Material Studies in a High Energy Spark Gap

Abstract

who all helped with the critical design and construction phases of this project. I would like to thank many others whose help on this project and processing this manuscript is appreciated. Some of these include Marie Byrd, Telesforo de la Cruz, Jim Semrad, and Dale Coleman. Some of the voltage distribution data was supplied by Richard Ness, and is greatly appreciated. The financial support by the Air Force Office of Scientific Research and Texas Tech University is appreciated. I owe my excellent education to the Department of Electrical Engineering at Texas Tech University. Finally, I would like to dedicate this work to my parents, C. M. Gordon and Barbara Gordon, who made it possible for me to achieve this goal, and to my wonderful wife, Jeanette, for her patience and encouragement.

Electrode erosion and lifetime performance of a triggered corona-stabilized switch in SF6at a repetition rate of 1 kHZ

“…In high-duty (high-charge transfer per shot) spark gaps, the erosion mechanism is dominated by the processes of electrode material melting and vaporisation, as well as the ejection of liquid metal from the discharge site [8]. In lower-duty switches, the gas-electrode chemistry enhances the erosion mechanism, especially when SF 6 is used as a switching gas [13,16]. The high temperatures developed during spark discharge can dissociate SF 6 resulting in a large number of highly reactive ionic species.…”

“…Elkonite displayed the lowest erosion rate of the tested materials, an expected result considering the rigidity of the tungsten matrix at high temperatures. On the other hand, due to its lower melting temperature, copper is slowly drawn out to the surface of the electrodes [13]. As the plasma ionic species interact with the electrode material, mainly copper and tungsten fluorides (CuF/CuF 2 , WF 6 ) as well as smaller quantities of copper and tungsten sulfides (CuS, WS 2 ) are formed [10,16,19].…”

“…As the plasma ionic species interact with the electrode material, mainly copper and tungsten fluorides (CuF/CuF 2 , WF 6 ) as well as smaller quantities of copper and tungsten sulfides (CuS, WS 2 ) are formed [10,16,19]. Copper fluorides, being more volatile, can condense in a lower temperature zone [13] around the rod tip or close to the trigger edge, whilst most of the copper and tungsten sulfides or metallic tungsten can remain fixed on the central discharge areas. The above mechanism explains the observed preferential deposition of fluorine and sulphur compounds on the surfaces of the elkonite electrodes.…”

“…The predominant color of the material in this zone is pinkish-white for elkonite and brass electrodes, whilst for the SSt303/316 electrodes it is greenishwhite. This zone, which extends for about 1mm along the length of the rod electrodes, is composed mainly of accumulated gas-electrode compounds [13].…”

Electrode Erosion and Lifetime Performance of a Compact and Repetitively Triggered Field Distortion Spark Gap Switch

“…Electrode erosion plays an important role in the many impact factors on the lifetime of the switch. Extensive research has been performed on the electrode erosion in gas switches [12][13][14][15][16][17][18][19]. Electrode erosion occurs when the electrode material is permanently removed from the electrode surface and could be considered a result of the interaction between the electrode and the arc plasma.…”