Large-grained (4mm) specimens of 4N5-purity material were charged with high-purity H by heating (600C, 48h). The diffusion coefficients were deduced from desorption measurements. The diffusivity at temperatures of between 450 and 625C (table 3) could be described by:

D (m2/s) = 1.01 x 10-5 exp[-47.7(kJ/mol)/RT]

Diffusion of Hydrogen in Pure Large Grain Aluminum. R.A.Outlaw, D.T.Peterson, F.A.Schmidt: Scripta Metallurgica, 1982, 16[3], 287-92

 

Table 3

Diffusivity of H in Al

 

Temperature (C)

D (m2/s)

625

1.52 x 10-8

600

1.26 x 10-8

575

1.03 x 10-8

550

8.38 x 10-9

525

6.72 x 10-9

500

5.30 x 10-9

475

4.12 x 10-9

450

3.14 x 10-9