Preparation method of high-coercivity neodymium-iron-boron magnet

A high coercive force, neodymium iron boron technology, applied in the direction of magnetic objects, inductors/transformers/magnets manufacturing, magnetic materials, etc., can solve the problems of waste of precious metals, reduction of residual magnetism, increase of production costs, etc.

Active Publication Date: 2019-04-09
ZHEJIANG ZHONGHANG NEW MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this method can greatly increase the coercive force of the magnet, it will lead to a large decrease in remanence, and it will lead

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] The preparation method of a high coercive force NdFeB magnet provided in this embodiment comprises the following steps:

[0015] Step 1, the preparation of modified body, according to Li 3.8 Ni 0.3 Ti 4.9 o 12 Li:M:Ti molar ratio 3.8:0.3:4.9 Lithium acetate, nickel nitrate, titanium isopropoxide were dissolved in 20 ml of isopropanol to prepare a clear solution A, then 1g of PVP was added to the clear solution obtained in step a In solution A, stir until solution B is obtained; then add solution B obtained in step b into the electrospinning machine, and extrude from the needle at a speed of 1ml / h. The distance from the needle to the substrate was 15 cm, and the voltage was 10 kV. Finally, the sample obtained by electrospinning was pre-fired in an air atmosphere at 300 °C for 3 hours, and then in argon protective atmosphere at 850 °C. Medium roasting for 6 hours to obtain the modifier Li 3.8 Ni 0.3 Ti 4.9 o 12 -C.

[0016] Step 2, the preparation of NdFeB magnet...

Embodiment 2

[0018] The preparation method of a kind of high coercive force NdFeB magnet provided in this embodiment, its difference with embodiment 1 is that the preparation of described NdFeB magnet is by weight 3 parts of graphene, 15 parts of modified Agent and 90 parts of NdFeB powder are mixed evenly, and then a layer of rare earth metal film is sputtered on the surface of the above-mentioned powder particles by magnetron sputtering process, so as to obtain the coated NdFeB powder; then the above-mentioned coated NdFeB powder is shaped Then place it in the sintering furnace, heat up to 750-850°C for 150-180 minutes after vacuuming, and keep it for 20-40 minutes; then heat it up to 1000-1050°C for 60-70 minutes, and keep it for 10-30 minutes; Raise the temperature to 1050-1100°C in 0-10 minutes, keep it warm for 300-350 minutes; finally fill it with inert gas to cool, and obtain a sintered NdFeB magnet. Wherein the modifier is Li 3.6 co 0.6 Ti 4.8 o 12 -C.

Embodiment 3

[0020] The preparation method of a kind of high coercive force NdFeB magnet provided in this embodiment, its difference with embodiment 1 is that the preparation of described NdFeB magnet is by weight 2 parts of graphene, 12 parts of modified Agent and 90 parts of NdFeB powder are mixed evenly, and then a layer of rare earth metal film is sputtered on the surface of the above-mentioned powder particles by magnetron sputtering process, so as to obtain the coated NdFeB powder; then the above-mentioned coated NdFeB powder is shaped Then place it in the sintering furnace, heat up to 750-850°C for 150-180 minutes after vacuuming, and keep it for 20-40 minutes; then heat it up to 1000-1050°C for 60-70 minutes, and keep it for 10-30 minutes; Raise the temperature to 1050-1100°C in 0-10 minutes, keep it warm for 300-350 minutes; finally fill it with inert gas to cool, and obtain a sintered NdFeB magnet. Wherein the modifier is Li 3.7 mn 0.45 Ti 4.75 o 12 -C.

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Abstract

The invention provides a preparation method of a high-coercivity neodymium-iron-boron magnet. According to the preparation method, graphene is added to a neodymium-iron-boron powder, so as to effectively improve the strength of the neodymium-iron-boron magnet. Modifier Li<4-2x>M<3x>Ti<5-x>O<12>C is used to improve the magnetic energy product of the neodymium-iron-boron magnet, so as to perfect andimprove the performance of the neodymium-iron-boron magnet. A rare-earth metal film is sputtered onto the surface of each powder particle by using the magnetron sputtering process; grain boundaries are diffused by means of pressing and sintering; rare earth metals enter the superficial layers of neodymium, iron and boron to improve the anisotropies of the neodymium, iron and boron, with the neodymium, iron and boron hardly affected; and therefore, the purpose of greatly improving the coercivity of the neodymium-iron-boron magnet can be achieved under the condition that remanent magnetism hardly decreases. In addition, the neodymium-iron-boron magnet is pre-sintered by means of stepped heating, so that the temperature gradients at the exterior and center of the neodymium-iron-boron magnetdecrease; and when the sintering temperature is reached, the temperature of the central part of a neodymium-iron-boron compact is allowed to reach the sintering temperature rapidly, so as to improve the density and magnetic properties of the sintered neodymium-iron-boron compact.

Description

technical field [0001] The invention relates to the field of neodymium iron boron, in particular to a preparation method of a high coercive force neodymium iron boron magnet. Background technique [0002] As the third generation rare earth permanent magnet material, sintered NdFeB magnet has excellent magnetic properties and high cost performance that cannot be compared with other permanent magnet materials. Therefore, since its discovery, it has been extensively researched and developed rapidly, and has been widely used in high-tech fields such as computers, communication electronics, automobiles, and aviation. [0003] At present, the research on improving the coercive force of magnets is mostly the double alloy method. In this method, the coercive force of the magnet is generally improved by modifying the grain boundaries of the master alloy by crushing and mixing the ingot or the auxiliary alloy cast into strips and the NdFeB master alloy, and performing heat treatment ...

Claims

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Application Information

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IPC IPC(8): B22F3/10B22F3/24C22C38/04C22C38/10C23C14/16C23C14/35H01F1/057H01F41/02
CPCB22F3/1017B22F3/24B22F2003/248C22C38/002C22C38/005C22C38/04C22C38/105C23C14/165C23C14/35H01F1/0575H01F41/0253
Inventor 徐嘉诚
Owner ZHEJIANG ZHONGHANG NEW MATERIAL
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