Soft magnetic properties of Fe-based metallic glasses (MGs) are dependent on their nanocrystallization behavior, particularly the precipitation of α-Fe embedded in the amorphous matrix. In this study, the effects of metalloid elements of C, B, Si, and P on thermal stability, nanocrystallization behavior, and soft magnetic properties of typical Fe-based amorphous alloys, i.e., the Fe-Cu-(CBSiP) glassy alloys, were investigated systematically. It is found that the addition of the metalloid elements can effectively retard the precipitation process of α-Fe during reheating of the Fe-based MGs due to the long-range diffusion of the metalloids; however, their individual effects on the compositional portioning and formation of other crystalline phases are varied. To achieve desirable soft magnetic properties, a species of metalloids and their concentrations have to be carefully controlled so that the formation of α-Fe does not interfere with that of other crystalline phases, especially those hard-magnetic phases.

Coatings made from metallic glasses are a promising solution for protecting surfaces of materials in various challenging environments. From an engineering perspective, glassy alloy coatings containing carbon are of greater importance compared to those without carbon but containing boron. Despite anticipating improved coating characteristics, there is no data on using high entropy glassy alloy as a coating material. In this paper, we investigated the influence of the simultaneous addition of boron and carbon elements on the glass-forming ability, thermal stability, crystallization behavior, yield strength, hardness, and corrosion resistance of high entropy (Fe, Co, Ni, Cr, Mo)-(B, C) glassy alloys. It was found that the content of boron and carbon had a significant effect on the improvements of glass-forming ability, mechanical properties, and corrosion resistance. The (Fe_0.25Co_0.25Ni_0.25Cr_0.125Mo_0.125)₇₅(B_0.7C_0.3)₂₅ bulk glassy alloy exhibits high glass-forming ability, high yield strength of 3500 MPa, Vickers hardness of 1240, and the highest corrosion resistance among the alloys. We also discussed the reason for their good engineering properties, and the possibility of using high entropy glassy alloys as coating materials, in addition to the guidelines for designing high-performance multicomponent glassy alloys.