An electrochemical technique was used to study the effect of an elastic stress upon H permeation in a ferritic stainless steel. It was found that, in the stressed or unstressed condition, the H diffusivity always increased with the charging current, while the activation energy remained essentially constant. The imposition of elastic strains increased the activation energy for diffusion, but the variation in diffusivity was inconsistent. The average partial molar volume of H in the alloy, as deduced from the enhanced flux, was of the order of 2.3cm3/mol.

L.C.Hwang, T.P.Perng: Materials Chemistry and Physics, 1994, 36[3-4], 231-5

 

Table 77

Diffusion Coefficient, DCrCrFe, for the Fe-Cr-Al System

 

Al (at%)

Cr (at%)

Value (cm2/s)

11.34

40.16

-1.0 x 10-12

11.43

39.56

-1.0 x 10-12

11.88

36.72

-3.0 x 10-12

14.72

23.58

-9.0 x 10-12

14.95

22.75

-1.2 x 10-11

15.96

19.07

-1.4 x 10-11

16.17

18.32

-1.9 x 10-11

continued

 

Table 77 (continued)

Diffusion Coefficient, DCrCrFe, for the Fe-Cr-Al System

 

Al (at%)

Cr (at%)

Value (cm2/s)

17.56

13.50

-1.0 x 10-11

18.67

9.21

-1.1 x 10-11

18.75

8.90

-1.1 x 10-11

22.07

17.38

4.1 x 10-11

22.77

21.15

1.9 x 10-11

24.12

11.96

6.0 x 10-11

24.83

16.49

6.0 x 10-12

27.34

10.83

1.04 x 10-10

28.40

6.56

1.38 x 10-10

29.59

17.19

1.6 x 10-11

33.55

10.70

5.6 x 10-11

34.53

3.63

1.27 x 10-10

38.03

5.02

3.9 x 10-11

39.20

1.27

2.94 x 10-10

39.25

1.33

3.28 x 10-10

39.54

8.22

1.41 x 10-10

39.68

6.02

1.75 x 10-10

39.79

3.10

2.35 x 10-10

39.80

3.14

2.38 x 10-10

39.84

4.37

1.75 x 10-10

45.66

4.09

1.35 x 10-10

45.87

3.47

1.48 x 10-10

46.17

2.51

1.52 x 10-10

46.33

1.89

1.2 x 10-10