Preparation method for fine grain anisotropy densified neodymium iron boron permanent magnet

An anisotropic and densifying technology, used in the manufacture of inductors/transformers/magnets, permanent magnets, electrical components, etc., can solve the problems of non-anisotropy, low remanence and low maximum magnetic energy product of magnets, and avoid crystal formation. The growth of grains, the effect of ensuring the density

Active Publication Date: 2013-05-29
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, there are many researches on hot-pressed NdFeB magnets, but because this kind of magnets do not have anisotropy, their remanence and maximum energy product are low, which is far from being compared with sintered NdFeB magnets.

Method used

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  • Preparation method for fine grain anisotropy densified neodymium iron boron permanent magnet
  • Preparation method for fine grain anisotropy densified neodymium iron boron permanent magnet
  • Preparation method for fine grain anisotropy densified neodymium iron boron permanent magnet

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] 1. The alloy whose main alloy composition is Nd27.1Pr6.6Fe65.1B1.2 (mass percentage content) is made into thin slices by using quick-setting thin slice technology;

[0023] 2. Then use the hydrogen crushing and jet milling process to make the quick-setting flakes into a powder with an average particle size of 2.9 μm;

[0024] 3. Orient and press the alloy powder in a 2T magnetic field, and press isostatically for 20 seconds under a pressure of 300MPa;

[0025] 4. Place the green compact in a vacuum furnace and vacuumize to 3×10 -3 After Pa, pre-sinter at 800°C for 2 hours;

[0026] 5. Place the pre-sintered blank in a vacuum hot-press furnace and evacuate to 6×10 -3 After Pa, raise the temperature to 850°C, pressurize 500MPa along the orientation direction of the magnet blank, hold the pressure for 2 minutes, and then cool it out;

[0027] 6. Then heat-treat the hot-pressed blank at 900° C. and 500° C. for 2 hours in vacuum to obtain a final magnet.

[0028] The mag...

Embodiment 2

[0032] 1. The alloy whose main alloy composition is Nd30.5Fe67.2Co1.0Cu0.2Al0.1B1.0 (mass percentage) is made into thin slices by using quick-setting thin slice technology;

[0033] 2. Then use the hydrogen crushing and jet milling process to make the quick-setting flakes into a powder with an average particle size of 2.7 μm;

[0034] 3. Orient and press the alloy powder in a 2T magnetic field, and press isostatically for 20 seconds under a pressure of 300MPa;

[0035] 4. Place the green compact in a vacuum furnace and vacuumize to 3×10 -3 After Pa, pre-sinter at 900°C for 2 hours;

[0036] 5. Place the pre-sintered blank in a vacuum hot-press furnace and evacuate to 6×10 -3 After Pa, raise the temperature to 830°C, pressurize 300MPa along the orientation direction of the magnet blank, hold the pressure for 2 minutes, then cool and take it out;

[0037] 6. Then heat-treat the hot-pressed blank at 900° C. and 500° C. for 2 hours in vacuum to obtain a final magnet.

[0038] ...

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Abstract

The invention relates to a preparation method for a fine grain anisotropy densified neodymium iron boron permanent magnet. The preparation method comprises the steps: traditional firing neodymium iron boron technology is adopted; a magnetic blank with small grains and loose texture is obtained by means of low-temperature presintering after rapid hardening, hydrogen breaking, air-stream milling and orientation forming; then the blank is hot-pressed and densified; and the anisotropy neodymium iron boron magnet with the small grains and densified is obtained after tempering is performed to the blank. According to the method, the grains in sintering process of magnet can be prevented from being larger effectively, the prepared magnet has a fine grain structure and is high in densification and the grain size of the fine grain anisotropy densified neodymium iron boron permanent magnet is close to air-stream milling powder granularity.

Description

technical field [0001] The invention belongs to the field of magnetic materials, and in particular relates to a preparation method of an anisotropic densified fine-grain NdFeB permanent magnet. Background technique [0002] Since the discovery of the third-generation rare earth permanent magnet material NdFeB in the 1980s, due to its excellent permanent magnetic properties, it has been widely used in the fields of electronics, communications, transportation, automation, medical treatment and new energy. So far, NdFeB permanent magnet materials have the best permanent magnetic properties, known as the "king of permanent magnets", which is of great significance to the miniaturization, integration and high efficiency of devices. In recent years, with the rising price of rare earth raw materials, the development of low-rare-earth, low-cost and high-performance NdFeB materials has become an urgent scientific and technical problem to be solved. [0003] The coercive force reflect...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F7/02H01F41/02B22F3/16
Inventor 陈仁杰唐旭严长江付文标李东闫阿儒
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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