Heavy rear earth adhering method of sintered NdFeB magnet

Abstract

The invention provides a heavy rear earth adhering method of a sintered NdFeB magnet, and belongs to the technical field of rear earth magnetic functional materials and preparation. The preparation technology particularly includes the steps that the sintered NdFeB magnet after surface pretreatment is placed in a heavy rear earth salt organic solution, under the action of currents, heavy rear earth elements are deposited on the surface of the sintered NdFeB magnet and form a dense heavy rear earth metal thin layer, and then the heavy rear earth elements in a heavy rear earth metal film diffuse into the magnet through grain boundaries in the process of high temperature diffusion treatment or high temperature diffusion and low temperature tempering two-stage thermal treatment. Coercivity of a sintered NdFeB rear earth permanent magnetic material prepared through the method is remarkably improved, remanence is not obviously reduced, heavy rear earth consumption is small, the process is simple and controllable, efficiency is high, and the method is suitable for industrial production.

Description

technical field [0001] The invention belongs to the technical field of rare earth magnetic functional materials, and the method is to sinter NdF e The surface of the B magnet is electroplated with a heavy rare earth metal film and treated with high temperature diffusion to increase the coercive force of the magnet. Background technique [0002] NdFeB has a very high magnetic energy product, and the advantages of high energy density make it widely used in modern industry and electronic technology. The disadvantage of NdFeB magnetic materials is that the Curie temperature is low and the temperature characteristics are poor. The fields of energy saving and environmental protection such as new energy put forward higher requirements for the permanent magnet materials used, which not only have high magnetic energy product, but also have high coercive force. [0003] The most common way to improve the coercive force is to directly add a certain amount of heavy dilute Dy and Tb to...

AI Technical Summary

Problems solved by technology

The disadvantage of NdFeB magnetic materials is that the Curie temperature point is low and the temperature characteristics are poor

Methods such as magnetron sputtering and vapor deposition are effective in improving the coercive force of magnets, but there are problems such as low production efficiency, high cost, difficulty in mass production, and large investment in equipment.

The coating thickness of the coating method is not easy to control and is uneven, easy to fall off, residue and cause waste, and the effect of improving the coercive force is not good

Deposited on electrodeposited surface (Dy) 2 (OH) 5 NO 3 ·nH 2 O and other compounds decompose into oxides with high melting point in the subsequent high temperature treatment stage, the diffusion coefficient is low, the diffusion and holding time is long, and the effect of improving the coercive force is not good.

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