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Preparation method for high coercivity sintered neodymium iron boron magnet

A high coercive force, NdFeB technology, applied in the direction of magnetic objects, inductors/transformers/magnet manufacturing, magnetic materials, etc., can solve the problems of expensive heavy rare earth, long diffusion time, low efficiency, etc., to increase the diffusion area and contact efficiency, high-efficiency adhesion, and improved diffusion efficiency

Active Publication Date: 2019-11-19
CHINA JILIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the efficiency of this method is low, often requires a long diffusion time, and the price of heavy rare earth is relatively expensive, the utilization rate of heavy rare earth raw materials is not high when using traditional diffusion technology, resulting in a large amount of heavy rare earth raw materials, making high coercivity Increased manufacturing cost of sintered NdFeB

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] In the present invention, an alloy ingot is prepared by arc melting or induction melting; the temperature of the alloy ingot is atomized at 1000° C., the atomizing medium is nitrogen, and the atomizing pressure is 15 MPa to obtain Tb powder. The sintered NdFeB magnet is under the condition of nitrogen protection. After uniformly mixing cemented carbide balls and heavy rare earth compound powders, the mixed balls are accelerated by high-speed airflow, so that the cobalt-based cemented carbide balls and heavy rare earth compound powders impact sintered neodymium. Iron boron magnet surface. Among them, the diameter of the cemented carbide ball is 3.0 μm, the average particle size of the heavy rare earth compound powder is controlled at 0.5 μm, the shot peening speed is controlled at 10 m / s, and the impact time is 10 min. Put the above-mentioned magnet into the quartz tube, and carry out one-stage tempering treatment in vacuum state, the tempering temperature is 750°C, the ...

Embodiment 2

[0019] First, the alloy ingot is prepared by arc melting or induction melting; the temperature of the alloy ingot is atomized at 1200°C, the atomizing medium is argon or nitrogen, and the atomizing pressure is 10MPa to obtain Tb powder. Under the condition of nitrogen protection, after uniformly mixing cemented carbide balls and heavy rare earth compound powders, the mixed balls are accelerated by high-speed airflow, so that the cobalt-based cemented carbide balls and heavy rare earth compound powders impact the surface of the sintered NdFeB magnet. Among them, the diameter of the cemented carbide ball is 4.0 μm, the average particle size of the heavy rare earth compound powder is controlled at 1.0 μm, the shot peening speed is controlled at 20 m / s, and the impact time is 20 min. Put the above-mentioned magnets into the quartz tube, and carry out one-stage tempering treatment in vacuum state, the tempering temperature is 850°C, the holding time is 11h, and finally cool down by ...

Embodiment 3

[0021] First, the alloy ingot is prepared by arc melting or induction melting; the temperature of the alloy ingot is atomized at 1000°C, the atomizing medium is argon or nitrogen, and the atomizing pressure is 5MPa to obtain Tb powder. The original sintered NdFeB magnet is under the condition of nitrogen protection, after uniformly mixing cemented carbide balls and heavy rare earth compound powders, the mixed balls are accelerated by high-speed airflow, so that the cobalt-based cemented carbide balls and heavy rare earth compound powders impact Sintered NdFeB magnet surface. Among them, the diameter of the cemented carbide ball is 5.0 μm, the average particle size of the heavy rare earth powder is controlled at 1.5 μm, the shot peening speed is controlled at 30 m / s, and the impact time is 30 min. Put the magnet above into the quartz tube, and carry out one-stage tempering treatment in a vacuum state. The tempering temperature is 950°C, and the holding time is 20h. Finally, it ...

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Abstract

The invention discloses a preparation method for a high coercivity sintered neodymium iron boron magnet, and belongs to the field of permanent magnet material preparation. Thus, the problems of long diffusion time of traditional diffusion technologies to prepare high coercivity sintered neodymium iron boron magnets, large consumption of heavy rare earth for diffusion and high costs can be solved.After cemented carbide balls and heavy rare earth compound powder are uniformly mixed and high-speed air flow is adopted to accelerate the mixed powder, the surface of a sintered neodymium iron boronmagnet can be impacted, and amorphous layer or microcrack areas can appear on the surface of the magnet; and tempering processing is performed on the magnet, and the high coercivity sintered neodymiumiron boron magnet can be prepared. The grain boundary diffusion mechanism of the sintered neodymium iron boron permanent magnet and grain and grain boundary cracking characteristics can be reasonablyutilized, so that surface diffusion efficiency can be enhanced; and the method is simple in technology, short in diffusion time and high in heavy rare earth utilization rate.

Description

technical field [0001] The invention relates to the field of permanent magnet material preparation, in particular to a preparation method of a high coercive force sintered NdFeB magnet. Background technique [0002] NdFeB permanent magnets are widely used in the fields of electronic equipment, medical equipment and motors because of their excellent magnetic properties, especially sintered NdFeB permanent magnets with ultra-high intrinsic coercive force are ideal for wind power generation and high-performance industrial motors. Key basic materials that are urgently needed in fields such as medical and medical equipment. [0003] The preparation of high intrinsic coercive force sintered NdFeB magnets in the traditional process is usually done by adding a large amount of heavy rare earth elements Dy, Tb, etc. to the formula to form (Nd,HRE) 2 Fe 14 B main phase, thereby increasing the magnetocrystalline anisotropy of the main phase, and greatly increasing the intrinsic coerci...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/057H01F41/02
CPCH01F1/0577H01F41/0293
Inventor 俞能君吴琼吉天驰泮敏翔杨杭福葛洪良
Owner CHINA JILIANG UNIV
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