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CN-121553902-B - Solvothermal method preparation process of rare earth hydride nano-particles

CN121553902BCN 121553902 BCN121553902 BCN 121553902BCN-121553902-B

Abstract

The invention discloses a solvothermal method process for preparing rare earth hydride nano-particles, which comprises the steps of taking rare earth metal salt, lithium hydride and graphene as raw materials, adding the raw materials into a high-pressure reaction kettle containing an organic solvent, uniformly mixing, stirring and heating to 100-120 ℃ under the inert atmosphere condition, carrying out heat preservation reaction for 1.5-2.5 h, cooling to room temperature after the reaction is finished, filtering and collecting black products, washing the black products with the organic solvent, and finally carrying out vacuum drying on the products at 65-75 ℃ for 1-2 h to obtain the rare earth hydride nano-particles. The method has the advantages of simple and efficient process, small particle size, uniform distribution and high purity of the obtained product, can be effectively attached to the grain boundary region of the neodymium-iron-boron magnet when being used in the grain boundary diffusion technology of the neodymium-iron-boron magnet, and decompose and release active rare earth elements at high temperature, so that the components and the structure of the grain boundary are regulated, the thermal stability and the coercive force of the magnet can be obviously improved, and the use amount and the production cost of heavy rare earth are reduced.

Inventors

  • QIN SIJIE
  • LIU XIAOQIONG
  • LI TAO
  • GAO JIALONG
  • GAO SHUWEN
  • Qin Dongmin
  • Gao Xuebiao
  • XU YING
  • ZHOU HONGLIANG

Assignees

  • 山西瑞科新材料股份有限公司

Dates

Publication Date
20260512
Application Date
20260122

Claims (7)

  1. 1. The solvothermal method of rare earth hydride nano-particles is characterized in that rare earth metal salt, lithium hydride and graphene are taken as raw materials, the raw materials are added into a high-pressure reaction kettle containing an organic solvent, the mixture is uniformly mixed, the mixture is stirred and heated to 100-120 ℃ under the inert atmosphere condition, the reaction is kept for 1.5-2.5 hours, the mixture is cooled to room temperature after the reaction is finished, black products are collected through filtration and are washed by the organic solvent, and finally the products are dried in vacuum for 1-2 hours at 65-75 ℃ to obtain the rare earth hydride nano-particles; the rare earth metal salt is dysprosium chloride or terbium chloride, and the molar ratio of the rare earth metal salt to lithium hydride is 1:3-4.
  2. 2. The solvothermal method process of rare earth hydride nano-particles according to claim 1, wherein the adding amount of graphene is 10mg/mmol of rare earth metal salt, and the adding amount of organic solvent in a high-pressure reaction kettle is 45-65mL.
  3. 3. The process for preparing rare earth hydride nanoparticles by solvothermal method according to claim 2, wherein the organic solvent is one of tetrahydrofuran, toluene, ethylene glycol dimethyl ether, dimethyl ether or cyclodiene.
  4. 4. A solvothermal process for preparing rare earth hydride nanoparticles as claimed in any one of claims 1-3, wherein the organic solvent used for cleaning is consistent with the organic solvent used for the reaction.
  5. 5. A solvothermal preparation process for rare earth hydride nanoparticles as set forth in any one of claims 1-3, wherein the inert atmosphere is an argon atmosphere.
  6. 6. A process for preparing rare earth hydride nanoparticles by solvothermal method according to any one of claims 1-3, wherein the temperature of the incubation reaction is 100 ℃ and the reaction time is 2h.
  7. 7. A solvothermal process for preparing rare earth hydride nanoparticles as claimed in any one of claims 1-3, wherein the vacuum drying temperature is 70 ℃.

Description

Solvothermal method preparation process of rare earth hydride nano-particles Technical Field The invention belongs to the technical field of nanoparticle preparation, and particularly relates to a solvothermal method for preparing rare earth hydride nanoparticles. Background Sintered neodymium iron boron (NdFeB) magnet materials have excellent magnetic properties and are therefore the most popular permanent magnet materials used in the world. Sintered NdFeB rare earth permanent magnet materials are rapidly developed in new energy industries such as hybrid electric vehicles, wind power generation and the like, the temperature of a permanent magnet motor of key parts of equipment in the industrial field is usually above 150 ℃, but the working temperature of a NdFeB magnet is usually lower than 100 ℃, and the sintered NdFeB rare earth permanent magnet materials are poor in thermal stability and are easy to thermally demagnetize at high temperature, so that the development of the sintered NdFeB rare earth permanent magnet materials in the field of high-temperature motors is limited. At present, the existing conventional method improves the thermal stability and coercive force of the sintered neodymium-iron-boron magnet by directly adding heavy rare earth dysprosium (Dy) or terbium (Tb) into the neodymium-iron-boron magnet, but excessive addition of dysprosium (Dy) or terbium (Tb) can cause the residual magnetism and magnetic energy product of the sintered neodymium-iron-boron magnet to be obviously reduced and increase the cost. The grain boundary diffusion technology takes rare earth hydride nano particles as a diffusion source, and forms a rare earth hydride nano particle coating on the surface of the sintered NdFeB magnet. Therefore, the thermal stability of the sintered NdFeB magnet can be effectively improved through the grain boundary diffusion technology, and the coercive force of the magnet can be greatly improved. Further, in the grain boundary diffusion technology, the rare earth hydride nano particles can adjust the chemical composition and structure of the grain boundary, optimize the microstructure of the magnet, and improve the magnetic isolation effect of the grain boundary, thereby remarkably improving the coercive force of the neodymium-iron-boron magnet, and simultaneously reducing the production cost and the rare earth resource consumption (the hydrogen of the hydride is finally released and does not obstruct the diffusion of the rare earth element, so the rare earth element can reach the inside of the magnet). Conventional rare earth hydrides are generally prepared by a rare earth metal hydrogen absorption-fragmentation method, and the main processes include reaction of rare earth metal with hydrogen and automatic fragmentation of materials. The rare earth hydride prepared by the method has the defect of large product particles, so that the diffusion efficiency is low. In contrast, the use of rare earth hydride nanoparticles can improve diffusion efficiency and increase diffusion depth, thereby improving the utilization rate of rare earth. Disclosure of Invention The invention aims to solve the technical problems of large product particles and low diffusion efficiency when used for grain boundary diffusion in the traditional rare earth hydride preparation method, provides a solvothermal method preparation process for producing high-efficiency rare earth hydride nano particles with low cost, and provides important technical support for improving the coercive force of neodymium iron boron. In order to achieve the purpose, the invention adopts the following technical scheme: The invention provides a solvothermal method process for preparing rare earth hydride nano-particles, which is characterized in that rare earth metal salt, lithium hydride and graphene are taken as raw materials, the raw materials are added into a high-pressure reaction kettle containing an organic solvent, the mixture is uniformly mixed, the mixture is stirred and heated to 100-120 ℃ under the inert atmosphere condition, the reaction is kept at 1.5-2.5 h, the mixture is cooled to room temperature after the reaction is finished, black products are filtered and collected, the products are washed by the organic solvent, and finally the products are dried in vacuum at 65-75 ℃ to obtain the rare earth hydride nano-particles. As a further preferable aspect of the present invention, the rare earth metal salt is dysprosium chloride or terbium chloride. Further, the molar ratio of the rare earth metal salt to the lithium hydride is 1:2.5-4, the adding amount of the graphene is 10 mg/mmol of the rare earth metal salt, and the adding amount of the organic solvent in the high-pressure reaction kettle is 45-65 mL. Further, the organic solvent is one of tetrahydrofuran, toluene, ethylene glycol dimethyl ether, dimethyl ether or cyclodiene. Further, the organic solvent used for washing is consistent with the organic solvent used for the