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A Method for Improving the Consistency of Magnetic Properties of NdFeB Magnet Grain Boundary Diffusion

A grain boundary diffusion, NdFeB technology, applied in inductor/transformer/magnet manufacturing, electrical components, circuits, etc., can solve the problems of complex preparation process, poor consistency of grain boundary diffusion magnetic properties, easy surface oxidation, etc. The effect of uniform boundary diffusion, good magnetic properties consistency, and high intrinsic coercivity

Active Publication Date: 2021-06-18
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 purpose of the present invention is to overcome the defect that the surface of NdFeB magnets in the prior art is easily oxidized during the preparation process, resulting in poor consistency of grain boundary diffusion magnetic properties, and at the same time, the preparation process is relatively complicated. Surface oxidation of NdFeB magnets, and a simple preparation process to improve the consistency of magnetic properties of NdFeB magnet grain boundary diffusion

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] The N50H magnet blank prepared through the steps of smelting, powder making, molding and sintering is processed into a semi-finished product of 60×45×3mm (3mm is the orientation direction).

[0036] Mix terbium hydride and alcohol in a weight ratio of 1:1.6 and stir evenly.

[0037] The mixture of terbium hydride and alcohol is coated on the semi-finished product, and the coating amount is controlled by 1.0%-1.5% of the mass of the sintered NdFeB magnet.

[0038] Install the coated product in a graphite box, and sprinkle 0.2% calcium hydride according to the weight ratio of the product.

[0039] Place the graphite containing the product and calcium hydride in the vacuum sintering furnace to evacuate to 5.0×10 -2 Below Pa, heat to 400°C for 120 minutes for debinding, then heat up to 700°C for 120 minutes for hydrogen removal, and finally heat up to 900°C for 16 hours for grain boundary diffusion to obtain diffused NdFeB magnets.

[0040] The diffused NdFeB magnet is su...

Embodiment 2

[0046] The N40SH magnet blank prepared by the steps of smelting, powder making, molding and sintering is processed into a semi-finished product of 50×40×2mm (2mm is the orientation direction).

[0047] Mix terbium fluoride and alcohol in a weight ratio of 1:1 and stir evenly.

[0048] The mixture of terbium fluoride and alcohol is sprayed onto the semi-finished product by spraying, and the spraying amount is controlled by 0.8%-1.3% of the mass of the sintered NdFeB magnet.

[0049] Install the coated product in a graphite box, and sprinkle 0.3% calcium hydride according to the weight ratio of the product.

[0050] Place the graphite containing the product and calcium hydride in the vacuum sintering furnace to evacuate to 5.0×10 -2 Below Pa, heat to 400°C for 90 minutes for debinding, then heat up to 700°C for 180 minutes for hydrogen removal, and finally heat up to 900°C for 18 hours for grain boundary diffusion to obtain diffused NdFeB magnets.

[0051] The diffused NdFeB m...

Embodiment 3

[0057] The N52 magnet blank prepared by the steps of smelting, powder making, molding and sintering is processed into a semi-finished product of 40×30×2.5mm (2.5mm is the orientation direction).

[0058] Mix terbium oxide and alcohol in a weight ratio of 1:2.5 and stir evenly.

[0059] The mixture of terbium oxide and alcohol is sprayed onto the semi-finished product by spraying, and the spraying amount is controlled by 1.2%-1.5% of the mass of the sintered NdFeB magnet.

[0060] Install the coated product in a graphite box, and sprinkle 0.5% calcium hydride according to the weight ratio of the product.

[0061] Place the graphite containing the product and calcium hydride in the vacuum sintering furnace to evacuate to 5.0×10 -2 Below Pa, heat to 400°C for 90 minutes for debinding, then heat up to 700°C for 180 minutes for hydrogen removal, and finally heat up to 900°C for 20 hours for grain boundary diffusion to obtain diffused NdFeB magnets.

[0062] The diffused NdFeB mag...

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PUM

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Abstract

The invention relates to the field of rare earth magnetic materials, in particular to a method for improving the uniformity of the magnetic properties of NdFeB magnet grain boundary diffusion. The method comprises the following steps: (1) mixing the heavy rare earth powder and an organic solvent to obtain a heavy rare earth powder slurry, and then covering the surface of the sintered NdFeB magnet to obtain a semi-finished product; (2) placing the above semi-finished product into the material box, and evenly spread a layer of reducing agent on its surface; (3) place the above-mentioned material box containing the product and reducing agent in a vacuum or an inert gas environment for grain boundary diffusion treatment; (4) put the The products after boundary diffusion treatment are subjected to secondary aging treatment. The invention overcomes the defect that the surface of the NdFeB magnet in the prior art is easily oxidized during the preparation process, which leads to poor consistency of grain boundary diffusion magnetic properties, and thus has more uniform grain boundary diffusion and better magnetic property consistency; It has the advantages of deep heavy rare earth diffusion depth and high intrinsic coercive force.

Description

technical field [0001] The invention relates to the field of rare earth magnetic materials, in particular to a method for improving the uniformity of the magnetic properties of NdFeB magnet grain boundary diffusion. Background technique [0002] NdFeB magnetic material is an alloy of neodymium, iron oxide, etc., also known as magnetic steel. As the latest result of the development of rare earth permanent magnet materials, it is called "Magnetic King" because of its excellent magnetic properties. NdFeB has extremely high magnetic energy product and coercive force, and the advantages of high energy density make NdFeB permanent magnet materials widely used in modern industry and electronic technology, so that instruments and meters, electroacoustic motors, magnetic separation and magnetization Miniaturization, light weight, and thinning of equipment such as equipment become possible. [0003] Sintered NdFeB magnets are an important class of basic functional materials with a w...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F41/02
Inventor 黎龙贵石高阳张燕李超
Owner ZHEJIANG DONGYANG DMEGC RARE EARTH MAGNET CO LTD