IBA and SIMS coupling to study glass alteration mechanisms

International audienceAlkali-alumin o-boro silicate glasses have been synthesized by melting the stoichiometric corresponding powder mixtures and heating at 1100 degrees C in a platinum crucible. Electron microprobe analyses were then carried out in order to determine their initial composition. Glass samples were submitted to static aqueous leaching tests in deionized water during 1 month (surface/ratio = 0. 3 cm(-1)) at temperature of 96 degrees C. The leachates were analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The leached samples were then characterized by ion beam analytical (IBA) methods: Rutherford backscattering and elastic recoil spectrometries (RBS and ERDA), proton-induced X-ray or gamma ray emission (PIXE and PIGE) and secondary ion mass spectrometry (SIMS). The role of the presence of one or several contained transition elements (Fe, Mo, and Nd) and the effect of their respective contents on the chemical durability of alkali-borosilicate glasses were investigated. This work outlines the fact that a competition may occur between congruent and selective dissolution. Both surface hydration thickness and mobile element depletion amplitude cannot be considered as the unique reliable glass durability indicators. (c) 2007 Published by Elsevier B.V

Static Leaching and Alteration Mechanisms of Zirconium Alkali Resistant Glasses Containing Heavy Metals

International audienceThe aim of this study is to understand mechanisms that occur during leaching of alkali-resistant zirconium-containing glasses in acid and alkaline solutions. For this, we have developed 5 glass compositions: two alkali-resistant model glasses type CEMFIL, V1 (with zirconium and without heavy metals) and V2 (with zirconium and heavy metals), then three glasses of fly ashes V3 (without zirconium and with heavy metals), V4 (with 30 % of V3, zirconium and heavy metals) and V5 (with 60% of V3, zirconium and heavy metals). V4 and V5 are obtained using V3 as raw material and supplementing with SiO2, ZrO2 and Na2O to give them alkali-resistant properties. Glasses leaching in acidic and basic medium led to an important basification from the first times of alteration at pH = 4 when a basification decrease is observed for solutions initially at pH = 13. Normalized elementary mass losses results showed that, glass alteration is higher for low-calcium glasses (V1 and V2) and V4 and V5 glasses have the lowest elemental mass losses at pH = 4 and 13. SIMS profiles made on glass alteration films permitted to observe behaviour of H, Na, Ca, Si and Zr elements after 28 days at pH = 4 and 13 and understand the different dissolution mechanisms involved. SIMS profiles showed that a hydrated film develops on glass surface characterized by hydrogen enrichment and sodium depletion irrespective of the glass. These glasses are also characterized by a surface enrichment of zirconium (except V3 which does not contain zirconium) whatever the pH. Hydrated film thickness confirm that V1, V2 and V3 glasses are more altered than V4 and V5 glasses. These results are confirmed by ICP-AES leachate analysis

Chemical durability of alkali-borosilicate glass studied by analytical SEM, IBA, isotopic tracing and SIMS

Communication par affich

Characterization of the surface composition of exposed grisaille sensors using highly sensitive chemical analysis techniques. Potentiality and limits regarding research in conservation

International audienc

Chemical durability of alkali-borosilicate glass studied by analytical SEM, IBA, isotopic tracing and SIMS

Communication par affich