Theoretical study on the interaction of heptafluoro-iso-butyronitrile decomposition products with Al (1 1 1)
Seeking environmentally friendly gas-insulated medium has become a research hotspot in recent years. At present, C3F7CN (Heptafluoro-iso-butyronitrile) is considered to be a potential SF6 environment-friendly alternative gas and some achievements have been made in the study of its insulation and decomposition characteristics, but there are few reports on the compatibility between its characteristic decomposition products and materials. The investigation of compatibility between gas-insulated medium and material is an important part of evaluating its comprehensive performance. In this paper, we investigated the interaction between C2F5CN, CF3CN, COF2 and CF4 with the aluminium widely used in electrical equipment. It was found that the interaction between C2F5CN, CF3CN and Al (1 1 1) surface is strong. There are obvious charge transfer and electron orbital overlap between the C atom, N atom in CN group and Al (1 1 1). The interaction between COF2, CF4 and Al (1 1 1) surface is weak and van der Waal’s forces play the major role. Relevant results reveal the characteristics of C3F7CN decomposition products and provide theoretical guidance for evaluating the material compatibility between C3F7CN decomposition products and aluminium.
