Electrical Conductivity of a Space-Used Silicone Elastomer: Evolution Under Electron Irradiation
Résumé
The electrical conductivity of a space-used commercial silicone adhesive has been measured and its temperature dependence evidenced. It was shown to obey an Arrhenius law with an activation energy of 0.4 eV, associated with an electron-hopping transport. In parallel, this material was deprived from its fillers in the laboratory, and the dc conductivity of the resulting polysiloxane matrix was shown to obey the same Arrhenius law as the filled material. When exposed to high-energy electrons, the dc conductivity of both materials decreases, probably due to a predominant chain cross-linking process. For the highest experimental ionizing dose, the dc conductivity of this commercial silicone elastomer fell from 6×10^−13 down to 2×10^−16 S.m^−1.Consequently, the associated electrostatic discharge triggering risk in space applications moved from safe to critical.