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.