A kind of preparation method of sintered NdFeB sheet magnet

A neodymium-iron-boron and sheet technology, which is applied in the fields of magnetic objects, inductance/transformer/magnet manufacturing, magnetic materials, etc., can solve the problems of insufficient improvement ability, reduced magnetic flux of sintered neodymium-iron-boron sheet magnets, limited effect, etc., to avoid The effect of grain size refinement, improvement of low magnetic phenomenon, reduction of direct contact

Active Publication Date: 2019-03-26
NINGBO YUNSHENG +2
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Problems solved by technology

[0004] At present, there are three main methods in the industry to improve the anti-magnetic attenuation ability of sintered NdFeB thin sheet magnets: the first method is to add trace elements to improve the temperature coefficient, such as adding trace elements such as Co can improve the temperature coefficient of sintered NdFeB magnets, Improve the ability to resist magnetic attenuation, but this method has limited effect, and basically has no effect on products with a magnetization direction size smaller than 1.5mm
The second method is to add heavy rare earth elements such as Dy and Tb to generate Dy(Tb) inside the sintered NdFeB thin film magnet. 2 Fe 14 B, Dy(Tb) 2 Fe 14 B has a higher anisotropy field, which can increase the intrinsic coercive force of the magnet, thereby improving the anti-attenuation ability. This method is effective, but the material cost will be greatly increased, and Dy(Tb) 2 Fe 14 The magnetic polarization of phase B is lower than that of Nd 2 Fe 14 Phase B will cause the remanence value of the sintered NdFeB thin sheet magnet to drop significantly, resulting in a decrease in the magnetic flux of the sintered NdFeB thin sheet magnet. This method can be used on some products with low magnetic flux requirements, but with the component Higher flux requirements and smaller component sizes place limitations on this approach
However, when the third method is used, when the thickness of the sintered NdFeB thin sheet magnet drops to 0.6mm, the thickness of the affected layer on both sides is still 72μm, accounting for 12% of the total thickness; Its effect gradually decreases, and its improvement ability is stretched when the thickness of sintered NdFeB thin sheet magnet is below 1mm, and as the grain size is further reduced, the difficulty of its manufacturing process is greatly increased, and it is difficult to achieve

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  • A kind of preparation method of sintered NdFeB sheet magnet
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  • A kind of preparation method of sintered NdFeB sheet magnet

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Effect test

Embodiment 1

[0027] Embodiment 1: A kind of preparation method of sintered NdFeB sheet magnet, comprises the following steps:

[0028]① Configure the raw materials of sintered NdFeB sheet magnets according to the design requirements, melt the raw materials in a vacuum electromagnetic induction furnace, cast them into quick-setting sheets with a thickness of 0.2-0.6mm at a temperature of 1450°C, and then speed them up in a hydrogen crushing furnace The condensed sheet is subjected to hydrogen crushing treatment to obtain a coarse powder with a particle size of 0.1-3mm, and then the coarse powder is accelerated by a high-pressure gas of 0.4-0.6Mpa in the airflow milling equipment to make it collide with each other to form a specific surface area and an average particle size 2.0 ~ 4.0μm powder;

[0029] ②Put the powder into the mold cavity of the forming press, and press the powder under the action of the orientation magnetic field to obtain a sintered NdFeB green body;

[0030] ③ Sintering ...

Embodiment 2

[0039] Embodiment two: a kind of preparation method of sintered NdFeB sheet magnet, comprises the following steps:

[0040] ① Configure the raw materials of sintered NdFeB sheet magnets according to the design requirements, melt the raw materials in a vacuum electromagnetic induction furnace, cast them into quick-setting sheets with a thickness of 0.2-0.6mm at a temperature of 1450°C, and then speed them up in a hydrogen crushing furnace The condensed sheet is subjected to hydrogen crushing treatment to obtain a coarse powder with a particle size of 0.1-3mm, and then the coarse powder is accelerated by a high-pressure gas of 0.4-0.6Mpa in the airflow milling equipment to make it collide with each other to form a specific surface area and an average particle size 2.0 ~ 4.0μm powder;

[0041] ②Put the powder into the mold cavity of the forming press, and press the powder under the action of the orientation magnetic field to obtain a sintered NdFeB green body;

[0042] ③ Sinteri...

Embodiment 3

[0051] Embodiment three: a kind of preparation method of sintered NdFeB sheet magnet, comprises the following steps:

[0052] ① Configure the raw materials of sintered NdFeB sheet magnets according to the design requirements, melt the raw materials in a vacuum electromagnetic induction furnace, cast them into quick-setting sheets with a thickness of 0.2-0.6mm at a temperature of 1450°C, and then speed them up in a hydrogen crushing furnace The condensed sheet is subjected to hydrogen crushing treatment to obtain a coarse powder with a particle size of 0.1-3mm, and then the coarse powder is accelerated by a high-pressure gas of 0.4-0.6Mpa in the airflow milling equipment to make it collide with each other to form a specific surface area and an average particle size 2.0 ~ 4.0μm powder;

[0053] ②Put the powder into the mold cavity of the forming press, and press the powder under the action of the orientation magnetic field to obtain a sintered NdFeB green body;

[0054] ③ Sinte...

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Abstract

The invention discloses a preparation method of a sintering neodymium iron boron sheet magnet. The preparation method comprises the following steps of manufacturing a sintering neodymium iron boron blank into a sheet blank with thickness of 0.4 to 1.0mm by a mechanical processing technology; when grains at the surface layer of the sheet blank are damaged, cleaning and drying the surface of the sheet blank, packaging a black sheet by a metal bag or metal foil paper, putting into a vacuum sintering furnace, and performing heat treatment under a vacuum state; then, performing vibration, grinding and chamfering, and pickling surface activation. The preparation method has the advantages that excessive noble elements, such as cobalt, dysprosium and terbium, do not need to be added, so that the material cost of a component is hardly increased; the size critical point of the component thinning corresponding to the size fining of the grains is avoided; the cost is lower, the difficulty in technology manufacturing is little, and the degrading of anti-magnetic decay ability caused by damage to the surface grains is relieved.

Description

technical field [0001] The invention relates to a preparation method of a sintered NdFeB magnet, in particular to a preparation method of a sintered NdFeB thin sheet magnet. Background technique [0002] Sintered NdFeB permanent magnet material is currently the strongest magnetic material, widely used in electromagnetics, electroacoustics, magnetism, nuclear magnetism and electron acceleration and other disciplines, such as various motors, speakers, magnetic coupling devices, medical camera equipment and Instruments and devices such as free electron oscillators. With the development of science and technology, people have more and more stringent requirements for the miniaturization of electronic products, so the miniaturization of magnetic material devices is an important application direction in the future. As miniaturized magnetic material devices, the application of sintered NdFeB thin sheet magnets is becoming more and more widely. Existing sintered NdFeB sheet magnets ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F41/02H01F1/057B22F3/10
CPCB22F3/1007B22F2999/00H01F1/0576H01F1/0577H01F41/0266B22F2201/20
Inventor 程英欧阳习科翁春雷
Owner NINGBO YUNSHENG
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