Electrical conductivity of the ceramic AIN under irradiation

Aluminum nitride has been proposed as electrically insulating coating in connection with blankets made of vanadium alloys. Irradiations were performed with an applied DC electric field of 100 kV/m, using a 104 MeV α-particle beam. The dose achieved were 0.1 dpa at 300 C, 0.05 dpa at 400 C, and 0.06 dpa at 500 C. The out-of-beam conductivity σ0 decreased at all temperatures employed during early stage of irradiation. Before 0.02 dpa had been reached, σ0 dropped to low values of typically (2-4) x 10-11 (Ω m)-1. Although a moderate increase can be observed during further irradiation, σ0 remained below the initial value of the unirradiated specimen for all temperatures. That is, there is no significant evidence for radiation induced electrical degradation. The in-beam conductivity σ, measured continuously during irradiation, also decreased by at least one order of magnitude. Relevant damage dose and ionization rate dependencies of σ and σ0 will be discussed. (orig.)