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arXiv · 2410.06540

Understanding High Coercivity in ThMn12-Type Sm-Zr-Fe-Co-Ti Permanent Magnet Powders through Nanoscale Analysis

Nikita Polin·Alexander M. Gabay·Chaoya Han·Christopher Chan·Se-Ho Kim·Chaoyang Ni·Oliver Gutfleisch·George C. Hadjipanayis·Baptiste Gault
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Abstract

ThMn12-type (Sm,Zr)1(Fe,Co,Ti)12 compounds show great potential for permanent magnets. Magnetically hard anisotropic powders prepared via reduction-diffusion exhibit a significant increase in coercivity from 0.45 T to 1.26 T as the processing temperature is raised from 990{\deg}C to 1220{\deg}C. Structural and microchemical analyses at high-resolution reveal that high-temperature processing annihilates grain boundaries (GBs) and reduces the density of twin boundaries (TBs), which are defects acting as weak links limiting the coercivity in the 1:12 system. Ostwald ripening is proposed as the mechanism behind the reduction of GB and TB densities at higher temperature, driven by the reduction in interfacial energy and enhancing atomic structural uniformity.

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Nikita Polin, Alexander M. Gabay, Chaoya Han, Christopher Chan, Se-Ho Kim, Chaoyang Ni, Oliver Gutfleisch, George C. Hadjipanayis, Baptiste Gault. 2024-10-09. Understanding High Coercivity in ThMn12-Type Sm-Zr-Fe-Co-Ti Permanent Magnet Powders through Nanoscale Analysis. https://arxiv.org/abs/2410.06540

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