Method for improving performance of sintered NdFeB magnet

Abstract

The invention discloses a method for improving performance of a sintered NdFeB magnet. According to the method, a metal oxide is reduced with hydrogen under a high temperature by means of the characteristic of low-melting metal oxide, low-melting metal is sequentially obtained according to a reduction sequence, a discontinuous crystal boundary rare-earth phase of a magnet surface layer is preferably diffused and recovered, a continuous low-melting point rare-earth phase is obtained and is used as a rapid diffusion passage of a heavy rare-earth element, the diffusion depth of the heavy rare-earth element in the magnet is effectively improved, the dosage of the heavy rare-earth element is reduced, the improvement of magnet coercivity is achieved, meanwhile, the dosage of the heavy rare-earthelement is also remarkably reduced, the method is simple in process, is easy to implement and has a wide application prospect.

Description

technical field [0001] The invention belongs to the technical field of rare earth permanent magnet materials, and in particular relates to a method for improving the magnetic properties of sintered NdFeB magnets. Background technique [0002] NdFeB permanent magnets are known as the "Magnetic King" due to their excellent magnetic properties, and are widely used in aerospace, wind power generation, energy-saving home appliances, electronic appliances, and new energy vehicles. And with the continuous improvement of manufacturing technology and the improvement of people's awareness of environmental protection, it has attracted the attention of the market in the three major fields of energy conservation and environmental protection, new energy, and new energy vehicles. Application prospect. [0003] For magnets, coercive force is an important index to evaluate the magnetic properties of Nd-Fe-B permanent magnet materials. The heavy rare earth elements Dy and Tb, as important e...

AI Technical Summary

Problems solved by technology

The heavy rare earth elements Dy and Tb, as important elements for improving the coercive force, can effectively increase the anisotropy constant of the 2:14:1 phase magnetocrystal, but their price is high

The traditional surface deposition simply uses rare earth oxides or fluorides to increase the coercive force and reduce the manufacturing cost of magnets, but the melting point of heavy rare earth elements is high, the required diffusion activation energy is high, and the concentration drops from the surface to the inside. , so the diffusion depth is shallow and the performance improvement is limited

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