A low eddy current r-t-b sintered magnet, a method for producing the same, and use thereof

By setting "grid" cross-shaped dividing grooves on the orientation surface of RTB sintered magnets and filling them with an insulating layer, the problems of high eddy current loss and reduced mechanical strength are solved, achieving low eddy current and high strength magnet performance, which is suitable for the motor field.

CN122177611APending Publication Date: 2026-06-09YANTAI ZHENGHAI MAGNETIC MATERIAL CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
YANTAI ZHENGHAI MAGNETIC MATERIAL CO LTD
Filing Date
2024-12-06
Publication Date
2026-06-09

AI Technical Summary

Technical Problem

Existing RTB sintered magnets have high eddy current losses under alternating magnetic fields, which leads to a decrease in motor power. Furthermore, existing methods for reducing eddy current losses may affect the magnet's remanence, mechanical strength, or increase costs.

Method used

A grid-like intersecting groove is set on the orientation surface of the magnet and filled with an insulating layer. The width, depth, intersection angle and number of the grooves are adjusted to increase the resistivity of the thin outer layer of the magnet, reduce eddy current loss, and maintain or improve mechanical strength.

Benefits of technology

It significantly reduces motor power loss caused by eddy current effect in magnets, reduces magnetic flux loss and magnet temperature rise, and improves the processing qualification rate and mechanical strength of magnets.

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Abstract

This invention discloses an R-T-B sintered magnet with reduced eddy current losses, its preparation method, and its application. The magnet has partition grooves on one or two orientation surfaces, where each orientation surface is perpendicular to the orientation direction of the magnet. The partition grooves extend through the magnet in a first extension direction but not in a second extension direction. The first extension direction of the partition grooves is perpendicular to the orientation direction of the magnet, and the second extension direction is parallel to the orientation direction of the magnet. By creating crisscrossing partition grooves on the magnet and filling them with an insulating layer, this invention increases the resistivity of a thin layer on the magnet's surface by a certain thickness, significantly reducing motor power loss due to eddy current effects. The insulating layer filling the grooves increases the resistivity of both the magnet surface and the grooves, effectively preventing conduction due to poor processing or current breakdown when the groove width is narrow. It also compensates for the reduction in mechanical strength caused by the grooving, ultimately resulting in a low-eddy-current, high-strength sintered magnet.
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