The permeation of D in various alloys (table 51) was studied by using the gas-phase breakthrough technique at temperatures of between 100 and 500C, and pressures of between 10Pa and 100kPa. It was found that the most permeable alloys were the AISI 430 and AISI 431 stainless steels. The occurrence of D-trapping within the alloys appeared to affect the bulk diffusivity values (table 52).

Permeation Characteristics of Some Iron and Nickel Based Alloys. D.J.Mitchell, E.M.Edge: Journal of Applied Physics, 1985, 57[12], 5226-35

 

Table 54

Diffusivity of H in 1Cr-½%Mo Steel

 

Temperature (F)

PH2 (psig)

D (cm2/s)

700

600

9.8 x 10-5

700

1000

6.6 x 10-5

850

600

8.70 x 10-4

850

1000

1.19 x 10-4

1000

250

1.44 x 10-4

1000

600

1.55 x 10-4

1000

1000

1.69 x 10-4

1150

600

1.84 x 10-4

 

 

Table 55

Diffusivity of H in 2¼Cr-1%Mo Steel

 

Temperature (F)

PH2 (psig)

D (cm2/s)

700

1000

1.01 x 10-4

850

250

0.88 x 10-4

850

500

1.50 x 10-4

850

1000

1.17 x 10-4

1000

125

1.22 x 10-4

1000

500

1.34 x 10-4

1000

1000

1.43 x 10-4