The ion-driven permeation technique was used to determine the diffusivity. It was found that the results could be described by:

D (cm2/s) = 8.2 x 10-4 exp[-5.6(kcal/mol)/RT]

at 500 to 1100K.

Y.Furuyama, T.Tanabe, S.Imoto: Journal of the Japan Institute of Metals, 1986, 50[8], 688-94