Glass - Back to the Future!

Presenting Author:

article posted 25 August 2016

Dr. Prashant Rajbhandari is a Postdoctoral Research Associate of Department of Materials Science and Engineering at the University of Sheffield. He received her doctorate in chemistry from the University of Lille 1, France. His research interests includes formulation and characterization of advanced glasses using various techniques such as XRD, Raman, solid state NMR, SEM etc. His recent publications include:

A. Saitoh, G. Tricot, P. Rajbhandari, S. Anan, H. Takebe. Effect of B2O3/P2O5 substitution on the properties and structure of tin boro-phosphate glasses, Mat. Chem. Phys, 149-150, 2015, 648-656.
P. Rajbhandari, G. Tricot and L. Montagne, Investigation of zinc alkali pyro-phosphate glasses. Part I: development of low-Tg and high stability glasses. Mat. Chem. Phys. submitted, 115, 2015, 17-22.
P. Rajbhandari, G. Tricot, Y.Chen, B. Doumert and L. Montagne, Investigation of zinc alkali pyro-phosphate glasses. Part II: local and medium range orders analysed by 1D/2D NMR. Mat. Chem. Phys. Submitted155, 2015, 23-29.

The effect of Al2O3 doping on its thermal stability of low-Tg phosphate based glasses.

Rajbhandari P.1,2*, Montagne L.,1 & Tricot G.1,3
1 Unité de Catalyse et de Chimie du Solide, UMR CNRS 8181, USTL-ENSCL, Université de Lille 1, Villeneuve d’Ascq F-59652, France.
2 Now at: ISL, Department of Materials Science and Engineering, The University of Sheffield, UK.
3 Now at : LASIR UMR-CNRS 8516, Universite de Lille1, Villeneuve d'Ascq, France

The phosphate based glasses have received increased interest in association with the development of low-Tg/stable phosphate glasses for low temperature applications such as sealing glasses, confining volatile radioactive wasteform, high power lasers, or antioxidation coatings etc. These applications benefit from its lower thermal characteristics, higher thermal expansion coefficient or high oxide-acceptation ability. However poor chemical and thermal stability of pure phosphate glass severely hinder its straightforward application. In this work, we present the results of a project dedicated to improve the thermal stability of low glass transition temperature (Tg) (≤ 360°C) glasses. At first, a low-Tg pyrophosphate composition was formulated in the (66.6-x)MO- xN2O- 33.4P2O5 system where M = Zn, Pb, Cd, Cu and N= Li, Na, K. Then, the influence of the doping of small amounts (1-5 %) of Al2O3 on their thermal stability was assessed employing the Angell parameter (KA= Tx-Tg) and the resistance against crystallization after isothermal treatments. The effect of doping on the pyrophosphate glass structure was also investigated with 1D/2D advanced solid state NMR (27Al/31P D-HMQC, D-INEPT, REDOR, 27Al & 31P DQ-SQ techniques) in order to understand how the doping elements enter into the network and how it interacts with the phosphate network to finally induce the macroscopic material properties.

Figs. Evolution of relative % of P in crystalline phase with the increase in Al2O3 after treating isothermally (left). 27Al{31P} D-HMQC solid state NMR (Right).