Sintering method for neodymium-iron-boron magnet

A sintering method, NdFeB technology, applied in the direction of magnetic objects, magnetic materials, inorganic materials, etc., can solve the problems of rare earths being easily oxidized, and the coercive force of magnetic properties is not ideal

Active Publication Date: 2016-05-04
廊坊京磁精密材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, in recent years, with the wide application of NdFeB magnets, the production of NdFeB magnets requiring higher stability and lower cost has been promoted. However, rare earths are easily oxidized during the sintering process of sintered NdFeB permanent magnets. , resulting in the need to add more rare earths when designing the formula, or the unsatisfactory magnetic properties, especially the coercive force after sintering, have gradually become obstacles to its further development.

Method used

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  • Sintering method for neodymium-iron-boron magnet
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  • Sintering method for neodymium-iron-boron magnet

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0078] Preparation of 38SH Sintered NdFeB

[0079] First, weigh Pr and Nd according to the mass percentage composition: 25.1wt%, Dy: 2wt%, Ho: 4wt%, Al: 0.44wt%, B: 0.94wt%, Cu: 0.15wt%, Co: 1.5wt%, Zr: 0.15wt%, Ga: 0.2wt%, and the rest of Fe, through ingot casting, crushing, grinding, magnetic field orientation, and press molding to obtain the NdFeB green body.

[0080] Then put the green body into the vacuum sintering furnace, evacuate the vacuum to 0.3Pa, and burn the NdFeB magnet green body at 200°C for the first time at a constant temperature for 90 minutes to obtain the first intermediate; then the above steps are obtained After the first intermediate is fired at 500°C for the second time at constant temperature for 60 minutes, the second intermediate is obtained; and the second intermediate obtained in the above steps is fired at 750°C for the third time at constant temperature for 90 minutes to obtain neodymium iron Boron magnet intermediate.

[0081] After the NdFeB...

Embodiment 2

[0100] Preparation of 42SH Sintered NdFeB

[0101] First, according to the 42SH formula, the NdFeB green body is obtained through ingot casting, crushing, grinding, magnetic field orientation, and pressing.

[0102] Then put the green body into the vacuum sintering furnace, evacuate the vacuum until the vacuum degree is less than 0.3Pa, and after the first constant temperature firing of the NdFeB magnet green body at 230 ° C for 70 minutes, the first intermediate is obtained; then the above steps are obtained After the first intermediate is fired at 520°C for the second time at a constant temperature for 80 minutes, the second intermediate is obtained; after the second intermediate obtained in the above steps is fired at a third time at 780°C for 120 minutes, the neodymium iron is obtained Boron magnet intermediate.

[0103] After the NdFeB magnet intermediate obtained in the above steps is subjected to constant temperature liquid phase sintering at 1040 ° C for 30 minutes, t...

Embodiment 3

[0122] Preparation of 52M sintered NdFeB

[0123] First, according to the 52M formula, the NdFeB green body is obtained through ingot casting, crushing, grinding, magnetic field orientation, and pressing.

[0124] Then put the green body into the vacuum sintering furnace, evacuate the vacuum until the degree of vacuum is less than 0.2Pa, and burn the NdFeB magnet green body at 180°C for the first time at a constant temperature for 80 minutes to obtain the first intermediate; then the above steps are obtained After the first intermediate is fired at 480°C for the second time at a constant temperature for 70 minutes, the second intermediate is obtained; after the second intermediate obtained in the above steps is fired at a third time at 790°C for 150 minutes, the neodymium iron is obtained Boron magnet intermediate.

[0125] After the NdFeB magnet intermediate obtained in the above steps is sintered in a constant temperature liquid phase at 1038 ° C for 30 minutes, the above N...

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Abstract

The invention provides a sintering method for a neodymium-iron-boron magnet. The method comprises the following steps: firstly, carrying out continuous warming or stepped warming on a green neodymium-iron-boron magnet body to reach a sintering temperature under a vacuum or protective gas condition, and obtaining a neodymium-iron-boron magnet intermediate; and carrying out constant-temperature firing on the neodymium-iron-boron magnet intermediate obtained in the previous step under a hydrogen condition, and obtaining a neodymium-iron-boron magnet blank. In a plurality of steps for preparing the neodymium-iron-boron magnet, hydrogen is filled into a system at a specific high-temperature sintering stage in the sintering process from the sintering method, so that a neodymium-rich phase in the blank material is uniform in distribution; a rare-earth phase is prevented from being consumed; a rare-earth phase oxide is avoided; rare earth does not need to add when a formula is designed; the cost is saved; the coercivity of a product is also improved; and the sintering method has very important significance for development of a neodymium-iron-boron magnet product.

Description

technical field [0001] The invention belongs to the technical field of magnet preparation, and in particular relates to a sintering method of an NdFeB magnet. Background technique [0002] Whether in industrial production or in daily life, hard magnets are permanent magnets, magnets that can maintain their magnetism for a long time, are not easy to lose their magnetization, and are not easy to be magnetized. They are also one of the most commonly used strong materials. Hard magnets can be divided into natural magnets and artificial magnets. Artificial magnets mean that by synthesizing alloys of different materials, the same effect as natural magnets (magnets) can be achieved, and the magnetic force can also be improved. Artificial magnets appeared as early as the 18th century, but the process of manufacturing stronger magnetic materials was very slow. It was not until the manufacture of AlNiCo magnets (AlNiCo) in the 1930s that the large-scale application of magnets became p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F41/02H01F1/057H01F1/08B22F3/10
CPCB22F3/101B22F2999/00H01F1/0575H01F41/0266B22F2201/013
Inventor 刘月玲庞再升
Owner 廊坊京磁精密材料有限公司
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