Detection and analysis of spark discharge products of C₅F₁₀O by electron attachment mass spectrometry

C₅F₁₀O has the potential to replace SF₆ as an insulation gas in switchgears due to its high breakdown field strength and low global warming potential. However, as a newly synthesized gas, the chemical characteristics of C₅F₁₀O are not well known. In particular, the discharge products of C₅F₁₀O are not clear, which limits its insulating capability evaluation in long-term use, and further hinders the development of a gas sensor to monitor the insulation deterioration of C₅F₁₀O-containing switchgears. In this paper, electron attachment mass spectrometry (MS) was proposed to detect the decomposed products of C₅F₁₀O under pulsed spark discharge condition. It was found that the ionization source of the MS had an optimal electron energy of 2 eV to avoid decomposing the gas molecules to be detected while having a high detection sensitivity. The detected discharge products mainly included CF₄, C₂F₄, C₃F₆, C₃HF₅, C₃F₈, C₃HF₇, C₄F₁₀, C₅F₁₀, C₆F₁₂, C₃F₄O and C₂F₆O, while CF₄, C₃HF₅, C₃HF₇, C₅F₁₀, C₆F₁₂, C₃F₄O and C₂F₆O were not detected using GCMS. Based on the nonionization measurement, the decomposition mechanism was deduced. Also, it was found that the densities of some products, such as C₃F₆, C₃F₈, C₄F₁₀ were increasing with the discharge voltage and the number of discharge pulses, implying that these species might be used as indicators for the discharge accumulation effects such as the insulation deterioration of switchgears. (paper)