Preparation method of rare-earth permanent magnet, preparation device and rare-earth permanent magnet prepared thereby

Abstract

The invention discloses a preparation method of a rare-earth permanent magnet, a preparation device and a rare-earth permanent magnet prepared thereby, and relates to the preparation technology of sintered rare-earth permanent magnet with high coercivity. The invention is characterized in that the preparation method is carried out in two-chamber vacuum equipment which can be communicated with each other and also can carry out pressure increasing and decreasing treatment and heating treatment, and comprises the following steps of: firstly putting an evaporation material in a first chamber for crushing; putting a treated piece in a second chamber, vacuumizing the second chamber and enabling the vacuum degree of the second chamber to be equivalent to that of the first chamber; transferring the treated piece into the first chamber and carrying out heat diffusion treatment in the first chamber; carrying out pressure decreasing on the first chamber, and enabling the vacuum degree of the first chamber to be equivalent to that the second chamber; and transferring the treated piece back into the second chamber, and carrying out aging treatment in the second chamber. The preparation method disclosed by the invention has the advantages that no powder is remained on the surface of the magnet; the metal powder is adopted for evaporation, so that the evaporation efficiency is greatly increased, and the purpose of providing high-coercivity and high-remanence magnet by using fewer heavy rare-earth materials can be realized; and simultaneously, the magnet has stronger corrosion resistance.

Description

technical field [0001] The invention relates to a preparation method and a preparation device of a rare earth permanent magnet and the prepared rare earth permanent magnet, in particular to a preparation method of a sintered rare earth permanent magnet with high coercive force, a preparation device and the prepared rare earth permanent magnet. Background technique [0002] Rare earth permanent magnets have excellent magnetic properties. In recent years, they have been widely used in air-conditioning motors, hybrid vehicles and wind power generation. The use of magnets in these fields often needs to face high temperature and humid environments, and sometimes they may be used in in salty humidity. Therefore, not only magnets are required to have high magnetic properties, but also high corrosion resistance, which requires an increase in the coercive force of the magnet, and the improvement of the coercive force depends on the addition of expensive heavy rare earth elements. ...

AI Technical Summary

Problems solved by technology

[0007] The method of Patent Document 1 is difficult to avoid the residue of rare earth metal fluorides, oxides and other powders after melting on the surface of the magnet. Since the activity of rare earth elements is relatively strong, it is easy to cause the corrosion resistance of the magnet to deteriorate, even if electroplating, etc. Protective treatment can also easily lead to problems such as poor bonding with the coating

[0008] The method of Patent Document 2 is to configure a volume body in the processing chamber. The volume body with the same loading capacity has a smaller surface area than the powder, and its evaporation efficiency is low, which limits the improvement of diffusion and coercive force.

[0009] The method of Patent Document 3 is to directly provide heavy rare earth metal powder in the treatment chamber for evaporation, which improves the evaporation efficiency compared to the volume body, but the fine rare earth metal powder is very unsafe. Due to the easy oxidation of rare earth metals, when the powder contacts air, It is easy to catch fire. In the actual production, when transporting and transferring these powders, it is easy to cause fire and hazards to people and property. Be very careful

Although Patent Document 3 has considered this problem and limited the particle size of the heavy rare earth metal powder, even within the specified range, it still requires the staff to operate quickly and reduce the time that the powder is exposed to the air, so it is not suitable mass production

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