Spark decomposition of SF/sub 6//H/sub 2/O mixtures

The spark decomposition of mixtures of SF/sub 6/ (partial pressure from 100 to 500 kPa) and water (concentrations between 600 and 2000 VPM) has been studied. The sparks were generated between a point (stainless steel) and a plane (aluminum) either under 50-Hz AC voltage or by discharging a capacitor. Owing to the high water content the only stable gaseous oxyfluorides detected were, in order of decreasing importance, SOF/sub 2/ and SO/sub 2/F/sub 2/. The yields of these two byproducts have been measured as a function of the number of sparks, the SF/sub 6/ pressure, and the H/sub 2/O pressure. When the sparks additionally struck a solid insulator (polytetrafluoroethylene or biphenolic resin), CF/sub 4/ was detected. Its appearance was paralleled by a sharp increase in the yield of SOF/sub 2/, whereas that of SO/sub 2/F/sub 2/ remained unchanged.<
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