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Magnetic field gel injection molding method for large scale rare-earth sintering magnet

A technology of gel injection molding and sintering magnets, which is applied in the fields of inorganic material magnetism, inductor/transformer/magnet manufacturing, electrical components, etc. The effect of reducing, residual oxygen and carbon residue, and low price

Inactive Publication Date: 2007-02-07
UNIV OF SCI & TECH BEIJING
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] However, in general, injection molding sintered Nd-Fe-B needs to add 15% to 50% by volume of thermoplastic polyester (such as polyamide, polyolefin, polyvinyl chloride, polystyrene, etc.) as a binder, high temperature The mixing process and the pyrolysis removal process of organic matter can easily oxidize and increase the carburization of Nd-Fe-B, and the residual carbon and oxygen content in the alloy are too high to damage the magnetic properties of the magnet; moreover, a large amount of organic adhesive Long binder removal process makes powder injection molding of large parts difficult

Method used

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  • Magnetic field gel injection molding method for large scale rare-earth sintering magnet

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Embodiment 1

[0031] NdFeB powder is commercially available jet mill powder with a purity of 99.9% and an average particle size of 3.7μm; the chemical composition of the powder is Nd 2 Fe 14 B matrix phase components; hydroxyethyl acrylate, solvent toluene, initiator benzoyl peroxide, catalyst dimethylaniline, oleic acid are all analytically pure.

[0032] Dissolve 30ml of hydroxyethyl acrylate in 70ml of toluene, add 760g of NdFeB powder and 3g of polyacrylic acid dispersant, add initiator and catalyst after ball milling for 24 hours, and vacuum defoam for 30 minutes to obtain a solid phase volume fraction of 50% Slurry. Inject the slurry into a plastic mold, keep the mold in a magnetic field at 80°C for 60 minutes, and vacuum dry for 12 hours after demolding to obtain a magnetic field gel injection molded magnet body; the body is sintered and heat treated to obtain NdFeB Sintered magnet. The X-ray diffraction spectrum of the vertical orientation cross section of the sintered NdFeB magnet prep...

Embodiment 2

[0034] The composition of Sm-Co alloy powder is Sm(Co 0.72 Fe 0.17 Cu 0.08 Zr 0.03 ) 7.5, The average particle size is 4.1μm; hydroxyethyl acrylate, solvent toluene, initiator benzoyl peroxide, catalyst dimethylaniline, oleic acid are all analytically pure.

[0035] Dissolve 10 grams of hydroxyethyl acrylate in 90 milliliters of toluene to make a solution, add 840 grams of titanium powder and 6 grams of polyacrylamide dispersant, add initiator and catalyst after ball milling for 24 hours, and vacuum defoam for 20 minutes to obtain a solid A slurry with a phase volume fraction of 50%. Inject the obtained slurry into a glass mold, heat the mold in a magnetic field at 60°C for 120 minutes, and solidify the slurry in the mold into a green body. After demolding, vacuum dry for 48 hours to obtain a magnetic field gel injection molded magnet body; SmCo sintered magnet is obtained after the green body is sintered and heat treated.

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Abstract

The invention relates to a magnetic gel injection molding method of large-scale rare-earth sinter magnet, wherein it comprises: dissolving ethyl acrylate into toluene to be the pre-mixed solution at 5-50vol.%; adding disperse agent into the pre-mixed solution to be mixed with magnetic powder in Ar condition inside vacuum operation box; grinding the mixture material for 2-24hours; adding initiator, defoaming the slurry room for 5-30mins; pouring slurry into mould; heating mould to 40-80Deg. C; heeping the temperature of magnetic field for 30-150mins; demoulding; vacuum drying, to obtain the rare-earth magnetic blank; vacuum sintering the blank, thermally treating to obtain the rare-earth sintered magnet. The invention has the advantages that: it can improve the magnetic directed degree to obtain high magnetic property, with simple operation and lower cost.

Description

Technical field [0001] The invention belongs to the technical field of powder metallurgy molding, and particularly provides a magnetic field gel injection molding method for large-size rare earth sintered magnets. Background technique [0002] At present, the production of Nd-Fe-B series or Sm-Co series rare earth sintered magnets mainly adopts traditional powder metallurgy pressing process. In the magnetic field pressing process, the improvement of the orientation of the magnetic powder in the magnetic field is the key factor to improve the magnetic performance of the permanent magnet. However, the magnetic powder will encounter resistance in the process of orientation rotation. The resistance mainly comes from the friction force generated when the powder particles are in contact with each other, the mechanical resistance caused by the irregular shape of the powder, and the friction force between the magnetic powder and the mold. And as a micron-sized powder, the magnetic powder...

Claims

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Application Information

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IPC IPC(8): H01F1/08H01F41/00B22F3/10
Inventor 郭志猛李艳隋延力郝俊杰
Owner UNIV OF SCI & TECH BEIJING
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