US 12,092,707 B2
Method for identifying irreversible demagnetization of grain boundary diffusion NdFeB magnet
Jinghui Di, Zhejiang (CN); Huiqiang Liu, Zhejiang (CN); Xiongfei Wu, Zhejiang (CN); Shengli Jia, Zhejiang (CN); Hui Meng, Zhejiang (CN); and Qifeng Wei, Zhejiang (CN)
Assigned to Hangzhou Magmax Technology Co., Ltd., Zhejiang (CN); and Hangzhou Foresee Group Holding Co., Ltd., Zhejiang (CN)
Filed by Hangzhou Magmax Technology Co., Ltd., Zhejiang (CN); and Hangzhou Foresee Group Holding Co., Ltd., Zhejiang (CN)
Filed on Jan. 25, 2024, as Appl. No. 18/422,131.
Application 18/422,131 is a continuation of application No. 18/220,392, filed on Jul. 11, 2023, granted, now 11,921,174.
Claims priority of application No. 202211458259.1 (CN), filed on Nov. 17, 2022.
Prior Publication US 2024/0168110 A1, May 23, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. G01R 33/12 (2006.01); H01F 1/057 (2006.01)
CPC G01R 33/1215 (2013.01) [H01F 1/0571 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A method for identifying an irreversible demagnetization of a grain boundary diffusion NdFeB magnet, comprising applying a reverse magnetic field to a saturatedly magnetized grain boundary diffusion NdFEB magnet, and, when a number of magnetic poles on a non-diffusion face of the grain boundary diffusion NdFeB magnet is increased and divided into layers, determining that there is an irreversible demagnetization in the grain boundary diffusion NdFeB magnet, wherein a shape of the grain boundary diffusion NdFeB magnet is columnar.