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Surface coating slurry of high coercive force NdFeB magnet and preparation method of NdFeB magnet

A surface coating, high coercivity technology, applied in the direction of magnetic materials, magnetic objects, inductance/transformer/magnet manufacturing, etc., to achieve the effect of reducing residual magnetism, low cost, and reducing usage

Active Publication Date: 2020-09-11
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] Process a 40H sintered NdFeB magnet into a sheet magnet with a size of 20mm*20mm*4mm (recorded as the original sample); coat the surface coating slurry on the surface of the magnet, the slurry thickness is 30um, and the Cure at ℃ for 30min, heat treatment at 750℃ for 4h, annealing temperature at 500℃, time 3h.

[0028] 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 a 48M sintered NdFeB magnet into a sheet magnet with a size of 20mm*20mm*4mm; prepare the surface coating slurry for coating, in which the average particle size of the 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 a mixture of light aromatic solvent naphtha and absolute ethanol (mass ratio is 1:2 ). Coating it on the surface of the magnet with a slurry thickness of 20um, curing at 220℃ for 20min, heat treatment at 700℃ for 8h, annealing temperature at 650℃, time 3h, its magnetic properties are shown in the following table:

[0038] sample name Remanence (kGs) Coercivity (kOe) Maximum Magnetic Energy Product (MGOe) Original13.7514.6645.69 Example 213.7216.7345.66

[0039] The above results show that the surface coating slurry prepared by the present invention is coated on the surface of the magnet, after ...

Embodiment 3

[0041] Process a sintered NdFeB magnet of model N52 into a sheet magnet with a size of 20mm*20mm*5mm; in the slurry used for coating, 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%, the mass fraction of crosslinking agent hydroxypropyl acrylate and divinylbenzene is 5% (weight ratio 1:1) , The balance is a mixture of hydrogenated petroleum sulfonated heavy naphtha and acetone (weight ratio is 1:1). Coating it on the surface of the magnet with a slurry thickness of 50um, curing at 240℃ for 15min, heat treatment at 900℃ for 10h, annealing temperature at 500℃, time 5h, its magnetic properties are shown in the table below:

[0042] sample name Remanence (kGs) Coercivity (kOe) Maximum Magnetic Energy Product (MGOe) Original14.3611.6849.72 Example 314.3516.5649.69

[0043] The above results show that after the slurry prepared by the present invention is coated on the surface of the mag...

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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 neodymium iron boron magnet with high coercivity and a preparation method for the neodymium iron boron magnet. Background technique [0002] As the core material application material for green energy, the demand for sintered NdFeB is increasing rapidly, especially in the working environment of micro-motors, hybrid vehicles, etc., for the coercivity and temperature stability of magnets at high temperatures. Strict requirements. It is well known that adding elements such as Dy / Tb is an effective way to increase the coercivity of magnets, but the traditional alloying method requires the addition of a large amount of heavy rare earth elements to achieve the purpose of increasing the coercivity, which not only causes the remanence and energy product of the magnet Significantly reduced, but also increased raw material production costs. [0003] Compared with the al...

Claims

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Application Information

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Patent Type & Authority Patents(China)
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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