High-coercivity Nd-Fe-B rare-earth permanent magnet and fabrication process thereof

Abstract

The invention provides a fabrication process of a high-coercivity Nd-Fe-B rare-earth permanent magnet. A technology of preparing a rare-earth thin film from an ion liquid is applied to fabricate a high-performance magnet, a Rb thin film is grown on a surface of the magnet by the technology, a Rb element plated on the surface of the magnet is diffused to the interior of the magnet by primary high-temperature thermal processing, a rare-earth rich phase is uniformly distributed around the magnet by secondary low-temperature tempering, and meanwhile, unbalanced tissue and internal stress brought by high-temperature processing are eliminated. The intrinsic coercivity of the magnet after being processed by the process can be obviously improved, so that the high-coercivity Nd-Fe-B rare-earth permanent magnet is fabricated. By the process, the production efficiency can be improved, the heavy rare-earth dosage during the fabrication process is reduced, and meanwhile, high coercivity is obtainedunder the condition that residual magnetism and magnetic energy product of the magnet are not reduced.

Description

technical field [0001] The invention belongs to the technical field of magnetic functional materials, and relates to a permanent magnet and a preparation process thereof, more specifically, to a high-coercivity Nd-Fe-B rare earth permanent magnet, a preparation process thereof and a device containing the same. Background technique [0002] Nd-Fe-B permanent magnet is the most magnetic permanent magnet material so far. It is widely used in electromechanical, electronic and medical fields. It is the fastest growing permanent magnet material with the best market prospect in the world. However, Nd-Fe-B permanent magnets have an obvious disadvantage, that is, poor temperature stability, and it is difficult to apply in a working environment above 150°C, so they are greatly limited in high-temperature applications. In particular, the rapid development of energy-saving gasoline-electric hybrid vehicles in recent years puts forward higher requirements for Nd-Fe-B permanent magnets in...

AI Technical Summary

Problems solved by technology

[0004] However, the addition of Tb and Dy brings two serious problems: (1) Most of Tb and Dy enter the grain, and form Tb with Fe and B elements 2 Fe 14 B or Dy 2 Fe 14 B compound, the magnetization of this type of compound is much lower than the main phase Nd of NdFeB permanent magnet 2 Fe 14 B, thereby greatly reducing the remanence and energy product of the material; (2) Heavy rare earth elements such as Tb and Dy are expensive and are scarce resources, and their reserves are only 1 / 10 to 1 / 100 of Nd, and the ore veins are limited to several production is very limited

However, the above methods have the following disadvantages: (1) the equipment is expensive; (2) the material utilization rate is low; (3) there are strict requirements on the thickness of the magnet, and it is difficult to prepare a magnet with a thickness greater than 10 mm, which hinders its further application; (4) ) The temperature is too high (1000°C and above) when preparing the Dy film, which affects the microstructure of the magnet; (5) The uniformity of the film is difficult to control and it is difficult to realize industrialization

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