Improvement of Magnetic Property for Melt Spun CeCo5 Ribbons Due to Fe and C-Doping

Improvement of hard magnetic property for melt spun CeCo ₅ ribbons by doping proper Fe and C is demonstrated. Low magnetic properties, remanence (B _r ) of 4.2 kG, coercivity ( i H _c ) of 1.6 kOe and energy product ((BH) _max ) of 1.8 MGOe, are found for binary CeCo ₅ ribbons due to extremely large size of grains, even prepared at high wheel speed of 40 m/s. i H _c is largely enhanced to 12.8 kOe by doping C and 15.0 kOe by co-doping Fe and C, and therefore, (BH) _max is increased to 3.5 MGOe and 5.1 MGOe, respectively. The coercivity achieved in this work is superior to those reported ever before, and (BH) _max is also larger than the theoretical value of 4.7 MGOe for isotropic CeCo ₅ alloy. XRD and TMA results reveal Fe and C enter into 1:5 phase to modify lattice constant and increase T _C , and the increased c/a ratio of 1:5 phase may improve H _a and contribute to enhance the coercivity. Microstructure analysis indicates the grain size is effectively refined by doping C and co-doping Fe and C. Fine microstructure for C-containing ribbons contributes to attain high coercivity of 12.8-15.0 kOe. Besides, Fe-doping may increase the magnetization of 1:5 phase, and therefore improve the remanence and (BH) _max . The results of this work suggest that magnetic properties of CeCo ₅ ribbons could be improved by modification of 1:5 crystal and microstructure refinement due to proper Fe and C-codoping.