Study of Metal and Ceramic Thermionic Vacuum arc Discharges

Abstract

The thermionic vacuum arc (TVA) is a new type of plasma source,which generates a pure metal and ceramic vapour plasma containingions with a directed energy. TVA discharges can be ignited in highvacuum conditions between a heated cathode (electron gun) and ananode (tungsten crucible) containing the material. The acceleratedelectron beam, incident on the anode, heats the crucible, togetherwith its contents, to a high temperature. After establishing asteady-state density of the evaporating anode material atoms, andwhen the voltage applied is high enough, a bright discharge isignited between the electrodes. We generated silver and Al2O3TVA discharges in order to compare the metal and ceramic TVAdischarges. The electrical and optical characteristics of silver andAl2O3 TVA discharges were analysed. The TVA is also a newtechnique for the deposition of thin films. The film condenses onthe sample from the plasma state of the vapour phase of the anodematerial, generated by a TVA. We deposited silver and Al2O3thin films onto an aluminium substrate layer-by-layer using theirTVA discharges, and produced micro and/or nano-layer Ag-Al2O3composite samples. The composite samples using scanning electronmicroscopy was also analysed.