Microstructure, mechanical and thermal properties of chalcogenide glasses and glass-ceramics based on Se-As-Ge system nucleated by Sn

In particular, chalcogenide glasses and glass-ceramics are new materials that exhibit good transparency in infrared region (0.8-12µm). We can overcome the main weakness of these glasses by improving the hardness through controlling crystallization. In this paper, we report results of a study on chalcogenide glasses in the ternary system of As-Se-Ge with nominal composition of Snx (Se0.6As0.1Ge0.3)100-x (x=0, 2, 4 and 6 mol %) which is suitable for use in optical devices. Melt quench technique was used for preparing alloy specimens. Glass-ceramics were made using an appropriate heat-treatment temperature and time from Snx (Se60As10Ge30)100-x glasses in order to improve the mechanical properties. The temperature of the heat treatment started with the peak temperature (Tp) for glasses and different characteristics of prepared glasses such as glass transition temperature, hardness, density, transmittance, and microstructure were determined. Initially, Tg temperature was decreased with the addition of Sn, but with an increase of Sn up to 6 mol%, Tg was increased due to structural cohesion and formation of long chains of selenium. In this study, the highest value of the hardness for the Se60Ge30As10Sn6 glass was obtained after heat treatment and forming a crystalline phase while maintaining the initial transmittance.