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

D (cm2/s) = 9.27 x 10-4 exp[-5.5(kcal/mol)/RT]

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