Dresden 2003 – wissenschaftliches Programm
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MA: Magnetismus
MA 3: Magnetische Materialien
MA 3.3: Vortrag
Montag, 24. März 2003, 10:45–11:00, HSZ/401
Local Texture and Magnetisation Processes in Nd-Fe-B Magnets with Maximized Energy Density — •Kirill Khlopkov1, Oliver Gutfleisch1, Boris Wall2, Werner Rodewald2, Dieter Eckert1, Dietrich Hinz1, Karl-Hartmut Müller1, and Ludwig Schulz1 — 1Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, PO Box 270116, D-01171 Dresden, Germany — 2Vacuumschmelze GmbH & Co. KG, P.O. Box 2253, D-63412 Hanau, Germany
Sintered Nd-Fe-B magnets, one of which showed a maximized, world record, energy density of (BH)max = 451 kJ/m3 (56.7 MGOe) at room temperature, have been produced by optimisation of alloy composition, minimization of impurities, improved alignment of the powder particles and a controlled sintering process. Microtexture analysis in both easy and hard directions of magnetization has been carried out using electron backscatter diffraction (EBSD), thereby acquiring large orientation maps, in a thermal field emission gun scanning electron microscope (FEGSEM). At the same areas domain patterns have been obtained with magneto-optical Kerr microscopy. Using these methods, a quantitative description of local texture could be correlated effectively with domain patterns of individual grains and with backscattered electron images. Distinction between individual grains in the Kerr images was difficult due to the excellent alignment of the magnet with the maximized energy density. Pole figures were used to evaluate the EBSD patterns.