DIFFUSION DISTRIBUTION OF CO-57 ATOMS IN NANOCRYSTALLINE CO79NB14B7 ALLOY

Distribution of Co-57 atoms in a nanocrystalline Co79Nb14B7 alloy afte r annealing at different temperatures was studied by means of Co-57 em ission Mossbauer spectroscopy. After annealing below the recrystalliza tion temperature, the diffusing Co-57 atoms were found in all phases e xpected to be present in the nanocrystalline alloy. They do not prefer the intergranular phase. Paths of diffusing atoms are probably close to interfaces between crystallites (grain boundaries) and/or intergran ular phase. With increasing annealing temperature, when the nanocrysta lline state transforms into a coarse polycrystal, the Co-57 atoms occu py regular sites in the bulk Co and Co3B phases.