The diffusion mechanism of N atoms in ThMn12-type compounds was investigated by using X-ray diffraction, Mössbauer spectroscopy and differential thermal analysis. The results indicated that the distribution of N atoms in R(Fe,M)12 particles with moderate N contents was characterized by the presence of a nitrided region and a non-nitrided region. The results confirmed that this 2-phase region was stable, and that the N atoms did not diffuse further into the particle. On the basis of the nitrogenation characteristics, a trapping diffusion model was developed.

Nitrogenation of the Magnetic Compound R(Fe,M)12 J.Yang, W.Mao, Y.Yang, S.Ge, Z.Zhao, F.Li: Journal of Applied Physics, 1998, 83[4], 1983-7