Exchange coupling dual-phase nano composite permanent magnet particles and preparation method thereof

A nano-composite and exchange-coupling technology, applied in the direction of magnetic materials, magnetic objects, inorganic materials, etc., can solve the problems of reducing the maximum magnetic energy product, low exchange coupling effect, and high cost, reducing rare earth content and material cost, and comprehensive magnetic properties. Can improve the effect of less environmental pollution

Inactive Publication Date: 2011-04-06
SOUTH CHINA UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although these methods can also adjust the microstructure of the composite material, it is difficult to precisely control the grain size and distribution of the hard magnetic phase and the soft magnetic phase, especially the size and composition of the two phases.
Therefore, it is difficult to increase the maximum energy product of isotropic nanomaterials
And these methods need to use high-purity simple substance as raw material, and the cost is higher
The smelted block alloy needs strong grinding to reach the particle size required by the permanent magnet material, and it is not easy to maintain the integrity of the magnetic crystal
In addition, the recently studied method of preparing nanocomposite hard magnetic powders by directly ball milling soft magnetic and hard magnetic mixed powders also has shortcomings such as uneven particle size, serious agglomeration, and inability to control the components of hard magnetic and soft magnetic phases separately. As a result, the exchange coupling between soft and hard magnets is low, and the combination size of the two phases cannot be optimized, reducing the maximum magnetic energy product

Method used

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  • Exchange coupling dual-phase nano composite permanent magnet particles and preparation method thereof
  • Exchange coupling dual-phase nano composite permanent magnet particles and preparation method thereof
  • Exchange coupling dual-phase nano composite permanent magnet particles and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] Embodiment 1 Co-precipitation method prepares NdFeB+nano-Fe nanometer composite particle (process flow chart is as follows figure 2 as shown in a)

[0045] The Fe nanoparticles were deposited on the hard magnetic particles by the chemical co-precipitation method, and the specific steps were as follows:

[0046] (1) dissolving the metal salt in distilled water and stirring evenly to obtain a metal salt solution with a total metal ion concentration of 0.085M; dissolving the reducing agent in distilled water and stirring uniformly to obtain a reducing agent solution with a concentration of 0.05M; The metal salt is FeSO 4 ; The reducing agent is sodium borohydride;

[0047] (2) In an argon atmosphere, immerse the single-phase NdFeB quenching magnetic powder in the reducing agent solution obtained in step (1), stir evenly, then add the metal salt solution dropwise and stir at a speed of 750rpm, and react for 2 minutes Magnetic particles are obtained; the molar ratio of b...

Embodiment 2

[0051] Example 2 Co-precipitation method to prepare NdFeB+nano-Fe nanocomposite particles

[0052] The Fe nanoparticles were deposited on the hard magnetic particles by the chemical co-precipitation method, and the specific steps were as follows:

[0053] (1) dissolving the metal salt in distilled water and stirring evenly to obtain a metal salt solution with a total metal ion concentration of 0.085M; dissolving the reducing agent in distilled water and stirring uniformly to obtain a reducing agent solution with a concentration of 0.0425M; The metal salt is FeSO 4 ; The reducing agent is sodium borohydride;

[0054] (2) In a nitrogen atmosphere, immerse the NdFeB powder of the single-phase component prepared by the mechanical alloying method in the reducing agent solution obtained in step (1), stir evenly, then add the metal salt solution dropwise and stir at a speed of 400rpm, Magnetic particles are obtained after reacting for 2 minutes; the molar ratio of the borohydride i...

Embodiment 3

[0058] Example 3 Co-precipitation method to prepare NdFeB+nano-Fe nanocomposite particles

[0059] The Fe nanoparticles were deposited on the hard magnetic particles by the chemical co-precipitation method, and the specific steps were as follows:

[0060] (1) dissolving the metal salt in distilled water and stirring evenly to obtain a metal salt solution with a total metal ion concentration of 0.075M; dissolving the reducing agent in distilled water and stirring uniformly to obtain a reducing agent solution with a concentration of 0.05M; The metal salt is FeSO 4 ; The reducing agent is sodium borohydride;

[0061] (2) In an argon atmosphere, immerse the NdFeB quick-quenching magnetic powder of single-phase composition in the reducing agent solution obtained in step (1), stir evenly, then add the metal salt solution dropwise and stir at a speed of 500rpm, and react for 15 minutes Magnetic particles are obtained; the molar ratio of borohydride ions in the reducing agent soluti...

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Abstract

The invention discloses exchange coupling dual-phase nano composite NdFeB permanent magnet particles and a preparation method thereof. The nano composite rare-earth permanent magnet particles are formed by uniformly distributing soft magnetic nano particles on the surface of hard magnetic particles, wherein the soft magnetic nano particles are iron, cobalt or iron cobalt alloy nano particles and account for 3-20 percent by weight of the nano composite rare-earth permanent magnet particles, and the hard magnetic particles are NdFeB magnetic powder. In the invention, the nano composite permanent magnet powder is prepared by wrapping the iron, cobalt or iron cobalt alloy nano particles on the surfaces of the single-phase hard magnet particles NdFeB by using a coprecipitation method or microwave-assisted polyalcohol reduction method. The preparation method of the invention has simple process and relatively lower cost and is suitable for mass production, the permanent magnet powder obtained by the method disclosed in the invention can be prepared into high-performance nano composite permanent magnets after being sintered, bonded or densified subsequently; in addition, the invention canremarkably reduce the rare-earth content in a permanent magnet material, decrease the production cost and improve the magnetic performance of the prepared product.

Description

technical field [0001] The invention belongs to nanocomposite rare earth permanent magnet materials, in particular to an exchange coupling two-phase nanocomposite NdFeB permanent magnet particle and its preparation method and application. Background technique [0002] Rare earth permanent magnet materials are widely used in computer, network information, communication, aerospace, transportation, office automation, home appliances, medical equipment and other fields because of their high coercive force, high residual magnetization and high maximum energy product. Compared with traditional single-phase rare earth permanent magnet materials, nanocomposite permanent magnet materials have higher remanence and low rare earth content, and have good exploration value and application prospects. It is well known that soft magnetic materials have a high saturation magnetization M s (for example, the M of α-Fe s 2.15T, Fe 65 co 35 Alloy M s can reach 2.4T), but its magnetocrystalli...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F1/00B22F9/24H01F1/01H01F1/057H01F1/06
Inventor 刘仲武苏昆朋邱万奇余红雅钟喜春曾德长
Owner SOUTH CHINA UNIV OF TECH
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