Method for preparing heavy rare earth hydride nano-particle doped sintered NdFeB permanent magnet

Abstract

The invention discloses a method for preparing a heavy rare earth hydride nano-particle doped sintered NdFeB permanent magnet, which belongs to the technical field of magnetic materials. The prior preparation method improves the coercive force and the temperature stability of magnets by adding heavy rare earth elements, namely terbium or dysprosium into master alloy, but the method can cause the residual magnetism of the magnets, the reduction of magnetic energy product and the increase of manufacturing cost. The method adopts heavy rare earth terbium hydride and dysprosium hydride nano-powder doping technology to prepare the sintered NdFeB permanent magnet with high coercive force and excellent magnetic property. The method comprises the following steps: preparing NdFeB powder by a rapidly solidified flake process and a hydrogen decrepitation process; preparing the terbium hydride or the dysprosium hydride nano-powder by physical vapor deposition technology; mixing the two powders, and performing magnetic field orientation and press forming; and performing dehydrogenation treatment, sintering and heat treatment on a green compact at different temperatures, and obtaining the sintered magnet. The coercive force of the magnet prepared by the method is higher than that of the prior sintered magnet with the same ingredients; and compared with the sintered magnet with the equivalent coercive force, the proportion of the terbium and dysprosium needed by the magnet prepared by the method is remarkably reduced.

Description

technical field [0001] The invention relates to a method for preparing NdFeB permanent magnet materials with high coercive force by doping heavy rare earth hydride nanoparticles, which belongs to the technical field of magnetic materials. Background technique [0002] Sintered NdFeB is the most magnetic permanent magnet material so far. It is widely used in many fields such as electronics, electromechanical, instrumentation and medical treatment. It is the fastest growing permanent magnet material with the best market prospect in the world today. However, an obvious disadvantage of sintered NdFeB is that it has poor temperature stability and is difficult to apply in a working environment above 100°C, so its application in high-temperature motors and other fields is greatly limited. Especially in recent years, the rapid development of energy-saving gasoline-electric hybrid vehicles has put forward very challenging and attractive requirements for sintered NdFeB in terms of qua...

AI Technical Summary

Problems solved by technology

However, since the nano-powder particles of heavy rare earth elements terbium and dysprosium are easily oxidized, the final magnetic properties of the magnet may be deteriorated, which puts forward higher requirements for the magnet preparation process and equipment, and requires the transformation of traditional equipment. Strictly control the oxygen content in the production process to prevent magnet oxidation, thus greatly increasing the production cost