Proton relaxation times were used to estimate H diffusivities in ß-phase Ni5-yAlyLaHx, for y-values of between 0 and 1.2 (table 111). It was found that the substitution of Al significantly increased the observed activation energy, with a corresponding 2-fold increase in the diffusion coefficient at 300K (table 112).

R.C.Bowman: Solid State Communications, 1979, 32[7], 501-6

 

 

 

Table 111

Diffusivity of H in Ni5-yAlyLaHx at 300K

 

y

x

D (cm2/s)

0

6.2

1.5 x 10-8

0.4

5.4

8.1 x 10-9

0.5

5.24

7.8 x 10-9

0.7

4.64

1.5 x 10-9

1.0

4.33

2.3 x 10-10

1.2

4.04

1.1 x 10-10

 

 

Table 112

Arrhenius Parameters for H Diffusion in Ni5-yAlyLaHx

 

y

x

Temperature (K)

D (cm2/s)

E (eV)

0

6.2

230-311

1.6 x 10-3

0.30

0.4

5.4

230-360

6.1 x 10-4

0.30

0.5

5.24

240-332

3.9 x 10-4

0.28

0.7

4.64

260-370

7.9 x 10-4

0.34

1.0

4.33

301-446

2.6 x 10-3

0.42

1.2

4.04

300-507

2.8 x 10-3

0.44