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Method for improving coercive force of sintered neodymium ferrum boron (NdFeB)

A neodymium-iron-boron and coercive force technology is applied in the field of improving the coercive force of sintered neodymium-iron-boron, which can solve the problems of not being easily broken, consuming rare earths, and decreasing, so as to reduce the coercive force, promote the sintering behavior, and improve the sintering behavior. Effect

Active Publication Date: 2012-05-30
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The present invention mainly aims at the existing disadvantages of increasing the coercive force of sintered NdFeB magnets, consuming a large amount of rare earths, and reducing the magnetic moment of iron atoms due to the antiferromagnetic coupling between heavy rare earth elements and iron, which leads to the decrease of Bs and Br , provides a method of adding a small amount of rare earth hydride to increase the coercive force of sintered NdFeB, controlling the distribution of added elements in the grain boundary can make up for the shortcomings of the traditional method, and at the same time, the invention solves the difficult problem of direct addition of rare earth that is not easy to break , to improve the utilization of rare earth

Method used

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  • Method for improving coercive force of sintered neodymium ferrum boron (NdFeB)
  • Method for improving coercive force of sintered neodymium ferrum boron (NdFeB)
  • Method for improving coercive force of sintered neodymium ferrum boron (NdFeB)

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Experimental program
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Effect test

Embodiment 1

[0024] The design composition is Nd 31 co 1.2 Cu 0.04 Fe bal B 0.96 The quick-setting sheet is the main phase alloy, and after hydrogen crushing, it is put into the jet mill for grinding, and the main phase alloy magnetic powder with an average particle size of 3.38 μm is obtained;

[0025] Put the rare earth Tb with a purity of 99.9 into the hydrogen furnace, absorb hydrogen and saturate it at 200°C under a hydrogen pressure of 300kpa, then take it out and send it to the jet mill for jet milling to obtain TbHx powder with an average particle size of 1.84 μm;

[0026] Put the two powders into the powder mixing machine for powder mixing, in which the TbHx powder accounts for 1.2% of the total mass of the mixed powder. After mixing evenly, press it under the protection of an inert gas, sinter at 1050 ° C for 2 hours, and then proceed to Secondary tempering heat treatment at 900°C and 500°C for 2 hours each;

[0027] Table 1 shows the performance comparison between the sampl...

Embodiment 2

[0031] The design composition is Nd 31co 1.2 Cu 0.04 Fe bal B 0.96 The quick-setting sheet is the main phase alloy, and after hydrogen crushing, it is put into the jet mill for grinding, and the main phase alloy magnetic powder with an average particle size of 3.38 μm is obtained;

[0032] Put the rare earth Dy with a purity of 99.9 into the hydrogen furnace, absorb hydrogen and saturate it at 200°C under a hydrogen pressure of 300kpa, then take it out and send it to the jet mill for jet milling to obtain DyHx powder with an average particle size of 1.75 μm;

[0033] Put the two powders into the powder mixing machine for powder mixing, in which the DyHx powder accounts for 2% of the total mass of the mixed powder. After mixing evenly, press it under the protection of an inert gas, and sinter at 1050°C for 2 hours, and then proceed Secondary tempering heat treatment at 900°C and 500°C for 2 hours each;

[0034] Table 2 shows the performance comparison between the sample pr...

Embodiment 3

[0039] The design composition is Nd 31 co 1.2 Cu 0.04 Fe bal B 0.96 The quick-setting sheet is the main phase alloy, and after hydrogen crushing, it is put into the jet mill for grinding, and the main phase alloy magnetic powder with an average particle size of 3.38 μm is obtained;

[0040] Mix the rare earths Dy and Tb with a purity of 99.9 in a ratio of 2:3 and put them into a hydrogen furnace. After absorbing hydrogen and saturating them at 200°C and a hydrogen pressure of 300kpa, they are taken out and then sent to a jet mill for jet milling to obtain an average Mixed rare earth hydride powder with a particle size of 1.8 μm;

[0041] Put the two powders into a powder mixing machine for powder mixing, wherein the mixed rare earth hydride powder accounts for 1% of the total mass of the mixed powder, after mixing evenly, press it under the protection of an inert gas, and sinter at 1050 ° C for 2 hours. Then carry out secondary tempering heat treatment at 900°C and 500°C ...

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Abstract

The invention relates to a method for improving coercive force of sintered neodymium ferrum boron (NdFeB) by adding rare earth hydride in a grain boundary phase, which is characterized in that a rare earth or a rare earth mixed hydride is adopted as a grain boundary phase to be added into a NdFeB principal phase alloy to achieve the purpose of improving the coercive force of the sintered NdFeB. The invention provides a process for improving coercive force by adding less amount of rare earth hydride. According to the invention, the distribution of added elements in the grain boundary is controlled, the adverse effect of some alloy elements to the principle phase is avoided, and the improvement potential of the NdFeB magnet property is fully developed.

Description

technical field [0001] The invention relates to a method for increasing the coercive force of sintered NdFeB by adding rare earth hydrides in the grain boundary phase. Background technique [0002] As the third generation of rare earth permanent magnet materials, NdFeB rare earth permanent magnet materials have been commercialized and developed by Sumitomo Metal of Japan and GM of the United States in 1983. Due to the characteristics of high remanence, high coercive force and high magnetic energy product , are widely used in power electronics, communications, information, motors, transportation, office automation, medical equipment, military and other fields, and make it possible to apply some small, highly integrated high-tech products, such as voice coil motors for hard disks (VCM )Wait. With the growing need for environmental protection, the use of hybrid, electric or fuel cell vehicles to replace traditional internal combustion locomotives has become an inevitable choic...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F1/057H01F1/08H01F41/02B22F9/04B22F3/16C21D1/18C22C38/06C22C38/10C22C38/12C22C38/16
Inventor 郭帅闫阿儒李东
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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