Investigating Replacements for Sulfur Hexafluoride in High Voltage Gas Switches

SF
6
has been the gas of choice in high-voltage spark gap switches due to its high dielectric strength, stable breakdown voltage, and low acute toxicity hazard; however, SF
6
is a greenhouse gas with a 100-year global warming potential (GWP) 23,500 times greater than CO
2
. Lower GWP alternatives are desired to reduce the environmental impact of large pulsed-power systems such as the Z facility at Sandia National Laboratories. The fluoronitrile C4F7N and fluoroketone C
5
F
10
O (marketed as Novec™ 4710 and Novec™ 5110, respectively, by 3M™) have shown promise in mixtures with low overall GWP for on-grid SF
6
replacement. However, their suitability for repetitive switching applications has not been well explored.