Methods for tailoring the magnetic permeability of soft magnets, and soft magnets obtained therefrom

Abstract

Some variations provide a method of tailoring the surface of a soft magnet, comprising: depositing an austenite-phase-stabilizing donor material on one or more first surface regions of a ferromagnetic receiver material; not depositing the austenite-phase-stabilizing donor material on one or more second surface regions of the ferromagnetic receiver material; laser melting the austenite-phase-stabilizing donor material into the first surface regions; and solidifying the molten austenite-phase-stabilizing donor material within the first surface regions, thereby selectively alloying the ferromagnetic receiver material in the first surface regions. Laser ablation may be utilized instead of laser melting. The first surface regions have a significantly higher magnetic permeability, following the selective alloying of the donor material, compared to the second surface regions. Soft magnets with surface-tailored magnetic permeability are provided by this technology, which is demonstrated using several examples. One commercial application is selectively alloyed soft magnets for a rotor in an electric motor.