MECHANICALLY ALLOYED AND GAS-PHASE CARBONATED HIGHLY COERCIVE SM2FE17CX

Microcrystalline Sm2Fe17Cx powders with high carbon content (x almost-equal-to 2) were prepared by mechanical alloying and a subsequent solid-gas reaction in acetylene atmosphere to introduce carbon atoms interstitially into the 2:17 lattice. Such processing results in magnetically isotropic material with a room-temperature coercivity of up to 18.5 kA/cm (23.2 kOe) and a maximum energy product of 59 kJ/m3 (7.4 MGOe). It is unstable at high temperatures and decomposes into the equilibrium phases SmC and alpha-Fe upon heating to 700-degrees-C in vacuum.