Modified Sm/sub 2/Fe/sub 17/N/sub y/ permanent magnets

Abstract

The substitution of elements M (M=Nb, V, Ti, Co) for Fe in Sm/sub 2/Fe/sub 17/N/sub y/ is investigated regarding its structural and magnetic properties. Zn-bonding as well as milling of Sm/sub 2/(Fe/sub 1-x/M/sub x/)/sub 17/N/sub y/ is studied as a means of improving the properties of their corresponding permanent magnets. Co-substitution improves the temperature dependence of remanence while V-containing magnets show a better shape of the demagnetization curve. Additional milling of nitrides enhances the coercivity, due to pinning of domain walls or to single domain particle behavior. Zn bonding of very fine Sm/sub 2/Fe/sub 17/N/sub y/ powders, followed by heat treatment, e.g., 425 degrees C for 100 min, leads to an overall decrease of the permanent-magnet properties caused by the formation of alpha -Fe.< >