High-resistivity neodymium-iron-boron permanent magnet alloy and preparation method thereof

A permanent magnet alloy, high resistivity technology, applied in permanent magnet manufacturing, inductor/transformer/magnet manufacturing, circuits, etc., can solve the limitation of magnet resistivity improvement, and the key technical problems of NdFeB composite magnet preparation are not well solved. , the problem of low maximum magnetic energy product

Active Publication Date: 2020-06-05
CENT IRON & STEEL RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the methods to improve the service stability of NdFeB magnets mainly include the following aspects: (1) Reduce the eddy current loss through the design of the motor rotor, such as dividing the magnet unit. However, when the magnet is protected by a metal casing, this method becomes not very effective
In addition, this method has high manufacturing cost and poor economy
(2) Magnets that use part of Co instead of Fe can increase Nd 2 Fe 14 Curie temperature of B, but can not increase the maximum operating temperature, because Co is not good for anisotropy field
(3) Increase H ci The inversion temperature coefficient β, the traditional method is to replace Nd with Dy to increase its intrinsic coercive force H at room temperature ci , but the magnetic moment of Dy is antiparallel to those of Fe and Nd, the saturation magnetization M of this Nd-Dy-Fe-B magnet s and maximum en

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] The permanent magnet is prepared by the preparation method of the present invention. First, 10ml of 7wt% polyvinyl alcohol aqueous solution is prepared at 90°C, 0.2g of aluminum nitride is added to the solution, and the insulating binder is obtained by stirring evenly. The nanocrystalline NdFeB fast Add 20g of the quenching powder into the insulating binder, stir evenly, and vacuum-dry to obtain NdFeB pellets coated with insulating binder on the surface, put them into a hot-pressing mold, and carry out vacuum degreasing in a vacuum hot-pressing furnace. At 250°C, 350°C, 400°C, and 500°C for 60 minutes respectively in multi-stage heat preservation, keep a vacuum higher than 10Pa, heat press at 550°C, hold for 1 minute, and then heat deform at a temperature of 830-850°C.

[0027] Under the above-mentioned preparation process conditions, the resistivity of the prepared high-resistivity permanent magnet alloy is 2.4mΩcm, and the magnetic energy product is 48MGsOe.

Embodiment 2

[0029] The permanent magnet is prepared by the preparation method of the present invention. First, 10ml of 7wt% polyvinyl alcohol aqueous solution is prepared at 90°C, 0.4g of zirconium nitride is added to the solution, and the insulating binder is obtained by stirring evenly. The nanocrystalline NdFeB fast Add 20g of the quenching powder into the insulating binder, stir evenly, and vacuum-dry to obtain NdFeB pellets coated with insulating binder on the surface, put them into a hot-pressing mold, and carry out vacuum degreasing in a vacuum hot-pressing furnace. At 250°C, 350°C, 400°C, and 500°C for 60 minutes, keep a vacuum higher than 10 Pa, heat press at 550°C, hold for 1 minute, and then heat deform at a temperature of 850°C.

[0030] Under the above-mentioned preparation process conditions, the resistivity of the prepared high-resistivity permanent magnet alloy is 2.6mΩcm, and the magnetic energy product is 47.3MGsOe.

Embodiment 3

[0032] The permanent magnet is prepared by the preparation method of the present invention. First, prepare 10ml of 7wt% polyvinyl alcohol aqueous solution at 90°C, add 1g of aluminum nitride into the solution, stir evenly to obtain an insulating binder, and quickly quench the nanocrystalline NdFeB Add 20g of the powder into the insulating binder, stir evenly, and vacuum-dry to obtain NdFeB pellets coated with insulating binder on the surface, put them into a hot-pressing mold, and carry out vacuum degreasing in a vacuum hot-pressing furnace. 250°C, 350°C, 400°C, and 500°C for 60 minutes in multiple stages of heat preservation, keeping a vacuum higher than 10Pa, hot pressing at 550°C, holding time for 1min, and then heat deformation, the temperature is 850°C.

[0033] Under the above-mentioned preparation process conditions, the resistivity of the prepared high-resistivity permanent magnet alloy is 3.8mΩcm, and the magnetic energy product is 46MGsOe.

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Abstract

The invention belongs to the field of preparation of permanent magnet materials, and in particular relates to a high-resistivity neodymium-iron-boron rare earth alloy and a preparation method thereof.The microstructure of the neodymium-iron-boron rare earth alloy is that a neodymium-iron-boron substrate is uniformly divided into different units by a high-resistivity insulating material, and the neodymium-iron-boron rare earth alloy is composed of neodymium-iron-boron nanocrystalline alloy powder and a nano inorganic insulating material layer wrapping the surface of neodymium-iron-boron nanocrystalline alloy powder. The nano inorganic insulating material is AlN, SiN, ZrN and SiC, and the weight of the nano inorganic insulating material is 1% to 5% of the weight of neodymium-iron-boron. Theparticle size of the neodymium-iron-boron nanocrystalline alloy powder is 0.1 to 0.3 mm, and the particle size of the insulating coating material is 1 to 100 nm. According to the method, the dosage of the insulating material can be greatly reduced, and the distribution uniformity of the insulating material in the substrate is improved, so that the insulating effect is improved.

Description

technical field [0001] The invention belongs to the field of preparation of permanent magnet materials, in particular to a high-resistivity neodymium-iron-boron permanent magnet alloy and a preparation method thereof. Background technique [0002] NdFeB rare earth permanent magnets have high magnetic energy product, low price and good processing performance, and have been widely used in permanent magnet motors. But its disadvantages are high electrical conductivity, low Curie temperature, high absolute value of coercivity temperature coefficient, Nd 2 Fe 14 The Curie temperature of B is only 312°C, and the Curie temperature of H ci The inversion temperature coefficient β reaches -0.55~-0.6% / ℃. During the service process of the permanent magnet motor, eddy current loss is generated, and the temperature rises, causing thermal demagnetization. Thermal demagnetization is irreversible demagnetization, that is, it cannot be re-magnetized, and the original magnetic flux cannot ...

Claims

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Application Information

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IPC IPC(8): H01F1/057H01F41/02
CPCH01F1/0576H01F1/0578H01F41/026H01F41/0266H01F41/0273
Inventor 郑立允李卫朱明刚郭朝晖周栋方以坤姜瑞姣白杨
Owner CENT IRON & STEEL RES INST
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