Centrifugal Atomization and Characterization of Fe-Si-B Amorphous Alloys

The centrifugal atomization process is a rapid solidification method that achieves high cooling rates. Although this technique is typically used to produce common metal powders, it has not been extensively explored for amorphous powder production, despite its clear advantage of generating nearly perfect spherical particles, which is beneficial for subsequent powder consolidation. In this paper, a characterization of three iron-based alloys from the Fe-Si-B system, specifically Fe_91.72Si_5.32B_2.96 (wt%), Fe_87.37Si_6.94B_2.49Cr_2.46C_0.75 (wt%), and Fe_89.41Si_2.02B_1.13P_5.89C_1.55 (wt%), produced by centrifugal atomization, is presented. The amorphous fractions of the powders were quantified using DSC, with further characterization performed via optical microscopy, SEM, and XRD. The amorphous fractions increased with the addition of Cr, C, and P, reaching up to 90% in the Fe_89.41Si_2.02B_1.13P_5.89C_1.55 alloy for particles of <100 μm. The onset cooling rates were estimated to be approximately 10⁶ K/s for Fe_91.7Si_5.32B₃, 10⁵ K/s for Fe_87.36Si_6.9B_2.48Cr_2.45C_0.75, and 10⁴ K/s for Fe_89.41Si_2.02B_1.13P_5.89C_1.55, respectively.