Abstract
The purposes of this research are to develop new Fe-based bulk nanocrystallines,“thicker” nanocrystalline ribbons and as-quenched nanocrystalline ribbons. Themotivation and design of Fe-based alloys is based on the composition of theFINEMET and Fe-Y-B alloy that were developed in our lab before, and dopeddifferent elements to investigate the behavior of crystallization and soft magneticproperties.In bulk nanocrystallines(BNCs), Fe70Y4Nb2Cu2B22 alloy has the GFA up to 2mm indiameter, and precipitates bcc-Fe and Fe23B6 phases during nanocrystallization. Weobtained the magnetic properties of Ms=1.4T and Hc=142A/m. In this research, wefound that Y and Ta can retard the precipitation of Fe23B6 phase and the doping of Agcan enhance the soft magnetic properties. The composition, Fe71Y5Ta1Ag1B22, afternanocrystallization, only one phase, bcc-Fe, was precipitated on the amorphousmatrix which, and its GFA can up to 3mm in diameter and also exhibits excellent softmagnetic properties.In “thicker” nanocrystalline ribbons, the Fe71Y1Ta5Ag1B22 alloy shows good GFAto form ribbon with thickness of 150μm and exhibits good soft magnetic propertiesafter nanocrystallization process. We also discovered that Fe23B6 phase is also a softmagnetic phase, therefore it provided us a new choice for new nanocrystallinematerials. In as-quenched nanocrystalline ribbons, we discovered that doping Agmakes it possible for as-quenched nanocrystalline ribbon in Fe77.4-xSi15.5NbxB7Ag0.1alloy system. After stress release annealing, the permeability of materials enhanceobviously, and can up to 27764(in 1KHz). With the combination of the easiermanufacture and excellent magnetic properties, these alloys are more attractive andpotential for industrial applications.