Line broadening of the Mössbauer resonance, due to diffusion in the pure metal, was studied at 1200C to almost 1536C. The study included the upper region of the face-centered cubic γ-phase (1200 to 1390C) and almost the entire region of the body-centered cubic δ-phase. Marked line broadening appeared at the γ-δ phase transition (1390C). For the pure element, a so-called microscopic diffusion coefficient could be deduced from the line broadening without making any assumptions about vacancy-impurity jump frequencies. Diffusion in the γ phase was described by:

D (cm2/s) = 1.5 x 100 exp[-3.1(eV)/kT]

In the case of the δ-phase, the scatter in Mössbauer data was large and no study of the above type was attempted.

A.Heiming, K.H.Steinmetz, G.Vogl, Y.Yoshida: Journal of Physics F, 1988, 18[7], 1491-503