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) = 7.45 x 10-10 exp[-168(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, there were large difference in DNi and DIr, with the latter being 5 times lower.

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

Table 140

Bulk and Grain-Boundary Diffusion of 63Ni in Fe-Ni Bicrystals

Table 141

Diffusion Coefficients for Ni Diffusion in Fe-Ni Martensites