Study on the Adsorption of SF6 and its Major Superheated Decomposition Products on the Surface of Al(1 1 1)

Sulfur hexafluoride (SF 6) is widely used in gasinsulated equipment. When partial discharge, spark discharge, or local overheating occurs in gas-insulated equipment, the insulation medium SF
6
will decompose and generate $\mathrm{SOF}_{2},\ \mathrm{SO}_{2}\mathrm{~F}_{2},\mathrm{SOF}_{4},\mathrm{SO}_{2},\mathrm{HF},\mathrm{H}_{2}\mathrm{~S}$, and other products. The role of the metal interface in the generation of these products remains unclear. In this paper, the calculations are conducted in the framework of Dmol3 modules in Materials Studio. It is found that SF
6
is adsorbed on the Al surface by chemisorption. When chemisorption occurs, SF
6
and SO
2
are bonded to the Al surface by the 2p orbital, while $\mathrm{SOF}_{2},\mathrm{SO}_{2}\mathrm{~F}_{2},\mathrm{HF}$, and $\mathrm{H}_{2}\mathrm{~S}$ are only physisorbed. The adsorption energy, bond length change, charge transfer, and density of states analysis revealed that SF
6
and SO
2
interacted strongly with the Al surface and were less compatible, and the atomic 2p orbital was the primary cause of bonding. The findings establish the groundwork for ultimately understanding how SF
6
and Al respond at their interfaces.