A nanocrystalline composite rare earth permanent magnet material and its surface treatment method

Abstract

The invention relates to a nanocrystalline composite rare earth permanent magnet material and a surface treatment method thereof. The surface treatment method of the nanocrystalline composite rare earth permanent magnet material comprises the steps of (1) preparation of the nanocrystalline composite rare earth permanent magnet material, (2) surface cleaning, (3) shot blasting, (4) activating treatment, (5) surface coating, (6) secondary coating, (7) passivating treatment, and (8) aging treatment. According to the nanocrystalline composite rare earth permanent magnet material, the coercive force and the maximum magnetic energy product of the nanocrystalline composite rare earth permanent magnet material are improved obviously, a more reasonable microstructure can be obtained with the heating processing technique, and the performance is improved due to the reasonable microstructure. According to the surface treatment method of the nanocrystalline composite rare earth permanent magnet material, due to the fact that the surface of a base body is coated with a uniform and compact clad layer free of holes step by step in a layering mode from inside to outside, the base body is blocked, then the passivation and aging are carried out to enable the clad layer and the base body to be combined more tightly, the clad layer can be more compact, and then the base body can be better protected by the clad layer.

Description

technical field [0001] The invention relates to a nanocrystalline composite rare earth permanent magnet material and a surface treatment method thereof. Background technique [0002] Rare earth metal-based permanent magnets, such as R-Fe-B-based permanent magnets represented by Nd-Fe-B-based permanent magnets, or R-Fe-N-based permanent magnets represented by Sm-Fe-N-based permanent magnets Magnets and the like utilize inexpensive materials that are abundant in resources and have excellent magnetic properties, and especially for the above-mentioned two types of permanent magnets, R-Fe-B-based permanent magnets are used in various fields today. However, since the rare earth metal-based permanent magnets contain highly reactive rare earth metals, namely: R, they are prone to oxidation and corrosion in the atmospheric environment, and when the permanent magnets are used without any surface treatment, in the presence of a small amount of acid Or alkaline substances or water cond...

AI Technical Summary

Problems solved by technology

However, since rare-earth metal-based permanent magnets contain highly reactive rare-earth metals, namely: R, they are prone to oxidation and corrosion in the atmospheric environment, and when the permanent magnets are used without any surface treatment, they are prone to oxidation and corrosion in the presence of a small amount of acid Or alkaline substances or water conditions corrosion tends to start from the surface, resulting in rust, which causes a drop and fluctuation in magnetic properties

Also, when such rusty magnets are embedded in magnetic circuits and similar devices, the rust can spread around and contaminate surrounding components