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Deciphering the Non-Linear Impact of Al on Chemical Durability of Silicate Glass

37 Pages Posted: 1 Jul 2021 Publication Status: Published

See all articles by Kamalesh Damodaran

Kamalesh Damodaran

University of Montpellier - DES, ISEC, DE2D

Jean-Marc Delaye

University of Montpellier - DES, ISEC, DE2D

Andrey G. Kalinichev

Université de Nantes - Laboratoire SUBATECH

Stephane Gin

University of Montpellier - DES, ISEC, DE2D

Abstract

The role of Al in aluminosilicate glasses remains somewhat a mystery: at low concentrations, it increases the resistance to hydrolysis of the glass, whereas at high concentrations an opposite effect is observed. To understand the origin of the phenomenon on a fundamental atomistic scale, we performed 577 MD simulations and applied potential mean force (PMF) calculations to estimate the activation barriers for hydrolysis and to statistically correlate them with local structural features of the glass. Models of pure silicate and aluminosilicate glasses are constructed and investigated. PMF simulation results are further validated by the experimental measurements and revealed that Al is very easy to dissociate, but it also increases the glass chemical durability through significantly increasing both the strength of Si and network connectivity of the glass. In contrast, at high Al concentration, preferential dissolution of Al weakens the silicate network, which it supposes to strengthen, and so the glass resistance becomes poor. Through PMF calculations, we evaluated the activation barriers for dissociating bonds around Al as 0.49 eV, which is less than a half of the energy to dissociate bonds around Si in pure silicate (1.22 eV) and around Si in aluminosilicate glass (1.34 eV), all these energy differences being statistically significant. Molecular structural level investigation revealed that Si with Al as a second neighbour in the glass network has a significantly higher activation energy for dissociation than Si in pure silicate glass. The proposed approach opens the way to the development of quantitative predictive models of glass durability.

Keywords: Molecular dynamics simulation; Glass water resistance; Non-metallic glasses; Metallic glasses; Statistics

Suggested Citation

Damodaran, Kamalesh and Delaye, Jean-Marc and G. Kalinichev, Andrey and Gin, Stephane, Deciphering the Non-Linear Impact of Al on Chemical Durability of Silicate Glass. Available at SSRN: https://ssrn.com/abstract=3878341 or http://dx.doi.org/10.2139/ssrn.3878341

Kamalesh Damodaran (Contact Author)

University of Montpellier - DES, ISEC, DE2D ( email )

Bagnols sur Cèze
France

Jean-Marc Delaye

University of Montpellier - DES, ISEC, DE2D ( email )

Bagnols sur Cèze
France

Andrey G. Kalinichev

Université de Nantes - Laboratoire SUBATECH ( email )

1, quai de Tourville BP
Nantes Cedex 1
Nantes, 44313
France

Stephane Gin

University of Montpellier - DES, ISEC, DE2D ( email )

Bagnols sur Cèze
France

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