Unveiling the correlation between oxidation and magnetic properties in dual-phase FeNiBCu nanocrystalline alloys

Abstract

Achieving the industrial production of high-performance nanocrystalline alloys is an active research topic in which oxidation is an inescapable and top-priority issue that needs to be addressed. In this study, we conducted a comprehensive investigation into the oxidation and crystallization behaviors of dual-phase FeNiBCu nanocrystalline alloys, as well as the mechanisms underlying the relationship between oxidation and magnetic properties. The chemical valence states and microstructures analysis, indicative of galvanic cell structures, demonstrated that the concentration and activity of Fe in nanocrystals were higher than those in the matrix, thus providing effective nucleation sites for Fe-oxides. Unique delamination morphology and inner structure distinctly regulated the magnetization-magnetic softness (Bs-Hc) tradeoff. Consequently, the alloy underwent simultaneous crystallization and oxidation, affording a high Bs of 1.70 T and a low Hc of 3.5 A/m. These results enhance our understanding of the effect of oxidation on magnetic properties and provide a theoretical reference for the industrial heat treatment of high-performance nanocrystalline alloys.

Keywords

• FeNiBCu nanocrystalline alloy
• Oxidation
• Microstructure
• Magnetic properties