HIGH COERCIVITIES IN MECHANICALLY ALLOYED SM FE X MAGNETS

New iron-rich and RE-containing phases were investigated with respect to their hard magnetic properties. Mechanical alloying was used as a non-equilibrium processing tool. For the binary Sm-Fe and the ternary Sm-Fe-TM systems (TM = vanadium, titanium, zirconium) it initially produces amorphous or two-phase (amorphous + alpha-Fe) material, which can be transformed into a microcrystalline intermetallic phase by heat treatment. In Sm-Fe-V with the ThMn12 crystal structure, coercivities up to 11.8 kOe were achieved; in Sm-Fe-Zr with the PuNi3 crystal structure, coercivities up to 14.8 kOe were achieved; and in A2-phase Sm-Fe-Ti, giant coercivities up to 64.5 kOe (at room temperature) were achieved. The soft magnetic binary Sm2Fe17 phase with basal-plane easy magnetization can be transformed into a hard magnetic material with uniaxial anisotropy by nitriding. These isotropic microcrystalline Sm2Fe17Nx samples show coercivities up to 30 kOe. At elevated temperature they are superior to similarly prepared Nd-Fe-B samples.