Experimental investigations of high voltage breakdown in water

The water breakdown system was designed to investigate various techniques for increasing the high-voltage breakdown strength of water and increase the time before breakdown. The initial breakdown mechanism is believed to be an electrode surface effect in which case the use of a coating to grade the field effects at the electrode surface would have the greatest chance for improvement in the voltage holdoff capability of water. Several techniques were tried during this investigation which included magnetic fields, SF/sub 6/ gas, HCl, polymer coatings, anodized aluminum electrodes and black wax coatings. The magnetic fields showed a small effect on the voltage and the time-width of the pulse. Initial use of SF/sub 6/ gas with the water appeared promising but the results could not be reproduced. Adding HCl caused the voltage holdoff capability of the water to decrease with increasing amounts of HCl. Coating electrodes with poly(ethersulfone) or polycarbonate showed no beneficial effects. The anodized aluminum electrodes did not show the same increase in holdoff strength as in other research. It was also shown that over larger surface areas, the use of black wax to coat the electrode surfaces did not increase the voltage breakdown level as seen in previous research.