Synergism in SF6 mixtures with C=C−C backbone compounds.

A positive synergy in the electric strength was observed in a previous study in SF₆/HFO1234ze(E) mixtures which was shown to result from a strong electron energy moderation capability of HFO1234ze(E) combined with thermal electron attachment of SF₆ (Egüz et al 2022 J. Phys. D: Appl. Phys. 55 315203). In the present work, the electron energy moderation properties of compounds with a similar C=C−C backbone are investigated. Swarm and breakdown measurements are performed in pure gases and in mixtures with SF₆. Compounds with a trifluoromethyl group (−CF₃) showed lower characteristic energy and as a consequence a positive synergism with SF₆. Descriptors related to electron energy moderation are identified and computed; a clear trend is found from the analysis of descriptors related to inelastic processes which suggest(s) that vibrational excitations may be the main source of electron energy loss in the compounds showing positive synergy. [ABSTRACT FROM AUTHOR]