The self-diffusion coefficient of Na into ''-alumina doped with Na2O was measured at -45 to 18C. The measurements were carried out on the same sintered material used in the Na-S battery, where the ''-alumina was the solid electrolyte. The results could be described by:

D (cm2/s) = 6.3 x 10-3 exp[-0.30(eV)/kT]

Tracer Diffusion of Na in Na20, β”-A12O3. F.Beniere, J.I.Franco, J.P.Louboutin: Radiation Effects and Defects in Solids, 1983, 75[1], 139-144