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CN-122025396-A - Rare earth permanent magnet diffusion source slurry and preparation method and application thereof

CN122025396ACN 122025396 ACN122025396 ACN 122025396ACN-122025396-A

Abstract

The invention relates to rare earth permanent magnet diffusion source slurry and a preparation method and application thereof, and belongs to the technical field of diffusion source slurry. Solves the problems that the prior diffusion source slurry is easy to oxidize, agglomerate, precipitate, coat unevenly and have poor magnet binding force, and is not suitable for large-scale production. The preparation method comprises the steps of weighing raw materials according to the proportion of each element in a chemical formula RE 100‑x M x , smelting and throwing tablets to obtain a multi-component alloy rapid hardening tablet, then subjecting the multi-component alloy rapid hardening tablet to hydrogen explosion to obtain diffusion source coarse powder, subjecting the diffusion source coarse powder to air flow grinding to obtain diffusion source fine powder, finally uniformly mixing the diffusion source fine powder, a diluent, an anti-settling agent and an anti-oxidation agent under the protection of inert atmosphere, grinding until the D50 is 0.2-3.5 mu m, and mixing with a binder to obtain rare earth permanent magnet diffusion source slurry. The preparation method has the advantages of high production efficiency, low cost, good uniformity of the prepared diffusion source slurry, good adhesive force, oxidation resistance, wide process window and high diffusion efficiency.

Inventors

  • LIU RENHUI
  • Zhou Toujun
  • XIE WEICHENG

Assignees

  • 江西理工大学

Dates

Publication Date
20260512
Application Date
20260310

Claims (10)

  1. 1. The preparation method of the rare earth permanent magnet diffusion source slurry is characterized by comprising the following steps of: (1) Weighing raw materials according to the proportion of each element in a chemical formula RE 100-x M x , smelting and throwing the slices to obtain a multi-component alloy rapid hardening slice; In RE 100-x M x , x=10-90, RE is at least one of La, ce, pr, nd, dy, tb, sm, gd, and M is at least one of Al, cu, co, fe, ni, sn, zn, ga, ti, zr; (2) Hydrogen explosion is carried out on the multicomponent alloy rapid hardening sheet to obtain diffusion source coarse powder; (3) Carrying out air current grinding on the diffusion source coarse powder until the D50 is 5-50 mu m to obtain diffusion source fine powder; (4) Under the protection of inert atmosphere, uniformly mixing the diffusion source fine powder, the diluent, the anti-settling agent and the anti-oxidation agent, grinding until the D50 is 0.2-3.5 mu m, and mixing with the binder to obtain rare earth permanent magnet diffusion source slurry.
  2. 2. The method for preparing rare earth permanent magnet diffusion source slurry according to claim 1, wherein in the step (4), one or more of the following features are provided: the dosages of the diffusion source fine powder, the binder, the anti-settling agent and the anti-oxidation agent are respectively 20-80wt%, 1-15wt%, 0.1-5wt% and 0.1-5wt%, and the rest is the diluent; the diluent is one or more of terpineol, dibasic acid ester, methanol, ethanol, propanol, butanol and ethylene glycol; The anti-settling agent is one or more of polyamide wax, 7500DP anti-settling agent, polyoxyethylene fatty alcohol sulfate and nonionic polyoxyethylene fatty amine; The binder is one or more of copolymer of styrene and divinylbenzene, polyvinylpyrrolidone, phenolic resin, tributyl citrate, stearic acid and polyvinyl butyral.
  3. 3. The method for preparing rare earth permanent magnet diffusion source slurry according to claim 1, wherein in the step (4), the inert atmosphere is argon or nitrogen.
  4. 4. The method for preparing rare earth permanent magnet diffusion source slurry according to claim 1, wherein in the step (4), the diluent, the anti-settling agent and the anti-oxidation agent are stirred and mixed uniformly, then the mixture is stirred and mixed uniformly with the diffusion source fine powder, and finally the mixture is ground until the D50 is 0.2-3.5 μm.
  5. 5. The method for preparing rare earth permanent magnet diffusion source slurry according to claim 1, wherein in the step (4), a grinding machine is adopted for grinding treatment, the rotating speed of the grinding machine is 1500-2500 rpm, and the time is 0.5-5h.
  6. 6. A rare earth permanent magnet diffusion source slurry prepared by the method for preparing a rare earth permanent magnet diffusion source slurry according to any one of claims 1 to 5.
  7. 7. The use of rare earth permanent magnet diffusion source slurry according to claim 6 for preparing grain boundary diffusion neodymium-iron-boron magnet.
  8. 8. The application of rare earth permanent magnet diffusion source slurry in preparing grain boundary diffusion neodymium-iron-boron magnet according to claim 7, wherein the rare earth permanent magnet diffusion source slurry is coated on the surface of the neodymium-iron-boron magnet by adopting at least one of spraying, dipping and screen printing, and then diffusion heat treatment is carried out.
  9. 9. Use of rare earth permanent magnet diffusion source slurry according to claim 8 for the preparation of grain boundary diffusion neodymium-iron-boron magnets, characterized by one or more of the following features: polishing, degreasing, pickling and drying the surface of the neodymium-iron-boron magnet in sequence before the rare earth permanent magnet diffusion source slurry is coated on the surface of the neodymium-iron-boron magnet; the thickness of the neodymium-iron-boron magnet is below 10 mm; The diffusion heat treatment comprises degumming treatment, dehydrogenation treatment, diffusion treatment and tempering treatment.
  10. 10. The application of the rare earth permanent magnet diffusion source slurry according to claim 9 in preparing a grain boundary diffusion neodymium-iron-boron magnet, The degumming treatment temperature is 80-350 ℃, the vacuum degree is less than 1X 10 -2 Pa, and the treatment time is 1-5h; The dehydrogenation treatment temperature is 450-650 ℃, the vacuum degree is 7 multiplied by 10 -3 Pa or below, and the treatment time is 1-5h; The temperature of the diffusion treatment is 850-950 ℃, the vacuum degree is 7 multiplied by 10 -3 Pa or less, and the treatment time is 2-15h; The tempering treatment temperature is 450-550 ℃, the vacuum degree is 7 multiplied by 10 -3 Pa or below, and the treatment time is 2-6h.

Description

Rare earth permanent magnet diffusion source slurry and preparation method and application thereof Technical Field The invention belongs to the technical field of diffusion source slurry, and particularly relates to rare earth permanent magnet diffusion source slurry, a preparation method and application thereof, in particular to application of the rare earth permanent magnet diffusion source slurry in preparation of a grain boundary diffusion neodymium-iron-boron magnet. Background The neodymium iron boron (NdFeB) magnet has high coercivity, and can effectively resist thermal demagnetization, so that the magnet is ensured to be applied in a high-temperature environment. With the continuous promotion of the national double-carbon strategic targets, the requirements of NdFeB magnets in the application fields of rail transit, wind power generation, energy-saving household appliances and the like are rapidly increased. The grain boundary diffusion method can greatly improve the coercive force of the magnet and ensure that the remanence and the magnetic energy product are not greatly reduced by coating and diffusing a small amount of compound containing heavy rare earth on the surface of the magnet. The surface coating means that rare earth compound slurry is directly coated on the surface of an original magnet sample, then dried and subjected to high-temperature diffusion treatment under an inert atmosphere, and although the method can remarkably improve the coercive force of the magnet, the rare earth compound is easily oxidized in the coating process, so that rare earth elements are not easy to diffuse into the magnet, and the problem that the rare earth elements are difficult to uniformly coat and cause uneven diffusion also exists. Therefore, it is necessary to develop a rare earth diffusion source slurry capable of preventing oxidation of rare earth metal elements and achieving ultra-thin uniform coating. From the perspective of diffusion sources, the types of diffusion sources in the prior art have been developed from rare earth simple substances into rare earth oxides, fluorides, hydrides, rare earth alloys and the like, wherein the rare earth alloys are considered as one of the most potential diffusion source types due to better modification strengthening effects and higher rare earth utilization efficiency. But the rare earth alloy has higher toughness, and is finished by adopting the technological processes of alloy smelting, rapid hardening casting, hydrogen crushing, air flow grinding and the like, and only micro-rice flour can be prepared finally. The problem group Yue Ming of Beijing university of industry discloses an application (MATERIALS TODAY COMMUNICATIONS (2024) 110728) of TbF 3 nano powder prepared by a sand milling process in a high-performance grain boundary diffusion Nd-Fe-B magnet, but the application requires to prepare stable suspension, the solid content of the system is 6.25%, the slurry utilization rate is low, nano-scale powder is too fine to oxidize and agglomerate, the slurry concentration of 30g/L is thin, homogenization is not easy in the slurry preparation process, and long-time stability is difficult to maintain. Disclosure of Invention The invention provides rare earth permanent magnet diffusion source slurry and a preparation method thereof, and application of the rare earth permanent magnet diffusion source slurry in preparing a grain boundary diffusion neodymium-iron-boron magnet, aiming at solving the technical problems that diffusion source slurry in the prior art is easy to oxidize, agglomerate, precipitate, coat unevenly, has poor magnet binding force and is not suitable for large-scale production. According to the invention, after the micron fine powder diffusion source subjected to air current grinding is prepared, the nano-scale diffusion source is obtained through further grinding processing by adding the additive, the nano-scale diffusion source has higher coercive force and comprehensive magnetic property than the micron-scale diffusion source, and then slurry proportioning is carried out, so that the industrial nano diffusion source slurry with good uniformity, good coating adhesion and oxidation resistance is obtained on the premise of ensuring the stable high-performance diffusion effect, the process window is greatly widened, the mass production efficiency is effectively improved, and the cost is reduced. The technical scheme adopted by the invention for achieving the purpose is as follows. In a first aspect, the invention provides a method for preparing rare earth permanent magnet diffusion source slurry, comprising the following steps: (1) Weighing raw materials according to the proportion of each element in a chemical formula RE 100-xMx, smelting and throwing the slices to obtain a multi-component alloy rapid hardening slice; In RE 100-xMx, x=10-90, RE is at least one of La, ce, pr, nd, dy, tb, sm, gd, and M is at least one of Al, cu, co, fe, ni, sn, z