Filed emission cathodes for electrodynamic tethers: identifying compatible cathode materials

Several material combinations were considered as candidates for the electrodynamic tether application in the investigation discussed in this paper. Critical characteristics like work function, resistance, sputter yield and sensitivity to oxidizing environments were considered. The material investigation included, ZrC/Mo, Mo, MgPt, Pt, NbC/Nb, NbNi/Nb, Nb, RuTa/Ta, Ru/Ta and Ta. The results of the measurements suggest that NbC/Nb, NbNi/Nb, and MgPt are the most promising candidates.