Glass - Back to the Future!

Presenting Author:
Ralf Müller

article posted 20 april 2016

Ralf Müller is head of Glass division at the Federal Institute for Materials Research and Testing (BAM) in Berlin. His main research areas are crystallization and sintering of glass powders. He is a member of TC07 and coordinates the DGG-DKG joint working committee Glassy-Crystalline Multifunctional Materials.

Hydrogen Permeability of Glass Measured with VHE-MS Powder Methods

U. Marzok1, R. Müller*1, T. Welter2, J. Deubener2
1 Bundesanstalt für Materialforschung und –prüfung (BAM), Berlin
2 Institut für Nichtmetallische Werkstoffe, TU Clausthal

Glasses are can serve as exceptionally tight hydrogen barriers e.g. used for hydrogen storage in micro glass containers or cover glasses in micro electronic systems. Respective glass development, however, requires precise measurements of minimal hydrogen permeability, PH2. Recent studies showed that PH2 can be measured down to 2 10-21 mol s-1 Pa-1m-1 by means of Vacuum Hot Extraction (VHE) powder methods [1]. In this respect the isothermal gas release from glass powder particles is fitted in terms of classical diffusion models assuming spherical particles of uniform size thus obtaining the hydrogen diffusion coefficient, DH2. PH2 is then given by D H2 × S H2, where hydrogen solubility, SH2, is obtained from VHE studies of glass powders exposed to hydrogen atmosphere for different exposure time and hydrogen pressure. Measurements of minimal values of hydrogen permeability, however, require a careful evaluation and error discussion of this method. Against that background, we modeled hydrogen degassing during heating and subsequent isothermal annealing of glass powder particles of different shape and particle size distribution by means of COMSOL Multiphysics® [2] and verified related effects on DH2 obtained by the VHE powder method.

[1] P. Ried, M. Gaber, R.Müller, J. Deubener: Hydrogen permeability of a barium-aluminoborosilicate glass— A methodical approach, Journal of Non-Crystalline Solids 394–395 (2014) 43–49