| Popis: |
The aggregation at 673 K of Pd atoms in the first-neighbour shell of a 119Sn atom dissolved in iron is followed by Mossbauer spectroscopy of 119Sn. The author deduces a jump frequency of Pd atoms of 3.5*10-4 s-1 leading to a diffusion constant of D=3.6*10-20 cm2 s-1, whereas the value obtained by extrapolating measurements in the literature made between 1373 K and 1523 K is 5.0*10-22. The difference is attributed to a temperature dependence of the activation energy. He has also observed a small change of isomer shift at the 119Sn nucleus as the concentration of Pd atoms in the first-neighbour shell increases, and makes some comments on the strength of the Pd-Sn bond at first- and second-neighbour distances in alpha and gamma iron. |
