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High-coercivity neodymium iron boron magnet surface coating slurry and neodymium iron boron magnet preparation method

A surface coating, high coercivity technology, used in the manufacture of magnetic materials, magnetic objects, inductors/transformers/magnets, etc., to achieve the effect of improving coercivity, hardening grain boundary structure, and reducing remanence

Active Publication Date: 2018-10-09
大地熊(包头)永磁科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The sintered NdFeB magnet of model 40H is processed into a sheet magnet with a size of 20mm*20mm*4mm (recorded as the original sample); the surface coating slurry is coated on the surface of the magnet, and the thickness of the slurry is 30um. Curing at ℃ for 30min, heat treatment at 750℃ for 4h, annealing at 500℃ for 3h.

[0028] Among them, in the surface coating slurry, the rare earth alloy powder Nd 70 Cu 30 The average particle size is 3.2um, the mass fraction is 50%, the mass fraction of epoxy resin is 40%, the mass fraction of crosslinking agent hydroxyethyl methacrylate is 5%, and the balance is organic solvent absolute ethanol.

Embodiment 2

[0037] Process the sintered NdFeB magnet of model 48M into a sheet magnet with a size of 20mm*20mm*4mm; prepare the surface coating slurry used for coating, in which the average particle size of metal Zn powder is 3um, and the mass fraction is 35% , the mass fraction of melamine formaldehyde resin is 35%, the mass fraction of crosslinking agent hydroxypropyl methacrylate is 7%, and the balance is the mixed solution of light aromatic hydrocarbon solvent naphtha and absolute ethanol (mass ratio is 1:2 ). Coat it on the surface of the magnet with a slurry thickness of 20um, cure at 220°C for 20 minutes, heat treat at 700°C for 8 hours, anneal at 650°C for 3 hours, and its magnetic properties are shown in the table below:

[0038] sample name

[0039] The above results show that the coercive force increases from 14.66kOe to 16.73kOe after the surface coating slurry prepared by the present invention is coated on the surface of the magnet and the grain boundaries diffuse. ...

Embodiment 3

[0041] Process the sintered NdFeB magnet model N52 into a sheet magnet with a size of 20mm*20mm*5mm; in the slurry used for coating, the rare earth alloy powder Pr 60 Dy 20 al 20 The average particle size is 2.8um, the mass fraction is 55%, the mass fraction of diisocyanate is 30%, and the mass fraction of crosslinking agent hydroxypropyl acrylate and divinylbenzene is 5% (weight ratio 1:1) , and the balance is a mixture of hydrogenated petroleum sulfonated heavy naphtha and acetone (the weight ratio is 1:1). Coat it on the surface of the magnet with a slurry thickness of 50um, cure at 240°C for 15 minutes, heat treat at 900°C for 10 hours, anneal at 500°C for 5 hours, and its magnetic properties are shown in the table below:

[0042] sample name

[0043] The above results show that the coercive force is increased from 11.68kOe to 16.56kOe after the slurry prepared by the present invention is coated on the surface of the magnet and the grain boundary is diffused, w...

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PUM

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Abstract

The invention provides high-coercivity neodymium iron boron magnet surface coating slurry and a neodymium iron boron magnet preparation method. The high-coercivity neodymium iron boron magnet surfacecoating slurry is prepared from, in weight percent, 35-60% of low-melting-point metal powder or rare earth alloy powder, 20-40% of poly-hydrocarbon resin, 5-12 % of cross-linking agents and the rest organic solvents. The preparation method of a neodymium iron boron magnet includes the steps: coating the surface of a sintered magnet with the slurry; performing heating, curing, diffusion heat treatment and homogenizing annealing to obtain a needed high-coercivity neodymium iron boron magnet. The slurry solves the problem that coated powder easily falls off, a boundary structure and grain boundary phase distribution are improved, and the coercivity of the magnet is improved without reducing residual magnetism.

Description

technical field [0001] The invention belongs to the field of magnetic materials and provides a surface coating slurry of a high-coercivity NdFeB magnet and a preparation method of the NdFeB magnet. Background technique [0002] As a core material application material for green energy, the demand for sintered NdFeB is rapidly increasing, especially in the working environment of micro motors and hybrid vehicles, which have great influence on the coercive force and temperature stability of magnets at high temperatures. Stringent requirements. As we all know, adding elements such as Dy / Tb is an effective way to increase the coercive force of magnets, but the traditional alloying method needs to add a large amount of heavy rare earth elements to achieve the purpose of increasing the coercive force, which not only causes the remanence of the magnet, the magnetic energy product Significantly reduced, but also increased raw material production costs. [0003] Compared with the all...

Claims

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Application Information

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IPC IPC(8): H01F1/057H01F41/02
CPCH01F1/0572H01F41/0253
Inventor 汪洋刘友好查善顺卢嘉黄秀莲陈静武衣晓飞熊永飞
Owner 大地熊(包头)永磁科技有限公司
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