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Method for improving coercive force of sintered neodymium-iron-boron magnet

A technology of NdFeB and coercive force, which is applied in the field of improving the coercive force of sintered NdFeB magnets, which can solve the problems of material magnetic decline and non-uniform distribution, so as to improve the coercive force, uniform distribution, and weaken the lattice The effect of the degree of distortion

Inactive Publication Date: 2018-11-16
NINGBO ZHAOBAO MAGNET
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] On the other hand, the oxygen content in sintered NdFeB magnets has an important impact on the performance of the magnet. When the NdFeB magnet contains too much oxygen, the magnetic properties of the material will be significantly reduced, mainly because oxygen will oxidize the crystal. The neodymium-rich phase of the boundary phase causes the neodymium-rich phase to shrink and concentrate in the triangular connection area of ​​the grain boundary during sintering, instead of being evenly distributed between the crystal planes

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Put the Cu powder with a particle size of about 3 microns in the steam environment of red phosphorus, and let it stand for 24 hours to make the surface fully react with P and form Cu on the surface. 3 P 2 layer, and then use the double alloy method with (Pr 0.25 Nd 0.75 ) 2.03 Fe 14.1 Nb 0.2 co 0.2 Al 0.3 B 1 The magnet powder is mixed, and the doping amount is 0.5wt% of the magnet powder. After fully mixing, the magnetic field orientation is pressed into a block. After sintering and annealing, a high coercive force sintered NdFeB magnet is obtained. The test performance is shown in Table 1.

Embodiment 2

[0030] The metal Ga powder with an average particle size of about 5 microns is placed in a mixed gas made of white phosphorus and argon. In the mixed gas, white phosphorus accounts for 5% of the volume fraction, and the surface of the powder is fully reacted by gas flow. The reaction lasts for 5 hours. Phosphate the surface fully. Incorporated into (Pr 0.25 Nd 0.75 ) 27 Fe 65.93 Nb 0.4 co 1.5 Dy 3.5 Cu 0.2 Al 0.3 Ga 0.2 B 0.97 In the powder, its doping amount is 0.5wt%. After being fully mixed, it is oriented and pressed into a block. After sintering and annealing, a high-coercivity sintered NdFeB magnet is obtained. The test performance is shown in Table 2.

Embodiment 3

[0036] The Dy / Cu alloy (mass ratio is 3:1) powder with an average particle diameter of about 2.8 microns is placed in a mixed gas made of white phosphorus and argon, and the white phosphorus accounts for 5% by volume in the mixed gas, and the gas flow is used to make The surface of the alloy powder was fully reacted, reacted for 5 minutes to fully phosphate the surface, and incorporated into (Pr 0.3 Nd 0.7 ) 2.01 Fe 14.1 Zn 0.4 co 0.6 Tb 0.2 Al 0.1 B 1 In the powder, its doping amount is 1.5wt%. After being fully mixed, it is oriented and pressed into a block. After sintering and annealing, a high-coercivity sintered NdFeB magnet is obtained. The test performance is shown in Table 3.

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Abstract

The invention discloses a method for improving the coercive force of a sintered neodymium-iron-boron magnet. The method includes the following steps that 1, neodymium-iron-boron powder is prepared through a conventional method; 2, metal or alloy powder M is obtained and subjected to surface phosphating treatment; 3, the powder obtained after surface phosphating is doped into the neodymium-iron-boron powder through a double-alloy method; 4, after uniform mixing, the powder is sintered after forming and pressing, and the sintered sample is subjected to annealing treatment to obtain the sinteredneodymium-iron-boron magnet. The method of properly adding metal phosphide to a magnet crystal boundary through the double-alloy method is the method for effectively improving the magnetic performanceof the neodymium-iron-boron magnet, and the coercive force of the sintered neodymium-iron-boron magnet is effectively improved.

Description

technical field [0001] The invention relates to the technical field of magnetic materials, more specifically, it relates to a method for improving the coercive force of a sintered NdFeB magnet. Background technique [0002] In 1983, on the basis of extensive research on RE-Fe-X ternary alloys, Sagawa Masato and others in Japan prepared a magnetic energy product as high as 290kJ / m by powder metallurgy. 3 The advanced neodymium iron boron (Nd-Fe-B) sintered magnets created the third generation of rare earth permanent magnet materials. Sintered NdFeB magnets have been widely used for their excellent comprehensive performance and relatively low price since their invention. In recent years, with the accelerated development of science and technology, the promotion speed and application scope of sintered NdFeB magnets in high-end fields such as new energy vehicles, inverter compressors and wind power have expanded rapidly. These fields require sintered NdFeB magnets to have high ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/057H01F41/02
CPCH01F1/0577H01F41/0266
Inventor 贺琦军林建强
Owner NINGBO ZHAOBAO MAGNET
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