Nanocrystalline rapid quenching rare-earth permanent magnet material, minishing method of grain size of rare-earth permanent magnet material and bonded permanent magnet

Abstract

The invention relates to an nanocrystalline rapid quenching rare-earth permanent magnet material, a minishing method of the grain size of the rare-earth permanent magnet material and a bonded permanent magnet. According to the method, a proper amount of Y, Ho or Gd and the like is added in the alloy smelting process, the feature that the enthalpy generated by (Y, Ho, Gd)-Fe is lower than that generated by Nd-Fe14 is made used of, the grain size of the nanocrystalline rapid quenching rare-earth permanent magnet material is effectively minished, the grain size distribution is more uniform, and the exchange coupling enhancement effect brought by grain size minishing achieves the improvement of residual magnetization; at the same time, since the magnetocrystalline anisotropy field of (Y, Ho, Gd)2Fe14B is larger than 0, coercive force losses caused by the exchange coupling effect can be compensated to a certain extent. Moreover, the uniform grain size distribution and the optimized grain boundary state also contribute to the increase of coercivity.

Description

technical field [0001] The invention relates to a nano-crystal quick-quenching rare-earth permanent magnet material, a method for refining its grain size, and a bonded magnet. Background technique [0002] During the application of ferromagnets, due to the existence of its magnetic poles, the demagnetization field is inevitable, and in most cases, the demagnetization field is unevenly distributed. For each grain, if the shape is irregular, there are sharp edges or protruding parts, a large demagnetization field may appear in these parts, making the local magnetic moment distribution uneven, and even making the magnetic moment reverse. turn, resulting in reverse magnetization domains. It is very difficult to numerically calculate the demagnetization field and the resulting inhomogeneous magnetization or the formation of reverse magnetization domains due to the sharp edges or protrusions of NdFeB crystal grains with arbitrary shapes. In 1989, Gronefeld and Kronmuller studied...

AI Technical Summary

Problems solved by technology

As stated in the Chinese patent application CN1210344A, the NdFeB nanocrystal refinement technology is mainly through the addition of trace high melting point alloy elements such as Ti, Zr, Si, Nb, etc. during the alloy smelting process to precipitate non-magnetic grain boundary phases during the crystallization process Inhibit grain growth, and then achieve the purpose of grain refinement. However, most of the alloying elements added are non-magnetic elements, which not only lead to the consequences of magnetic dilution, but also cannot compensate for the loss of coercive force caused by exchange coupling.

[0005] The existing technology is to add trace alloy elements such as Ti, Zr, Nb, Cu, etc. to the alloy to precipitate non-magnetic grain boundary phases during the crystallization process to inhibit grain growth, thereby achieving the purpose of controlling the grain size inside the magnet , however, the added alloying elements do not contribute to the intrinsic magnetic properties such as anisotropy of the material, and cannot compensate for the loss of coercive force due to the enhanced exchange coupling due to grain refinement, resulting in "magnetic dilution"

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