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

Highly coercive Sm₁₄Co₈₆ 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 ~10^-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°C. Magnetic measurements showed room temperature coercivities of at least 1 T and Curie temperatures around 820°C. The behavior of the initial magnetization curve lies in between those observed for low H_c 2:17 precipitation hardened magnets and SmCo₅ or Nd₂Fe₁₄B 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