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 16

Diffusivity of H in Fe

 

Temperature (K)

Annealing Time at 80C (h)

D (m2/s)

7

11

1.569 x 10-11

7

144

1.800 x 10-10

20

11

4.940 x 10-11

20

144

2.558 x 10-10

25

11

6.333 x 10-11

25

144

4.378 x 10-10

35

11

1.160 x 10-10

35

144

6.000 x 10-10

42

11

1.750 x 10-10

42

144

1.035 x 10-9