Preparation and magnetic properties of (Co0.6Fe0.3Ni0.1)(70-x) (B0.811Si0.189)(25+x) Nb-5 bulk glassy alloys

The preparation and soft magnetic properties of (Co0.6Fe0.3Ni0.1)(70-x) (B0.811Si0.189)(25+x) Nb-5 (x = 0-4) glassy alloys were investigated. This multicomponent system was found to exhibit a distinct glass transition and a wide supercooled liquid region of over 50 K before crystallization. As a result, the (Co0.6Fe0.3Ni0.1)(70-x) (B0.811Si0.189)(25+x) Nb-5 bulk glassy alloys with diameters up to 5 mm were produced by copper mold casting. In addition to high glass-forming ability, the Co-based glassy alloys also exhibit excellent soft-magnetic properties, i.e., saturation magnetization of 0.54-0.72 T, low coercive field of 0.7-1.4 A/m, and high effective permeability of 18,600-22,400 at 1 kHz under a field of 1 A/m. Furthermore, the giant magneto impedance effects of the (Co0.6Fe0.3Ni0.1)(68)(B0.811Si0.189)(27)Nb-5 glassy ribbon at different driving frequencies were also investigated. The results show that the largest impedance ratio is as high as 138 % at the frequency of 2.5 MHz under an ac current of 0.2 mA, together with high field sensitivity of 12.5 %/Oe