The diffusion of T was studied by using time-lag techniques. The β-radiation which originated from T decay within a thin layer near to the external surface was used to monitor changes in T concentration with time in this layer. No passage of T atoms through the phase boundary was necessary, and no energy barriers which might retard their passage could therefore interfere. The results for Pd, at temperatures of between 16.5 and 50C, could be described by:

D (cm2/s) = 1.05 x 10-2 exp[-6.35(kcal/mol)/RT]

In the case of alloys which contained up to 70%Ag, the diffusion coefficients at 25C first decreased slowly with increasing Ag content up to 30% and then fell sharply to very low values at higher Ag contents.

G.Sicking, H.Buchold: Zeitschrift für Naturforschung A, 1971, 26[12], 1973-80