The diffusivity of 51Cr in the stainless steels was studied at between 680 and 870C by using standard sectioning techniques (table 108). It was found that the penetration distances were very limited, and decreased with decreasing O potential. Also, Cr diffusion along the grain boundaries was enhanced in samples which had been pre-loaded with Cs. The bulk and grain-boundary diffusion data for Cr in DIN1.4970 could be described by:
D (cm2/s) = 2.9 x 10-3 exp[-56.3(kcal/mol)/RT]
D (cm2/s) = 1.3 x 10-4 exp[-62.4(kcal/mol)/RT]
respectively, whereas the corresponding expressions for material pre-diffused with Cs were:
D (cm2/s) = 2.7 x 10-2 exp[-61.2(kcal/mol)/RT]
D (cm2/s) = 2.1 x 10-7 exp[-48.0(kcal/mol)/RT]
H.Matzke, S.Pickering: Journal of Nuclear Science and Technology, 1983, 20[3], 237-45
Table 110
Diffusion of 14C in Fe-Cr-Ni-Mo Alloys
Alloy (wt%) | Temperature (C) | D (cm2/s) |
Fe-15Cr-15Ni-2Mo | 1000 | 8.06 x 10-8 |
Fe-20Cr-15Ni-2Mo | 1000 | 7.40 x 10-8 |
Fe-15Cr-20Ni-2Mo | 1000 | 9.71 x 10-8 |
Fe-20Cr-20Ni-2Mo | 1000 | 7.90 x 10-8 |
Fe-15Cr-15Ni-2Mo | 900 | 1.78 x 10-7 |
Fe-20Cr-15Ni-2Mo | 900 | 2.44 x 10-8 |
Fe-15Cr-20Ni-2Mo | 900 | 3.19 x 10-8 |
Fe-20Cr-20Ni-2Mo | 900 | 3.45 x 10-8 |
Fe-15Cr-15Ni-2Mo | 800 | 3.59 x 10-9 |
Fe-20Cr-15Ni-2Mo | 800 | 4.68 x 10-9 |
Fe-15Cr-20Ni-2Mo | 800 | 8.15 x 10-9 |
Fe-20Cr-20Ni-2Mo | 800 | 5.73 x 10-9 |
Fe-15Cr-15Ni-2Mo | 750 | 2.49 x 10-9 |
Fe-20Cr-15Ni-2Mo | 750 | 2.80 x 10-9 |
Fe-15Cr-20Ni-2Mo | 750 | 4.47 x 10-9 |
Fe-20Cr-20Ni-2Mo | 750 | 1.90 x 10-9 |
Fe-15Cr-15Ni-2Mo | 650 | 3.25 x 10-10 |
Fe-20Cr-15Ni-2Mo | 650 | 5.79 x 10-10 |
Fe-15Cr-20Ni-2Mo | 650 | 8.11 x 10-10 |
Fe-20Cr-20Ni-2Mo | 650 | 1.43 x 10-10 |