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Optimization process method for preparing high-coercivity permanent magnet by adding heavy rare earth hydroxide into neodymium iron boron

A technology with high coercive force and processing method, which is applied in the direction of magnetic objects, inductance/transformer/magnet manufacturing, magnetic materials, etc., can solve the limited range of sintered NdFeB coercive force improvement and the magnetic orientation arrangement of difficult magnetic powder , affect the performance of magnets and other issues, to achieve the effect of improving local coercive force, high hydrogenation saturation, and stable product quality

Active Publication Date: 2012-03-07
严高林
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In this technical scheme, heavy rare earth metals such as Dy or Tb cannot carry out hydrogen absorption reaction according to their temperature and hydrogen pressure, and what is added is heavy rare earth such as Dy or Tb itself, not its hydride, which leads to the coercive force of sintered NdFeB The improvement is limited
[0004] In addition, in the above-mentioned two technical solutions, after mixing the two powders, performing magnetic field orientation and compression molding, it is difficult to obtain high magnetic orientation alignment of the magnetic powder, and its residual magnetic strength is low, which affects the performance of the magnet.

Method used

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  • Optimization process method for preparing high-coercivity permanent magnet by adding heavy rare earth hydroxide into neodymium iron boron
  • Optimization process method for preparing high-coercivity permanent magnet by adding heavy rare earth hydroxide into neodymium iron boron
  • Optimization process method for preparing high-coercivity permanent magnet by adding heavy rare earth hydroxide into neodymium iron boron

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0075] Example 1: Place the heavy rare earth Dy in a vacuum furnace and pass through hydrogen, the hydrogen pressure is 8bar, heated to 450 ° C, and cooled naturally to obtain the hydride of Dy, and the hydrogenation of Dy is carried out under the protective atmosphere of nitrogen, argon or helium Put the particles into cyclohexane for ball milling to obtain 3-7 μm micropowders, and then move them into an oxygen-free glove box under the protective atmosphere of nitrogen, argon or helium to dry. Under the protective atmosphere of nitrogen, argon or helium, mix the Nd16Fe76B8 hydrogen explosion micropowder with the average particle size of 10μm and the hydride micropowder of heavy rare earth Dy. The atomic percentage of the hydride micropowder of heavy rare earth Dy in the mixed micropowder is 3at.%. , the mixed micropowder after powder mixing is sealed in a rubber mold, and it is magnetized by a small frequency alternating reverse magnetic field pulse and isostatically pressed a...

Embodiment 2

[0077] Example 2: The heavy rare earth Dy was placed in a hydrogen environment of 8 bar, heated to 450° C. in a vacuum furnace, and cooled naturally to obtain Dy hydride. Put the crude heavy rare earth Dy hydride particles into cyclohexane for ball milling to obtain 3-7 μm micropowder, then move it into a glove box for drying, and pass in argon gas to prevent oxidation. Under the protective atmosphere of argon, the ball-milled Nd13.5Fe79.75B6.75 hydrogen explosion micropowder is mixed with the hydride micropowder of heavy rare earth Dy, and the hydride micropowder of heavy rare earth Dy accounts for 0 at.% of the mixed micropowder respectively , 1 at.%, 2 at.%, 3 at.%, 4 at.%, it is best to make the heavy rare earth hydride fine powder accounts for the atomic percentage of the mixed fine powder is 1at% ~ 3at%, the mixed fine powder after the mixed powder Enclosed in a rubber mold, magnetized by a small frequency alternating reverse magnetic field pulse and isostatically presse...

Embodiment 3

[0079] Example 3: The heavy rare earth Tb was placed in a hydrogen environment of 8 bar, heated to 450° C. in a vacuum furnace, and cooled naturally to obtain a hydride of Tb. Put the crude Tb hydride particles into cyclohexane for ball milling to obtain 3-7 μm micropowder, then move it into a glove box for drying, and pass through argon gas to prevent oxidation. Under the protective atmosphere of argon, the ball-milled Nd13.5Fe79.75B6.75 hydrogen explosion micropowder is mixed with the hydride micropowder of heavy rare earth Tb, and the atomic percentage of the hydride micropowder of heavy rare earth Tb in the mixed micropowder is (a): 0 at.%; (b):1 at.%; (c):2 at.%; (d):3 at.%; (e):4 at.% , seal the mixed fine powder into rubber In the mold, it adopts small-frequency alternating reverse magnetic field pulse magnetization and isostatic pressing at room temperature. The magnetic field strength is 4.5T and the pressure is 1200kgcm -2 , to get about 50% of the density of the gr...

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Abstract

The invention relates to an optimization process method for preparing a high-coercivity permanent magnet by adding heavy rare earth hydroxide into neodymium iron boron. The optimization process method comprises the following steps of: 1, putting heavy rare earth R into a hydrogen environment and heating the heavy rare earth R to 350-450 DEG C to obtain hydroxide of the heavy rare earth R; 2, carrying out ball milling or jet milling in a protective atmosphere of nitrogen or inert gas to obtain micro-powder of the heavy rare earth hydroxide; 3, carrying out hydrogen decrepitation treatment and ball milling or jet milling on an Nd-Fe-B alloy to obtain Nd-Fe-B hydrogen decrepitation micro-power; 4, uniformly mixing two kinds of the micro-power, magnetizing by using a small-frequency alternative and reverse magnetic field pulse, and then isostatically pressing to obtain a press blank; and 5, placing the press blank into a vacuum furnace to sinter and carry out a heat treatment to obtain a high-coercivity sintered magnet. The optimization process method is convenient, simple and reasonable in technology, saves cost and achieves the purpose of improving the coercivity by controlling a microstructure distribution of the magnet, so that the industrial application to preparing the high-temperature high-coercivity rare earth permanent magnet by using trace quantities of heavy rare earth elements with high magneto-crystalline anisotropy becomes possible.

Description

technical field [0001] The invention relates to a preparation method of an NdFeB permanent magnet, in particular to an optimized treatment method for preparing a high coercivity permanent magnet by adding heavy rare earth hydrides to NdFeB (Nd-Fe-B). Background technique [0002] my country is a big country with rare earth resources, accounting for 80% of the world's reserves. Nd-Fe-B permanent magnet material has extremely high magnetic energy density. Therefore, any device that needs to efficiently convert electrical energy into mechanical energy requires the extensive use of ultra-strong permanent magnets to reduce size and improve efficiency. It is precisely because of the high magnetic energy product of Nd-Fe-B permanent magnets that it has been used in many applications, such as: drive motors in hard disks, electric motors, generators, wind power generators, nuclear magnetic resonance imaging and other fields. The next generation of electric vehicles will have greate...

Claims

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Application Information

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IPC IPC(8): H01F41/02H01F7/02H01F1/057B22F1/00B22F3/16B22F3/24
Inventor 严高林
Owner 严高林
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