Preparation method of permanent magnet material

Abstract

The invention provides a preparation method of a permanent magnet material, comprising the steps of (1) preparing raw powder of permanent magnet material having a particle size of 0.01-5 Mum; (2) orient-forming the raw powder in the magnetic field 0.5-2 T under the protection an inert gas; (3), placing oriented magnet in a hot isostatic press, and pressing under 30-400 Mpa and 200-1100 DEG C for 0.1-4 h. After magnet powder is oriented, the magnet powder is subjected to hot isostatic sintering, the magnet is sintered with all-directional high pressure, it is possible to provide rapid sintering without a hot deformation process, and therefore, energy consumption is reduced and more excellent comprehensive permanent magnet performance is exhibited.

Description

technical field [0001] The invention relates to a method for preparing a permanent magnet material, in particular to a method for preparing a rare earth permanent magnet material using a hot isostatic pressing sintering technique. Background technique [0002] Rare earth permanent magnet materials (mainly NdFeB) can be used not only in civil products such as wind power generation, electric vehicles, nuclear energy safety, electronic instruments, and home appliances, but also in cutting-edge electronic communications, electronic interference and countermeasures, radar, aerospace, etc. In the field of technology, it is one of the important basic materials of modern industry, so it has received extensive attention at home and abroad. Although with the development of modern technology, the performance of rare earth permanent magnet materials has been greatly improved, but compared with theoretical calculations, its permanent magnetic properties (especially coercive force) still ...

AI Technical Summary

Problems solved by technology

Although with the development of modern technology, the performance of rare earth permanent magnet materials has been greatly improved, but compared with theoretical calculations, its permanent magnetic properties (especially coercive force) still have a lot of room for improvement.

[0003] Sintered NdFeB magnets are currently the most widely used in the market. This magnet has a high magnetic energy product and a relatively high coercive force, and has an important application range. However, the preparation of this sintered magnet still retains the traditional sintered magnet. process (vacuum sintering or low pressure sintering), due to the high sintering temperature and long sintering time required for complete densification, the grains of this magnet will grow during the sintering process, resulting in a decrease in coercive force and high energy consumption. Long preparation period

In order to reduce the grain size, plasma sintering (SPS) is used to prepare NdFeB magnets. This technology not only consumes less energy, but also can obtain higher coercive force, but it cannot achieve the orientation of the magnet, so its magnetic energy Product still needs to be improved

In order to further realize the orientation (or texture), the hot pressing-hot deformation sintering method is also used to prepare sintered magnets. The particles will rotate under high temperature and high pressure, so anisotropic sintered magnets can be prepared. Due to the application of pressure, the densification process of the magnets is accelerated. This kind of magnets has small grains and anisotropy (realizes orientation or Texture), so it can show more excellent comprehensive permanent magnetic properties (high magnetic energy product and relatively high coercive force), but compared with SPS sintering technology, this technology requires longer sintering time (requires thermal deformation process , will cause a certain grain growth)

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