The Science & Technology
of Glass
Cambridge - Monday 4th to
Wednesday 6th September 2017



Odile Majérus
<odile.majerus@chimie-paristech.fr>

article posted 19 June 2017

After a Master degree in general chemistry at the Ecole Nationale Supérieure de Chimie de Paris (ENSCP) in 2000, Odile Majérus obtained her PhD in Materials Sciences at the Université Pierre et Marie Curie (UPMC) in 2003. Her thesis dealt with structural modifications of oxide glasses induced by high temperature or high pressure conditions. She spent one year as a post-doctoral fellow at Aberystwyth University (Wales, UK) in the Physics Department, working on in situ high temperature characterization of oxide melts using synchrotron radiation. Then, she obtained a lecturer position at Chimie Paristech in 2005 (new name for ENSCP), where she takes part to the teaching in inorganic chemistry, solid state chemistry and materials characterization. Her research is localized at the Institute of Research of Chimie Paristech and focuses on the structure, thermal stability and alteration of oxide glasses.


An insight into the mechanisms of glass atmospheric alteration and their temperature dependence
Fanny Alloteau1,2, Odile Majérus*1, Patrice Lehuédé2, Isabelle Biron2, Daniel Caurant1, Thibault Charpentier3, Antoine Seyeux1

Although glass alteration in liquid water has raised numerous research efforts for decades, glass alteration in atmospheric conditions is far less well known and studied. However, active atmospheric degradation is observed on the surface of numerous glass objects stored in the museums, through macroscopic manifestations, mainly white salt deposits and crizzling, resulting in loss of transparency and material disintegration. Atmospheric alteration of glasses is also an issue in the glass industry, during the storage and transport of flat glass, and in the field of glass nuclear wasteforms, for the assessment of their long-term containment performances. The related mechanisms strongly depend on the glass composition, the environmental conditions and the surface state, and are not well understood.

In this study, the mechanisms underlying the atmospheric alteration are investigated by the mean of ageing experiments (T °C and % RH control) on a mixed alkali (Na, K)-lime silicate glass. Glass samples, prepared as polished plates or calibrated powders, were altered in atmospheric conditions (85 % RH, 80°C, 50°C, 40°C) for various lengths of time and carefully characterized at all scales. At 80°C, the altered glass forms a hydrated solid phase bearing about 10 wt % of H2O in the form of Si-OH groups and molecular water. No alkali depletion was observed. Structural results from 1H, 23Na and 29Si solid-state NMR point out the close proximity of Si-OH, H2O and embedded Na+ species. At 50°C and 40°C, the formation of lime and alkali carbonate salts are observed together with the alkali depletion of the hydrated layer. The kinetics of the glass alteration, as obtained by measuring the hydrated thickness as a function of the duration of the ageing test, does not follow a simple Arrhenius dependence. At 80°C, this kinetics is dramatically high, so that atmospheric conditions reveal more aggressive towards this glass than immersion conditions (80°C, pure water, free pH, Figure). These results point out a global mechanistic change of atmospheric alteration between the high temperature (80°C) and the low temperature (40°C). An attempt to unify both mechanisms is made on the basis of the hydrated layer structural study [1].



Figure. Glass hydration thickness as a function of ageing time for the alkli-lime silicate glass of this study, in atmospheric conditions (thickness measured by Tof-SIMS or SEM as pictured in the onset) and in immersion conditions at 80°C, free pH (thickness corresponds to the equivalent leached thickness of glass from the Na normalized mass loss). Atmospheric conditions at 80°C and 85%RH are more aggressive toward this glass than immersion conditions.

Reference:

[1] F. Alloteau, P. Lehuédé, O. Majérus, I. Biron, A. Dervanian, D. Caurant, T. Charpentier, New Insight into Atmospheric Alteration of Alkali-Lime Silicate Glasses, Corrosion Science, accepted (2017).

Institutions:

1PSL Research University, Institut de Recherche de Chimie Paris, CNRS – Chimie ParisTech, 11 rue Pierre et Marie Curie, 75005 Paris, France
2Centre de Recherche et Restauration des Musées de France, Palais du Louvre, 14 Quai François Mitterrand, 75001 Paris, France
3NIMBE, CEA, CNRS, Paris-Saclay University, CEA Saclay, Gif-sur-Yvette, France