Method for preparing rare earth-iron-boron permanent magnet

Abstract

The invention discloses a method for preparing a rare earth-iron-boron permanent magnet. The method includes the steps of adding metal gallium (Ga) which is cooled to be in a lamellar shape in a coarse powder mixing stage in the hydrogen crushing process and after the hydrogen crushing of a cast piece, evenly mixing the metal Ga and the coase powder, and ensuring that the liquid phase Ga is evenly wrapped outside neodymium iron boron (NdFeB) powder on the condition that temperature of an airflow grinding chamber is higher than 30 DEG C. The method eliminates adverse effects on the magnetic performance of the magnet after the Ga enters NdFeB principal phase Nd2Fe14B, and avoids the loss due to the fact that the Ga is attached to a crucible in the smelting process. Therefore, compared with an NdFeB magnet which is prepared in the traditional process and has the same components with the rare earth-iron-boron permanent magnet, the rare earth-iron-boron permanent magnet is high in remanence Br, coercive force Hc and maximum magnetic energy product (BH) max. In addition, compared with an NdFeB magnet with high coercive force, the proportion of Ga which needs adding in the magnet prepared through the method is obviously decreased, and production and manufacture costs are reduced, and rare earth resources are saved.

Description

technical field [0001] The invention relates to a method for preparing a rare earth-iron-boron permanent magnet, belonging to the field of magnetic materials. Background technique [0002] As the third-generation permanent magnet material, NdFeB rare-earth permanent magnet material has become the most magnetic permanent magnet in contemporary times due to its high remanence, high coercive force and high energy product since its commercial development in the 1980s. It is widely used in many fields such as aviation, aerospace, microwave communication technology, motors, automobiles, and wind power generation. [0003] The main technical indicators of NdFeB rare earth permanent magnet materials include remanence Br, coercive force Hc (intrinsic coercive force Hcj and magnetic induction coercive force Hcb) and maximum magnetic energy product (BH) max. People have been adjusting the composition distribution Ratio, improving the production process and other means to improve these...

AI Technical Summary

Problems solved by technology

[0005] At present, for the smelting of NdFeB permanent magnet alloy ingots and slabs containing Ga in the formula, our common method is to directly add them to the crucible or cool them into a solid state and add them Crucible, but because the melting point of Ga is only 29.78°C, and the pure liquid has a significant tendency to supercool, it is liquid at room temperature, and it is easy to adsorb on the crucible during the melting process, resulting in the loss and waste of Ga

Moreover, when liquid phase Ga is added during smelting, part of Ga will enter the main phase matrix Nd2Fe14B. Since Ga is a non-magnetic atom, it will decrease after entering the main phase. Molecular magnetic moment, thereby reducing the remanence Br and maximum energy product (BH)max of the material