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- xN2
where M = Zn, Pb, Cd, Cu and N= Li, Na, K. Then, the influence of the doping of small amounts (1-5 %) of Al2
on their thermal stability was assessed employing
the Angell parameter (KA
) 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 (27
P D-HMQC, D-INEPT, REDOR, 27
Al & 31
P 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 Al2
after treating isothermally (left). 27
P} D-HMQC solid state NMR (Right).