The diffusivity of H in solid solutions was measured by using an electrochemical technique at temperatures of between 285 and 322K. The H concentration was of the order of 0.0001at%. In each case, the diffusivity for a given Y concentration obeyed an Arrhenius relationship and, at each temperature, the presence of Y caused a decrease in H mobility as compared with Pd without Y (figure 36). The results were evaluated in terms of a simple statistical model in which it was assumed that both H and Y atoms occupied octahedral interstitial sites in the face-centered cubic lattice.

T.Ishikawa, R.B.McLellan: Acta Metallurgica, 1987, 35[3], 781-6

Figure 36

Diffusivity of H in Pd-Y

(a: 0%Y, b: 2.6%Y, c: 4.98%Y, d: 8.1%Y, e: 10.1%Y)