Studies of spark decomposition products of SF/sub 6/ and SF/sub 6//perfluorocarbon mixtures
The ion and neutral species produced in electrical discharges in SF/sub 6/ and SF/sub 6//PFC (Perfluorocarbon) mixtures were studied. A variety of experimental techniques were employed. An attempt was made to distinguish among early products, products formed by later reaction with the ambient gas, and the final, long-lived species. For ionic species formed early following the spark discharge in SF/sub 6/, it was found that O/sub 2/ and N/sub 2/ played an influential role when present at the ppM level. The major positive ions detected at P approx. > 40 kPa in unpurified (99.65%) SF/sub 6/ were N/sub 2/O/sub 2/F +, H/sub 2/SOF/sub 2//sup +/, N/sub 2/F/sub 4//sup +/, S/sub 2/NF/sub 4//sup +/, SO/sub 2/F/sub 5//sup +/, S/sub 2/NOF/sub 4//sup +/, S/sub 2/NO/sub 2/F/sub 4//sup +/, and S/sub 2/NF/sub 8//sup +/. After extensive purification of SF/sub 6/, the predominant ion at these pressures was S/sub 2/F/sub 7//sup +/ and, to a lesser extent, SF/sub 3//sup +/. Of the early neutral products, we have so far concentrated on the key role played by SF/sub 4/. Preliminary results will be presented for the amount of SF/sub 4/ formed in sparked SF/sub 6/. We have observed the reaction of SF/sub 4/ with water via SF/sub 4/ + H/sub 2/O SOF/sub 2/ + 2HF, and have estimated the rate constant for this reaction to be approx. 1.8 +- 0.9 x 10/sup -19/ cm/sup 3//s at 350/sup 0/K. The effect of SF/sub 4/ and its subsequent reaction products in degrading insulator materials will be discussed. Finally, as an example of the practical utility of these studies, we will describe how the problem of SF/sub 6/ corrosion can be reduced by the addition of PFC gases to SF/sub 6/.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 5404149
- Report Number(s):
- CONF-820331-5; ON: DE82008845
- Country of Publication:
- United States
- Language:
- English
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BINARY MIXTURES
BREAKDOWN
CHEMICAL REACTIONS
DECOMPOSITION
DIELECTRIC MATERIALS
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