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[ISSP Colloquiums]
Dy-free high coercivity Nd-Fe-B permanent magnet
Title : Dy-free high coercivity Nd-Fe-B permanent magnet
Date :
Time :
4:00 PM -  
Place : Lecture Room (A632), 6th Floor, ISSP   
Lecturer : Dr. Kazuhiro Hono
Affiliation : NIMS Fellow and Director of Magnetic Materials Unit, National Institute for Materials Science (NIMS)
Summary : Due to the recent concern about the stable supply of heavy rare earth elements, attaining high coercivity in Nd-Fe-B magnets without Dy has received intense research interest. In this talk, we will update our recent progresses toward the development of high coercivity Nd-Fe-B permanent magnets. To obtain complete understanding of the microstructure-coercivity relationships, we revisited the microstructures of Nd-Fe-B sintered and hot-deformed magnets using aberration-corrected STEM complemented by atom probe tomography (APT). We found that the structure and chemical composition of the grain boundary phase varies depending on the orientation of grain boundaries, i.e., the grain boundary phase parallel to the c-planes are mostly crystalline with a higher Nd concentration in contrast to that lying parallel to the c-axis that contains higher Fe content with an amorphous structure. Based on these new findings, we developed a method to enhance the coercivity of the anisotropic Nd-Fe-B magnets substantially without relying on Dy.
Contact : Yukio Hasgawa, Takeo Kato (ext.63325)