Influence of P and C co-alloying on soft magnetic properties and crystallization behavior of FeSiBPCCu nanocrystalline alloys

In this study, multicomponent synergistic effects were adopted to enhance the glass-forming ability (GFA), processing window (PW), thermal stability, and soft magnetic properties (SMPs) of FeCuSiB nanocrystalline alloys (NAs) with high Fe and Cu contents via P and C co-alloying. The co-addition of P and C is beneficial for enhancing the GFA, expanding the PW, and increasing the crystallization resistance of the compound phases in present FeCuSiBPC alloys. Consequently, the Fe 81.5 Cu 1.7 Si 3.8 B 9 P 3 C 1 alloy exhibited a large optimum T A window of up to 100 °C and a large t A window of 40 min for nanocrystallization. Crystallization kinetic analysis showed that the co-addition of P and C led to a high-frequency factor ( v ) in the precipitation of α-Fe crystals, which was related to the high nanocrystal density ( N d ) of α-Fe. This result may be attributed to the nucleation of α-Fe by Cu and CuP clusters. Additionally, the co-addition of P and C increased the growth active energy ( E p ) of the α-Fe crystals because of their larger atomic diffusion resistance. The high N d and E p values led to the formation of fine nanostructures and excellent SMPs in FeCuSiBPC alloys. Therefore, the Fe 81.5 Cu 1.7 Si 3.8 B 9 P 3 C 1 NA obtained by annealing at 420 °C for 30 min exhibited excellent SMPs with a B s of up to 1.78 T, a low H c of 7.5 A/m, and a high μ e of 9863 (@1kHz). This study provides technical and theoretical guidance for optimizing the composition and processability of NAs with high Fe and Cu contents, paving the way for mass production of high-performance soft magnetic NAs.