Electrical conductivity and current-voltage characteristics of alumina with or without neutron and electron irradiation

The in situ measurement of electrical conductivity and of current-voltage (I-V) characteristics of single- and polycrystal alumina have been carried out both in HFIR (high flux isotope reactor; Oak Ridge National Laboratory) at 723 K with or without neutron irradiation and in a high voltage electron microscope (HVEM) from room temperature to 723 K with or without 1 MeV electron irradiation. Radiation induced conductivity (RIC) was observed for all specimens under neutron and electron irradiation. The RIC under electron irradiation increased with increasing electron flux. There was no catastrophic bulk or surface conductivity degradation under neutron and electron irradiation up to >2 dpa and 9.1 x 10-5 dpa, respectively. Non-ohmic I-V behavior was observed for all specimens with or without neutron and electron irradiation. The I-V behavior with irradiation was similar to that without irradiation. The reason for non-ohmic behavior is discussed on the basis of the difference of work function between electrode and specimen materials. (orig.)