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Method for preparing high-coercivity sintered NdFeB through pressurized diffusion heat treatment

A diffusion heat treatment, high coercivity technology, applied in the manufacture of inductors/transformers/magnets, electrical components, circuits, etc., can solve the problems of slow magnetron sputtering process, difficult to achieve batches, etc., to shorten the heat treatment time, easy to chemical Responsive, cost-saving effect

Inactive Publication Date: 2020-08-18
NANJING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the magnetron sputtering process is slow, and for mass production, it is difficult to realize in batches

Method used

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  • Method for preparing high-coercivity sintered NdFeB through pressurized diffusion heat treatment
  • Method for preparing high-coercivity sintered NdFeB through pressurized diffusion heat treatment
  • Method for preparing high-coercivity sintered NdFeB through pressurized diffusion heat treatment

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Step (1) Prepare a Dy68Cu32at% alloy by arc melting, and the alloy is repeatedly smelted 4 times to ensure the uniformity of the composition;

[0029] Step (2) Perform mechanical coarse crushing and sieving in an inert gas (Ar gas) glove box to obtain a coarse powder with an average particle size of about 200 μm;

[0030] Step (3) The coarse powder and absolute ethanol are mixed and put into a ball mill tank, and high-energy ball milling is performed to obtain a fine powder slurry with an average particle size of about 2 μm.

[0031] Step (4) Coat the fine powder slurry on the surface of the smooth block magnet (2*2*2cm3), and put it in the high temperature and high pressure furnace at the same time;

[0032] Step (5) After the high-temperature and high-pressure furnace is evacuated, and filled with a certain amount of argon, the temperature is raised to 800 ° C, and the pressure is adjusted to 15 MPa, kept for 3.5 hours, and cooled to room temperature with the furnace ...

Embodiment 2

[0037] Step (1): Prepare Pr by induction melting 33 Dy 35 Cu 32 at% alloy;

[0038] Step (2): through the quick-setting strip, the Pr 33 Dy 35 Cu 32 The at% alloy is prepared into a quick-quenched thin strip and mechanically crushed into a coarse powder with a particle size of less than 5mm;

[0039] Step (3): pass N 2 The air jet mill grinds the coarse alloy powder to a fine powder with an average particle size of less than 2 μm;

[0040] Step (4): fine powder and dehydrated alcohol are mixed to obtain fine powder mud;

[0041] Step (5): Coat the fine powder slurry on the smooth block magnet (2*2*2cm 3 ) surface, and at the same time as in the high temperature and high pressure furnace;

[0042] Step (6): After vacuuming the furnace, fill it with a certain amount of argon, raise the temperature to 650°C, and adjust the pressure to 15MPa, keep it warm for 3.5h, and cool down to room temperature with the furnace to obtain high coercive force sintered NdFeB magnet.

...

Embodiment 3

[0047] Step (1) prepares Tb by arc melting 63 co 37 at% alloy, the alloy is repeatedly smelted 4 times to ensure the uniformity of the composition;

[0048] Step (2): Perform mechanical coarse crushing and sieving in an inert gas (Ar gas) glove box to obtain a coarse powder with an average particle size of about 200 μm;

[0049] Step (3): Mix the coarse powder and absolute ethanol into a ball mill tank, perform high-energy ball milling, and obtain a fine powder slurry with an average particle size of about 2 μm.

[0050] Step (4): Coat the fine powder slurry on the smooth block magnet (2*2*2cm 3 ) surface, and at the same time as in the high temperature and high pressure furnace;

[0051] Step (5): After evacuating the high temperature and high pressure furnace, fill it with a certain amount of argon, raise the temperature to 850°C, adjust the pressure to 10MPa, keep it warm for 3 hours, and cool down to room temperature with the furnace to obtain high coercive force sinter...

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Abstract

The invention belongs to the field of permanent magnet materials, and particularly relates to a method for preparing high-coercivity sintered neodymium iron boron through pressurized diffusion heat treatment. The method specifically comprises the following steps of preparing a low-melting-point alloy containing one or two of heavy rare earth elements Tb or Dy; crushing the alloy into fine powder and mixing the fine powder with an organic solvent to form slurry; coating the alloy slurry on the surface of a clean sintered magnet and putting the sintered magnet into a heat treatment furnace; andfilling a certain amount of high-purity Ar gas into a specially-made high-temperature and high-pressure furnace, and carrying out pressure heat treatment to finally obtain the magnet subjected to pressurization diffusion treatment. According to the present invention, the coercive force of the neodymium-iron-boron sintered magnet prepared through the method is higher than that of a magnet which isnot pressurized and diffused under the same condition; in the high-temperature heat treatment process, isostatic pressure is applied in the furnace, so that the diffusion efficiency of heavy rare earth elements is improved, and the coercive force of the magnet is more efficiently improved; the diffusion heat treatment time can be properly reduced in the actual production process, the energy consumption is effectively reduced, and the production cost is reduced.

Description

technical field [0001] The invention belongs to the field of permanent magnet materials, and in particular relates to a method for preparing high-coercivity sintered NdFeB by pressurized diffusion heat treatment. Background technique [0002] Since the early 1980s Nd 2 Fe 14 Since the discovery of B compounds, sintered Nd-Fe-B magnets have developed into permanent magnet materials with the strongest magnetism, the widest application and the most rare earth consumption. In recent years, clean energy and sustainable development have become the focus of global attention. Industries represented by wind power generation, hybrid vehicles, and pure electric vehicles consume a large amount of sintered Nd-Fe-B rare earth permanent magnets. In these clean energy fields , requires the magnet to serve in a higher working temperature environment. This requires the magnet to have a high coercive force at room temperature to resist the thermal demagnetization effect, thereby ensuring th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F41/02
CPCH01F41/0293H01F41/0266
Inventor 张玉晶姚旻皓徐锋缪雪飞赵惠琨
Owner NANJING UNIV OF SCI & TECH
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