Nanocrystalline complex phase neodymium iron boron permanent magnet texturing enhancement preparation method

Abstract

The invention provides a nanocrystalline complex phase neodymium iron boron permanent magnet texturing enhancement preparation method. According to the method, an NdFeB complex green body obtained bythermal pressing treatment is subjected to thermal deformation treatment at a low temperature and low rate to obtain a total-compact anisotropic NdFeB complex phase permanent magnet. Compared with theconventional process, the permanent magnet is subjected to deformation and orientation at a low temperature, so that grain growth can be suppressed effectively; and meanwhile, grain boundary phase uniform distribution at a low temperature can be facilitated by thermal deformation at low rate, so that hard magnetic phase texturing can be reinforced, crack formation and expansion in the deformationprocess can be suppressed, and the compaction and magnetic performance of the block body can be improved.

Description

technical field [0001] The invention relates to the technical field of magnetic materials, in particular to a preparation method for texture enhancement of nanocrystalline composite-phase NdFeB permanent magnets. Background technique [0002] In 1993, Skomski and Coey theoretically predicted that the anisotropic nanocomposite permanent magnet has a magnetic energy product of 120MGOe, which is much higher than the theoretical value of 64MGOe of the existing powder sintered NdFeB magnet, and the rare earth content is low, which makes it expected to become the next generation magnet. A generation of high-performance, low-cost permanent magnet materials. However, experimentally fabricating such ideal nanostructures is a great challenge. [0003] Hot pressing and thermal deformation technology is an effective means to prepare fully dense anisotropic single-phase NdFeB permanent magnets. It is generally considered that the rare earth-rich phase acts as a liquid phase at the grain...

AI Technical Summary

Problems solved by technology

However, the traditional heat distortion temperature is relatively high, usually above 700°C, which causes the excessive growth of flaky crystals, and the lateral size reaches several microns, far exceeding the exchange coupling size required by the soft and hard magnetic phase.

In addition, the traditional hot deformation process has short deformation time and uneven distribution of low melting point grain boundary phases, which will deteriorate the anisotropy of the composite magnet

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