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MA: Fachverband Magnetismus
MA 50: Bulk Materials: Soft and Hard Permanent Magnets
MA 50.4: Vortrag
Donnerstag, 12. März 2026, 15:45–16:00, POT/0151
Nanoscale origins of coercivity in Cu-modified Sm(Co,Zr)6.7 alloys with globular 1:5/2:17 nanostructure — •Burcak Ekitli1, Alex Aubert1, Xinren Chen2, Konstantin Skokov1, Fernando Maccari1, Esmaeil Adabifiroozjaei3, Leopoldo Molina-Luna3, Baptiste Gault2, and Oliver Gutfleisch1 — 1Functional Materials, TU Darmstadt, 64287 Darmstadt, Germany — 2Max-Planck-Institut for Sustainable Materials, 40237 Düsseldorf, Germany — 3Advanced Electron Microscopy, TU Darmstadt, 64287 Darmstat, Germany
Sm-Co permanent magnets are commercially available in two main forms: the SmCo5 nucleation type and the more complex Sm(Co,Fe,Cu,Zr)7-7.5 (2:17-type), where coercivity is controlled by domain-wall pinning linked to a Cu concentration gradient within a cellular nanostructure. In this work, we investigate the Sm(CobalCuyZr0.023)6.7 composition to examine how Cu content affects microstructure and magnetic performance. HRSEM, TEM, and atom probe tomography reveal a previously unreported globular nanostructure, consisting of nanoscale 2:17 regions embedded in a continuous 1:5 matrix. Coercivity increases with Cu concentration and reaches up to 2 T when the Cu gradient is sufficiently strong. This underscores the superior efficiency of the cellular structure, which achieves comparable coercivity with less Cu. However the globular structure provides more stable coercivity at elevated temperatures (>700 K). These results connect microstructure and thermal stability, guiding new designs for high-temperature Sm-Co magnets.
Keywords: Sm-Co magnets; pinning; Atom Probe Tomography