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Production method for nanocrystalline anisotropic rare earth permanent magnetic powder

An anisotropic, rare-earth permanent magnet technology, applied in the manufacture of inductors/transformers/magnets, magnetic materials, magnetic objects, etc., can solve the problems of difficult manufacturing of magnetic powder, decreased coercive force, and difficulty in preparing nanocrystalline anisotropic magnetic powder , to achieve the effect of improving cost performance and high magnetic performance

Inactive Publication Date: 2008-05-07
NINGBO UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since the RE 2 Fe 14 B releases heat when absorbing hydrogen, and absorbs heat when releasing hydrogen. It is difficult to control the temperature, and the control of temperature is very important for the anisotropic RE 2 Fe 14 The magnetic effect of B is significant; on the other hand, the invention also points out that: when the grain size of the magnetic powder is greater than 1.0 μm, the coercivity decreases; and the grain size of the magnetic powder is less than 0.1 μm and it is difficult to manufacture, that is to say, the magnetic powder The grain size is controlled in a very narrow range
Difficult control of temperature and grain size are the two main reasons why this invention is difficult to popularize
[0004] Chinese patent CN1593820A "high energy gas atomization Fe 3 B / R 2 Fe 14 B Nanocomposite Permanent Magnet Powder and Preparation Method" (publication date: March 16, 2005) discloses a method using high-energy atomization to prepare nano-two-phase magnetic powder, and the best magnetic properties in the examples are only 102kJ / m 3 , less magnetic
[0005] In summary, the existing technology is difficult to prepare nanocrystalline anisotropic magnetic powder

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] hard magnetic alloy Nd 12.5 Fe 82.2 B 5.3 Vacuum induction melting master alloy ingot first, and then vacuum filled with argon for quick quenching, the speed of the quick quenching roller is 25m / s; the above vacuum reaches 10 -2 Pa. The sheet obtained by rapid quenching is hot rolled twice at 850°C, and the line speed of the hot rolling roll is 25m / s; compared with before hot rolling, the thickness of the sheet after two hot rollings is reduced by 50-62%. After the second hot rolling, the flake forms a magnetic texture, and the texture direction is perpendicular to the direction of the flake, that is, the direction of the hot rolling stress; then the hot rolled flake is crushed and classified by sieve to obtain two kinds of magnetic powders with an average particle size of 3 μm and 8 μm (also That is, the size of the magnetic powder conforms to the normal distribution, but the central size of the normal distribution is 3 μm and 8 μm respectively). Measured by the vi...

Embodiment 2

[0023] Alloy composition Nd 9.8 Dy 0.4 Fe 77.5 co 6.5 Al 0.2 Ga 0.3 B 5.3 , where the hard magnetic phase is (Nd, Dy) 2 (Fe,Co) 14 (B, Al, Ga), the soft magnetic phase is α-Fe. Vacuum induction melting the alloy first, quick quenching to obtain amorphous flakes; the thin slices are hot rolled three times, the hot rolling temperature is 840 ℃, and the hot rolling roll line speed is 21m / s; compared with before hot rolling, the thin slices are hot rolled after the third hot rolling The thickness is reduced by 55-65%; the final hot-rolled sheet forms a magnetic texture; the magnetic powder with an average particle size of 5 μm is obtained by crushing and sieving; the magnetic properties are measured by a vibrating sample magnetometer, and the magnetic properties along the magnetic texture direction of the magnetic powder are The remanence is 1.15T, the coercive force is 510kA / m, and the magnetic energy product is 152kJ / m 3 .

[0024] Put the magnetic powder and phenolic ...

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Abstract

The invention belongs to the technical field of rare-earth permanent magnetic material, aiming to solve the problem of weak magnetic property of nano-sized rare-earth permanent magnet powder produced according to prior art. The invention is characterized in that the rare earth-transition metal permanent magnet alloys are processed by vacuum induction melting and vacuum rapid quenching; then the quenched flakes must be hot-rolled at least one time with hot rolling temperature from 500DEG C to 1000DEG C; and the linear velocity of hot roller reaches 0.5to 55.0m / s; compared with the temperature before hot rolling, the final thickness of the flakes after hot rolling is reduced by 10 to 95%; the flakes is made into magnetic texture by controlling the thickness reduction of the flakes with the direction of the magnetic texture parallel with the direction of hot rolling power; the crystalline grain of the flakes are nano-grains; then the hot-rolling flakes are broken; the average particle size of the magnetic powder is 3to 30Mu m. Each particle has magnetic texture; then the magnetic power is graded according to size; finally, the graded magnetic powder is packed by following methods respectively: non-vacuum package, vacuum package or package by charging protective air under the condition of vacuum. The magnetic powder is of anisotropic and high magnetic properties.

Description

technical field [0001] The invention discloses a preparation method of nanocrystalline anisotropic rare earth permanent magnetic powder, which belongs to the technical field of rare earth permanent magnetic materials. Background technique [0002] The cost performance requirements of rare earth permanent magnet materials for many products such as nuclear magnetic resonance imaging instruments, motors, instruments and meters are gradually increasing. How to meet the market demand? On the one hand, the magnetic performance should be improved, and on the other hand, the production cost should be reduced. The work of improving rare earth permanent magnet materials must start from the source, and high-performance magnetic powder must be prepared. [0003] Chinese patent CN1198291C "Manufacturing method of anisotropic magnetic powder and raw material powder of anisotropic magnetic powder and plastic magnet" (authorized announcement date April 20, 2005) discloses a method for prep...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/053H01F1/06B22F3/00H01F41/00
Inventor 刘新才潘晶
Owner NINGBO UNIV
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