A kind of preparation method of hot-pressed nitrided magnet

Abstract

The invention discloses a preparation method of a hot-pressed nitrogenized magnet. The method includes: subjecting neodymium-iron-boron powder and nitrogenized powder undergoing ball milling to ball-mill mixing under an oxygen isolated condition, wherein the nitrogenized powder accounts for 0.5%-3.5% of the total powder; using a die for vacuum hot pressing for 450-800 DEG C under a nitrogen condition, heating for 5-15 minutes, keeping the temperature for 1-5min by 100-300MP, and cooling to the room temperature in 20-30min to obtain isotropic magnets; under the nitrogen condition, putting the isotropic magnets into dies with different inner diameters to realize thermal deformation at 500-850 DEG C, heating for 5-15min, and keeping the temperature for 0.5-10min under the pressure of 30-60MP to realize uniform deformation of the magnet, wherein the deformation time is 30-90s, and the pre-deformation time is 10-30s; cooling to the room temperature in 20-30min, and stripping to obtain the isotropic magnets different in deformation quantity. The hot-pressed nitrogenized magnet has a better magnetic property and a higher use temperature and is applicable to the field of permanent magnetic motors and sensors.

Description

technical field [0001] The invention relates to a rare earth permanent magnetic alloy, especially a hot-pressed magnet doped with nitride, and relates to a preparation method thereof. Background technique [0002] Since its birth, NdFeB rare earth permanent magnet materials have been widely used in aerospace and navigation, information electronics, energy transportation, medical and health, audio and video, Information storage and other fields. The preparation technology of high-performance Nd-Fe-B permanent magnet materials mainly includes powder metallurgy process and thermal deformation process. The maximum magnetic energy product of the magnet prepared by powder metallurgy technology has reached 4.76×10 5 T (A / m), the maximum magnetic energy product of the magnet prepared by hot pressing and thermal deformation process has reached 4.352 ×10 5 T·(A / m). [0003] Hot-press & Hot-deformation was first proposed by R. W. Lee et al. in 1985. The process is mainly divided ...

AI Technical Summary

Problems solved by technology

[0005] During the use of NdFeB magnets, if the use temperature of the magnet is low, the magnetic performance of the magnet will decrease when the use environment temperature is high and reaches the use temperature of the magnet, which will affect the actual use effect.