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Method for Improving the Coercive Force of Sintered NdFeB Magnets

A neodymium-iron-boron and coercive force technology is applied in the field of improving the coercive force of sintered neodymium-iron-boron magnets, which can solve the problems of low coercivity and large grain size of the sintered neodymium-iron-boron magnets, and improve the coercivity of the magnets. force effect

Active Publication Date: 2021-03-30
BAOTOU RES INST OF RARE EARTHS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, although some sintered NdFeB magnets without adding heavy rare earths are prepared by adding titanium, molybdenum or light rare earth elements, the grain size of the obtained sintered NdFeB magnets is still large and the coercive force is still relatively low. Low

Method used

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  • Method for Improving the Coercive Force of Sintered NdFeB Magnets

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Prepare the mixture according to the following formula:

[0038] Pr-Nd alloy: 32wt%; Fe: 66.4wt%; Al: 0.5wt%; Cu: 0.1wt%; B: 1.0wt%.

[0039] Put the prepared mixture into a vacuum quick-setting casting furnace, vacuumize to 1Pa, fill it with argon protection for heating and melting, and then pour the melted liquid on the rotating cooling copper roller to obtain a thickness of about 0.3mm NdFeB alloy cast sheet.

[0040] Hydrogen crushing of NdFeB alloy castings to obtain NdFeB coarse powder, mix NdFeB coarse powder with antioxidant and lubricant for 1 hour, and then obtain NdFeB fine powder with an average particle size D50 of 3.04 μm by jet mill . Mix tungsten powder with a volume ratio of 0.5:100 (average particle diameter D50 is 500nm) and NdFeB fine powder for 1.5h to obtain mixed powder. In a 2T magnetic field, the mixed powder is subjected to orientation molding and isostatic pressing to obtain a compact; the compact is vacuum sintered at 1050°C for 2h, and th...

Embodiment 2

[0042] Prepare the mixture according to the following formula:

[0043] Pr-Nd alloy: 32wt%; Fe: 66.4wt%; Al: 0.5wt%; Cu: 0.1wt%; B: 1.0wt%.

[0044] Put the prepared mixture into a vacuum quick-setting casting furnace, vacuumize to 1Pa, fill it with argon protection for heating and melting, and then pour the melted liquid on the rotating cooling copper roller to obtain a thickness of about 0.3mm NdFeB alloy cast sheet.

[0045] Hydrogen crushing of NdFeB alloy castings to obtain NdFeB coarse powder, mix NdFeB coarse powder with antioxidant and lubricant for 1 hour, and then obtain NdFeB fine powder with an average particle size D50 of 3.04 μm by jet mill . Mix tungsten powder, Cu-Ga alloy and NdFeB fine powder according to the volume ratio of 0.5:0.5:100 for 1.5h to obtain mixed powder; wherein, the average particle diameter D50 of tungsten powder is 500nm, and the average particle size of Cu-Ga alloy The particle size D50 is 1.3 μm, and the Ga content in the Cu-Ga alloy is...

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Abstract

The invention discloses a method for improving coercive force of a sintered neodymium iron boron magnet. The method comprises the following steps that (1) neodymium-iron-boron fine powder is preparedfrom the following components: 26-35wt% of Pr-Nd alloy, 0.1-0.8wt% of Al, 0.01-0.3wt% of Cu, 0.5-1.5wt% of B and the balance of Fe, wherein the average particle size of the neodymium-iron-boron fine powder is 0.5-10 microns; and (2) the neodymium-iron-boron fine powder, tungsten powder and Cu-Ga alloy are mixed uniformly and then magnetic field orientation compression molding, isostatic pressing,vacuum sintering and tempering treatment are carried out to obtain the sintered neodymium iron boron magnet. According to the method disclosed by the invention, the sintered neodymium iron boron magnet with relatively small grain size and relatively high coercive force can be obtained and free of heavy rare earth can be obtained.

Description

technical field [0001] The invention relates to a method for increasing the coercive force of a sintered NdFeB magnet. Background technique [0002] Take Nd 2 Fe 14 Neodymium iron boron (NdFeB) magnet material with B as the main component has high remanence, coercive force and maximum magnetic energy product, and excellent comprehensive magnetic properties. It is used in wind power generation, new energy vehicles, frequency conversion household appliances, energy-saving elevators, etc. . NdFeB material has a low Curie temperature point and poor temperature stability, which cannot meet the requirements of high working temperature (>200°C) in many new application fields. At present, adding heavy rare earth elements dysprosium and terbium, or adding transition group elements such as cobalt, niobium, molybdenum or gallium, etc. increases the coercive force and Curie temperature, thereby increasing the working temperature of the magnet to meet the use requirements. However...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F1/057H01F41/02
CPCH01F1/0577H01F41/0253H01F41/0266
Inventor 李泉付建龙刘国征赵明静高岩吕科任少卿王东波杨光磊周博阳孟恒武斌赵瑞金鲁富强
Owner BAOTOU RES INST OF RARE EARTHS
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