Effect of the substitution of C for Si on microstructure, magnetic properties and bending ductility in high Fe content FeSiBCuPC alloy ribbons

The microstructure, magnetic properties and bending ductility of the Fe85Si1.5-xB9Cu0.5P4Cx (x = 0, 0.1 0.2, 0.3, 0.4, 0.5) alloy ribbons with high Fe content were investigated. The partial substitution of C for Si increases the amorphous forming ability and enlarges the maximum thickness of glassy from 19 μm to 25 μm of the alloys. It is clearly seen that the addition of C increases the first crystallization temperature (Tx1), while the reduction of Si slightly decreases the second crystallization temperature (Tx2). The amorphous alloys exhibit the low Curie temperature (Tc), and large Tx1 - Tc allows the alloys to obtain better soft magnetic properties. In amorphous state, with the increase of C, the saturation magnetization (Ms) and the coercivity (Hc) of the amorphous alloys descend slightly, which decrease from 168.0 emu/g to 166.8 emu/g and 10.0 A/m to 9.3 A/m, respectively. Through the optimum annealing treatments, the Fe85Si1.4B9Cu0.5P4C0.1 nanocrystalline alloy exhibits highest Ms of 205 emu/g (Bs ≈ 1.93 T) and lowest Hc of 5.8 A/m. Both of the amorphous alloys exhibit good bending ductility before and after annealing.