An electrolytic double-cell system was used to monitor variations in the diffusivity of H through membranes, at temperatures of between 280 and 333K, for Ag contents ranging from 0 to 30at% (table 134). The experimentally determined diffusivities were analyzed in terms of the cell theory of interstitial solid solutions. At a given temperature, the H diffusivity exhibited an initial small increase with increasing Ag concentration. This was attributed to lattice dilation effects. As the Ag concentration increased beyond 0.05at%, the H diffusivity decreased due to the generation of trapping sites for H atoms.
T.Ishikawa, R.B.McLellan: Acta Metallurgica, 1986, 34[9], 1825-32
Table 134
Diffusion of H in Pd-Ag
Ag (at%) | Do (m2/s) | E (kJ/mol) |
0 | 3.86 x 10-7 | 22.99 |
1.5 | 3.33 x 10-7 | 22.37 |
3.8 | 3.49 x 10-7 | 21.91 |
5.3 | 3.38 x 10-7 | 21.95 |
11.3 | 3.96 x 10-7 | 23.00 |
15.1 | 7.64 x 10-7 | 24.93 |
22.7 | 1.54 x 10-6 | 27.88 |
30.2 | 8.55 x 10-7 | 29.27 |