Effects of Ce-doping on the Structure and Magnetic Properties for Nd-Fe-B Melt-spinning Ribbons

The melt-spinning ribbons with a nominal composition of (Nd_1-xCe_x)_13.5Fe_73.5Co_6.7Ga_0.5B_5.6(x=0.1~0.9) were prepared by melt-spinning technique. It was found that the wheel velocity had crucial effects on the magnetic properties and squareness of demagnetization curves. The optimum magnetic properties can be obtained, when the wheel velocity of 30 m/s was adopted. With increasing Ce content, the coercivity and remanence of the ribbons decrease. However, an abnormal increase of H_ci was observed when x=0.3, a high coercivity of 1 295 kA/m was achieved. Mixed valence states of Ce and phase separation phenomenon should contribute to the abnormal increase of coercivity. It is indicated that Ce has a great potential value for preparing rare earth permanent magnets with low cost and high coercivity.