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Rare earth neodymium iron boron magnet grain boundary diffusion method

A rare earth neodymium iron boron and grain boundary diffusion technology, which is applied in the manufacture of magnetic objects, magnetic materials, inductors/transformers/magnets, etc., can solve the problems of magnet remanence decrease, manufacturing cost increase, heavy rare earth element consumption, etc.

Inactive Publication Date: 2020-07-07
ZHEJIANG DONGYANG DMEGC RARE EARTH MAGNET CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The present invention aims to overcome that when adding heavy rare earth elements such as Dy and Tb in the prior art to improve the internal coercive force of sintered NdFeB magnets in industrial production, it will lead to a significant decrease in the remanence of the magnet, and the consumption of heavy rare earth elements is large, resulting in a product To solve the problem of rising manufacturing costs, a method for grain boundary diffusion of rare earth NdFeB magnets is provided, which can effectively improve the intrinsic coercive force of NdFeB magnets while ensuring that the original remanence and maximum energy product of the magnets will not be significantly reduced. , control the amount of heavy rare earth elements and save production costs

Method used

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  • Rare earth neodymium iron boron magnet grain boundary diffusion method

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Embodiment 1

[0029] A rare earth NdFeB magnet grain boundary diffusion method, comprising the following steps:

[0030](1) prepare the RTM alloy cast sheet that thickness is 0.3mm through the vacuum quick-setting process according to the following formula: R is Tb, T is Fe, M is Al, and the mass percentages of Tb, Fe, Al in the powder are respectively 75%, 20% % and 5%;

[0031] (2) N48H NdFeB magnet blanks are prepared through smelting, powder making, molding, and sintering steps, and processed into blank square pieces with a size of 42×31×3mm (3mm is the orientation direction);

[0032] (3) Carry out surface activation to the rough square: put the rough square into a 20g / L degreasing aqueous solution with a temperature of 60°C for degreasing treatment for 3 minutes; then put the degreased rough square into 3% pickling in the nitric acid solution for 45s; finally put the pickled product in alcohol for 15s and then dry it;

[0033] (4) Lay the RTM alloy cast sheet on the bottom of the gr...

Embodiment 2

[0036] A rare earth NdFeB magnet grain boundary diffusion method, comprising the following steps:

[0037] (1) prepare the RTM alloy cast sheet that thickness is 0.28mm through the vacuum quick-setting process according to the following formula: R is Dy, T is Co, and M is Cu; The mass percents of Dy, Co, Cu are respectively 80%, 5% in the powder % and 5%;

[0038] (2) N42SH NdFeB magnet blanks are prepared through smelting, powder making, molding, and sintering steps, and processed into blank square pieces with a size of 50×20×4mm (4mm is the orientation direction);

[0039] (3) Carry out surface activation to the rough square: put the rough square into a 25g / L degreasing aqueous solution with a temperature of 60°C for degreasing for 3.5 minutes; then put the degreased rough into 3.5% pickling in nitric acid solution for 50s; finally put the pickled product in alcohol for 18s and then dry it;

[0040] (4) Lay the RTM alloy cast sheet on the bottom of the graphite box, and th...

Embodiment 3

[0043] A rare earth NdFeB magnet grain boundary diffusion method, comprising the following steps:

[0044] (1) Prepare the RTM alloy cast sheet that thickness is 0.32mm through the vacuum quick-setting process according to the following formula: R is Nd, T is Co, and M is Al; the mass percentages of Nd, Co, and Cu are respectively 75%, 15% in the powder % and 10%;

[0045] (2) N50 NdFeB magnet blanks are prepared through smelting, powder making, molding, and sintering steps, and processed into blank square pieces with a size of 50×20×2.5mm (2.5mm is the orientation direction);

[0046] (3) Carry out surface activation to the rough square: put the rough square into a 26g / L degreasing aqueous solution with a temperature of 65°C for degreasing treatment for 4 minutes; then put the degreased rough square into 3.6% pickling in nitric acid solution for 45s; finally put the pickled product in alcohol for 16s and then dry it;

[0047] (4) Lay the RTM alloy cast sheet on the bottom o...

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Abstract

The invention relates to the technical field of permanent magnet preparation, and discloses a rare earth neodymium iron boron magnet grain boundary diffusion method. The method comprises the followingsteps: preparing an RTM alloy cast sheet containing heavy rare earth elements; preparing a neodymium-iron-boron magnet blank, and processing the neodymium-iron-boron magnet blank into a blank squaresheet; performing surface activation on the blank square sheet; placing the RTM alloy cast sheet and the blank square sheet subjected to surface activation in a graphite box in an up-down overlappingmanner until the graphite box is full of the RTM alloy cast sheet and the blank square sheet; and carrying out vacuum heat treatment on the graphite box filled with the product to obtain the neodymium-iron-boron magnet subjected to diffusion treatment. The grain boundary diffusion process is adopted, the heavy rare earth elements in the RTM alloy casting piece enter the magnet from the surface ofthe magnet through grain boundary diffusion and exist in a grain boundary area, magnetic hardening of a main phase grain surface layer area is achieved, the residual magnetism of the prepared sinteredneodymium-iron-boron magnet high in intrinsic coercive force is reduced by a small amplitude, and the consumption number of the heavy rare earth elements is obviously reduced.

Description

technical field [0001] The invention relates to the technical field of permanent magnet preparation, in particular to a grain boundary diffusion method of a rare earth NdFeB magnet. Background technique [0002] Sintered NdFeB magnet is a kind of permanent magnet material with excellent magnetic properties, and it is also an important basic functional material. There are a wide range of applications in the field of technology. With the rapid development of high-tech fields, there is an increasing demand for sintered NdFeB magnets with high magnetic properties, high operating temperature, and high operating stability. Having a high intrinsic coercive force is a basic condition for sintered NdFeB magnets to have high operating temperature and high working stability. In the prior art, adding heavy rare earth elements such as Dy and Tb is the key to improving the industrial production of sintered NdFeB magnets. The main technical means of intrinsic coercivity in the body. [...

Claims

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Application Information

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IPC IPC(8): H01F41/02H01F1/057
CPCH01F1/0577H01F41/0253H01F41/0293
Inventor 黎龙贵李超张燕石高阳谢宝祥
Owner ZHEJIANG DONGYANG DMEGC RARE EARTH MAGNET CO LTD
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