Effects of Tuning Fe/B Contents on Crystallization Behaviors and Magnetic Properties in Novel Si-Free Fe-B-C-Cu-Nb Alloys

Due to the absence of inhibitor elements (Nb, V, Mo, etc.) in the newly developed inexpensive Fe-B-C-Cu alloys, the Fe-(B,C) compounds co-precipitate easily during alpha-Fe crystallization, making the uniform alpha-Fe/amorphous dual phase structure difficult to adjust in self-controllable and the relatively low saturation magnetization (M-s). Linked to Fe-B/C phase diagrams and Inoue criteria, based on the department of compounds precipitation away from alpha-Fe crystallization, the novel approach to optimizing the Fe-B-C-Cu amorphous alloys is successful. For the Fe83+xB10.25-xC6Cu0.5Nb0.25 alloys, by introducing minor Nb, limiting total metalloid elements ad tuning Fe/B contents with Fe addition, the self-controlled alpha-Fe crystallization behaviors become easier as the enlarged & UDelta;T-x value reached to above 110 K. After annealed by 420celcius x 30 min, obtaining the uniform alpha-Fe/amorphous dual phase structure and the crystallized M-s maximum value of 196 emu/g in Fe84.5B8.75C6Cu0.5Nb0.25 alloys. Therefore, the novel Si-free Fe-B-C-Cu-Nb alloys with high M-s exhibit significant utilization potentiality towards the miniaturization of magnetoelectric devices.