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Method for preparing high-magnetic energy product high-coercive force low-cost sintered neodymium iron boron

A technology with high coercive force and high magnetic energy product, applied in the direction of magnetic materials, magnetic objects, electrical components, etc., can solve the problem of the decrease of magnetic flux Bs and remanence Br of NdFeB magnets, the reduction of coercive force, and the reduction of iron atom magnetic moment and other problems, to achieve the effect of reducing the average particle size of the surface area, reducing the average grain size, and increasing the coercive force

Inactive Publication Date: 2011-04-27
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since heavy rare earth elements are expensive, increasing the coercive force of NdFeB magnets by adding heavy rare earth elements will significantly increase the cost of the magnet
At the same time, due to the antiferromagnetic coupling between heavy rare earth elements and iron, the magnetic moment of iron atoms is reduced, which leads to the decrease of magnetic flux Bs and remanence Br of NdFeB magnets, and finally reduces the magnetic properties of high coercivity NdFeB magnets.
[0004] At present, the production process of preparing high-performance NdFeB is to use quick-setting flakes, followed by crushing the quick-setting flakes into coarse powder through hydrogen crushing process, and then making fine powder through jet milling. The average particle size of the surface area of ​​fine powder is generally 3.2 microns ~4.0 microns, the lower or higher the average particle size of the surface area will lead to the decrease of the coercive force, the lower the average particle size of the surface area, the occurrence of transgranular fracture will reduce the coercive force, and the increase of the average particle size of the surface area will increase the coercive force due to the increase of the average grain size of the magnet force reduction

Method used

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  • Method for preparing high-magnetic energy product high-coercive force low-cost sintered neodymium iron boron

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Embodiment 1: the NdFeB permanent magnet material in the present embodiment is produced according to the following steps:

[0033] Step 1: according to the composition molecular formula representing the composition and mass percentage content of NdFeB alloy: (PrNd) 30％ Fe 66.9％ B 1.0％ Dy 1.0％ Cu 0.1％ Al 0.2％ Nb 0.2％ co 0.6％ preparation of raw materials;

[0034] Step 2: Put the prepared raw materials into the quick-setting furnace, in a vacuum of 2×10 -2 Heating the oven under a vacuum of Pa, then filling it with Ar gas for smelting, pouring the molten steel onto a copper roll with a roll speed of 2.5m / s after refining, and throwing it into a quick-setting thin strip with an average thickness of 0.25mm;

[0035] Step 3: Put the quick-setting thin strip into the hydrogenation furnace for hydrogen crushing process. The powder after hydrogen crushing is jet milled. During the jet mill, the average particle size of the surface area of ​​the magnetic powder is contro...

Embodiment 2

[0037] Embodiment 2: the NdFeB permanent magnet material in the present embodiment is produced according to the following steps:

[0038] Step 1: according to the composition molecular formula representing the composition and mass percentage content of NdFeB alloy: (PrNd) 30％ Fe 66.9％ B 1.0％ Dy 1.0％ Cu 0.1％ Al 0.2％ Nb 0.2％ co 0.6％ preparation of raw materials;

[0039] Step 2: Put the prepared raw materials into the quick-setting furnace, in a vacuum of 2×10 -2 Heating the oven under a vacuum of Pa, then filling it with Ar gas for smelting, pouring the molten steel onto a copper roll with a roll speed of 4.0m / s after refining, and throwing it into a quick-setting thin strip with an average thickness of 0.16mm;

[0040] Step 3: Put the quick-setting thin strip into the hydrogenation furnace for hydrogen crushing process. The powder after hydrogen crushing is jet milled. During the jet mill, the average particle size of the surface area of ​​the magnetic powder is contro...

Embodiment 3

[0042] Embodiment 3: the NdFeB permanent magnet material in the present embodiment is produced according to the following steps:

[0043] Step 1: according to the composition molecular formula representing the composition and mass percentage content of NdFeB alloy: (PrNd) 28％ Fe 66.9％ B 1.0％ Dy 3.0％ Cu 0.1％ Al 0.2％ Nb 0.2％ co 0.6％ preparation of raw materials;

[0044] Step 2: Put the prepared raw materials into the quick-setting furnace, in a vacuum of 2×10 -2 Heating the oven under a vacuum of Pa, then filling it with Ar gas for smelting, pouring the molten steel onto a copper roll with a roll speed of 3.0m / s after refining, and throwing it into a quick-setting thin strip with an average thickness of 0.20mm;

[0045] Step 3: Put the quick-setting thin strip into the hydrogenation furnace for hydrogen crushing process. The powder after hydrogen crushing is jet milled. During the jet mill, the average surface area of ​​the magnetic powder is controlled at 2.0 μm, and it ...

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Abstract

The invention discloses a method for preparing high-magnetic energy product high-coercive force low-cost sintered neodymium iron boron (NdFeB). The method comprises the following steps of: throwing raw materials into a rapid coagulating furnace and smelting in the protective atmosphere of inert gases or nitrogen, and pouring smelting liquid onto a copper roller at a roller speed of 2 to 4m / s to form a rapid coagulating thin strip with the mean thickness of 0.1 to 0.3mm; performing hydrogen breaking and jet milling to obtain magnetic powder with the superficial area mean particle size of 1.5 to 3 mu m, and orientating and molding the magnetic powder in a magnetic field to obtain a blank; and finally, sintering, cooling and ageing to obtain a sintered NdFeB magnet with the mean grain size of 5 to 6 mu m. Compared with the conventional preparation method, by optimizing the rapid coagulating process and combining the adjustment of raw materials, the preparation method makes NdFeB columnar crystals reduced during smelting; therefore, the superficial area mean particle size of the magnetic powder is reduced in the process of performing jet milling, the mean grain size of the sintered NdFeB magnet is reduced finally, and the coercive force of the sintered NdFeB magnet is improved. Therefore, the preparation method is suitable for preparing a high-magnetic energy product and low-cost high-coercive force magnet.

Description

technical field [0001] The invention relates to the technical field of magnetic materials, in particular to a method for preparing sintered NdFeB with high magnetic energy product, high coercive force and low cost. Background technique [0002] Sintered Nd-Fe-B magnets play an extremely important role in our lives today due to their excellent magnetic properties. Sintered NdFeB materials are mainly used in pillar industries and high-tech industries around the world, such as computer industry, automobile industry, communication information industry, medical industry, transportation industry, audio equipment, video playback industry, office automation and home appliance industry, etc. [0003] With the requirement of energy saving and emission reduction, the application of high-grade magnets is mainly high-coercive force magnets, which have strong anti-demagnetization ability, high temperature stability and low coercive force temperature coefficient. The coercive force of sin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/00C22C33/02H01F1/057
Inventor 刘兴民刘壮陈必成严长江闫阿儒李东
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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