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CN-122012981-A - Alloy foil for grain boundary diffusion, preparation method and application thereof, and preparation method of neodymium-iron-boron diffusion magnet

CN122012981ACN 122012981 ACN122012981 ACN 122012981ACN-122012981-A

Abstract

The invention discloses an alloy foil for grain boundary diffusion, a preparation method and application thereof, and a preparation method of a neodymium-iron-boron diffusion magnet. The alloy foil for grain boundary diffusion is prepared by depositing a rare earth element-containing film on the surface of a copper-zinc alloy foil, wherein the rare earth element-containing film is a rare earth simple substance metal film or a rare earth alloy film, the rare earth element-containing film does not contain Cu, co, ga, sn, ag, fe, zn, mg and must contain terbium, and the mass ratio of copper to zinc in the copper-zinc alloy foil is (70-90 wt%) (10-30 wt%). The alloy foil for grain boundary diffusion can solve the problems of low preparation efficiency, high cost, single component and the like of a magnet grain boundary diffusion source, realize gravity assisted diffusion and magnet selective diffusion, improve the utilization rate of heavy rare earth for grain boundary diffusion, and simultaneously improve the coercive force of a magnet.

Inventors

  • CUI HONGBING
  • CHENG YAN
  • ZHANG MAOCAI
  • AI JINGWEN
  • TIAN SHIYAN
  • XIN BO
  • LOU SHUPU
  • ZHAO MINGJING
  • LI ZHIQIANG

Assignees

  • 包头稀土研究院

Dates

Publication Date
20260512
Application Date
20241108

Claims (10)

  1. 1. The alloy foil for grain boundary diffusion is characterized in that the alloy foil is prepared by depositing a rare earth element-containing film on the surface of a copper-zinc alloy foil, wherein the rare earth element-containing film is a rare earth simple substance metal film or a rare earth alloy film, cu, co, ga, sn, ag, fe, zn, mg is not contained in the rare earth element-containing film and terbium is necessarily contained in the rare earth element-containing film, and the mass ratio of copper to zinc in the copper-zinc alloy foil is (70-90 wt%) (10-30 wt%).
  2. 2. Alloy foil for grain boundary diffusion according to claim 1, characterized in that the alloying element in the rare earth alloy thin film is Al.
  3. 3. Alloy foil for grain boundary diffusion according to claim 1 or 2, characterized in that the copper zinc alloy foil has a thickness of 3.5-20 μm and a surface roughness of 0.5-2.8 μm.
  4. 4. A method for producing the alloy foil for grain boundary diffusion according to any one of claims 1 to 3, comprising the steps of: (1) Selecting a copper zinc alloy foil with the thickness D 0 of 3.5-20 mu m as a coating substrate, depositing rare earth elements or rare earth alloy elements on at least one surface of the copper zinc alloy foil, and stopping sputtering when the thickness D 1 of the single-sided deposited rare earth film reaches 1.4-2.85 of D 0 ; (2) And (3) performing heat treatment on the copper-zinc alloy foil subjected to single-sided film coating in the step (1) to obtain the alloy foil for grain boundary diffusion.
  5. 5. The method according to claim 4, wherein in the step (2), the temperature of the heat treatment is 180 to 480 ℃.
  6. 6. Use of the alloy foil for grain boundary diffusion according to any one of claims 1 to 5 for increasing coercive force of neodymium-iron-boron magnets.
  7. 7. The preparation method of the neodymium-iron-boron diffusion magnet is characterized by comprising the following steps of: (A) Attaching at least one layer of alloy foil for grain boundary diffusion according to any one of claims 1-5 to a neodymium-iron-boron magnet to be diffused to obtain a sample to be subjected to grain boundary diffusion; (B) And (C) carrying out vacuum heat treatment on the sample to be subjected to grain boundary diffusion in the step (A) to obtain the neodymium-iron-boron diffusion magnet.
  8. 8. The method of claim 7, wherein the step of vacuum heat treating comprises: s1, placing a sample to be subjected to grain boundary diffusion in a vacuum heat treatment furnace, vacuumizing, heating the sample to a first temperature, and carrying out heat preservation treatment for 95-150 min; s2, continuously heating the sample obtained in the step S1 to a second temperature, performing heat preservation treatment for 350-450 min, and cooling to room temperature; And S3, heating the sample obtained in the step S2 to a third temperature, carrying out heat preservation treatment for 70-115 min, and cooling to obtain the neodymium-iron-boron diffusion magnet.
  9. 9. The method according to claim 8, wherein the first temperature is 650-750 ℃, the second temperature is 850-900 ℃, and the third temperature is 520-650 ℃.
  10. 10. The method for preparing a ceramic material according to any one of claims 7 to 9, wherein the combination mode between the alloy foil for grain boundary diffusion and the neodymium-iron-boron magnet to be diffused is single-sided lamination, double-sided lamination or multi-layer arrangement at intervals.

Description

Alloy foil for grain boundary diffusion, preparation method and application thereof, and preparation method of neodymium-iron-boron diffusion magnet Technical Field The invention relates to an alloy foil for grain boundary diffusion, a preparation method and application thereof, and a preparation method of a neodymium-iron-boron diffusion magnet. Background Neodymium iron boron (Nd-Fe-B) magnets have excellent magnetic properties and become key functional materials for developing high-precision industries. However, the coercivity (intrinsic coercivity Hcj) of the Nd-Fe-B magnet produced in industrial quantities at present is only 15-25% of the theoretical value, and Hcj with low magnet cannot meet the use requirements of a large number of high-temperature service scenes, so that improving the Hcj of the Nd-Fe-B magnet to inhibit high-temperature thermal demagnetization behavior becomes a key problem to be solved by the material. The existing film forming technology of rare earth diffusion sources is mainly divided into Physical Vapor Deposition (PVD) and screen printing technology (SCREEN PRINTING), and the problems that firstly, a large amount of high-value rare earth metal cannot be completely deposited on the surface of a magnet in physical vapor deposition, a rare earth alloy film deposited on the magnet cannot be processed secondarily, materials are seriously wasted, the preparation efficiency is low, the cost is high and the production time is long, secondly, a large amount of high-molecular organic adhesive used in screen printing introduces impurity elements such as carbon, nitrogen and oxygen, the utilization efficiency of rare earth is influenced, the performance of a diffusion magnetic material is improved, the metal loading amount of the screen printing load on the surface of the magnet is small, the diffusion efficiency is low, and the selected heat treatment time is long are mainly solved. CN118507186a discloses a rare earth amorphous alloy for grain boundary diffusion of iron-based rare earth permanent magnet and a diffusion process thereof, wherein the rare earth amorphous alloy film is of a continuous and uniform amorphous structure, the film resistivity is 150-284 m omega cm, the glass transition temperature is less than 650 ℃ and no organic matters are contained, and the rare earth amorphous alloy contains rare earth elements which are single light rare earth elements, single heavy rare earth elements or both light and heavy rare earth elements. The film is directly covered on the surface of the magnet, single deposition amount is small, the fixture is required to fix, the magnet specification can influence the coating efficiency and the target utilization rate, quick preparation cannot be realized, and the film is not suitable for batch production. Disclosure of Invention In view of the above, an object of the present invention is to provide an alloy foil for grain boundary diffusion, which can solve the problems of low preparation efficiency, high cost, single component, etc. of a magnet grain boundary diffusion source, realize gravity-assisted diffusion and magnet selective diffusion, and improve the utilization rate of heavy rare earth for grain boundary diffusion. Another object of the present invention is to provide a method for preparing an alloy foil for grain boundary diffusion. It is still another object of the present invention to provide a use of the alloy foil for grain boundary diffusion as described above for improving coercive force of a neodymium-iron-boron magnet. The invention also aims at providing a preparation method of the neodymium-iron-boron diffusion magnet. The technical aim is achieved by the following technical scheme. On the one hand, the invention provides an alloy foil for grain boundary diffusion, which is prepared by depositing a rare earth element-containing film on the surface of a copper-zinc alloy foil, wherein the rare earth element-containing film is a rare earth simple substance metal film or a rare earth alloy film, cu, co, ga, sn, ag, fe, zn, mg is not contained in the rare earth element-containing film and terbium is necessarily contained in the rare earth element-containing film, and the mass ratio of copper to zinc in the copper-zinc alloy foil is (70-90 wt%). According to the alloy foil for grain boundary diffusion of the present invention, preferably, the alloying element in the rare earth alloy thin film is Al. According to the alloy foil for grain boundary diffusion of the present invention, preferably, the copper zinc alloy foil has a thickness of 3.5 to 20 μm and a surface roughness of 0.5 to 2.8 μm. In another aspect, the present invention provides a method of preparing an alloy foil for grain boundary diffusion, comprising the steps of: (1) Selecting a copper zinc alloy foil with the thickness D 0 of 3.5-20 mu m as a coating substrate, depositing rare earth elements or rare earth alloy elements on at least one surface of the copper zin