Nondestructive Analysis of Coercivity Distributions in Permanent Magnets with Locally Enhanced Magnetic Properties

A nondestructive method is proposed for characterizing the local variations of coercivity in locally enhanced permanent magnets. Such magnets enable a reduction in heavy rare earth element usage by improving magnetic properties only in specific regions where required for the application in electrical machines. For quality control of such magnets, precise analysis of the coercivity distribution to support both material optimization and process reliability is required. The proposed nondestructive approach combines magnetic stray field mapping with closed‐circuit hysteresisgraph measurements at different stages of the demagnetization curve. This allows reconstruction of local coercivity variations. Validation through destructive sequential analysis confirms the method's reliability and accuracy.