STUDY OF THE NITROGEN DIFFUSION MECHANISM IN R(2)FE(17)

Previously, nuclear magnetic resonance experiments and diffusion calcu lations have indicated that the distribution of nitrogen atoms in a Y2 Fe17Nx particle with intermediate N content is characterized by a nitr ided region and an unnitrided region. In order to directly detect this two-region configuration, x-ray diffraction experiments have been car ried out on systematically ground nitrogenated samples. Furthermore, x -ray diffraction and Y-89 nuclear magnetic resonance on vacuum-anneale d samples show that the two-region configuration is stable, and that t he nitrogen atoms do not diffuse further into the particle. Thermal co nductivity detection measurements indicate that only 5% of the inserte d N atoms can be released by vacuum annealing at the nitrogenation tem perature. (C) 1996 American Institute of Physics.