Title: A general mechanism for gel layer formation on borosilicate glass under aqueous corrosion

Abstract

Mineral and glass dissolution is a scientific topic deeply investigated but incompletely understood and of a great interest for the geochemical and materials science communities. If the interfacial dissolution/reprecipitation mechanism seems to be applicable to most of silicate minerals, the debate remains open concerning glass. Here we studied two model glasses, a ternary borosilicate (CJ1) and the same glass doped with 4.1 mol% of Al2O3 (CJ2). The two glasses were altered at 90°C, pH 9, and in conditions far and close to saturation with respect to amorphous silica, to determine the initial and residual rates. Moreover, a specific experiment was conducted for a short duration with a solution highly enriched with 18O and 29Si isotopes to understand how passivating gels form. SEM, TEM and ToF-SIMS characterization, along with Monte Carlo simulations were used to understand the rate limiting reactions at play and infer the role of Al. We show that Al yields a slower matrix dissolution in dilute conditions. However, it slows down he formation and the maturation of the passivating gel and favors alteration by partial hydrolysis of Si and Al entities followed by in-situ reorganization/relaxation into a porous network. Unexpectedly, CJ1 experienced both interfacial dissolution/reprecipitation and partial hydrolysismore » followed by in situ reorganization of the silicate network during the course of a single experiment. This study offers a unified concept that can pave the way for the future development of a predictive kinetic model based on a detailed description of bond breaking and bond forming as a function of glass composition and alteration conditions.« less

Authors:

Gin, Stephane ^[1]; Mir, Anamul Haq ^[2]; Jan, Amreen ^[3]; Delaye, Jean-Marc ^[4]; Chauvet, Elodie ^[5]; de Puydt, Yves ^[5]; Gourgiotis, Alkiviadis ^[6]; Kerisit, Sebastien N. ^[7]

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+ Show Author Affiliations

1. CEA Marcoule
2. University of Huddersfield
3. UNIVERSITY PROGRAMS
4. CEA
5. Tescan Analytics
6. Institut de Radioprotection et de Sûreté Nucléaire
7. BATTELLE (PACIFIC NW LAB)

Publication Date:

2020-03-05

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Center for Performance and Design of Nuclear Waste Forms and Containers (WastePD); Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1605359

Report Number(s):

PNNL-SA-149447

DOE Contract Number:  

AC05-76RL01830

Resource Type:

Journal Article

Journal Name:

Journal of Physical Chemistry C

Additional Journal Information:

Journal Volume: 124; Journal Issue: 9

Country of Publication:

United States

Language:

English