## 2 Experiment Platform  
The experiment platform shown in Figure 1 mainly comprises a heating system, a temperature feedback monitoring control system, and a detection system. The heating system includes a heat source and a copper outer casing outside of the heat source, whereas the heat source transfers heat to the surface of the heating device through the copper outer casing. The copper shell has the same material as the experiment copper sheet sample, whereas the air chamber shell is made from stainless steel. To prevent the heating device from transmitting the high temperature to the inner wall of the air chamber, the heating device does not directly contact the air chamber wall, thereby avoiding stainless steel interference during the experiments. The temperature feedback monitoring control system includes a temperature sensor and a proportional-integral-derivative (PID) controller. The copper sample and temperature sensor for the PID controller feedback control are fixed on the copper casing to monitor the temperature of the copper sample in real time and to control the experiment process. The detection system includes GC-MS and FESEM. GC-MS is a GCMS-QP2010 Ultra manufactured by Shimadzu for analyzing the composition of matter in gas mixture. The column type, film thickness, length, inner diameter, inlet temperature, and mass ion source temperature were CP-SIL 5 CB, 8 \(\upmu\)m, 60 m, 0.32 mm, 200 \({}^{\circ}\)C, and 200 \({}^{\circ}\)C, respectively [20]. This tool can also be used to check whether C\({}_{5}\)F\({}_{10}\)O decomposes after coming in contact with the C\({}_{5}\)F\({}_{10}\)O/N\({}_{2}\) and C\({}_{5}\)F\({}_{10}\)O/air gas mixture under different temperature conditions. FESEM is a Zeiss SIGMA FESEM produced by Carl Zeiss for observing the surface morphology of the test sample. The acceleration voltage range of FESEM is 0.1-30 kV, and the maximum resolution is 1.3 nm at 20 kV. The changes in the microstructure of the copper surface after coming into contact with the C\({}_{5}\)F\({}_{10}\)O/N\({}_{2}\) and C\({}_{5}\)F\({}_{10}\)O/air gas mixture under different temperature conditions are also studied.  
The copper samples were fastened to the surface of the copper casing before performing the experiments in order for the samples to adhere to the heat source during the experiments. The C\({}_{5}\)F\({}_{10}\)O gas has a volume fraction of 7.5%. After the gas filling, the mixtures were allowed to stand for 24 h to thoroughly mix the gas mixture. The experiment group temperatures were 120 \({}^{\circ}\)C, 170 \({}^{\circ}\)C, and 220 \({}^{\circ}\)C, whereas the heating time was 8 h. After 1 h of natural cooling, the experiment was terminated. Given that the C\({}_{5}\)F\({}_{10}\)O gas at a pressure of 0.1 MPa had a liquefaction temperature of 26.9 \({}^{\circ}\)C, the compatibility of the pure C\({}_{5}\)F\({}_{10}\)O gas with the copper material at a gas pressure of 0.3 MPa cannot be studied.  
Figure 1: Experiment platform.  
Therefore, the pressure of the pure C\({}_{5}\)F\({}_{10}\)O gas was set to 0.1 MPa for the experimental group, and the results are compared with those of the C\({}_{5}\)F\({}_{10}\)O/N\({}_{2}\) and C\({}_{5}\)F\({}_{10}\)O/air gas mixture experimental group.