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CN-122025330-A - FeNi soft magnetic composite material for axial flux motor and preparation method thereof

CN122025330ACN 122025330 ACN122025330 ACN 122025330ACN-122025330-A

Abstract

The invention discloses a FeNi soft magnetic composite material for an axial flux motor and a preparation method thereof, wherein a compact SiO 2 -based composite insulating layer with firm interface bonding is constructed on FeNi alloy powder with D50=20-30 mu m by controlling the hydrolysis and surface bonding reaction of KH550, and the thickness is as low as about 5 nm. After high-pressure forming and reduction annealing, the obtained composite material has high effective magnetic conductivity, low iron loss and excellent mechanical strength. The method is used for preparing the stator core of the axial flux motor, can obviously reduce the iron loss and excitation loss of the motor, improves the efficiency and power density of the motor, and is particularly suitable for high-requirement application scenes such as a humanoid robot driving motor and the like.

Inventors

  • ZHANG XUEFENG
  • ZHANG ERPAN
  • QI XINYU

Assignees

  • 杭州电子科技大学

Dates

Publication Date
20260512
Application Date
20260311

Claims (9)

  1. 1. A FeNi soft magnetic composite material for an axial flux motor iron core is characterized by comprising FeNi alloy powder and a composite insulating coating layer coated on the surface of the alloy powder, wherein D50=20-30 μm of the FeNi alloy powder is obtained by hydrolysis and condensation of a silane coupling agent KH550 and bonding with the surface of the alloy powder, the thickness is 5-50 nm, the effective magnetic permeability of the soft magnetic composite material at the frequency of 1kHz is not lower than 250, the iron loss at the frequency of 1kHz/0.5T is not higher than 20W/kg, the iron loss at the frequency of 10kHz/0.5T is not higher than 200W/kg, and the radial crushing strength of a pressed blank is not lower than 50 MPa.
  2. 2. A preparation method of a FeNi soft magnetic composite material for an axial flux motor iron core is characterized by comprising the steps of preparing and mixing a silane coupling agent KH550, deionized water and an alcohol solvent, adjusting the pH to 4-6, stirring at room temperature for a period of time, and carrying out prehydrolysis to obtain a clear and transparent KH550 hydrolysis solution, wherein the volume fraction of KH550 in the hydrolysis solution is 0.5% -5%; Weighing FeNi alloy powder with the D50 of 20-30 mu m, mixing the FeNi alloy powder with KH550 hydrolysis solution, stirring under heating conditions to enable a silane coupling agent KH550 to be fully hydrolyzed and condensed on the surface of the FeNi alloy powder and bonded with the surface of metal, coating the surface of the FeNi alloy powder, separating solid powder after the reaction is finished, and drying and carrying out low-temperature heat treatment to obtain the FeNi soft magnetic composite material with the SiO 2 -based composite insulating layer coated on the surface.
  3. 3. The method for preparing the FeNi soft magnetic composite material for the axial flux motor core according to claim 2, wherein the FeNi alloy powder comprises 50-60 at% of Fe and 40-50 at% of Ni.
  4. 4. The method for preparing the FeNi soft magnetic composite material for the axial flux motor core according to claim 2, wherein the alcohol solvent is ethanol or isopropanol, and the volume ratio of KH550 to deionized water to the alcohol solvent is 1 (3-10): 20-200.
  5. 5. The method for preparing the FeNi soft magnetic composite material for the axial flux motor core according to claim 2, wherein the mass-volume ratio of FeNi alloy powder to KH550 hydrolysis solution is 1g (2-5 mL).
  6. 6. The method of claim 5, wherein the silane coupling agent KH550 is coated on the surface of the FeNi alloy powder after the FeNi alloy powder is mixed with the KH550 hydrolysis solution and stirred at 40-80 ℃ for 0.5-3 hours.
  7. 7. The method for preparing the FeNi soft magnetic composite material for the axial flux motor core according to claim 2, wherein the separated solid powder is dried for 1-4 hours at 80-120 ℃, and then subjected to low-temperature heat treatment for 0.5-2 hours at 200-400 ℃ in an inert atmosphere or air.
  8. 8. The method for preparing the FeNi soft magnetic composite material for the axial flux motor core according to claim 2, wherein the thickness of the SiO 2 -based composite insulating layer is 5-50 nm, and the SiO 2 is amorphous and the residual amino functional group is from KH 550.
  9. 9. A preparation method of an axial flux motor iron core is characterized in that the FeNi soft magnetic composite material for the axial flux motor iron core, which is prepared by the method of any one of claims 1 to 8, is pressed into a blank body matched with the shape of an axial flux motor stator iron core, and then annealed for 1 to 3 hours at 600 to 750 ℃ in a reducing atmosphere.

Description

FeNi soft magnetic composite material for axial flux motor and preparation method thereof Technical Field The invention belongs to the technical field of soft magnetic materials, relates to an axial flux motor iron core material with high magnetic permeability and low loss, and in particular relates to a FeNi soft magnetic composite material for an axial flux motor and a preparation method thereof. Background The axial flux motor has the advantages of compact structure, short axial dimension, high torque density and the like, and has wide application prospect in the fields of new energy automobiles, servo systems, aerospace, robots and the like. The core component of the stator core is usually pressed by soft magnetic materials. The material of the stator core is required to have high saturation magnetic flux density, high effective magnetic permeability (mu e) and low loss (Pcv) and good mechanical strength to bear centrifugal stress and assembly pressure under high-speed rotation. Currently, iron powder core materials are mostly used as soft magnetic materials for preparing stator cores. However, the resistivity of the iron powder is too low, so that the stator core is easy to generate larger intra-particle eddy current loss when running at high speed in an alternating magnetic field, and the loss of the motor is improved. The insulating coating is a method for effectively improving the performance of the soft magnetic material, and can be divided into an organic coating and an inorganic coating according to the selection of the materials. The organic matter used for organic coating has strong cohesiveness, can ensure that the magnetic powder core has enough strength, but has lower heat-resistant temperature, and the coating layer is difficult to keep insulating in the high-temperature annealing process and has poor magnetic property. The inorganic coating has higher heat-resistant temperature, high resistivity, low eddy current loss, but poor cohesiveness, and the mechanical property is difficult to meet the application requirement when no other binder is introduced. In order to solve the problem, part of methods propose to simultaneously introduce organic materials and inorganic materials for multiple coating, but the common process flow is complex, the performance improvement is limited, the effective magnetic permeability is concentrated at 100-150, no relevant report that the effective magnetic permeability is more than 200 exists at present, and the requirements of an axial magnetic flux motor on high magnetic permeability, low loss and mechanical strength cannot be met. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a FeNi soft magnetic composite material for an axial flux motor and a preparation method thereof, wherein a layer of ultrathin, compact and chemically-bonded SiO 2 -based composite insulating layer is constructed on the surface of FeNi powder in situ through hydrolysis of a silane coupling agent KH550, and the obtained composite material remarkably improves the resistivity, reduces the high-frequency loss and has excellent interface bonding strength and thermal stability while keeping the high intrinsic permeability of FeNi, and is particularly suitable for being used as an axial flux motor iron core, so that the motor efficiency, the power density and the operation stability can be effectively improved. A FeNi soft magnetic composite material for an axial flux motor iron core is FeNi alloy powder and a composite insulating coating layer coated on the surface of the alloy powder. D50=20 to 30 μm of the FeNi alloy powder. The thickness of the composite insulating coating layer is 5-50 nm, and the composite insulating coating layer comprises amorphous SiO 2 and amino functional groups. The effective magnetic permeability (mu e) of the soft magnetic composite material at the frequency of 1kHz is not lower than 250, the iron loss (Pcm) at the condition of 1kHz/0.5T is not higher than 20W/kg, the iron loss at the condition of 10kHz/0.5T is not higher than 200W/kg, and the radial crushing strength of the pressed compact is not lower than 50 MPa. A preparation method of a FeNi soft magnetic composite material for an axial flux motor iron core comprises the following steps: And step 1, weighing FeNi alloy powder with the D50 of 20-30 mu m, performing surface cleaning activation, and then drying for later use. Preferably, in the FeNi alloy powder, the Fe content is 50 to 60 at.% and the Ni content is 40 to 50 at.%. And 2, preparing a hydrolysis solution containing a silane coupling agent KH550, deionized water and an alcohol solvent, regulating the pH to 4-6, stirring at room temperature for a period of time, and carrying out pre-hydrolysis to obtain a clear and transparent KH550 hydrolysis solution. The volume fraction of KH550 in the hydrolysis solution is 0.5% -5%. Preferably, the alcohol solvent is ethanol or isopropanol, and the volume ratio of KH550