Diffusion and Permeation of He, Ne, Ar, Kr, and D2 through Silicon Oxide Thin Films

A technique for the preparation of pinhole‐free glass films on porous substrates is described. The permeabilities of He, Ne, Ar, Kr, and D2 and the diffusivities of Ne, Ar, and D2 in the films are reported. The temperature range studied for He, Ne, and D2 was 25–500°C, while the range for Ar and Kr was 650–920°C. Activation energies reported for the permeabilities are: He, 5.22 kcal/mole; Ne, 9.13 kcal/mole; Ar, 25.2 kcal/mole; Kr, 44 kcal/mole; and D2, 8.32 kcal/mole. Activation energies reported for diffusivities are: Ne, 9.55 kcal/mole; Ar, 28.7 kcal/mole; and D2, 9.26 kcal/mole. A technique of nonlinear least squares curve fitting for the calculation of diffusion coefficients is described, and various interpretations of the temperature dependence of the diffusivity preexponential factor are discussed.