Thermal and electrical decomposition products of C5F10O and their compatibility with Cu (1 1 1) and Al (1 1 1) surfaces

[Display omitted] •C5F10O starts to decompose at 500 ℃ and CO2, C3F6, and C4F10 are dominant by-products.•A unique by-products C2F6O3 is produced under partial discharge in C5F10O-air mixture.•Decomposition products CF4, C3F6, CF2O, CHF3, and C3HF7 have good compatibility with Al (1 1 1) and Cu (1 1 1) surfaces.•The O atoms in C2F6O3 show strong reaction activity with Al (1 1 1) and Cu (1 1 1) surfaces. Perfluoroketone C5F10O has drawn much attention in recent years as a promising environmental-friendly gas to substitute SF6 in power equipment. In this paper, the decomposition characteristics of C5F10O and C5F10O/air mixture under pyrolysis and partial discharge conditions were explored by experiments using a gas chromatography/mass spectrometer. Besides, the compatibility of decomposition products with the copper and aluminum was evaluated based on the density functional theory calculation. We found that C5F10O has good thermal stability at 300 ℃. At 500 ℃, C5F10O starts to decompose and it produces CO, CO2, C2F6, C2F4, C3F8, C3F6, C4F10, C4F8 and CHF3, among which CO2, C3F6, and C4F10 are dominant. For C5F10O/air mixtures, the pyrolysis products are mainly saturated fluorocarbons and more CO2 is produced. Partial discharges in C5F10O/air mixture mainly produce CO2, saturated fluorocarbons and a unique compound C3F6O3. It is found that CF4, C3F6, CF2O, CHF3, and C3HF7 have good compatibility with Al (1 1 1) and Cu (1 1 1) surfaces, while the interactions between C2F6O3 and Al (1 1 1), Cu (1 1 1) surfaces are relatively strong, which are chemisorption. The identified by-products of C5F10O and C5F10O/air mixture under different conditions as well as their compatibility with metal materials is essential for online fault-diagnostic and long-term maintenance in engineering applications.