Method for forming isotropic neodymium-iron-boron magnet

Abstract

The invention provides a method for forming an isotropic neodymium-iron-boron magnet. The method comprises the step of smelting an alloy raw material into a prealloyed cast ingot, the step of performing non-crystallizing treatment on the prealloyed cast ingot to obtain a fast-quenched alloy, the step of performing ball milling on the fast-quenched alloy to obtain a powder, the step of mixing the powder with a binder to obtain a slurry, and the step of forming the slurry into the magnet. The binder is a water-based binder, preferably a methylcellulose aqueous solution, and the solid content in the slurry ranges from 30vol% to 60vol%. The method is capable of realizing the formation of the isotropic neodymium-iron-boron magnet large in dimension and complex in shape, and therefore, the purpose of reducing the oxygen content is achieved, and simultaneously, the carbon residue in a degreasing process can be greatly reduced.

Description

technical field [0001] The invention relates to a forming method of an isotropic NdFeB magnet. Background technique [0002] Metal injection molding (Metal injection molding, MIM) is a new type of near-net forming technology introduced from the plastics industry to powder metallurgy. It is a combination of traditional powder metallurgy and modern injection molding. This process can produce small precision parts with complex shapes and uniform structure. Metal injection molding technology has long been used in the preparation of bonded NdFeB permanent magnets. The shape of the magnets can be relatively complex and the performance is excellent, which makes up for the shortcomings of the traditional powder metallurgy dry forming technology, and many products have achieved industrial production. [0003] However, there are few studies on the injection molding technology of sintered NdFeB permanent magnets. The main process difficulties are: 1) The magnetic powder and thermoplas...

AI Technical Summary

Problems solved by technology

[0006] However, there are still some problems in the preparation of sintered NdFeB magnets by gel injection molding technology.

For example, since the base phase and the Nd-rich phase inside the sintered NdFeB have a strong affinity with oxygen, even if the temperature is not high, there is still an oxidation problem in the air

The binder system is still not perfect, the main problem is that the content of organic matter is too high, and the phenomenon of excessive carbon residue is easy to appear in the later degreasing and sintering process

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