C (see...). Figure 6 ).
[0041] Step 5: Transfer the nanopowder collected in Step 4 to a glove box, and pour a certain amount of nanopowder into a cold-pressing mold. Remove the mold and place it in an electronic universal testing machine, pressurize to 100 MPa, hold the pressure for 3 minutes, then unload the pressure, demold, and remove the pressed magnetic powder core. A picture of the actual magnetic core is shown below. Figure 4 As shown, the outer diameter is 13 mm, the inner diameter is 8 mm, and the height is 2 mm. (The magnetic powder core is prepared without additional insulation coating, the forming pressure is only 0.1 GPa, and there is no subsequent high-temperature heat treatment. It was only heat-treated at 250℃ for comparison with micron powder cores. Without heat treatment, the high-frequency loss of the magnetic core is much lower than that of micron powder cores).
[0042] Step 6: Place the nanopowder magnetic core prepared in Step 5 into a high-vacuum heat treatment furnace, and evacuate the chamber to a vacuum of 5 × 10⁻⁶. -3 Pa, the sample was heated to 250 °C at a heating rate of 40 K / min, held at that temperature for 10 min, then cooled to room temperature, and the sample was removed to remove the residual internal stress introduced during the preparation process.
[0043] Using MPMS to determine the sample hysteresis loop, such as Figure 8 As shown, it exhibits typical characteristics. S The curve indicates the soft magnetic properties of the sample, and the saturation magnetization of the original sample (NMC). M s (@800 kA / m) = 169 emu / g, heat-treated sample (NMC-A250) M s (@800 kA / m) = 178 emu / g.
[0044] The permeability of the sample (NMC-A250) as a function of frequency was measured using an impedance analyzer, as shown in the figure below. Figure 9 As shown, the effective permeability is 20 and the cutoff frequency exceeds 10 MHz.
[0045] The change in sample core loss as a function of frequency was determined using a BH instrument. Figure 10 and 11 As shown, the core loss increases rapidly with increasing frequency. P cv (0.05 T, 100 kHz) = 78 mW / cm 3 High frequency loss P cv (0.01 T, 1 MHz) = 11 mW / cm 3 It has a frequency loss that is far lower than that of traditional magnetic powder cores.
[0046] The mechanical properties of the sample, including the compressive strength of the magnetic core, were tested using an electronic universal testing machine. σ f 49.8 MPa (see) Figure 13 ). Example 2
[0047] The only difference between this embodiment and Embodiment 1 is that: A type of iron-based amorphous nanocrystalline nanoparticle, wherein the chemical formula of the alloy is Fe, based on the molar percentage of each atom. a B b Si c P d Cu e TM f a+b+c+d+e+f = 100, where a=72, b=10, c=9, d=5, e=1, f=3, b+d = 15, and TM is selected from Nb.
[0048] A method for preparing iron-based amorphous nanocrystalline nanoparticles includes the following steps: Step 1: Prepare the raw materials according to the alloy composition, where phosphorus (P) is added in the form of an iron-phosphorus alloy, and all other components are elemental. The purity of the raw materials is >99.9%, and the batching accuracy is ±0.0005 g. Place the raw materials into the alumina crucible of the induction melting furnace, melt at 1800 ℃, close the chamber, and evacuate the chamber to a vacuum of 2×10⁻⁶. -3 Pa, filled with high-purity Ar gas for protection, melted for 15 min to ensure the alloy liquid is fully melted and uniform, poured into a copper mold, and cooled to obtain the master alloy ingot.
[0049] Step 2: Use wire cutting to process the master alloy ingot prepared in Step 1 into a circular target material with a diameter of about 50 mm and a thickness of about 3 mm. Use 1000-grit sandpaper to polish the surface of the target material clean, and then use anhydrous ethanol and an ultrasonic cleaner to clean the target material.
[0050] Step 3: Place the FeSiBP alloy target prepared in Step 2 into the target position of the laser inert gas condensation device, and evacuate the cavity to 10... -6 In a vacuum-sealed chamber, high-purity helium (purity > 99.99%) is introduced to maintain a constant pressure of 600 Pa. Liquid nitrogen is then introduced into the cold trap within the powder-making chamber. Once the rotating cold trap (5 r / min) is full of liquid nitrogen, a high-energy laser beam (40 W laser power, 1 kHz pulse frequency) bombards the target material. The sputtered atomic clusters collide with inert gas molecules, losing energy and condensing into nanoscale amorphous nanocrystalline particles. These nanoparticles are deposited onto the liquid nitrogen cold trap in the center of the equipment under thermal convection. The particles are then scraped off the cold trap and collected using a scraper.
[0051] Step 4: Transfer the nanoparticles prepared in Step 3 to a glove box, and take out a certain amount of nanoparticle powder and pour it into a cold pressing mold. Remove the mold and place it in an electronic universal testing machine, pressurize it to 0.05 GPa, hold the pressure for 5 min, then unload the pressure, demold and take out the pressed magnetic powder core (NMC-2). Example 3
[0052] The only difference between this embodiment and Embodiment 1 is that: A type of iron-based amorphous nanocrystalline nanoparticle, wherein the chemical formula of the alloy is Fe, based on the molar percentage of each atom. a B b Si c P d Cu e TM f , a+b+c+d+e+f = 100, where a=85, b=5, c=0, d=10, e=0, f=0, b+d = 15.
[0053] A method for preparing iron-based amorphous nanocrystalline nanoparticles includes the following steps: Step 1: Prepare the raw materials according to the alloy composition, where phosphorus (P) is added in the form of an iron-phosphorus alloy, and all other components are elemental. The purity of the raw materials is >99.9%, and the batching accuracy is ±0.0005 g. Place the raw materials into the alumina crucible of the induction melting furnace, melt at 2000 ℃, close the chamber, and evacuate the chamber to a vacuum of 3 × 10⁻⁶. -3 Pa, filled with high-purity Ar gas for protection, melted for 20 minutes to ensure the alloy liquid is fully melted and uniform, poured into a copper mold, and cooled to obtain the master alloy ingot.
[0054] Step 2: The master alloy ingot prepared in Step 1 is processed into a circular target material with a diameter of about 30 mm and a thickness of about 2.5 mm by wire cutting. The surface of the target material is polished clean with 1000-grit sandpaper, and then the target material is cleaned with anhydrous ethanol and an ultrasonic cleaner.
[0055] Step 3: Place the FeSiBP alloy target prepared in Step 2 into the target position of the laser inert gas condensation device, and evacuate the cavity to 10... -6 In a vacuum-sealed chamber, high-purity helium (purity > 99.99%) is introduced to maintain a constant pressure of 550 Pa. Liquid nitrogen is then introduced into the cold trap within the powder-making chamber. Once the rotating cold trap (100 r / min) is full of liquid nitrogen, a high-energy laser beam (65 W laser power, 500 kHz pulse frequency) bombards the target material. The sputtered atomic clusters collide with inert gas molecules, lose energy, and condense into nanoscale amorphous nanocrystalline particles. These nanoparticles are deposited onto the liquid nitrogen cold trap in the center of the device under thermal convection. The particles are then scraped off the cold trap and collected using a scraper.
[0056] Step 4: Transfer the nanoparticles prepared in Step 3 to a glove box, take out a certain amount of nanoparticle powder and pour it into a cold pressing mold. Take out the mold and place it in an electronic universal testing machine, pressurize it to 0.5 GPa, hold the pressure for 3 min, then unload the pressure, demold and take out the pressed magnetic powder core (NMC-3).
[0057] Step 5: Place the nanopowder magnetic core prepared in Step 4 into a high-vacuum heat treatment furnace, and evacuate the chamber to a vacuum of 1×10⁻⁶. -3 Pa, the sample was heated to 250 °C at a heating rate of 40 K / min, held at that temperature for 10 min, then cooled to room temperature, and the sample was removed to remove the residual internal stress introduced during the preparation process.
[0058] Comparative Example 1
[0059] The comparative example uses an iron-based amorphous soft magnetic composite material prepared from atomized micron-sized amorphous powder. The specific composition of this composite material is the same as that in the examples, consisting of Fe. 79 Si6B 10 P5, its preparation process is as follows: Step 1: According to the alloy composition, induction melt the master alloy ingot, place the melted master alloy ingot into a quartz tube with an open bottom, close the atomizing equipment cavity, and evacuate the cavity to a vacuum of 5×10⁻⁶. -3 Under high pressure (10 MPa), the alloy ingot was filled with high-purity argon gas for protection. The heating power was turned on and the current was applied to remelt the ingot. Under the injection of high-pressure argon gas (10 MPa), the molten droplets were broken up and cooled into amorphous powder. The powder was then passed through a 500-mesh sieve for subsequent experiments.
[0060] The Fe prepared above 79 Si6B 10 The XRD pattern of P5 powder is as follows: Figure 5 As shown, only two broad peaks (approximately 45° and 80°) were observed, with no sharp crystallization peaks, indicating that the sample has a completely amorphous structure. The DSC curve of the sample is shown below. Figure 6 As shown, glass transition temperature T g = 507 ℃, initial crystallization temperature T x = 543 ℃, Curie temperature T C = 398 ℃. Sample SEM image as follows Figure 7 As shown, the powder has a smooth surface and high sphericity.
[0061] Step 2: Weigh 10 g of the amorphous powder prepared in Step 1; weigh 0.05 g of concentrated phosphoric acid and dissolve it in acetone solution, stirring thoroughly and then sonicating until homogeneous; pour the aforementioned amorphous powder into the acetone-phosphate solution, stir and sonicate for 15 min to complete powder passivation; weigh 0.2 g of silicone resin and dissolve it in acetone solution, stirring thoroughly and then sonicating until homogeneous; pour the passivated amorphous powder into the solution, stirring continuously and then sonicating until the solution is completely evaporated to complete powder insulation coating; place the passivated and coated powder in an oven, set the temperature to 60 ℃, and keep it at that temperature for 12 h until the powder is completely dry; remove the powder, grind it, and pass it through a 200-mesh sieve for subsequent powder core forming (this is the traditional micron-sized powder core preparation process, which requires a cumbersome insulation coating process).
[0062] Step 3: Weigh 1.5 g of the powder coated in Step 2 and place it into a cold press mold. Use a hydraulic press to press it into a ring-shaped sample. The outer diameter of the magnetic ring is 13 mm, the inner diameter is 8 mm, the thickness is 3 mm, and the pressing force is 2 GPa (the forming pressure is 2 GPa, and it cannot be formed if the pressure is too low).
[0063] Step 4: Place the magnetic powder core formed in Step 3 into the sample stage of the high vacuum heat treatment furnace, and evacuate the cavity to a vacuum level of 5×10⁻⁶. - 3Pa, the sample was heated to 200 °C at a heating rate of 40 K / min and held at that temperature for 30 min to complete the curing. The cured magnetic core was then heated to 450 °C at a heating rate of 40 K / min and held at that temperature for 30 min for stress relief heat treatment. The heat-treated sample was then placed in water to cool to room temperature and removed (high-temperature stress relief heat treatment is required).
[0064] Measurement of hysteresis loop of amorphous powder using MPMS Figure 8 As shown, it exhibits typical characteristics. S The shape curve indicates the soft magnetic properties of the sample. M s (@800 kA / m) = 168 emu / g.
[0065] The permeability of the sample (SMC-A450) as a function of frequency was measured using an impedance analyzer, as shown in the figure below. Figure 9 As shown, the effective permeability is 34, and the cutoff frequency exceeds 10 MHz.
[0066] The core loss of the sample (SMC-A450) as a function of frequency was measured using a BH instrument. Figure 10 and 12 As shown, the core loss increases rapidly with increasing frequency. P cv (0.05 T, 100 kHz) = 295 mW / cm 3 High frequency loss P cv (0.01 T, 1 MHz) = 257 mW / cm 3 .
[0067] The mechanical properties of the sample, including the compressive strength of the magnetic core, were tested using an electronic universal testing machine. σ f It is 18.3 MPa (see) Figure 13 ).
[0068] Comparative Example 2
[0069] This comparative example uses an iron-based amorphous soft magnetic composite material prepared from atomized micron-sized amorphous powder. The specific composition of this composite material is Fe. 79 Si6B 10 P5, its preparation process is as follows: Steps 1 to 3 are the same as those in Comparative Example 1.
[0070] Step 4: Place the magnetic powder core formed in Step 3 into the sample stage of the high vacuum heat treatment furnace, and evacuate the cavity to a vacuum level of 5×10⁻⁶. -3The sample was heated to 250 °C at a rate of 40 K / min and held at that temperature for 10 min to complete curing and stress relief. The heat-treated sample was then placed in water to cool to room temperature before being removed.
[0071] The permeability of the sample (SMC-A250) as a function of frequency was measured using an impedance analyzer, as shown in the figure below. Figure 9 As shown, the effective permeability is 15 and the cutoff frequency exceeds 10 MHz.
[0072] The change in sample core loss as a function of frequency was determined using a BH instrument. Figure 10 As shown, the core loss increases rapidly with increasing frequency. P cv (0.05 T, 100 kHz) = 1621 mW / cm 3 .
[0073] The mechanical properties of the sample, including the compressive strength of the magnetic core, were tested using an electronic universal testing machine. σ f It is 12.4 MPa.
[0074] Comparative Example 3
[0075] This comparative example uses an iron-based amorphous soft magnetic composite material prepared from atomized micron-sized amorphous powder. The specific composition of this composite material is Fe. 79 Si6B 10 P5, its preparation process is as follows: Steps 1 and 2 are the same as those in Comparative Example 1.
[0076] Step 3: Weigh 1.5 g of the powder coated in Step 2 and place it into a cold press mold. Use a hydraulic press to press it into a ring-shaped sample. The outer diameter of the magnetic ring is 13 mm, the inner diameter is 8 mm, the thickness is 3 mm, and the pressing force is 0.5 GPa.
[0077] Step 4: Place the magnetic powder core formed in Step 3 into the sample stage of the high vacuum heat treatment furnace, and evacuate the cavity to a vacuum level of 5×10⁻⁶. - 3 The sample was heated to 200 °C at a rate of 40 K / min and held at that temperature for 30 min to complete the curing. The heat-treated sample was then placed in water to cool to room temperature before being removed.
[0078] The mechanical properties of the sample, including the compressive strength of the magnetic core, were tested using an electronic universal testing machine. σ f It is 5.1 MPa (see) Figure 13 ).
[0079] Comparative Example 4
[0080] The only difference between this comparative example and Example 1 is that: The specific composition of iron-based amorphous nanocrystalline nanoparticles and their pressed magnetic cores is Fe. 83 Si6B 10 P1.
[0081] This comparative example did not yield iron-based nanoparticles with an amorphous nanocrystalline structure.
[0082] Comparative Example 5
[0083] The only difference between this comparative example and Example 1 is that: The specific composition of iron-based amorphous nanocrystalline nanoparticles and their pressed magnetic cores is Fe. 84 Si6B 10 .
[0084] This comparative example did not yield iron-based nanoparticles with an amorphous nanocrystalline structure.
[0085] The soft magnetic properties and mechanical properties of the magnetic powder cores prepared in Examples 1-3 and Comparative Examples 1-3 are shown in Table 1 below.
[0086] Table 1 shows the soft magnetic properties and mechanical properties of the magnetic powder cores prepared in Examples 1-3 and Comparative Examples 1-3.
[0087] If the composition of the iron-based alloy does not conform to the molecular formula specified in this invention, it is impossible to prepare iron-based nanoparticles with an amorphous nanocrystalline structure using the laser inert gas condensation technology described in this invention, such as the Fe alloy composition described in the literature. 84 Ni 16 (Nature Communications 13 (2022) 5468), Co 20 Cr 20 Fe 20 Ni 20 Mn 20 (Journal of Materials Science & Technology 77 (2021) 126-130) According to the basic principles of soft magnetic materials, the prepared nanoparticle material does not possess the excellent high-frequency soft magnetic properties of the nanoparticles in this embodiment, and is not within the scope of protection of this invention.
[0088] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. An iron-based amorphous nanocrystalline nanoparticle, characterized in that, The chemical formula of the alloy, based on the molar percentage of each atom, is Fe. a B b Si c P d Cu e TM f a+b+c+d+e+f = 100, where 72≤a≤85, 0<b≤10, 0≤c≤9, 0<d≤10, 0≤e≤1, 0≤f≤3, b+d = 15, and TM is selected from one of Nb, Cr, V, Mo, Zr, Co, and Ni.
2. The method for preparing iron-based amorphous nanocrystalline nanoparticles according to claim 1, characterized in that, Includes the following steps: Step 1: According to the molecular formula, the raw materials are prepared, with phosphorus (P) added in the form of an iron-phosphorus alloy, and all other components being elemental. The purity of the raw materials is >99.9%. The raw materials are placed in the alumina crucible of the induction melting furnace, and the melting temperature is 1800-2000 ℃. The chamber is closed, and the chamber is evacuated to a vacuum of 3×10⁻⁶. -3 Below Pa, high-purity Ar gas is introduced for protection, and the alloy liquid is melted for 15-20 minutes to ensure it is fully melted and uniform. The melt is then poured into a copper mold and cooled to obtain a master alloy ingot. The uniformly melted master alloy ingot is processed by wire cutting to prepare a target material with a diameter of 2-5 cm and a thickness of 2-3 mm. The surface of the target material is polished smooth using 1000-2000 grit sandpaper, and then the target material is cleaned with anhydrous ethanol and an ultrasonic cleaner. Step 2: Place the alloy target material prepared in Step 1 into the target position of the laser inert gas condensation device, and evacuate the cavity to a vacuum of 10. -6 Below Pa, a high-purity inert gas is filled into a vacuum-sealed chamber to maintain a fixed gas pressure of 500-600 Pa. Then, liquid nitrogen is injected into the cold trap in the powder preparation chamber. After the rotating cold trap is filled with liquid nitrogen, the target material is bombarded with a high-energy laser beam. The sputtered atomic clusters are deposited on the liquid nitrogen cold trap. The particles are then scraped off the cold trap and collected to obtain iron-based amorphous nanocrystalline nanoparticles.
3. The method for preparing iron-based amorphous nanocrystalline nanoparticles according to claim 1, characterized in that, In step 2, the high-purity inert gas includes nitrogen, argon, or helium, with a purity > 99.99%.
4. The method for preparing iron-based amorphous nanocrystalline nanoparticles according to claim 1, characterized in that, In step 2, the rotational speed of the rotating cold trap is 0-100 r / min.
5. A method for preparing iron-based amorphous nanocrystalline nanoparticles according to claim 1, characterized in that, In step 2, the power of the high-energy laser beam is 40-65 W, and the pulse frequency is 1 kHz-500 kHz.
6. A method for preparing a pressed powder magnetic core, characterized in that, Includes the following steps: Weigh the iron-based amorphous nanocrystalline nanoparticles prepared according to claim 2, place them in a cold pressing mold, and press them into shape. The pressing force is 0.05-0.5 GPa. The sample weighing process is carried out in a glove box to obtain the pressed powder magnetic core.
7. A method for preparing a pressed powder magnetic core according to claim 6, characterized in that, It also includes the following steps: The pressed magnetic core is placed in a high vacuum heat treatment furnace and held at 250 ℃ for 10 min.
8. A method for preparing a pressed powder magnetic core according to claim 7, characterized in that, High vacuum is 10 -3 Pa.
9. The application of the pressed powder magnetic core obtained by the method for preparing the pressed powder magnetic core according to any one of claims 6-8 in integrally molded inductive soft magnetic materials.