First Principles Calculation of Compatibility between Environmentally Friendly Insulating Gas C₅F₁₀O and CuW Contacts

The insulating gas and contacts in the arc extinguishing chamber of high-voltage circuit breakers are the focus of research. In practical applications, the gas may react with the surface of the contacts. In this paper, C5F10O environmental friendly insulating gas, which has one of the potential alternatives, is selected as the research object. The compatibility of C5F10O and its decomposition products with Cu-W contacts was studied. This article uses the Dmol(3) program based on density functional theory. The adsorption energy, transfer charge, and density of electronic states of C5F10O and selected typical decomposition products on the Cu (111) surface and Cu-W surface were calculated, respectively. It was found that the original Cu-W metal properties were not changed before and after adsorption. The carbonyl O atom in C5F10O is easily adsorbed on the top of the Cu (111) surface, forming a stable Cu-O bond, which belongs to chemical adsorption. The interaction of the other three adsorption sites is weaker than that of the top site adsorption, which belongs to physical adsorption. C5F10O exhibits more active charge transfer and forms active W-O chemical bonds when adsorbed on Cu-W surfaces than SF6. C5F10O has poorer compatibility with Cu-W alloy than SF6. C2F4 and C3F6 in the decomposition gas are chemically adsorbed on the Cu-W surface. CO2, CF4, C2F6, and C3F8 do not form chemical bonds on the Cu-W surface. The adsorption stability of COF2 is weaker than that of CF4, C2F6, and C3F8. Compared with SF6 adsorption, the compatibility of C5F10O and CO2 on the surface of Cu-W contact is inferior to that of Cu contact. CF4, C2F6, C3F8, and COF2 in the decomposition gas can be compatible with the surface of the Cu-W contact. C2F4 and C3F6 cannot be well compatible with the surface of Cu-W contacts. (c) 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.