It was pointed out that there had been relatively few determinations of the diffusivity of H in this material. The apparent H diffusion coefficient could however be easily measured by using the technique of sub-surface micro-hardness profiling after cathodic hydrogen charging. The technique was used here in order to determine the diffusivity of H in stoichiometric samples, and in material which was alloyed with Cr and Ti (table 41). The diffusivities were estimated at 298K, on the basis of micro-hardness profiles, after cathodic H charging in 0.05mol/1H2SO4 solution.

P.Banerjee, R.Balasubramaniam: Scripta Materialia, 1998, 39[9], 1215-9

Table 39

Bulk Diffusion of Fe in Fe3Al

 

Temperature (K)

D (m2/s)

1503

2.26 x 10-12

1365

5.24 x 10-13

1324

3.34 x 10-13

1276

1.96 x 10-13

1224

5.02 x 10-14

1106

7.64 x 10-15

1083

3.48 x 10-15

1079

3.25 x 10-15

1042

2.10 x 10-15

1021

1.54 x 10-15

1001

7.21 x 10-16

974

1.95 x 10-16

949

8.30 x 10-17

943

7.46 x 10-17

899

1.54 x 10-17

898

1.25 x 10-17

972

5.16 x 10-18

847

1.40 x 10-18