Radiation damage in neutron-irradiated yttria-stabilized-zirconia single crystals

Optical absorption measurements and luminescence experiments have been made in neutron-irradiated or thermochemically reduced yttria-stabilized-zirconia (YSZ) crystals. Two absorption bands centered at about 375 and 470 nm were observed after irradiation or reduction; however, the thermal stability of these bands in each case is very different. In irradiated crystals the bands disappear with heat treatments at similar to 600 K, whereas in reduced crystals they anneal out at similar to 1300 K. This difference is probably due to interstitial-vacancy recombination in the oxygen sublattice of the former crystals. Nano-indentation tests show that hardness and the elastic modulus remain practically unchanged after TCR or neutron-irradiation. These results confirm that YSZ single crystals are radiation resistant and that the radiation damage can be easily removed by anneals in air at temperatures above 600 K. (C) 2000 Elsevier Science B.V. All rights reserved.