Enhanced coercivity and grain boundary chemistry in diffusion-processed Ce13Fe79B8 ribbons

Abstract Ce 13 Fe 79 B 8 ribbons were prepared by melt-spinning and diffusion-processing with minor amounts of Nd 70 Cu 30 and Nd 80 Ag 20 alloys. Low coercivities of ∼0.2 T were obtained in the as-melt-spun ribbons and annealed ribbons although Ce-rich grain boundaries were observed. By diffusion process, the coercivity was increased to be over 0.7 T, due to the formation of magnetically hardened (Nd,Ce) 2 Fe 14 B shell. The chemistry of Ce-rich grain boundary phase was studied and face-center-cubic crystallographic structure was determined by nano-beam diffraction. The Henkel plots confirmed the enhanced magnetocrystalline anisotropy due to the formation of core/shell microstructure.