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Analytical Electron Microscope Study of High- and Low-Coercivity SmCo 2:17 Magnets

Published online by Cambridge University Press:  25 February 2011

Josef Fidler
Affiliation:
Institute of Applied and Technical Physics, University of Technology, Karlsplatz 13, A-1040 Vienna, Austria.
J. Bernardi
Affiliation:
Institute of Applied and Technical Physics, University of Technology, Karlsplatz 13, A-1040 Vienna, Austria.
P. Skalicky
Affiliation:
Institute of Applied and Technical Physics, University of Technology, Karlsplatz 13, A-1040 Vienna, Austria.
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Abstract

Sintered, precipitation hardened SmCo 2:17 magnets contain a multiphase microstructure. Our electron microscopic investigations reveal that the size of the rhombic, cellular precipitation structure and the formation of cell interior and cell boundary phases is determined by the nominal composition of the alloy and the postsintering heat treatment conditions and primarily control the intrinsic coercivity of the magnet. Selected area electron diffraction together with high resolution electron microscopy showed a high density of basal stacking faults (microtwinning) of the cell interior phase of low coercivity (iHc < 700 kA/m) magnets with a (c/a)*- ratio of the basic structural unit of > 0.843. High coercivity magnets (iHc>) 1000 kA/m), containing a high density of the platelet phase perpendicular to the c-axis, exhibit cell diameters up to 200 nm with a (c/a)*-ratio of the basic structural unit of the cell interior phase of < 0.843.

Type
Research Article
Copyright
Copyright © Materials Research Society 1987

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References

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