Evading the refining-induced trade-off between performance enhancement and alloy composition deviation in Fe-based amorphous alloys

Understanding the slag-metal reactions in Fe-based amorphous alloys is of paramount importance to evade the refining-induced trade-off between performance enhancement and alloy composition deviation. In this study, the B 2 O 3 and B 2 O 3 –CaO slags refining-induced alloy composition deviation was theoretically and experimentally verified in Fe 83 Si 2 B 12 P 3 (at.%) amorphous alloy, and a quaternary SiO 2 –B 2 O 3 –CaO–Al 2 O 3 slag suitable for FeSiBP amorphous alloy was designed after the careful calculation of slag-metal equilibrium, slag viscosity and melting point. After refining with simple B 2 O 3 and B 2 O 3 –CaO slags, the enrichment of B element and depletion of Si element in the FeSiBP amorphous alloy was confirmed due to the oxidation of constituent Si element and the reduction of B 2 O 3 in the slag. The refining-induced alloy composition deviation can be effectively alleviated by using our designed slags, and the 20%SiO 2 –55%B 2 O 3 –10%CaO–15%Al 2 O 3 (wt.%) slag is effective in removing the impurities and enhancing the glass-forming ability (GFA). In terms of the removal of impurities, the high activity of B 2 O 3 in slag is crucial for the oxidation and removal of Mn, Al, Ti impurities. These results are quite vital for the design of refining slags suitable for Fe-based amorphous alloys and pave the way for the large-scale production of high-performance soft magnetic materials.