Kinetic modeling and iso-conversional analysis of glass-ceramics of selenium doped with carbon nanomaterials

Abstract

This study addresses a gap in understanding the impact of carbon nanomaterial doping on the crystallization kinetics of selenium glass, particularly when utilizing model-free iso-conversional methods. Previous research has explored the properties of elemental selenium; however, the role of dopants like multiwall carbon nanotubes (MWCNTs) and graphene in altering glass-to-crystal phase transitions at non-isothermal conditions has not been thoroughly analyzed. In the context of selenium glass crystallization, multiwall carbon nanotubes (MWCNTs), and graphene may alter the crystal growth kinetics significantly during glass/crystal phase transformation. Keeping in mind these facts, the present endeavor focuses on analyzing the doping effect of MWCNT and Graphene on the non-isothermal kinetic reaction mechanism of Selenium measured with differential scanning calorimetry (DSC) at different heating rates. The model-free relations such as Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), Tang, and Straink methods were applied using iso-conversional approach for determining the activation energy of amorphous to crystalline transformation as well as the Avrami index. Iso-conversional study yields adequate activation energy as a function of the conversion coefficient. We have observed the decreasing behavior of E<inf>c</inf>(α) along with the extent of crystallization of four iso-conversional methods. The kinetic triplet parameters (i.e., activation energy E<inf>α</inf>, rate constant K<inf>α</inf>, and order parameter n<inf>α</inf>) have been calculated using the VHR method derived from the Johnson-Mehl-Avrami (JMA) rate equation. The value of ‘n’ is reduced with the rise in the value of the extent of conversion α which indicates the reduction in the growth rate of crystallization because of its saturation. This study provides novel insights into the thermal stability and kinetic mechanisms within doped selenium glass-ceramics, expanding the potential applications of chalcogenide glasses in phase-change memory and other fields. © 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.