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Preparation method of bulk sintered neodymium-iron-boron permanent magnet

A neodymium-iron-boron and permanent magnet technology is applied in the direction of magnetic objects, inductance/transformer/magnet manufacturing, magnetic materials, etc., which can solve the problems of complex production process, low material utilization rate, low processing cost, etc. The effect of high material utilization and low processing cost

Inactive Publication Date: 2015-12-16
NINGBO YUNSHENG +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] However, the above-mentioned first method has complex production process, high process cost, low material utilization rate, and the glue has non-magnetic properties, which will form an air gap in the large sintered NdFeB permanent magnet, increase the reluctance, and weaken the magnetic properties; the above-mentioned Compared with the first method, the second method has simpler process, lower processing cost, and higher material utilization rate, but it is used in the preparation of large sintered NdFeB permanent magnets whose grade is N50 and above or whose average particle size is less than or equal to 2.9 μm. When the magnet is used, the cracking ratio of the splicing surface is high, and the product qualification rate is low

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  • Preparation method of bulk sintered neodymium-iron-boron permanent magnet

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Embodiment 1

[0031] Embodiment one: a kind of preparation method of bulk sintered NdFeB permanent magnet, comprises the following steps:

[0032] ① Raw materials such as metallic neodymium, praseodymium neodymium, dysprosium iron, pure iron, ferroboron, copper metal, aluminum and ferroniobium are mixed according to the formula required for the production of large sintered NdFeB permanent magnets, and then put into a vacuum electromagnetic induction furnace. Melting and casting at 1420-1520°C into quick-setting tablets with a grade of 52M, the thickness of the quick-setting tablets is 0.2-0.6mm, and then hydrogen crushing the quick-setting tablets in a hydrogen crushing furnace to make a coarse powder with a particle size of 0.1-3mm. Coarse powder is accelerated by 0.62MPa high-pressure gas in the jet milling equipment, and the coarse powder collides with each other to form a fine powder with a specific surface area and an average particle size of 2.85 μm;

[0033]② Weigh 1495g of fine powd...

Embodiment 2

[0042] Embodiment two: a kind of preparation method of bulk sintered NdFeB permanent magnet, comprises the following steps:

[0043] ①Put raw materials such as metal neodymium, praseodymium neodymium, dysprosium iron, pure iron, boron iron, metal copper, aluminum and zirconium into the vacuum electromagnetic induction furnace according to the formula required for the production of large sintered NdFeB permanent magnets. ~1520℃ melting and pouring into 52M quick-setting sheet, the thickness of the quick-setting sheet is 0.2-0.6mm, and then the quick-setting sheet is hydrogen-crushed in a hydrogen crushing furnace to make a coarse powder with a particle size of 0.1-3mm. The powder is accelerated by 0.63MPa high-pressure gas in the jet milling equipment, and the coarse powder collides with each other to form a fine powder with a specific surface area and an average particle size of 2.75 μm;

[0044] ② Weigh 1282g of fine powder and put it into the mold cavity of the sintered NdFe...

Embodiment 3

[0054] Embodiment three: a kind of preparation method of bulk sintered NdFeB permanent magnet, comprises the following steps:

[0055] ① Configure the raw materials according to the formula, and prepare the raw materials into powder. The average particle size of the specific surface area of ​​the powder is 2.0-4.0 μm;

[0056] ②Put the powder into the mold cavity of the forming press, and make the powder into a small green body by pressing under the orientation magnetic field formed by the electrified solenoid;

[0057] ③Arrange the small green bodies in the direction of the design size, and insert a piece of metal sheet between the joint surfaces of two adjacent small green bodies. The two side surfaces of the metal sheet are the same size as the joint surface of the small green bodies. The thickness between the two side surfaces of the metal sheet is 0.05mm; put together each small piece of green body and the metal sheet, and the two side surfaces of the metal sheet are resp...

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Abstract

The invention discloses a preparation method of a bulk sintered neodymium-iron-boron permanent magnet. The method comprises the following steps: firstly, preparing raw materials according to the formula, and preparing powder from the raw materials; secondly, enclosing the powder into a mold cavity of a molding press, and fabricating the powder into small green bodies in a compression molding manner in an oriented magnetic field formed by a solenoid with electric current; thirdly, arranging various small green bodies according to the design dimension direction, inserting a metal sheet between the combined surfaces of every two adjacent small green bodies, and putting various small green bodies and the metal sheets together to form a spliced green body; and finally, putting the spliced green body into a mold box made of rubber, carrying out vacuum packaging on the mold box, maintaining the isostatic pressure of 140-230MPa for 1-14 seconds and then sintering the green body, so as to obtain the bulk sintered neodymium-iron-boron permanent magnet. The preparation method has the advantages that the production technology is simple; the processing cost is relatively low; the material utilization rate is relatively high; and the spliced surface does not crack when the bulk sintered neodymium-iron-boron permanent magnet of which the trade mark is N50 or higher or the average powder particle size is less than 2.9 microns is prepared.

Description

technical field [0001] The invention relates to a preparation method of an NdFeB permanent magnet, in particular to a preparation method of a large sintered NdFeB permanent magnet. Background technique [0002] Sintered NdFeB permanent magnet material is the magnetic material with the highest magnetic energy product at present, and has been widely used in the magnetic medium source of the electromagnetic interaction field, such as replacing the magnetic source of the electric solenoid used in the past, used in various motors, audio and Nuclear Magnetic Resonance and other equipment to generate a fixed magnetic field. The production process of sintered NdFeB permanent magnet materials is usually: first put the raw materials in a vacuum electromagnetic induction furnace to melt and cast the alloy, then use mechanical crushing or hydrogen crushing to make the alloy into coarse powder, and the coarse powder passes through the grinding chamber of the jet mill The high-pressure g...

Claims

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Application Information

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IPC IPC(8): H01F41/02H01F1/057H01F1/08B22F9/04B22F3/16
Inventor 欧阳习科黄威程英任达兴郭峰
Owner NINGBO YUNSHENG