Study on the thermal decomposition reaction process and kinetics of SF6 and tungsten

¹ State Grid Shaanxi Electric Power Research Institute, 710054, Xi'an, China
² School of Chemistry and Chemical Engineering, Shaanxi Normal University, 710119, Xi'an, China
³ Shandong Taikai High Voltage Switchgear Co.,Ltd., 271000, Tai'an, China
⁴ State Grid Shaanxi Electric Power Company, 710054, Xi'an, China
⁵ South China Institute of Environmental Science, Ministry of Ecology and Environment, 510655, Guangzhou, China

^* Corresponding author: Weiqiang Zhang: zwq@snnu.edu.cn, Yajun Jian: yajunjian@snnu.edu.cn; [+] These authors contributed equally to this work.

Abstract

The thermal reaction of SF₆ with tungsten powder was investigated by thermogravimetry (TG) and differential scanning calorimetry (DSC), combined with the characterization of solid decomposition products of SF₆ and tungsten by SEM, EDS, XPS and Raman. Based on above experiments, a two-stage decomposition process of SF₆ with tungsten was proposed: the first stage is the surface vulcanization reaction W+SF₆→S₂, mainly taken place at 600 °C, with the activation energy valued at 152.8 kJ·mol^-1, according to Avrami-Erofeev equation; the second stage is the endothermic fluorination reaction WS₂+SF₆ →WF₆, mainly taken place at 750 °C,, with the activation energy valued at 126.0 kJ·mol^-1 according to the Avrami-Erofeev equation.