The effect of nitridation on the microstructure and lattice parameters of fine grained Sm2Fe17Nx

Fine-grained Sm2Fe17Nx compounds are easily prepared after nitridation for 4, 6 and 10 h. The structural, lattice parameters and saturation magnetization of the Sm2Fe17Nx system are presented. The pure Sm2Fe17 parent phase and nitrides all behave like the Th2Zn17-type structure. Little SmFe7 phase and αα-Fe phase are coexisting in all Sm2Fe17Nx compounds. No unnitrided phase is found. The deviation Δ2θ for the same nitrided sample almost decreases linearly with increasing 2θ2θ angles but that for the parent alloy is basically not changed. The lattice parameter aa, cc and saturation magnetization are initially increased with increasing nitriding time, and when nitrided for 6 h, Sm2Fe17Nx exhibits maximal lattice parameters: a=8.8277±0.0079a=8.8277±0.0079 Å, c=12.8324±0.0199c=12.8324±0.0199 Å, V=866.02 Å3, and ΔV/V=9.9% and gives the best saturation magnetization, Ms=152.14 emu/g. When the Sm2Fe17 parent phase is nitrided over 10 h, the lattice parameters and magnetization of Sm2Fe17Nx are all decreased. The maximal deviation angle of 2θ2θ at 2θ=70∘ for Sm2Fe17Nx overruns 2∘.