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Preparation method for high performance as cast condition neodymium iron boron magnet

A high-performance, neodymium-iron-boron technology, applied in the direction of magnetic objects, inductors/transformers/magnets, magnetic materials, etc., can solve poor temperature stability and corrosion resistance, coercive force value can not be effectively improved, can not Realize problems such as grains, and achieve the effects of improving coercive force, complete grain orientation, and uniform distribution of grain boundary phases

Active Publication Date: 2012-08-01
临沂银凤新材料技术服务有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0002] NdFeB permanent magnet materials are widely used in communication, medical, automotive, electronics, aviation and other fields due to their excellent magnetic properties and high cost performance; but their low coercive force and poor temperature stability and durability Corrosion performance severely limits the expansion of its application range. With the development of science and technology, the requirements for the comprehensive performance of NdFeB magnets in various fields are getting higher and higher. Therefore, the development of NdFeB magnets with high comprehensive performance has become an inevitable trend
[0003] The magnetic properties of NdFeB permanent magnet materials mainly come from Nd 2 Fe 14 B hard magnetic phase, but it is also closely related to the microstructure of the magnet. NdFeB magnet is a polycrystalline composite phase material, which is usually made by powder metallurgy process. Its grain size, grain boundary phase distribution, and grain orientation etc. have a significant impact on the magnetic properties; after years of research and development, the magnetic properties of NdFeB magnets have been greatly developed, and the maximum magnetic energy product has reached 474 kJ / m 3 , close to 93% of the theoretical value, but its coercive force value has not been effectively improved; although the magnetocrystalline anisotropy field of the hard magnetic phase is relatively high, the coercive force of the magnet is still very low, which is mainly due to It is caused by its microstructure; at present, the effective improvement of coercive force is mainly realized by the addition of heavy rare earth elements Dy and Tb, but this not only reduces its magnetic energy product, but also increases the cost; in addition, microstructure optimization, especially grain Refinement is also an important method to improve the coercive force, and the coercive force reaches the maximum when the grain size is refined to the single domain size; however, the traditional powder metallurgy preparation process cannot achieve effective grain refinement, and may also introduce More oxygen content destroys its grain boundary structure. It can be seen that obtaining a microstructure with complete orientation, fine grains and uniform distribution of grain boundaries is an effective way to ensure high magnetic energy product and high coercive force

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] 1) According to the magnet composition Nd 11 PR 5 Fe 78.9 B 5 Nb 0.1 Weigh the raw materials of each element and mix them;

[0026] 2) Put the mixed raw materials into a vacuum melting furnace for melting, and pour them after refining to obtain ingots;

[0027] 3) Temper the ingot at 1050°C for 4 hours in a vacuum at high temperature to eliminate α-Fe and homogenize the structure;

[0028] 4) Cover the homogenized ingot with metal aluminum and preheat it to 450°C, then carry out 4 passes of back pressure-equal channel corner large plastic deformation in the Bc path, the channel angle Φ is 110°, and the circumscribed angle Ψ is 10°, and the back pressure is 45Mpa, which refines the structure of the ingot;

[0029] 5) Thermally deform the ingot after refinement at 650°C with a pressure of 150MPa to control the magnetic texture;

[0030] 6) The heat-deformed ingot is subjected to vacuum heat treatment at 900°C under a 2T magnetic field for 4 hours to further strengt...

Embodiment 2

[0034] 1) According to the magnet composition Nd 11.9 Tb 0.1 Fe 81 B 5.5 Cu 1.5 Ga 0.5 Weigh the raw materials of each element and mix them;

[0035] 2) Put the mixed raw materials into a vacuum melting furnace for melting, and pour them after refining to obtain ingots;

[0036] 3) Tempering the cast ingot at 1000°C for 10h in vacuum at high temperature to eliminate α-Fe and homogenize the structure;

[0037] 4) Cover the homogenized ingot with metal copper and preheat it to 700°C, and then carry out one pass of back pressure-equal channel corner large plastic deformation in the Bc path, the channel angle Φ is 135°, and the circumscribed angle Ψ is 45°, and the back pressure is 200Mpa, which refines the ingot structure;

[0038]5) Thermally deform the ingot after refining the structure at 1000°C with a pressure of 100MPa to control the magnetic texture;

[0039] 6) The heat-deformed ingot is subjected to vacuum heat treatment at 500°C under a 10T magnetic field for 2 h...

Embodiment 3

[0043] 1) According to the magnet composition Nd 13 Dy 1 Fe 76 co 2.5 B 6 Al 1.5 Weigh the raw materials of each element and mix them;

[0044] 2) Put the mixed raw materials into a vacuum melting furnace for melting, and pour them after refining to obtain ingots;

[0045] 3) Temper the ingot at 1020°C for 8 hours in vacuum at high temperature to eliminate α-Fe and homogenize the structure;

[0046] 4) Cover the homogenized ingot with a low-carbon steel ladle and preheat it to 550°C, then carry out 10 passes of back pressure-equal channel corner large plastic deformation in the Bc path, the channel angle Φ is 120°, and the circumscribed angle Ψ is 30°, and the back pressure is 150Mpa, which refines the ingot structure;

[0047] 5) Thermally deform the ingot after refinement at 850°C with a pressure of 50MPa to control the magnetic texture;

[0048] 6) The heat-deformed ingot is subjected to vacuum heat treatment at 750°C under a 20T magnetic field for 1 hour to further...

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Abstract

The invention relates to the technical field of permanent magnetic material preparation and in particular to a preparation method for a high performance as cast condition neodymium iron boron magnet. By means of the composite process combining technology of casting and large strain plastic deformation and the technology of double orientation, grain size is effectively refined, and grain boundary and grain orientation are controlled, so that the high performance neodymium iron boron magnet which is fine in grains, even in grain boundary phase distribution and complete in grain orientation is prepared, and good matching of high coercivity and high magnetic energy product is obtained.

Description

technical field [0001] The invention relates to the technical field of permanent magnet material preparation, in particular to a preparation method of a high-performance cast NdFeB magnet. Background technique [0002] NdFeB permanent magnet materials are widely used in communication, medical, automotive, electronics, aviation and other fields due to their excellent magnetic properties and high cost performance; but their low coercive force and poor temperature stability and durability The corrosion performance severely limits the expansion of its application range. With the development of science and technology, the requirements for the comprehensive performance of NdFeB magnets in various fields are getting higher and higher. Therefore, the development of NdFeB magnets with high comprehensive performance has become an inevitable trend. [0003] The magnetic properties of NdFeB permanent magnet materials mainly come from Nd 2 Fe 14 B hard magnetic phase, but it is also cl...

Claims

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Application Information

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IPC IPC(8): H01F41/02H01F7/02H01F1/057C21D1/04C21D1/773
Inventor 崔熙贵崔承云程晓农许晓静
Owner 临沂银凤新材料技术服务有限公司
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