High performance permanent magnets made by mechanical alloying and hot pressing

The nonequilibrium process of mechanical alloying was used to prepare nanocrystalline powder. The crystallization of the -type structure in mechanically alloyed Sm - Fe(Ga) - C material begins at about C. The single phase structure can be obtained after homogenization for one hour at temperatures between C and C. The coercivity increases to a maximum value of about 1.5 T after annealing at a temperature of C. The nearly square shape of the demagnetization curve suggests a very homogeneous microstructure of the highly coercive powder. By hot pressing, a fully dense magnet was successfully obtained with a density of 7.6 g and a coercivity of 1.5 T. No texture could be observed after a 75% hot deformation at C.