Heavy-ion irradiation effects of Gd2Zr2O7 nanocrystalline ceramics as nuclear waste immobilization matrix

In this study, the irradiation response of Gd2Zr2O7 nanocrystalline ceramic was systematically studied under 5 MeV Xe20+ with radiation dose ranging from 2.6 dpa to 20.4 dpa. The grazing incidence X-ray diffraction (GIXRD) results demonstrate that the most severe irradiation area is located at a depth of about 180 nm under the maximum irradiation dose. The irradiated samples exhibit slight lattice expansion in the shallow superficial layer with maximum expansion ratio of 0.3% and corresponding amorphization rate of 62.2%. The Raman spectroscopy analysis show that there is a disorder in the local structure of Gd2Zr2O7 ceramics upon irradiation and the disorder increases with elevated radiation dose. FESEM-EDX indicates that the irradiation exhibits negligible effects on the elemental distribution. The HRTEM-SAED test confirms partial amorphization of the irradiated sample. Our work provides a detailed set of data for evaluating the radiation resistance of Gd2Zr2O7 nanocrystalline ceramics. (c) 2020 Elsevier B.V. All rights reserved.