The Impact of Electrode Material on the Pulsed Breakdown Strength of Water

In the experiments presented here, various electrode materials were tested in an effort to determine the impact each has on increasing the dielectric strength of water. Prior investigations have tested materials such as stainless steel, copper, nickel, gold, silver, and cuprous oxide [1-4]. In our experiments, thin film coatings of various metallic alloys and oxides were applied to Bruce profiled stainless steel electrodes with an effective area of 5 cm². An ion beam sputtering process was used to apply the coatings with thicknesses of several hundred nm. The electrodes were then tested across a water gap, with pulse lengths in both the microsecond and nanosecond time regimes. Electric fields in excess of 8 MV/cm were applied. Conclusions are made as to the impact electrode material has on the pulsed breakdown strength of water.