FeSiBCCr bulk metallic glasses with excellent soft magnetic properties prepared using spark plasma sintering technology

Abstract

Fe-based amorphous alloys have received much attention in the fields of electronics and electrical due to their excellent soft magnetic properties at high frequency. However, the controllable preparation of large-sized Fe-based bulk metallic glasses (BMGs) still faces numerous challenges. In this study, FeSiBCCr amorphous powders prepared by gas-water combined atomization were used as raw materials, and FeSiBCCr BMGs were prepared through spark plasma sintering (SPS) at different pressures. The microstructure, phase and magnetic properties of the compacts were systematically characterized using SEM, XRD, TEM, DSC, and VSM. The results showed that when the sintering pressure was 50 MPa, the slow densification process dominated by particle rearrangement at the initial densification process made the internal contact resistance of the compacts larger. This led to macroscopic inhomogeneous physical fields and severe local overheating during the later stages of sintering, causing the precipitation of α-(Fe, Si) and Fe₃B phases. Although the material exhibited a relatively high saturation magnetization (B_s) of 1.08 ± 0.01 T, the low density and amorphous fraction resulted in a high coercivity (H_c) of 1060.8 ± 37.8 A·m^-1. When the sintering pressure was increased to 250 MPa, the degree of particle densification significantly improved, and the temperature inhomogeneity was markedly suppressed due to reduced internal resistance. Thus, the prepared FeSiBCCr BMGs exhibited an extremely high density of 6.66 ± 0.06 g·cm^-3 and excellent soft magnetic properties with B_s of 1.23 ± 0.01 T and H_c of 18.8 ± 1.8 A·m^-1. This indicated that the FeSiBCCr BMGs prepared in this study exhibited broad application prospects in efficient electromagnetic conversion and advanced electronic devices.