An electrolytic technique, involving a double-cell system, was used to measure the H diffusivity in solutions (up to 12at%B) at 273 to 350K (tables 144 and 145). The presence of B atoms caused the H diffusivity to decrease by a factor of about 2 at the highest B contents which were studied. The Arrhenius plots were all linear, and the corresponding apparent activation energies for H diffusion decreased by about 4kJ/mol over the above range of B contents. The results were explained in terms of a model that was based upon rate theory and a statistical mechanical treatment of the thermodynamic properties of this system.

The Diffusion of Hydrogen in Palladium-Boron Solid Solutions. M.Yoshihara, R.B.McLellan: Acta Metallurgica et Materialia, 1990, 38[6], 1007-12

 

Table 145

Diffusion Parameters for H in Pd-B Alloys

 

B (at%)

Do (m2/s)

E (kJ/mol)

0

2.908 x 10-7

22.27

1.5

2.568 x 10-7

22.05

4

1.907 x 10-7

21.56

6

1.112 x 10-7

20.66

8

6.48 x 10-8

19.98

10

3.40 x 10-8

18.54

12

2.63 x 10-8

18.16