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Method and apparatus for improving square degree and corrosion resistance of demagnetizing curve of sintered neodymium iron boron

A technology of demagnetization curve and corrosion resistance, applied in the field of improving the magnetic properties of sintered NdFeB, can solve the problems of demagnetization and thin thickness, and achieve the effect of small input-output ratio, reducing risks and increasing cracks

Active Publication Date: 2017-04-26
NINGBO KETIAN MAGNET
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The thickness of the magnetic steel used in these fields is thin in the direction of magnetic orientation, and it is easy to demagnetize at high temperature

Method used

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  • Method and apparatus for improving square degree and corrosion resistance of demagnetizing curve of sintered neodymium iron boron
  • Method and apparatus for improving square degree and corrosion resistance of demagnetizing curve of sintered neodymium iron boron
  • Method and apparatus for improving square degree and corrosion resistance of demagnetizing curve of sintered neodymium iron boron

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] ① Use vacuum induction quick-setting furnace to prepare the initial alloy of quick-setting sheet for sintered NdFeB, and the alloy composition is Nd 31 Fe bal. co 1 Al 0.2 Cu 0.1 B 0.97 (mass percentage), the raw material weight of smelting alloy is 1000 kg;

[0021] ② Take out 500 kg of the quick-setting sheet in ①, and clean and crush the quick-setting sheet according to the cleaning and crushing method of the aforementioned NdFeB quick-setting sheet;

[0022] ③ The roughly crushed quick-setting tablets are subjected to hydrogen crushing to obtain a coarse powder with a particle size of 100-500 microns, and the hydrogen crushing process is a conventional process;

[0023] ④ Jet mill the crushed powder separately, and the process parameters of the jet mill are consistent, and the powder with an average particle size of 3 μm is obtained;

[0024] ⑤ The powder is made into a compact of 52 mm*52 mm*27 mm on an orientation forming press, the forming orientation magne...

Embodiment 2

[0028] Embodiment 2 The mass percent of the alloy composition is: (Pr 0.2 Nd 0.8 ) 30.5 Dy 0.5 co 1 Al 0.2 Cu 0.1 B 0.98 , and the rest of the process steps are the same as in Example 1.

Embodiment 3

[0029] Example 3 The mass percentage of the alloy composition is: (Pr 0.2 Nd 0.8 ) 29 Dy 2 Ga 0.5 co 1 Al 0.2 Cu 0.1 B 0.98 , and the rest of the process steps are the same as in Example 1.

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Abstract

The invention discloses a method and an apparatus for improving square degree and corrosion resistance of a demagnetizing curve of sintered neodymium iron boron. The apparatus comprises an air blowing apparatus and a quick coagulating sheet coarse crushing apparatus; according to the method, after a quick coagulating sheet is obtained and before a hydrogen decrepitation process is performed, a quick coagulating sheet cleaning and coarse crushing process is added, wherein the cleaning of the quick coagulating sheet is performed by enabling the quick coagulating sheet to pass through an air blowing wind belt so as to clean dust and needle-shaped amorphous neodymium iron boron alloy and other impurities, attached to the surface of the quick coagulating sheet, through wind power; the cleaned quick coagulating sheet is rolled and crushed by a reversely rotating roller with a rough surface; and next, subsequent processing of hydrogen decrepitation, airflow milling and the like is performed. By virtue of air-blowing wind power, foreign matters on the surface of the quick coagulating sheet can be effectively removed; and meanwhile, foreign matters are not introduced again, so that the component and structural uniformity of the base magnet are finally improved, and black spots on the surface after acid washing or electroplating are reduced, thereby improving the square degree and corrosion resistance of the demagnetizing curve of the magnet.

Description

technical field [0001] The invention relates to a method and a device for improving the magnetic properties of sintered NdFeB, in particular to a method and a device for improving the demagnetization curve squareness and corrosion resistance of sintered NdFeB. Background technique [0002] NdFeB permanent magnet materials are now used in smart phones, automotive motors and wind power generation. The thickness of the magnetic steel used in these fields is thin in the direction of magnetic orientation, and it is easy to demagnetize at high temperature. Therefore, these magnets not only require a sufficiently high coercive force, but also have a high squareness in their demagnetization curves. Squareness (SF) is the ratio (Hk / Hcj) of the knee point coercive force of the magnetic steel to the intrinsic coercive force on the demagnetization curve. This ratio reflects the uniformity of the internal microstructure of the magnetic steel and the strength of the anti-demagnetization...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/057B22F9/04
CPCB22F9/04H01F1/0577
Inventor 严长江
Owner NINGBO KETIAN MAGNET
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