Annealing Effect in Amorphous Fe-Co-B-Si-Nb According to Fe/Co Ratio

These days, electric motor qualities and energy-saving problems are significant to our society. The critical component of these problems is related to magnetic materials. In this respect, here, we investigated the (FexCo1-x)(72)B19.2Si4.8Nb4 (0 <= x <= 1, at 0.1 intervals) ribbon alloys' structural, thermal, and magnetic properties. Replacing Co with Fe turned out to increase saturation magnetization up to 127.7 emu/g and improve thermal stability. Additionally, we conducted heat treatment at 843, 893, and 943 K for 10 mins, and the annealing effect in the amorphous (FexCo1-x)(72)B19.2Si4.8Nb4 (0.4 <= x <= 0.9, at 0.1 intervals) ribbons on structural and magnetic properties are analyzed. The saturated magnetization (M-s) value has increased by about 20 to 30 emu/g by the heat treatment and tends to increase as the annealing temperature increases until the annealing temperature approaches 893 K. After annealing at 943 K for 10 mins, the highest saturation magnetization of 156.8 emu/g was achieved. In addition, all four samples show the same coercivity trend. The coercivity decreases when the initial heat treatment at 843 K is applied to the ribbons. However, after annealing at this high temperature, such as 893, 943 K, the Fe3B, and (Fe, Co)(23)B-6 phases are also generated and cancel out the good soft magnetic properties of alpha-(Fe, Co) phase.