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 th e annealing conditions. The powders were annealed in quartz tubes with a co ntinuous vacuum of similar to 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 crystalli zation event at around 500 degreesC. Magnetic measurements showed room temp erature coercivities of at least 1 T and Curie temperatures around 820 degr eesC. The behavior of the initial magnetization curve lies in between those observed for low H-c 2:17 precipitation hardened magnets and SmCo5 or Nd2F e14B magnets. The magnitude of coercivity is found to be sensitive to annea ling temperature. The detailed comparison of magnetic properties with annea ling conditions will be presented.