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A method for preparing highly magnetic sintered NdFeB by atmosphere diffusion

A NdFeB, high magnetic technology, applied in the direction of magnetic objects, magnetic materials, electrical components, etc., can solve the problems of volatilization, achieve the effect of refining grains, increasing coercive force, and easy access to raw materials

Active Publication Date: 2019-12-03
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, sulfur and phosphorus have the characteristics of low boiling point, so they are very volatile during the sintering process.

Method used

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  • A method for preparing highly magnetic sintered NdFeB by atmosphere diffusion
  • A method for preparing highly magnetic sintered NdFeB by atmosphere diffusion

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] A preparation process of highly magnetic sintered NdFeB prepared by atmosphere diffusion is as follows:

[0023] Step 1: Orient the NdFeB magnetic powder under a 1.2T magnetic field;

[0024] Step 2: Carry out semi-densification sintering of the compact in a vacuum sintering furnace, the sintering temperature is 950°C, the heat preservation is 1.5h, and the density is 90%;

[0025] Step 3: Put sintered NdFeB (40g) with a density of 90% in the quartz tube, add 0.1g of sulfur powder into the quartz tube, and then vacuum seal the quartz tube to a vacuum degree of 10 -2 Above Pa;

[0026] Step 4: Place the sample of the vacuum quartz sealed tube in a sintering furnace for vacuum sintering, the sintering temperature is 1040°C, heat preservation for 3h, and then go through primary tempering at 850°C for 3h and secondary tempering at 550°C for 5h;

[0027] Step 5: The prepared NdFeB magnet was subjected to VSM magnetic performance measurement, and the results are shown in Ta...

Embodiment 2

[0033] A preparation process of highly magnetic sintered NdFeB prepared by atmosphere diffusion is as follows:

[0034] Step 1: Orient NdFeB magnetic powder under a magnetic field of 2.0T;

[0035] Step 2: Carry out semi-densification sintering of the green compact in a vacuum sintering furnace, the sintering temperature is 950°C, the heat preservation is 3 hours, and the density is 95%;

[0036] Step 3: Put sintered NdFeB (35g) with a density of 95% in the quartz tube, add 0.03g of phosphorus powder into the quartz tube, and then vacuum seal the quartz tube to a vacuum degree of 10 -2 Above Pa;

[0037] Step 4: Place the sample of the vacuum quartz sealed tube in a sintering furnace for vacuum sintering, the sintering temperature is 1050°C, heat preservation for 5h, and then go through primary tempering at 885°C for 2h and secondary tempering at 500°C for 6h;

[0038] Step 5: The prepared NdFeB magnet was subjected to VSM magnetic performance measurement, and the results ar...

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Abstract

The invention relates to a method for preparing high magnetic sintered NdFeB by diffusion of atmosphere and belongs to the technical field of rare earth magnetic materials, wherein sintered NdFeB magnetic powder is subject to semi-densified sintering; the semi-densified NdFeB magnet is placed in a quartz tube, and a quantitative amount of simple substances of sulfur and phosphorus are added to thequartz tube; and then vacuum quartz sealing is performed, and finally heat preservation is carried out for 2-6 hours at 1000-1080 DEG C in a sintering furnace; primary tempering is carried out for 2-4 hours at 800-900 DEG C, and secondary tempering is carried out for 3-6 hours at 480-550 DEG C, so as to prepare the high magnetic sintered NdFeB material. In the sintering process, the low melting point sulfur and phosphorus elements diffuse along the grain boundary of the magnet, enter a grain boundary Nd-rich phase, and reduce the liquidus temperature of the Nd-rich phase, thereby refining thegrain, optimizing the boundary, and improving the coercivity; at the same time, the low boiling point simple substances of sulfur and phosphorus become gaseous and diffuse along the grain boundary ofthe semi-densified magnet, so that the sulfur and phosphorus elements are uniformly diffused and distributed in the magnet. The method in the invention has the advantages that the raw materials are easy to obtain, the price is low, the preparation process is simple, and the operation is convenient.

Description

technical field [0001] The invention belongs to the technical field of rare earth magnetic materials and provides a method for preparing highly magnetic sintered NdFeB by atmosphere diffusion. Background technique [0002] Sintered NdFeB permanent magnet material is the third generation permanent magnet, which was invented by Japanese scholars in 1983. Because of its extremely high coercive force and magnetic energy product, it is called "Magnetic King". Widely used in aerospace, automobile industry, electronic appliances, medical equipment, energy-saving motors, new energy, wind power and other fields, it is the fastest growing permanent magnet material with the best market prospects in the world today. With the advancement of science and technology and the adjustment of industrial models, Dalifa and the application of sintered Nd-Fe-B permanent magnets have broad and far-reaching prospects. [0003] Sintered Nd-Fe-B magnet mainly includes Nd 2 Fe 14 Phase B and Nd-rich...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F41/02H01F1/057B22F3/10B22F3/24
CPCB22F3/1007B22F3/24B22F2003/248H01F1/0577H01F41/0253H01F41/0266
Inventor 杨芳芦博昕邵艳茹张策郭志猛隋延力陈存广冯钊红陆天行李沛
Owner UNIV OF SCI & TECH BEIJING
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