NITROGENATION OF THE MAGNETIC COMPOUND R(FE,M)(12)

The diffusion mechanism of nitrogen atoms in ThMn12-type crystal struc ture compounds was investigated by using x-ray diffraction, Mossbauer spectroscopy measurements, thermopiezic analysis, and differential the rmal analysis. The studies indicate that the distribution of nitrogen atoms in a R(Fe,M)(12) particles with intermediate N content is charac terized by a nitrided region and an unnitrided region. The results con firmed that this two-phase region is stable, and the nitrogen atoms do not diffuse further into the particle. Based on the characteristics o f the nitrogenation, a trapping diffusion model is applied to the R(Fe ,M)(12) system. On the basis of this study high performance magnetic p owders of NdFe10.5Mo1.5Nx were successfully prepared. (C) 1998 America n Institute of Physics.