Magnetic Property Enhancement of Melt Spun YCo₅ Ribbons by Fe and C Doping

Magnetic properties and microstructure of melt spun YCo_5-x-yFe_xC_y (x = 0 -0.3 and y = 0 -0.3) ribbons are studied. Magnetic properties of YCo₅ ribbons (_iH_c = 144 kA/m and (BH) = 16.8 kJ/m³ are slightly improved to _iH_c = 160-224 kA/m and (BH) = 21.6 -27.2 kJ/m³ by Fe-doping, and are increased to _iH_c = 560-1128 kA/m and (BH) = 42.4 -51.2 kJ/m³ by C-doping, respectively. Most interestingly, the optimal (BH) of 72.8 kJ/m³ with high _iH_c of 1200 kA/m achieved for Fe and C-co-doped YCo_4.6Fe_0.3C_0.3 ribbons is the highest value in Y-Co alloy ribbons ever reported. The structural and thermo-magnetic analysis confirm that Fe and C enter the YCo₅ (5:1) crystal structure and lead to the increase of Curie temperature. Besides, C-doping uniformly refines grain size and, therefore, improves the squareness of demagnetization curve and (BH). The formation of YCo, Fe)₅C_x phase and the microstructure refinement are the main reasons to result in the enhancement of hard magnetic properties for the YCo_4.4Fe_0.3C_0.3 ribbons. The presented results suggest that the YCo₅ ribbons optimized by co-doping with Fe and C are promising candidate materials for making bonded magnets.