Microstructure, magnetic domain and dynamic loss of surface-textured Fe-based nanocrystalline alloy

Abstract

1 DO 3 dendritic-crystallites bear <001>-oriented fiber texture at free surface. 2 TFA slightly weakens the fiber texture and induces magnetic rotation process. 3 The surface-textured alloy after TFA exhibits low dynamic loss. 4 A correlation mechanism between microstructure, domain and loss was obtained. Heterogeneous coarse surface crystallites induced in the industrial Fe-rich nanocrystalline alloy is an obstacle for high-frequency and high-power commercial applications. Herein, the phase, crystal orientation, nanostructure and magnetic domain evolution of the surface-crystallized Fe-rich alloy were systematically investigated. Microstructure and inverse pole figures analysis confirms that the DO 3 ordered dendritic-crystallites bear <001>-oriented fiber texture before and after annealing at the free surface, while ultrafine nanocrystals are randomly oriented in the interior and wheel surface after annealing. As compared to zero magnetic-field-annealing, the transverse magnetic-field-annealing induces weakly oriented fiber texture and relatively uniform dendritic-crystallites at the surface, and uniform anisotropy in the interior and surface, which promotes smooth wall motion at the surface and magnetization rotation in the interior. This synergetic effect reduces the excess loss and leads reduction in dynamic loss at 1.0 T and 10 kHz by 36%.