Manufacturing method of neodymium-iron-boron magnet

Abstract

The invention discloses a manufacturing method of a neodymium iron boron magnet, and provides a manufacturing method of a permanent magnet capable of suppressing grain growth of magnet particles with single magnetic domain particle size during sintering and improving magnetic performance. Raw materials are placed in a screening and crushing device to be decomposed into small particles, preliminary screening is conducted, the small particles are crushed, an organometallic compound solution of an organometallic compound represented by M-(OR)<x> (in the formula, M is V, Mo, Zr, Ta, Ti, W or Nb, R is a substituent group composed of hydrocarbon and can be a straight chain or a branched chain, and x is an arbitrary integer) is added into neodymium magnet micro-powder obtained through crushing. so that the organometallic compound is uniformly attached to the particle surface of the neodymium magnet; then, the dried magnet powder is calcined by plasma heating, and the calcined powder is sintered after molding, thereby producing the permanent magnet. By screening, the content of impurities in the raw materials is reduced, and the permanent magnet is improved.

Description

technical field [0001] The invention belongs to the technical field of magnet production, and in particular relates to a method for manufacturing an NdFeB magnet. Background technique [0002] In recent years, permanent magnet motors used in hybrid vehicles, hard disk drives, and the like have been required to be smaller and lighter, higher in output, and higher in efficiency. Furthermore, in order to realize size reduction, high output power, and high efficiency in the above-mentioned permanent magnet motor, the permanent magnet embedded in the permanent magnet motor needs to be thinned and further improved in magnetic properties. In addition, as permanent magnets, there are ferrite magnets, Sm-Co-based magnets, Nd-Fe-B-based magnets, Sm2Fe17Nx-based magnets, etc., especially Nd-Fe-B-based magnets with high residual magnetic flux density are used as permanent magnet motors. The use of permanent magnets; [0003] Here, the powder sintering method is generally used as a met...

AI Technical Summary

Problems solved by technology

However, even if the magnet raw material pulverized into a fine particle size is formed and sintered, the grain growth of the magnet particles will occur during sintering, so the grain diameter of the sintered body after sintering is larger than that before sintering, so that it cannot be realized. grain diameter

Moreover, when the grain size increases, the magnetic domain walls generated in the grain tend to migrate, so the coercive force decreases significantly.

[0005] At the same time, in the production process, since the raw materials often contain a certain amount of impurities, the quality of the raw material minerals plays a very high decisive role when this method is used for production. Separation between impurities, and if the material is crushed into extremely small individuals, it is difficult to collect the material

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