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) = 1.22 x 10-4 exp[-287(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.
K.Righter, A.J.Campbell, M.Humayun: Geochimica et Cosmochimica Acta, 2005, 69[12], 3145-58
Table 133
Thermomigration Data for C in Fe-32.5wt%Ni
C (wt%) | Temperature (K) | Atmosphere | Specimen | E (kJ/mol) |
0.14 | 1025-1400 | vacuum | single-phase | -12.30 |
0.22 | 1330-1490 | Ar | single-phase | -11.70 |
0.22 | 1325-1500 | Ar | single-phase | -11.90 |
0.37 | 1210-1440 | Ar | two-phase | -11.90 |
0.50 | 1150-1400 | vacuum | two-phase | -13.27 |
0.62 | 1200-1450 | Ar | two-phase | -11.97 |
0.62 | 1210-1440 | vacuum | two-phase | -12.60 |
0.78 | 1125-1430 | vacuum | two-phase | -12.30 |
0.78 | 1250-1425 | vacuum | two-phase | -12.30 |