The diffusion coefficients were measured from 1150 to 1400C and at 1bar and 10kbar (figures 24 and 25). The 1bar data could be described by:

D (m2/s) = 7.19 x 10-7 exp[-231(kJ/mol)/RT]

The couples were prepared from high-purity Fe and from IIA meteorite Fe, and held for 3.5 to 123h. The profiles were measured by using laser ablation inductively coupled plasma mass spectrometry or electron microprobe. Many elemental data were measured in the same experimental runs, so that inter-element comparisons were improved in comparison to other data sets in which the data for the various elements came from separate experiments. Thus, some published coefficients for Co were up to a factor of 3 higher for Ni, than for Co, but the present results showed no difference (both being 2.2 x 10-15m2/s at 1150C).

K.Righter, A.J.Campbell, M.Humayun: Geochimica et Cosmochimica Acta, 2005, 69[12], 3145-58