Structure and Magnetic Properties of Amorphous $Fe_{60}Co_{10}Mo_{2}W_{x}Y_8 B_{20-x}$ (x=0, 1) Alloys

This paper presents studies of the bulk amorphous alloys: $Fe_{60} Co_{10} Mo_2 Y_{8} B_{20}$ and $Fe_{60} Co_{10} Mo_2 W_1 Y_8 B_{19}$; Both compounds were obtained by means of the injection-casting method in which liquid alloy is forced under pressure into a copper mould. The structure of the samples was studied using X-ray diffraction and scanning electron microscopy. Based on the results of the X-ray diffraction studies, it was found that the samples were in the amorphous state. Scanning electron microscopy image analysis of fractured alloy samples indicated the presence of areas of varying degrees of relaxation: "smooth", "vein", and "flake" fractures. The manufactured ferromagnetic samples were characterized by so-called soft magnetic properties with a relatively high Curie temperature of more than 520 K. In the investigated samples, the saturation magnetization was found to have been decreased from 1.14 T to 1.13 T after the addition of W. Tungsten also contributed significantly to an increase in the value of the coercive field, from 27 A/m to 8685 A/m. Following the addition of just 1% of W to the alloy, a substantial change was observed in the form: of the static magnetic hysteresis loop: characterized by the so-called "wasp" shape. This result shows that an additional magnetically hard phase had appeared within the sample.