| Stability and Percolation Threshold of
Ge42–xPbxSe58 (920) Glasses |
Deepika,a, * Hukum Singha and N. S. Saxenab
pages: 20-24
DOI : 10.1080/0371750X.2016.1159145 |
| Abstract |
| Ge42–xPbxSe58 (920) glassy alloys have been prepared using melt quenching
technique. The samples were then subjected to differential scanning calorimetry (DSC)
for recording the phase transformation occurring in the samples as a function of
temperature. The characteristic temperatures of transformation, i.e. glass transition
temperature, Tg, and crystallization temperature, Tc, were extracted from the DSC
scans. The values of Tg and Tc were further used to ascertain thermal stability of the
prepared glassy samples using Dietzel (T) stability parameter. The variations of Tg
with average coordination number, , were specified. It was found that T exhibited
a maximum at =2.44, close to the critical coordination number =2.40
optimized for maximum stability of glassy matrix. Thus, the obtained result follows
Phillips-Thorpe constraint theory where the maximum stability of the network is just
obtained if the percolation threshold limit is reached. The overall mean bond energies
of the glassy samples were also calculated using the covalent bond approach. Glass
transition temperature, Tg, was then deduced with a suitable proportionality with the
mean bond energy and was compared with the experimental values.
[Keywords: Stability, Coordination number, Mean bond energy] |
| Full text : Subscribe to Download Full Text |
| [Go Back] |
|
