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CN-122025324-A - High-performance cerium-containing rare earth permanent magnet and preparation method thereof

CN122025324ACN 122025324 ACN122025324 ACN 122025324ACN-122025324-A

Abstract

The invention belongs to the technical field of rare earth permanent magnets, and relates to a high-performance cerium-containing rare earth permanent magnet and a preparation method thereof. The invention firstly uses alloy A (Nd a B b M c Fe d ) to carry out diffusion heat treatment on the surface of a matrix to form a neodymium-rich shell structure on a main phase grain epitaxial layer, then introduces alloy B (R ' x Fe gamma H_z, R' is Dy/Tb and other heavy rare earth), and constructs a double-layer shell structure consisting of inner layer neodymium-rich and outer layer heavy rare earth-rich layers through secondary diffusion heat treatment. The structure not only effectively isolates the adverse effect of cerium on the anisotropic field of the main phase crystal grains, but also remarkably improves the coercive force of the material.

Inventors

  • PENG WEIBO
  • YANG XIA

Assignees

  • 宁波爱维森材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260331

Claims (10)

  1. 1. The high-performance cerium-containing rare earth permanent magnet is characterized by comprising a cerium-containing rare earth permanent magnet matrix and an alloy A and an alloy B which are sequentially arranged on the surface of the cerium-containing rare earth permanent magnet matrix; Wherein the alloy A component contains Nd a B b M c Fe d , nd is neodymium element, fe is iron element, B is boron element, M is at least one of Al, co, cu, mg elements, wherein a+b+c+d=100%, a is 33wt% or more and less than or equal to 50wt%, B is 0.8wt% or more and less than or equal to 1.0wt%, c is 0.1wt% or less and less than or equal to 2wt%, and d is the rest; The alloy B comprises R ' x Fe y H z , wherein R' is at least one of Dy and Tb, fe is an iron element, H is a hydrogen element, wherein x+y+z=100%, x is more than or equal to 70wt% and less than or equal to 89wt%, y is more than or equal to 10wt% and less than or equal to 29wt%, and the balance is z.
  2. 2. The high performance cerium-containing rare earth permanent magnet according to claim 1, wherein the cerium-containing rare earth permanent magnet has a matrix composition of (R, ce) FeMB; r is one or more of rare earth elements other than Ce, and must contain Nd; m is at least one of Al, co, cu, ga, zr, nb, O, C, S, N and H.
  3. 3. A method for preparing the high performance cerium-containing rare earth permanent magnet according to claim 1, comprising the steps of: S1, carrying out sand blasting treatment on the surface of a cerium-containing rare earth permanent magnet matrix, then coating slurry containing an alloy A component on the surface of the matrix, and carrying out diffusion heat treatment after drying; s2, performing sand blasting treatment on the surface of the diffused matrix, coating slurry containing alloy B components on the surface of the matrix, drying, performing diffusion heat treatment, and finally performing aging treatment to obtain the high-performance cerium-containing rare earth permanent magnet.
  4. 4. The method for preparing a high-performance cerium-containing rare earth permanent magnet according to claim 3, wherein in the step S1, the slurry containing the alloy a component is NdaBbMcFed fine powder and propylene glycol to prepare a slurry with a concentration of 30-80 wt%; and/or the spraying amount of the slurry containing the alloy A component sprayed on the surface of the substrate is 0.1-2.0% of the mass of the substrate.
  5. 5. The method for producing a high-performance cerium-containing rare earth permanent magnet according to claim 4, wherein the NdaBbMcFed fine powder has an average particle diameter of 1 to 10 μm.
  6. 6. The method for preparing a high-performance cerium-containing rare earth permanent magnet according to claim 3, wherein in the step S1, the diffusion heat treatment temperature is 900-980 ℃ and the diffusion heat treatment time is 6-12h.
  7. 7. The method for preparing a high-performance cerium-containing rare earth permanent magnet according to claim 3, wherein in the step S2, the slurry containing the alloy B component is prepared by mixing fine powder R' xFeyHz and propylene glycol to obtain slurry with the concentration of 30-80 wt%; and/or the spraying amount of the slurry containing the alloy B component sprayed on the surface of the substrate is 0.1-1.0% of the mass of the substrate.
  8. 8. The method for producing a high-performance cerium-containing rare earth permanent magnet according to claim 7, wherein the average particle diameter of R' xFeyHz is 1 to 10 μm.
  9. 9. The method for preparing a high-performance cerium-containing rare earth permanent magnet according to claim 3, wherein in the step S2, the diffusion heat treatment temperature is 880-950 ℃ and the diffusion heat treatment time is 10-20h.
  10. 10. The method for preparing a high-performance cerium-containing rare earth permanent magnet according to claim 3, wherein the first-stage aging treatment temperature is 600-680 ℃ for 3-6 hours, and the second-stage aging treatment temperature is 380-420 ℃ for 3-6 hours.

Description

High-performance cerium-containing rare earth permanent magnet and preparation method thereof Technical Field The invention belongs to the technical field of rare earth permanent magnets, and relates to a high-performance cerium-containing rare earth permanent magnet and a preparation method thereof. Background The preparation of high-performance cerium-containing rare earth permanent magnets is a key field in modern material science, and one of the main methods is by diffusing heavy rare earth dysprosium (Dy) or terbium (Tb) on a cerium-containing rare earth permanent magnet matrix. The method not only plays the advantage of high performance of the diffusion process, but also realizes the effect of reducing the cost of cerium. The cerium-containing rare earth permanent magnet matrix is composed of a main phase (Nd, ce) 2Fe14 B and a cerium-rich phase at the grain boundary. The epitaxial layer anisotropy field of the main phase (Nd, ce) 2Fe14 B is relatively low due to the presence of the cerium-rich phase. In the diffusion heat treatment process, heavy rare earth elements diffuse into the magnet along grain boundaries, and a new phase with (Nd, ce, dy/Tb) 2Fe14 B surrounded by (Nd, ce) 2Fe14 B as a sandwich shell structure is formed on the epitaxial layer of the main phase. This newly formed (Nd, ce, dy/Tb) 2Fe14 B phase has a higher magnetocrystalline anisotropy field than (Nd, ce) 2Fe14 B and they are distributed at the sites of the layer that easily lead to the formation of a reverse magnetic field. Therefore, the coercivity of the cerium-containing rare earth permanent magnet can be improved by grain boundary diffusion of Dy or Tb. However, due to the existence of cerium element in the main phase (Nd, ce) 2Fe14 B, the diffused coercive force is 1-2 koe lower than that of the rare earth permanent magnet without cerium, which is a commonly encountered difficulty in the industry at present. Disclosure of Invention Aiming at the defects, the invention provides a high-performance cerium-containing rare earth permanent magnet, which is characterized in that a neodymium-rich shell structure is formed on a main phase grain epitaxial layer of a magnet (Nd, ce) 2Fe14 B by means of NdaFebBcMd in an alloy A, and then a double-layer shell structure rich in neodymium and heavy rare earth is formed on the main phase grain epitaxial layer of the magnet by means of R' xFeyHz diffusion heat treatment of the alloy B, so that the influence of cerium on the anisotropic field of the main phase grain epitaxial layer is eliminated, and the double-layer shell structure improves the coercive force increasing amplitude. The aim of the invention can be achieved by the following technical scheme: The high-performance cerium-containing rare earth permanent magnet comprises a cerium-containing rare earth permanent magnet matrix, and an alloy A and an alloy B which are sequentially arranged on the surface of the cerium-containing rare earth permanent magnet matrix; Wherein the alloy A component contains Nd aBbMcFed, nd is neodymium element, fe is iron element, B is boron element, M is at least one of Al, co, cu, mg elements, wherein a+b+c+d=100%, a is 33wt% or more and less than or equal to 50wt%, B is 0.8wt% or more and less than or equal to 1.0wt%, c is 0.1wt% or less and less than or equal to 2wt%, and d is the rest; The alloy B comprises R 'xFeyHz, wherein R' is at least one of Dy and Tb, fe is an iron element, H is a hydrogen element, wherein x+y+z=100%, x is more than or equal to 70wt% and less than or equal to 89wt%, y is more than or equal to 10wt% and less than or equal to 29wt%, and the balance is z. According to the invention, the alloy A forms a Nd-rich shell structure on the main phase particle epitaxial layer of the cerium-containing rare earth permanent magnet through diffusion, so that the distribution of cerium elements on the main phase epitaxial layer is blocked, on the basis, the alloy B forms a second heavy rare earth shell structure of dysprosium (Dy) and terbium (Tb) on the Nd-rich shell through diffusion of dysprosium (Dy) and terbium (Tb), the influence of cerium on an anisotropic field is reduced by the double-layer shell structure, the anisotropic field of the epitaxial layer of the cerium-containing rare earth permanent magnet is greatly improved, and the coercive force of the magnet after diffusion is correspondingly greatly improved. In the high-performance cerium-containing rare earth permanent magnet, the matrix component of the cerium-containing rare earth permanent magnet is (R, ce) FeMB; r is one or more of rare earth elements other than Ce, and must contain Nd; m is at least one of Al, co, cu, ga, zr, nb, O, C, S, N and H. The invention also provides a preparation method of the high-performance cerium-containing rare earth permanent magnet, which comprises the following steps: S1, carrying out sand blasting treatment on the surface of a cerium-containing rare earth permanent magnet matrix, then coa