Abstract:In this paper, the Finemet-type amorphous-nanocrystalline ribbons with original Fe73Si15Nb3B8Cu1 and optimized composition Fe73Si15.5Nb1.1V2.4B7Cu1 substituted partial Nb for V as well as appropriately adjusted Si and B were prepared by single-roller rapid quenching and isothermal annealing technology. The microstructure and magnetic properties of the ribbons were studied by X ray diffraction, transmission electron microscopy and magnetic performance testers. The results show that two types of as-spun ribbons are mainly composed of amorphous phase, meaning that two kinds of alloys have good amorphous forming ability; According to Luborsky principle, the fracture srain λt is 5.05×10-2, which indicates that the toughness is poor; The nanocrystalline grain size of two kinds of annealed ribbons are 14.8 nm and 13.2 nm, respectively; Compared with the original composition ribbons,Curie temperature Tc and first crystallization temperature Tx1 of V-containing ribbons are slightly decreased; While the saturation magnetization of the V-containing ribbon is slightly lower than that of the V-free ribbon, the coercivity is smaller, initial permeability and static loss of the ring-shaped V-containing magnetic core samples reach 1.269×105 and 1.748 J/m3 respectively, and their AC iron loss advantage is more and more obvious than that of V-free ones with increasing frequency.