The effect of Sb content on glass-forming ability, the thermal stability, and crystallization of Ge–Se chalcogenide glass

Abstract

The glass formation and devitrification of intermediate alloys in the Sb-Ge-Se system were studied by differential scanning calorimetry. A comparison of various simple quantitative methods to assess the level of stability of the glassy materials in the bove mentioned system is presented. All of these methods are based on characteristic temperatures, such as the glass transition temperature, Tg, the onset temperature of crystallization, Tin, the temperature corresponding to the maximum crys- tallization rate, Tp, or the melting temperature, Tm. In this case, kgl may be more suitable for estimating the glass thermal stability in above composition range than XT. In this work the parameter Kr(T) is added to the stability criteria. The thermal stability of some ternary compounds of the Sb-Ge-Se type has been evaluated experimentally and correlated with the activation energies of crystalliza- tion by this kinetic criterion and compared with those evaluated by other criteria. All the results of criteria and kinetic parameter Kr(T) confirm that the thermal stability decrease with increasing Sb content in the glassy system. The crystallization results are analyzed and both the acti- vation energy of crystallization process and the crystalli- zation mechanism are characterized. Finally, identification of the crystalline phases was made by recording the X-ray diffraction pattern of the transformed material. This pattern shows the existence of microcrystallites of two phases, the first is germanium Selenide GeSe2 and the second is Sb2Se3 in amorphous matrix for annealed of Sb2.5Ge22.5Se75 and Sb10Ge15Se75 glass.