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

The thermal reaction of SF 6 with tungsten powder was investigated by thermogravimetry (TG) and differential scanning calorimetry (DSC), combined with the characterization of solid decomposition products of SF 6 and tungsten by SEM, EDS, XPS and Raman. Based on above experiments, a two-stage decomposition process of SF 6 with tungsten was proposed: the first stage is the surface vulcanization reaction W+SF 6 →S 2 , 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 WS 2 +SF 6 →WF 6 , mainly taken place at 750 °C,, with the activation energy valued at 126.0 kJ·mol -1 according to the Avrami-Erofeev equation.