A kind of high-coercivity high-performance nano-composite permanent magnet and its preparation method

Abstract

The invention provides a high-coercivity and high-performance nanocomposite permanent magnet and a preparation method thereof. A chemical formula of the high-coercivity and high-performance nanocomposite permanent magnet is RFe<100-a-b-c-d-e>YM<c>B<d>Si<e>. The preparation method comprises the steps of: obtaining an RFe<100-a-b-c-d-e>YM<c>B<d>Si<e> master alloy ingot with uniform ingredients; crushing the RFe<100-a-b-c-d-e>YM<c>B<d>Si<e> master alloy ingot into small pieces of alloy; obtaining a continuous RFe<100-a-b-c-d-e>YM<c>B<d>Si<e> alloy thin strip; putting the alloy thin strip into an ethanol solution containing Dy or Tb powder for high-voltage heat treatment; obtaining uniformly mixed nanocomposite magnetic powder; carrying out spark plasma sintering on the nanocomposite magnetic powder to prepare a full-dense nanocomposite permanent magnet; and carrying out magnetic field heat treatment on the nanocomposite permanent magnet to obtain the high-coercivity and high-performance nanocomposite permanent magnet. The obtained nanocomposite permanent magnet comprises nano-scale soft and hard magnetic phase grains, has high coercivity and maximum magnetic energy product and has high density; and meanwhile, the rare-earth content and the material cost can be further reduced. The preparation method is simple, easy to operate and suitable for large-scale mass production.

Description

technical field [0001] The invention relates to the technical field of permanent magnet materials, in particular to a high-coercivity high-performance nano-composite permanent magnet and a preparation method thereof. Background technique [0002] Nd-Fe-B based nanocomposite permanent magnet materials combine the advantages of high magnetocrystalline anisotropy of the hard magnetic phase and high saturation magnetization of the soft magnetic phase. Low-cost, high-performance rare-earth permanent magnet materials with application prospects. However, although the nanocomposite permanent magnet materials actually prepared at present have obvious remanence enhancement effect, the coercive force drops too much, which limits the improvement of magnetic energy product, making it difficult to greatly improve their comprehensive magnetic properties. [0003] The coercive force of nanocomposite permanent magnet materials mainly depends on the hard magnetic phase R 2 Fe 14 The conten...

AI Technical Summary

Problems solved by technology

The increase of the content of rare earth elements or the replacement of Dy and Tb can improve the coercive force of the magnet, but it will significantly reduce the amorphous formation ability of the alloy, making it difficult to obtain a good structure, and finally it is difficult to ensure that the magnet has high hard magnetic properties

[0004] On the other hand, most of the currently prepared nanocomposite permanent magnets are fast-quenched thin strips or powders. In order to realize practical application, it is necessary to prepare full-density block nanocomposite permanent magnets.

However, in the process of preparing bulk nanocomposite magnets, it is difficult to ensure that the full-density magnet has a large size and the crystal grains are controlled within the nanoscale range.