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CN-121983424-A - Neodymium-iron-boron magnet and preparation method thereof

CN121983424ACN 121983424 ACN121983424 ACN 121983424ACN-121983424-A

Abstract

The invention relates to a neodymium-iron-boron magnet and a preparation method thereof, wherein the neodymium-iron-boron magnet comprises the steps of immersing a neodymium-iron-boron substrate in a diffusion source solution to obtain a neodymium-iron-boron substrate comprising an immersing layer, heating and degreasing the neodymium-iron-boron substrate comprising the immersing layer to obtain a degreased neodymium-iron-boron substrate, performing diffusion treatment and aging treatment on the degreased neodymium-iron-boron substrate, wherein the diffusion source solution comprises light rare earth alloy diffusion source powder, the light rare earth alloy diffusion source powder is R1-Fe-M1 powder, R1 comprises Pr and/or Nd, M1 comprises at least one of Cu, ga and Al, the content of R1 in the light rare earth alloy diffusion source powder is 40-60wt%, the content of M1 is 10-20wt%, the content of Fe is 30-40wt%, the mass ratio a of Fe to R1 is 0.5-0.8, the mass ratio b of T to R in the neodymium-iron-boron magnet substrate is 2.0-2.3, and the a/b is 0.1-0.4. The method can effectively realize micro-restoration of the magnetic flux of the small-size electroplated magnet, inhibit fluctuation of residual magnetism, and enable the prepared magnet to have excellent magnetic performance after high temperature.

Inventors

  • XU DAOBIAO
  • TAO JUN
  • DU FEI
  • LIU CHENCHEN
  • WANG DENGXING
  • HU DIE

Assignees

  • 北京中科三环高技术股份有限公司
  • 中科三环(赣州)新材料有限公司
  • 宁波科宁达和丰新材料有限公司

Dates

Publication Date
20260505
Application Date
20260408

Claims (10)

  1. 1. A method of making a neodymium-iron-boron magnet, the method comprising: s1, dipping a neodymium iron boron matrix in a diffusion source solution to obtain a neodymium iron boron matrix comprising an dipping layer; s2, heating and degreasing the neodymium-iron-boron matrix comprising the impregnation layer to obtain a degreased neodymium-iron-boron matrix; s3, performing diffusion treatment and aging treatment on the degreased neodymium iron boron matrix; The neodymium-iron-boron magnet matrix comprises a rare earth element R, a transition metal element T, a metal element M and a B element, wherein the rare earth element R comprises Pr and Nd, the metal element M comprises at least one of Cu, ga, ti, zr, al, nb, and the transition metal element T comprises Fe or comprises Fe and Co; The content of R in the neodymium-iron-boron magnet matrix is 29-33wt%, the content of M is 0.1-3wt%, the content of B element is 0.78-0.90wt%, and the content of T is 64-69wt%; The diffusion source solution comprises light rare earth alloy diffusion source powder, wherein the light rare earth alloy diffusion source powder is R1-Fe-M1 powder, R1 comprises Pr and/or Nd, M1 comprises at least one of Cu, ga and Al; the content of R1 in the light rare earth alloy diffusion source powder is 40-60wt%, the content of M1 is 10-20wt%, and the content of Fe is 30-40wt%; wherein, in the light rare earth alloy diffusion source powder, the mass ratio of Fe to R1 is a, a is 0.5-0.8, and in the neodymium-iron-boron magnet matrix, the mass ratio of T to R is b, b is 2.0-2.3; a and b satisfy the following formula (1); a/b=0.1 to 0.4 formula (1).
  2. 2. The method of claim 1, wherein the neodymium-iron-boron magnet matrix has a dimension in a diffusion direction of less than 3mm.
  3. 3. The method of claim 1, wherein the diffusion source solution does not include heavy rare earth.
  4. 4. The method of claim 1, wherein the light rare earth alloy diffusion source powder has a particle size of 1-9 μm.
  5. 5. The method according to claim 1, characterized in that the method further comprises: a. Forming the alloy raw material to obtain a pressed compact; b. Sintering the pressed compact and ageing the pressed compact to obtain a neodymium-iron-boron magnet blank; c. and machining the NdFeB magnet blank to obtain the NdFeB matrix.
  6. 6. The method of claim 1, wherein the diffusion source solution further comprises an organic solvent, a resin, and a dispersant.
  7. 7. The method of claim 6, wherein the method satisfies at least one of the following conditions: The content of light rare earth alloy diffusion source powder in the diffusion source solution is 60-90wt%, the content of resin is 0.2-2wt%, the content of dispersing agent is 0.2-1wt%, and the content of organic solvent is 7-40wt%; the organic solvent comprises alkyl alcohol with 1-3 carbon atoms; the resin comprises a vinyl polymer resin; the molecular weight of the resin is 60000-120000; the dispersant comprises a fatty acid amide dispersant.
  8. 8. The method according to claim 1, wherein the method satisfies at least one of the following conditions: in the step S1, the temperature of the impregnation is 50-70 ℃; The heating degreasing treatment is carried out under the vacuum condition, wherein the vacuum degree is 10 2 -10 -2 Pa, the treatment temperature is 200-500 ℃ and the treatment time is 1-4h; The conditions of the diffusion treatment comprise vacuum condition, vacuum degree of 10 2 -10 -2 Pa, treatment temperature of 700-850 ℃ and treatment time of 1-6h; the aging treatment conditions comprise a treatment temperature of 400-650 ℃ and a treatment time of 2-6h.
  9. 9. The method of claim 1, further comprising electroplating the NdFeB magnet obtained by the aging treatment.
  10. 10. A neodymium-iron-boron magnet, characterized in that it is prepared by the method according to any one of claims 1-9.

Description

Neodymium-iron-boron magnet and preparation method thereof Technical Field The disclosure belongs to the field of neodymium-iron-boron magnets, and particularly relates to a neodymium-iron-boron magnet and a preparation method thereof. Background The sintered NdFeB magnet is widely applied to the fields of electric machinery, medical equipment, automobile industry, wind power generation, electronics and the like, with the development of downstream products to miniaturization, the market demand for small-sized precise magnetic components is increasing increasingly, and the technical route for preparing the sintered NdFeB magnet without heavy rare earth can obviously reduce the cost of raw materials and the dependence on the heavy rare earth, promote the balanced utilization of rare earth resources and enhance the toughness of a supply chain. However, the preparation of the high-performance heavy-rare-earth-free sintered NdFeB magnet not only depends on the optimization of a formula, but also needs to be combined with a grain refinement technology, the grain size of the high-performance heavy-rare-earth-free sintered NdFeB magnet is smaller than that of a conventional sintered NdFeB magnet, and the defects on the surface of the grains are increased due to the decrease of the grain size, so that the optimization difficulty of the grain boundary regulation of the heavy-rare-earth-free magnet is increased. On the other hand, after the heavy rare earth-free magnet is cut into small products through machining, the heavy rare earth-free magnet is easily damaged in the process, and the damage can be continued to the final electroplated magnet, so that the high-temperature demagnetizing rate of the batch electroplated magnets fluctuates, and the qualification rate is reduced. Disclosure of Invention The invention aims to provide a neodymium-iron-boron magnet and a preparation method thereof, and the method provided by the invention can effectively realize micro-restoration of magnetic flux of a small-size electroplated magnet, and inhibit fluctuation of remanence, so that the prepared magnet still has excellent magnetic performance after being subjected to high temperature. In order to achieve the above object, a first aspect of the present invention provides a method for preparing a neodymium-iron-boron magnet, the method comprising: s1, dipping a neodymium iron boron matrix in a diffusion source solution to obtain a neodymium iron boron matrix comprising an dipping layer; s2, heating and degreasing the neodymium-iron-boron matrix comprising the impregnation layer to obtain a degreased neodymium-iron-boron matrix; s3, performing diffusion treatment and aging treatment on the degreased neodymium iron boron matrix; The neodymium-iron-boron magnet matrix comprises a rare earth element R, a transition metal element T, a metal element M and a B element, wherein the rare earth element R comprises Pr and Nd, the metal element M comprises at least one of Cu, ga, ti, zr, al, nb, and the transition metal element T comprises Fe or comprises Fe and Co; The content of R in the neodymium-iron-boron magnet matrix is 29-33wt%, the content of M is 0.1-3wt%, the content of B element is 0.78-0.90wt%, and the content of T is 64-69wt%; The diffusion source solution comprises light rare earth alloy diffusion source powder, wherein the light rare earth alloy diffusion source powder is R1-Fe-M1 powder, R1 comprises Pr and/or Nd, M1 comprises at least one of Cu, ga and Al; the content of R1 in the light rare earth alloy diffusion source powder is 40-60wt%, the content of M1 is 10-20wt%, and the content of Fe is 30-40wt%; wherein, in the light rare earth alloy diffusion source powder, the mass ratio of Fe to R1 is a, a is 0.5-0.8, and in the neodymium-iron-boron magnet matrix, the mass ratio of T to R is b, b is 2.0-2.3; a and b satisfy the following formula (1); a/b=0.1 to 0.4 formula (1). Optionally, the size of the neodymium-iron-boron magnet matrix in the diffusion direction is smaller than 3mm. Optionally, the diffusion source solution does not include heavy rare earth. Optionally, the light rare earth alloy diffusion source powder has a particle size of 1-9 μm. Optionally, the method further comprises: a. Forming the alloy raw material to obtain a pressed compact; b. Sintering the pressed compact and ageing the pressed compact to obtain a neodymium-iron-boron magnet blank; c. and machining the NdFeB magnet blank to obtain the NdFeB matrix. Optionally, the diffusion source solution further comprises an organic solvent, a resin, and a dispersant. Optionally, the method satisfies at least one of the following conditions: The content of light rare earth alloy diffusion source powder in the diffusion source solution is 60-90wt%, the content of resin is 0.2-2wt%, the content of dispersing agent is 0.2-1wt%, and the content of organic solvent is 7-40wt%; the organic solvent comprises alkyl alcohol with 1-3 carbon atoms; the resin comprises a