A study was made of the diffusion of H by using a Sieverts cell at a H partial pressure of 1atm. It was found that the diffusivity, at temperatures of between 1222 and 1528C, depended upon the phase:

 

γ:     D (cm2/s) = 2.9 x 10-3 exp[-7.68(kcal/g-atom)/RT]

δ:     D (cm2/s) = 2.88 x 10-1 exp[-22.35(kcal/g-atom)/RT]

H.Schenck, K.W.Lange: Archiv für Eisenhüttenwesen, 1966, 37[10], 809-12

 

Table 33

Diffusivity of H in Fe at 20C as a Function of Rolling Deformation

 

Deformation (%)

D (cm2/s)

DensityTrap(/cm3)

DensityDislocation(/cm2)

8.8

5.1 x 10-5

5.7 x 1018

5.6 x 109

20

5.5 x 10-5

4.5 x 1018

8.6 x 109

22

5.1 x 10-5

5.7 x 1018

9.1 x 109

28

4.3 x 10-5

8.5 x 1018

1.07 x 1010

30

4.4 x 10-5

8.1 x 1018

1.13 x 1010

41

4.4 x 10-5

8.1 x 1018

1.42 x 1010

51

4.1 x 10-5

9.4 x 1018

1.68 x 1010

60

4 x 10-5

9.9 x 1018

1.92 x 1010