Method for preparing high-coercivity sintered neodymium-iron-boron magnet through grain boundary diffusion

A technology with high coercive force and grain boundary diffusion, applied in the direction of magnetic objects, magnetic films to substrates, magnetic materials, etc., can solve the problems of time-consuming, poor controllability of sputtering parameters, etc.

Pending Publication Date: 2021-06-08
KUNMING UNIV OF SCI & TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the magnetron sputtering coating method still has disadvantages. When the magnetron sputtering method is used to co-sputter heavy rare earth elements and auxiliary elements, due to the mutual i

Method used

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  • Method for preparing high-coercivity sintered neodymium-iron-boron magnet through grain boundary diffusion
  • Method for preparing high-coercivity sintered neodymium-iron-boron magnet through grain boundary diffusion
  • Method for preparing high-coercivity sintered neodymium-iron-boron magnet through grain boundary diffusion

Examples

Experimental program
Comparison scheme
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Embodiment 1

[0032] A method for preparing a high-coercivity sintered NdFeB magnet by grain boundary diffusion, specifically comprising the following steps:

[0033] (1) First use commercial degreasing powder to degrease the surface of sintered NdFeB magnets with a size of Φ10mm×5mm, then use a diluted concentration of 4vol% nitric acid solution to clean the sintered NdFeB magnets to remove rust, and finally use deionized Clean the magnet ultrasonically with water and absolute ethanol to remove impurities attached to the surface of the magnet, and dry it with a hair dryer for later use.

[0034] (2) Evacuate the vacuum chamber to the vacuum degree required for the experiment, and then fill the vacuum chamber with high-purity Ar (purity ≥ 99.999%) for ion activation sample treatment. The process of ion activation sample is to use ion source in vacuum chamber to ionize high-purity Ar into Ar + , apply a negative bias voltage on the sintered NdFeB magnet sample to attract high-energy Ar + B...

Embodiment 2

[0041] The preparation process of this embodiment is basically the same as in Example 1, the difference is that when depositing the heavy rare earth-metal multilayer film, the quality of the sputtering of each layer of the metal Al film is halved, and the number of layers remains unchanged; the diffusion magnet The demagnetization curve and the BSE-SEM image showing the diffusion depth of the film are shown in the appendix image 3 with 4 ,Depend on image 3 It can be seen that when the sputtered mass of the Al film is halved, the coercive force of the diffusion magnet decreases; Figure 4 It can be seen that the rare earth-rich shell formed after diffusion (light gray in the figure) is uniform and thin, indicating that the film diffuses deep into the magnet.

Embodiment 3

[0046] A method for preparing a high-coercivity sintered NdFeB magnet by grain boundary diffusion, specifically comprising the following steps:

[0047] (1) First use commercial degreasing powder to degrease the surface of sintered NdFeB magnets with a size of Φ10mm×5mm, then use a diluted concentration of 4vol% nitric acid solution to clean the sintered NdFeB magnets to remove rust, and finally use deionized Clean the magnet ultrasonically with water and absolute ethanol to remove impurities attached to the surface of the magnet, and dry it with a hair dryer for later use.

[0048] (2) Evacuate the vacuum chamber to the vacuum degree required for the experiment, and then fill the vacuum chamber with high-purity Ar (purity ≥ 99.999%) for ion activation sample processing. The process of ion activation sample is to use ion source in vacuum chamber to ionize high-purity Ar into Ar + , apply a negative bias voltage on the sintered NdFeB magnet sample to attract high-energy Ar + ...

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Abstract

The invention discloses a method for preparing a high-coercivity sintered neodymium-iron-boron magnet through grain boundary diffusion, belonging to the technical field of rare earth permanent magnet materials. The method comprises the following steps: preparing a heavy rare earth-alloy element multilayer film on the surface of a sintered neodymium-iron-boron magnet by adopting a magnetron sputtering method, then carrying out a vacuum thermal diffusion treatment process, and finally carrying out tempering treatment to obtain the high-coercivity neodymium-iron-boron magnet, wherein the temperature of the thermal diffusion treatment process is 600-900 DEG C, and the time of the thermal diffusion treatment process is 3-10 h. According to the method disclosed by the invention, time required for sputtering the heavy rare earth-alloy element thin film is shortened, and the diffusion depth of the thin film is deeper; and compared with a pure rare earth element diffusion method, the method of the invention has the advantages that the film diffusion depth is deeper, and the coercive force of the sintered neodymium-iron-boron magnet can be further improved.

Description

technical field [0001] The invention relates to a method for preparing high-coercivity sintered NdFeB magnets by grain boundary diffusion, in particular to a method for preparing high-coercivity NdFeB magnets by grain boundary diffusion of heavy rare earth-alloy element multilayer films, belonging to rare earth The technical field of permanent magnet materials. Background technique [0002] Sintered NdFeB permanent magnet materials are widely used in aerospace ships, power vehicles and other fields, and these fields require magnets to work stably under high temperature conditions, and the high temperature stability of magnets is closely related to coercive force. [0003] At present, the method of increasing the coercive force of magnets is mostly achieved by increasing the magnetocrystalline anisotropy field, and adding heavy rare earth elements is an effective method to increase the magnetocrystalline anisotropy field of sintered NdFeB magnets. Generally, a certain amount...

Claims

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Application Information

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IPC IPC(8): H01F41/02H01F41/18H01F1/057H01F1/055
CPCH01F41/0293H01F41/0253H01F41/18H01F1/057H01F1/0557
Inventor 马照坤宋振纶杨丽景宋鹏王庭辉江杰
Owner KUNMING UNIV OF SCI & TECH
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