The permeability of vitreous and glass-ceramic coatings was investigated from 350 to 500C by using 2-layer membranes. These membranes were prepared by depositing very thin films of ZnO-PbO-B2O3 glass onto glass substrates by using a powder method. The transient flux of He through the glass membranes was measured by using a mass spectrometer. The permeability coefficients for the coatings were some 1000 times lower than those for the glass substrate.

Helium Permeability of ZnO-PbO-B2O3 Vitreous and Glass Ceramic Coatings. B.Z.Pevzner, G.I.Niunin: Physics and Chemistry of Glasses, 2000, 41[6], 387-8