New Processing Routes for the Preparation of Sm2Fe17Mx (M : C and/or N) Materials.

Abstract Plasma carbonitriding, Zn metal coating via the chemical vapor deposition of Zn(C2H5)2 and high pressure sintering were studied as new processing routes to prepare Sm2Fe17Mx (M ≡ C and/or N) material with good magnetic properties. Two reactions of carbiding and nitriding for Sm2Fe17 simultaneously took place by glow discharges under differential pumping conditions of mixed gases in the ternary system CH4 + N2 + H2. The compound with chemical formula Sm2Fe17C>xNy (x + y ≈ 3) was produced by a plasma reaction at 723 K, and the coercivity value was increased to around 11 kOe after the ball milling treatment up to a particle size of about 3 μm. Furthermore, the surface coating of Sm2Fe17CxNy with the Zn metal derived by the decomposition of Zn(C2H5)2 showed good oxidation resistivity and much more enhancement of the coercive force. The high pressure sintering of Zn/Sm2Fe17CxNy provided the magnetic molding materials free from the α-Fe phase.