Dynamics of self-reorganization explains passivation of silicate glasses

S. Gin (1) , Marie Collin (1) , Patrick Jollivet (2, 1) , Maxime Fournier (1) , Yves Minet (1) , Laurent Dupuy (3) , Thiruvilla Mahadevan (4) , Sebastien Kerisit (5) , Jincheng Du (4)

1 DPME - Département de recherche sur les Procédés et Matériaux pour les Environnements complexes
2 LCLT - Laboratoire d'Etudes du Comportement à Long Terme des matériaux de conditionnement
3 Tescan Analytics
4 Department of Materials Science and Engineering
5 PNNL - Pacific Northwest National Laboratory

Understanding the dissolution of silicate glasses and minerals from atomic to macroscopic levels is a challenge with major implications in geoscience and industry. One of the main uncertainties limiting the development of predictive models lies in the formation of an amorphous surface layer–called gel–that can in some circumstances control the reactivity of the buried interface. Here, we report experimental and simulation results deciphering the mechanisms by which the gel becomes passivating. The study conducted on a six-oxide borosilicate glass shows that gel reorganization involving high exchange rate of oxygen and low exchange rate of silicon is the key mechanism accounting for extremely low apparent water diffusivity (∼10$^{−21} m^2 s^{−1}$), which could be rate-limiting for the overall reaction. These findings could be used to improve kinetic models, and inspire the development of new molecular sieve materials with tailored properties as well as highly durable glass for application in extreme environments.

Domains: Physics [physics]; Materials

S. Gin, Marie Collin, Patrick Jollivet, Maxime Fournier, Yves Minet, et al.. Dynamics of self-reorganization explains passivation of silicate glasses. Nature Communications, 2018, 9, pp.2169. ⟨10.1038/s41467-018-04511-2⟩. ⟨cea-01877346⟩