Glass - Back to the Future!

Presenting Author:
Ilyes Ben Kacem

article posted 6 April 2016

Ilyes Ben Kacem has been a Phd student at the Université Paris-Est since October 2014, working on the incorporation of lead and cadmium in glasses and glass ceramics. Prior to that he has been studying separative chemistry, materials and process applications to the nuclear fuel cycle at University of Montpellier II, France.

The role of Al and Ca on properties and structural variation in lead silicate glasses and melts

Ilyes Ben Kacem1,2, Laurent Gautron1 & Daniel R. Neuville2
1 Laboratoire Géomatériaux et Environnement, Université Paris-Est Marne-laVallée, 5 Bd Descartes 77454 Marne-la-Vallée cedex 02, France
2 Géomatériaux, CNRS-UMR7154, Institut de Physique du Globe de Paris, Sorbonne Paris Cité, F -75005 Paris, France

Lead silicate glasses are important materials from different points of view, societal, environmental and in material science. Indeed these glasses are known for a long time for their very high performance, they also play an important role in the management of lead as a waste. Lead silicate glasses and melts have been already investigated and showed an important decrease in viscosity and Tg when PbO is added to SiO2, whereas a large depolymerisation is observed by Raman spectroscopy where the Q species decrease from Q4 to Q0 when the PbO content varies from 2 up to 80% [1].
In order to better understand the role of Pb in silicate glasses, we have decided to substitute Pb by Ca or Al. We have synthesized different glasses with simple compositions in the systems (PbO–CaO–SiO2) and (PbO–Al2O3–SiO2). All new and previous glasses are investigated by XANES at the Pb LIII-edges, and reveal that Pb keeps its Pb2+ form in all compositions.
We present some new viscosity measurements and Raman spectroscopy results, and discuss them by using the Adam & Gibbs theory which gives the configurational entropy which can be discussed in terms of Q species as already shown by Le Losq et al (2014) [2].

[1] Ben Kacem, I., Gautron, L., Coillot, D. & Neuville, D. R. submitted to Chem. Geol. (2016).
[2] Le Losq, Ch., Neuville, D. R., Florian P., Henderson, G. S. & Massiot, D. (2014) Geochimica Cosmochimica Acta, 126, 495-517.