## 6 Conclusions  
C\({}_{5}\)F\({}_{10}\)O/N\({}_{2}\) and C\({}_{5}\)F\({}_{10}\)O/air mixtures have good application prospects as electrical insulating mediums that can replace SF\({}_{6}\). Studying the compatibility of materials before their application in engineering practice is of great significance to ensure the safe and stable operation of electrical equipment throughout their design lifecycle. In this paper, the compatibility of the environmentally friendly insulating medium C\({}_{5}\)F\({}_{10}\)O/N\({}_{2}\), C\({}_{5}\)F\({}_{10}\)O/air gas mixture, and metallic material copper inside GIS equipment at different temperatures (120 \({}^{\circ}\)C to 220 \({}^{\circ}\)C) was examined. The test gas and copper samples were analyzed via GC-MS and FESEM characterization, and the interaction between the C\({}_{5}\)F\({}_{10}\)O and Cu\({}_{13}\) nanoclusters was calculated via a simulation. The following conclusions were drawn:  
1. When the experiment temperature varies between 120 \({}^{\circ}\)C and 220 \({}^{\circ}\)C, the surface color of the copper material of the C\({}_{5}\)F\({}_{10}\)O/N\({}_{2}\) gas mixture experimental group changes from purple to golden yellow and then to pink. In the C\({}_{5}\)F\({}_{10}\)O/air gas mixture experimental group, the surface color of the copper material changes from purple to brown and then to dark brown as irritating gases are emitted. 2. The GC-MS characterization results show that the C\({}_{5}\)F\({}_{10}\)O/N\({}_{2}\) and C\({}_{5}\)F\({}_{10}\)O/air gas mixtures have a small amount of C\({}_{5}\)F\({}_{10}\)O decomposition. The C\({}_{5}\)F\({}_{10}\)O/N\({}_{2}\) gas mixture decomposes to produce C\({}_{3}\)F\({}_{6}\) and C\({}_{3}\)F\({}_{7}\)H, and the C\({}_{5}\)F\({}_{10}\)O/air gas mixture decomposes to produce C\({}_{3}\)F\({}_{6}\), C\({}_{3}\)F\({}_{7}\)H and C\({}_{3}\)F\({}_{6}\)O. 3. The FESEM characterization results show that the compatibility of the C\({}_{5}\)F\({}_{10}\)O/air gas mixture with copper at a low experiment temperature (120 \({}^{\circ}\)C) is better than that of the C\({}_{5}\)F\({}_{10}\)O/N\({}_{2}\) gas mixture with copper. However, due to the effect of O\({}_{2}\), when the experiment temperature is high (170 \({}^{\circ}\)C and 220 \({}^{\circ}\)C), the compatibility of the C\({}_{5}\)F\({}_{10}\)O/Air gas mixture with copper is significantly inferior when compared with that of C\({}_{5}\)F\({}_{10}\)O/N\({}_{2}\) gas mixture and copper. Therefore, when using the C\({}_{5}\)F\({}_{10}\)O/air gas mixture as the insulating medium in engineering applications, special attention should be paid to the condition of the copper material inside the equipment when local overheating occurs. At the same time, operation and maintenance personnel should wear gas masks to prevent the inhalation of toxic decomposition products from harming their health. Figure 9: Total energy change before and after simulation calculation. * The molecular adsorption of the C\({}_{5}\)F\({}_{10}\)O and Cu\({}_{13}\) nanocluster is an exothermic reaction. The F atom on the \(\alpha\)-position carbon atom of the C\({}_{5}\)F\({}_{10}\)O molecule and the oxygen atom on the carbonyl group have high chemical activity and are most likely to interact with Cu during the interaction process. Conceptualization, [PERSON] and Y.L. ([PERSON]); methodology, [PERSON] ([PERSON]); software, [PERSON] ([PERSON]); validation, [PERSON] ([PERSON]), [PERSON] and Y.W. ; formal analysis, [PERSON] ([PERSON]); investigation, [PERSON] ([PERSON]); resources, [PERSON] ([PERSON]); data curation, [PERSON] ([PERSON]); writing--original draft preparation, [PERSON] ([PERSON]); writing--review and editing, [PERSON] and Y.L. ([PERSON]); visualization, [PERSON]; supervision, [PERSON]; project administration, S.X. All authors have read and agreed to the published version of the manuscript. This research was funded by Science and Technology Project of State Grid Sichuan Electric Power Company, grant number 4Z20W1970018. The data presented in this study are available in article.