Magnetic properties of mechanically-alloyed Sm-Co nanophase hard magnets

Highly coercive Sm/sub 14/Co/sub 86/ powders were prepared by mechanical alloying with a view to enhance the high temperature magnetic properties by optimizing the annealing conditions. The powders were annealed in quartz tubes with a continuous vacuum of /spl sim/10/sup -6/ mbar at different temperatures. X-Ray diffraction studies confirmed the formation of a disordered 2:17 phase. DTA measurement on the as-milled amorphous powders revealed a single crystallization event at around 500/spl deg/C. Magnetic measurements showed room temperature coercivities of at least 1 T and Curie temperatures around 820/spl deg/C. The behavior of the initial magnetization curve lies in between those observed for low H/sub c/ 2:17 precipitation hardened magnets and SmCo/sub 5/ or Nd/sub 2/Fe/sub 14/B magnets. The magnitude of coercivity is found to be sensitive to annealing temperature. The detailed comparison of magnetic properties with annealing conditions will be presented.