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A kind of preparation method of samarium iron nitrogen rare earth permanent magnet powder

A technology of rare earth permanent magnet and samarium iron nitrogen, which is applied in the direction of magnetic materials, magnetic objects, electrical components, etc., can solve the problems of low nitriding efficiency, poor effect, complicated process, etc., and achieve low cost, simple process, and easy industrialization Effect

Active Publication Date: 2017-01-11
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to overcome the problems of complex process, low nitriding efficiency and poor effect of preparing samarium-iron-nitrogen rare earth permanent magnet powder in the prior art, and provide a two-step preparation of samarium-iron-nitrogen rare earth permanent magnet by "iron nitride-sarium iron nitrogen". A preparation method of magnetic powder, which can effectively control the nitrogen content and nitrogen distribution in SmFeN rare earth permanent magnet powder, and realize the preparation of high-performance SmFeN rare earth permanent magnet powder

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] (1) Lay water-atomized iron powder (-200 mesh) in a microwave rotary furnace, evacuate until the vacuum degree is below 10Pa, feed high-purity nitrogen with a purity of more than 99.9%, and keep the atmospheric pressure at 0.1MPa. Start microwave heating with a frequency of 2.45GHz, a power of 1KW, a synthesis temperature of 800°C, and keep warm for 2h. After cooling to room temperature, the synthesized product is iron nitride powder with a nitrogen content of 3wt.%.

[0025] (2) Mix the pure samarium powder and the iron nitride powder prepared above according to the molar ratio of Sm and Fe of 2:17, mix them initially, put the mixture and alumina balls into the ball milling tank, the ball-to-material ratio is 10:1, and the ball milling time 5h, the ball milling medium is high-purity nitrogen. After the ball milling is completed, the Sm 2 Fe 17 N x Rare earth permanent magnet powder, magnetic property is B r =0.8T, i h c =1950KA / m, (BH) m =156kJ / m 3 .

Embodiment 2

[0027] (1) Lay ultra-fine reduced iron powder (5 μm) in the boat of the microwave boat pusher, evacuate until the vacuum degree is below 10Pa, pass through the decomposed ammonia gas with a purity of more than 99.9%, and keep the atmospheric pressure at 0.05MPa . Start the microwave heating, the frequency is 2.45GHz, the power is 3KW, the synthesis temperature is 600°C, and the temperature is kept for 3h. After cooling to room temperature, the synthesized product is iron nitride powder with a nitrogen content of 4.8wt.%.

[0028] (2) Mix the pure samarium powder and the iron nitride powder prepared above according to the molar ratio of Sm and Fe of 2:17, mix them initially, put the mixture and alumina balls into the ball milling tank, the ball-to-material ratio is 15:1, and the ball milling time 8h, the ball milling medium is high-purity nitrogen. After the ball milling is completed, the Sm 2 Fe 17 N x Rare earth permanent magnet powder, magnetic property is B r =0.9T, ...

Embodiment 3

[0030] (1) Lay carbonyl iron powder (3 μm) in a microwave rotary furnace, evacuate until the vacuum degree reaches below 10 Pa, feed high-purity ammonia gas with a purity of more than 99.9%, and keep the atmospheric pressure at 0.01 MPa. Start microwave heating, the frequency is 2.45GHz, the power is 5KW, the synthesis temperature is 500°C, and the temperature is kept for 5h. After cooling to room temperature, the synthesized product is iron nitride powder with a nitrogen content of 6.2wt.%.

[0031] (2) Mix the pure samarium powder and the iron nitride powder prepared above according to the molar ratio of Sm and Fe of 2:17, mix them initially, put the mixture and alumina balls into the ball mill tank, the ball-to-material ratio is 20:1, and the ball milling time 10h, the ball milling medium is high-purity nitrogen. After the ball milling is completed, the Sm 2 Fe 17 N x Rare earth permanent magnet powder, magnetic property is B r =0.9T, i h c =2306KA / m, (BH) m =197kJ / ...

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Abstract

The invention belongs to the technical field of rare earth permanent magnet materials and discloses a preparation method for Sm2Fe17Nx rare earth permanent magnet powder. According to the preparation method for the Sm2Fe17Nx rare earth permanent magnet powder, the Sm2Fe17Nx rare earth permanent magnet powder is prepared by mechanical alloying, iron powder or ferric oxide powder serves as raw materials, high-pure nitrogen, ammonia gas or decomposed ammonia serves as a nitrogen source, and the atmosphere pressure is from 0.01 to 0.1MPa; microwaves are served as heat sources, the frequency is 2.45GHz, the power is from 1 to 5KW, the resultant temperature is from 500 to 800 DEG C, the heat preservation time is from 2 to 5h, iron nitride powder is synthesized, and the nitrogen content is from 3 wt.% to 8 wt.%. The preparation method for the Sm2Fe17Nx rare earth permanent magnet powder comprises the following steps of mixing pure samarium powder and the prepared iron nitride powder according to a Sm and Fe molar ratio of 2 to 17, and putting the pure samarium powder, the prepared iron nitride powder and aluminum oxide or zirconia ceramic balls into a high-energy ball milling pot after primary mixing, wherein a ratio of grinding media to material is from 10 to 1 to 20 to 1, the ball milling time is from 5 to 10h, and the ball milling medium is high-pure nitrogen; preparing powder in a vacuum glove box. thus obtaining the Sm2Fe17Nx rare earth permanent magnet powder. The preparation method for the Sm2Fe17Nx rare earth permanent magnet powder is simple in technology, low in cost and easy for industrialization, and high-performance Sm2Fe17Nx rare earth permanent magnet powder with different nitrogen contents can be efficiently synthesized according to requirements.

Description

technical field [0001] The invention belongs to the technical field of preparing rare earth permanent magnet materials by powder metallurgy, and in particular provides a preparation method for preparing samarium iron nitrogen rare earth permanent magnet powder by mechanical alloying. [0002] technical background [0003] In 1990, Coey et al. synthesized the interstitial intermetallic compound R by gas-solid reaction. 2 Fe 17 N x , has aroused extensive attention in the magnetic field. where Sm 2 Fe 17 N x The compound has excellent intrinsic magnetic properties. Its saturation magnetization reaches 1.54T, which is comparable to that of NdFeB at 1.6T. The Curie temperature of 470°C and anisotropy field of 14T (NdFeB is 8T) are higher than those of NdFeB. Much, and its corrosion resistance, thermal stability, and oxidation resistance are superior to NdFeB permanent magnet materials. Therefore, Sm 2 Fe 17 N x The interstitial nitride rare earth permanent magnet materi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F9/04B22F1/00H01F1/053
Inventor 郭志猛陈存广郝俊杰高学绪许恩恩罗骥
Owner UNIV OF SCI & TECH BEIJING