Title :
A new model for the coercivity mechanism of Sm2(Co,Fe,Cu,Zr)17 magnets
Author :
Katter, M. ; Weber, J. ; Assmus, W. ; Schrey, P. ; Rodewald, W.
Author_Institution :
Vacuumschmelze GmbH, Hanau, Germany
fDate :
9/1/1996 12:00:00 AM
Abstract :
A two-dimensional model for the coercivity mechanism of Sm2 (Co,Fe,Cu,Zr)17 magnets is proposed. The high coercivities of fully heat-treated magnets (>20 kA/cm) result from pinning sites which are formed by the intersections of the Zr-rich platelet phase (Z-phase) and the Cu-rich SmCo5 (1/5) boundary phase. The pinning strength of this site is assumed to be a result of the large difference between the domain wall energies of the 1/5 phase and the Z-phase. The domain wall energies of almost single phase samples of the Z-phase have been determined by magnetic measurements and by quantitative analysis of domain patterns. The small domain wall energy of the Z-phase of 4-11 mJ/m2 supports the presented model
Keywords :
cobalt alloys; coercive force; copper alloys; heat treatment; iron alloys; magnetic domain walls; permanent magnets; samarium alloys; zirconium alloys; 2D model; Cu-rich SmCo5 boundary phase; Sm2(CoFeCuZr)17; Zr-rich platelet phase; coercivity mechanism; domain patterns; domain wall energy; heat-treated magnets; pinning sites; Aging; Coercive force; Demagnetization; Isothermal processes; Magnetic domain walls; Magnetic field measurement; Magnets; Powders; Samarium; Temperature;
Journal_Title :
Magnetics, IEEE Transactions on
