Preparation method of high-performance sintered Nd-Fe-B magnet with multi-layer grain boundary structure and prepared product

Abstract

The invention discloses a preparation method of a high-performance sintered Nd-Fe-B magnet with a multi-layer grain boundary structure and a prepared product, and aims at solving the problems of a single grain boundary strengthening effect, serious waste of heavy rare-earth resources and the like due to the fact that fine control on the grain boundary structure cannot be achieved in an existing method. According to the multi-layer grain boundary structure of the prepared magnet, a heavy rare-earth thin shell distributed on a grain boundary of a main phase has a relatively high magnetocrystalline anisotropy field, so that magnetic domain inversion of a weak area of the grain boundary in a reverse magnetic field can be inhibited, thereby improving the coercivity and the high-temperature stability of the magnet. Meanwhile, the heavy rare-earth thin shell is only distributed on the grain boundary of the main phase and is rarely diffused to the main phase and a center area of the grain boundary, so that the dosage of heavy rare earth can be greatly reduced and the production cost of the magnet is reduced. In addition, an electrode potential difference between a grain boundary phase and the Nd2Fe14B main phase can be reduced through formation of a high-potential grain boundary center layer in the magnet, the electrochemical corrosion drive force is reduced and the corrosion resistance of the magnet is obviously improved.

Description

technical field [0001] The invention relates to the field of materials, especially the field of permanent magnet materials, and specifically relates to a method for preparing a high-performance sintered Nd-Fe-B magnet with a grain boundary multilayer structure and a product prepared therefrom. Background technique [0002] Nd-Fe-B magnets have excellent magnetic properties and have become the most widely used rare earth functional materials. After more than 30 years of development, sintered Nd-Fe-B magnets have become an indispensable material in social and economic construction and people's daily life, and are widely used in aerospace, generators, electronic computers, automobiles, communications, medical equipment, etc. field. The remanence and maximum energy product of Nd-Fe-B magnets have reached 97% and 93% of the theoretical value respectively, but the coercive force of the magnet is less than half of the theoretical value, and the corrosion resistance of the magnet i...

AI Technical Summary

Problems solved by technology

[0008] At present, the grain boundary phase is often used as a whole to study the changes of its melting point, magnetocrystalline anisotropy field, and corrosion potential. It is impossible to achieve fine control of the grain boundary structure, resulting in a single grain boundary strengthening effect and a serious waste of heavy rare earth resources. question

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