The diffusivity was studied via ion-driven permeation in which the implantation of energetic ions was used instead of gaseous or electrochemical charging. In general, the temporal behavior of D permeation which was induced in this way was similar to that of the permeation which was produced by using other methods. However, the steady-state permeation rate and diffusion coefficient tended to decrease with increasing implantation time or fluence because of bombardment-induced changes in the surface. The diffusion coefficients which were deduced from the initial increase in permeation rate in an annealed specimen were considered to be reliable. It was found that the results could be described by:

D (cm2/s) = 1.4 x 10-2 exp[-8.5(kcal/mol)/RT]

T.Tanabe, Y.Furuyama, N.Saitoh, S.Imoto: Transactions of the Japan Institute of Metals, 1987, 28[9], 706-14