Simultaneous enhancement of the coercivity and remanence at high temperatures in a sintered Nd-Fe-B magnet after grain boundary diffusion with Dy60Co40 alloy.

Abstract The grain boundary diffusion process (GBDP) using Dy 60 Co 40 alloy was applied to a sintered Nd-Fe-B magnet. After GBDP the temperature stability of remanence was improved greatly with the remanence temperature coefficient improving from −0.140%/°C to −0.095%/°C while the Curie temperature increased marginally. Both the coercivity and remanence were increased simultaneously at high temperatures. Microstructure and composition analysis revealed that Dy and Co enriched shells were formed on Nd 2 Fe 14 B grain boundaries after GBDP. The Dy enriched shell increased the coercivity while the Co enriched shell decreased the temperature sensitivity of remanence and then increased the remanence at high temperatures. Graphical Abstract Unlabelled Image Highlights • Dy and Co enriched shells were formed on the Nd 2 Fe 14 B grain boundaries. • Coercivity and remanence were increased simultaneously at high temperatures. • Remanence stability was improved with little change of the Curie temperature. [ABSTRACT FROM AUTHOR]