Micro-Alloyed P Optimizes AFA, Thermal Stability, Crystallization Behaviors, and Magnetic Properties of the Novel Fe-Rich FeBCuHf Alloys

Low amorphous forming ability (AFA) and weak thermal stability become the main obstacles in adjusting α-Fe crystallization behaviors and fabricating uniform α-Fe grains with nanosize and high density–inserted amorphous matrix, which effectively improve magnetic properties in Fe-rich amorphous/nanocrystalline alloys, as Fe content is over 85 at.%. In this study, the role of micro-alloyed P has been investigated in novel Fe-rich Fe86B13-xPxCu0.4Hf0.6 alloys; its relationship of appropriate micro-alloyed P and its positive role on controlling crystallization and optimizing magnetic properties have been researched systemically. Minor P less than x = 1.5 is beneficial for optimizing AFA and thermal stability and obtaining the ΔTx value over 140 K; different P also guide the discrepant crystallization behaviors and result in easily precipitating concomitant Hf3P2 phase during α-Fe crystallization. Ultimately, it has been founded that the Fe86B12.5P0.5Cu0.4Hf0.6 ribbons with entire amorphous structure become easier to be controlled for fabricating the uniform α-Fe/amorphous dual-phase structure; its Bs (saturation magnetization tensity) value reaches to the maximum of about 1.91 T as crystallized near Tp1. Meanwhile, the related Hc (coercivity) value can be decreased effectively from 17.1 to 3.1 A/m after an auxiliary annealing process was operated applying the magnetic field of 0.1 T. These novel-type Fe86B13-xPxCu0.4Hf0.6 alloys with uniform α-Fe/amorphous dual-phase structure show an excellent soft magnetic property and exhibit competitive advantages with the high Bs-oriented Si-steels.