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High-coercivity neodymium-iron-boron magnet preparation method and neodymium-iron-boron magnet thereof

A high coercive force, NdFeB technology, applied in the direction of magnetic objects, inductors/transformers/magnet manufacturing, magnetic materials, etc., can solve the problems of small coercive force improvement of NdFeB magnet materials, poor effect of heavy rare earth elements, etc. , to achieve good grain boundary diffusion effect, high coercive force enhancement effect, and improved stability

Pending Publication Date: 2019-08-09
宁波雄海稀土速凝技术有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] However, this process is the same as the existing grain boundary diffusion heavy rare earth element process, and has the same disadvantages, that is, it is limited to making thinner magnetic parts (thickness generally does not exceed 5mm). When preparing large magnets, the grain boundary The effect of diffusing heavy rare earth elements is poor, and the coercive force improvement of NdFeB magnet materials is small, so it needs to be improved

Method used

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  • High-coercivity neodymium-iron-boron magnet preparation method and neodymium-iron-boron magnet thereof
  • High-coercivity neodymium-iron-boron magnet preparation method and neodymium-iron-boron magnet thereof
  • High-coercivity neodymium-iron-boron magnet preparation method and neodymium-iron-boron magnet thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] A kind of high coercivity NdFeB magnet preparation method, it comprises the following steps:

[0045] S1: NdFeB powder with a particle size of 2.0-2.5 μm is obtained by distributing ingredients according to the design, casting and smelting, hydrogen crushing, and jet milling;

[0046] S2: Mix NdFeB powder and binder at a mass ratio of 1:0.08-0.09, and perform oriented static pressure molding on the mixture in a 1.5T magnetic field to obtain a compacted NdFeB rough billet;

[0047] S3: Mix the material containing heavy rare earth elements with NdFeB powder and heat it to the immersion temperature and keep it in a molten state. The immersion temperature is 1100-1300°C to obtain a heavy rare earth source melt;

[0048] S4: Put the NdFeB rough blank in a cage or basket and heat it under a protective atmosphere. The heating temperature is gradually increased until the heating temperature is 200-250°C higher than the melting point of the adhesive. Melt flows out from the surf...

Embodiment 2

[0087] A high coercive force NdFeB magnet preparation method, based on the first embodiment, the difference is:

[0088] S1: Dosing according to the design composition, casting smelting, hydrogen crushing, and jet milling to obtain coarse NdFeB powder with a particle size of 3.0-3.5 μm and fine NdFeB powder with a particle size of 2-2.5 μm;

[0089] S2: Mix the fine NdFeB powder and the coarse NdFeB powder at a mass ratio of 0.2-0.3:1, and then add a binder according to the mass ratio of the NdFeB powder and the binder at a mass ratio of 1:0.08-0.09 for mixing, Perform oriented static pressure molding on the mixture in a 1.5T magnetic field to obtain a compacted NdFeB rough billet;

[0090] Steps S3-S6 are the same as those in Embodiment 1.

[0091] The shape of the finished NdFeB magnet can be determined according to the actual situation, and its thickness is greater than 5mm. Here, a disc with a diameter of 25mm is used as a sample. The element composition of finished NdFe...

Embodiment 3

[0104] A high-coercivity NdFeB magnet preparation method, based on Example 2F, the difference is that the particle size of the binder powder is different, and Example 3A-3C is set, and the specific parameters are as follows.

[0105]

[0106] The grain boundary diffused heavy rare earth NdFeB magnet obtained in Example 3 was tested, and the test results are as follows.

[0107] Remanence / kGs Intrinsic coercive force / kOe Maximum energy product / MGOe Example 3A 12.85 17.70 40.04 Example 3B 13.54 22.77 44.52 Example 3C 14.14 24.65 48.60 Example 3E 14.22 23.46 49.14

[0108] By comparing Example 2 and Example 3, it can be seen that the closer the particle size of the binder powder is to the particle size of the coarse NdFeB powder, the smaller the possibility of deformation and collapse of the NdFeB rough blank during the heating process of S4 and S5, At the same time, the better the effect of solid solution and penetration betw...

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Abstract

The invention relates to a neodymium-iron-boron magnet, and discloses a high-coercivity neodymium-iron-boron magnet preparation method and neodymium-iron-boron magnet thereof. The preparation method comprises the following steps: mixing neodymium-iron-boron powder and a low-melting-point metal adhesive for static pressure molding so as to obtain a compacted rough neodymium-iron-boron blank; mixingthe material containing heavy rare earth elements with the neodymium-iron-boron powder to heat to the molten state so as to obtain a heavy rare earth source melt; heating the rough neodymium-iron-boron blank in a protective atmosphere until the heating temperature is 200-250 DEG C higher than the melting point of the adhesive and keeping the temperature for 2-3h; then heating the S4-treated roughneodymium-iron-boron blank processed in S4 to 950 DEG C and immersing the rough neodymium-iron-boron blank in the heavy rare earth source melt, vacuumizing the rough neodymium-iron-boron blank and pressurizing the rough neodymium-iron-boron blank by piping in protective gas to the environment and taking out the rough neodymium-iron-boron blank after the immersing time so as to obtain the rough neodymium-iron-boron blank product; and performing surface treatment on the rough neodymium-iron-boron blank so as to obtain the finished product of the neodymium-iron-boron magnet. The obtained neodymium-iron-boron magnet has good grain boundary diffusion effect and higher coercivity than that of the neodymium-iron-boron magnet obtained by the existing grain boundary diffusion heavy rare earth element process.

Description

technical field [0001] The invention relates to a neodymium-iron-boron magnet, in particular to a method for preparing a high-coercivity neodymium-iron-boron magnet and the neodymium-iron-boron magnet thereof. Background technique [0002] NdFeB permanent magnet materials are the most concerned rare earth application industry in my country's rare earth industry. With the development of science and technology and technological progress, the demand for high-performance NdFeB permanent magnet materials is becoming more and more extensive. In order to improve the coercive force and high-temperature usability of NdFeB, the commonly used method is to add a small amount of heavy rare earth elements (such as Dy, Tb, etc.) or optimize the process to refine the magnet grains. [0003] At present, the methods to reduce the usage of heavy rare earth mainly include double alloy process and grain boundary diffusion heavy rare earth element process. [0004] The double alloy process is to...

Claims

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Application Information

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IPC IPC(8): H01F1/057H01F41/02
CPCH01F1/0571H01F41/0293
Inventor 路河树朱海松杨道华
Owner 宁波雄海稀土速凝技术有限公司
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