Membranes of Marz-grade material were prepared by rolling to a thickness of 0.109mm and annealing (1273K, 20h) in vacuum. The diffusivity was then measured by using an electrolytic double-cell method. It was found that the results (table 32) could be described by:

D (m2/s) = 9.271 x 10-8 exp[-23.28(kJ/mol)/RT]

It was concluded that the simple classical model for H diffusion was sufficient to explain diffusion in this material at temperatures of between 280 and 1690K.

P.Sutter, R.B.McLellan: Scripta Metallurgica, 1985, 19[7], 879-80

Table 33

Diffusivity of H in Co