Thermal and magnetic properties of melt-spun Co-Fe-B-Si-(Cr/Ta) amorphous alloys

The ferromagnetic amorphous alloys Co-Fe-B-Si-Cr and Co-Fe-B-Si-Ta were systemically investigated. [(Co 1− x Fe x ) 0.75 B 0.2 Si 0.05 ] 96 Cr 4 ( x = 0, 0.1, 0.4, 0.7, 1.0) and [(Co 1− x Fe x ) 0.75 B 0.2 Si 0.05 ] 96 Ta 4 ( x = 0, 0.1, 0.3, 0.5, 1.0) ribbons were prepared by using the melt-spinning technique. Amorphous structures were confirmed by the presence of a broad and halo peak in X-ray diffraction (XRD). The thermal characteristics, such as the glass transition temperature ( T g ), the crystallization temperature ( T x ) and the supercooled liquid region (Δ T x = T x − T g ), were measured by means of a differential scanning calorimeter (DSC). For the Co-Fe-B-Si-Cr alloys, the values of Δ T x were in the range of 51.6–61.4 K, and for Co-Fe-B-Si-Ta alloys, they were in the range of 39.3–55.5 K. The magnetic properties were examined by means of a vibrating sample magnetometer (VSM) at a maximum field strength of 3000 Oe. These glassy ribbons exhibited soft magnetic properties. The saturation magnetization ( M s ) and the coercive force ( H c ) were in the ranges of 307.85–854.52 emu·cm 3 and 0.64–0.89 Oe, respectively.