The permeation rate of H through two α-Fe specimens was measured by using a low-pressure steady-state technique under conditions such that diffusion was the rate-controlling process for permeation. The permeation rate in these samples could be described by:

P (mol/s cm torr½) = 5.55 x 10-9 exp[-8095/RT]

for H pressures of 21 to 766torr and temperatures of 342 to 619K. These permeation data were combined with known solubility data to give an expression for H diffusivity in α-Fe:

D (cm2/s) = 1.01 x 10-3 exp[-1595/RT]

Permeation of Hydrogen through Alpha Iron. R.F.Miller, J.B.Hudson, G.S.Ansell: Metallurgical Transactions A, 1975, 6[1], 117-22

 

Table 41

Parameters for H Permeation in Fe-Ni

 

Ni (at%)

Phase

Po (mol/m s MPa½)

E (kJ/mol)

0

bcc

5.35 x 10-5

33.6

3

fcc

1.34 x 10-2

92.6

3

bcc

4.33 x 10-5

53.7

5

fcc

8.90 x 10-3

97.9

5

bcc

1.07 x 10-4

42.6

6

fcc

1.86 x 10-3

67.6

6

bcc

6.47 x 10-5

36.8

9

fcc

1.33 x 10-3

67.7

9

bcc

3.29 x 10-5

31.6

12

fcc

9.52 x 10-4

48.1

12

bcc

2.75 x 10-5

31.9

20

fcc

2.91 x 10-3

71.0

20

bcc

1.67 x 10-5

31.4

40

fcc

5.04 x 10-4

56.3

50

fcc

7.52 x 10-4

52.5

100

fcc

7.08 x 10-4

54.8