Study of defect formation mechanisms in Li2ZrO3/MgLi2ZrO4 ceramics using EPR spectroscopy

The article presents the results of experimental studies of the effect of the stabilizing MgO dopant using the electron spin resonance (ESP) method on enhancement of the stability of Li 2 ZrO 3 ceramics to defect formation processes and accumulation of radiolysis products in the near-surface layer in the case of high-dose irradiation with protons simulating the hydrogenation effects characteristic of processes associated with tritium production. During the conducted studies, it was established that the addition of the stabilizing MgO dopant results in formation of inclusions in the form of the tetragonal MgLi 2 ZrO 4 phase, which leads to an increase in the resistance of the near-surface layers to destructive damage due to the accumulation of structural damage (oxygen vacancies and point defects), as well as products of the physicochemical processes of radiolysis, characteristic of high irradiation fluence values. It was found that in the case of unmodified Li 2 ZrO 3 ceramics, the formation of HC 2 – centers is observed at a fluence of 10 16 proton/cm 2 , while for two-phase ceramics, the formation of HC 2 – centers is observed at higher fluences, while the intensity of the bands is significantly less than in the case of single-phase unmodified ceramics. The difference in the nature of changes in the intensities of singlet bands responsible for the presence of vacancy defects in the damaged layer, as well as HC 2 – centers for single-phase and two-phase ceramics is a direct confirmation of the inhibition of structural degradation mechanisms in two-phase ceramics. • Formation of the tetragonal phase of MgLi 2 ZrO 4 results in growth in resistance to radiation-induced destruction. • Using the EPR spectroscopy method, the main mechanisms of defect formation in lithium-containing ceramics were determined. • In the case of two-phase Li 2 ZrO 3 /MgLi 2 ZrO 4 ceramics, the mechanisms of accumulation of radiolysis products are less pronounced at fluences of 10 16 –10 17 proton/cm 2 . • The influence of the MgLi 2 ZrO 4 impurity phase on the rate of structural disorder caused by the accumulation of vacancy defects and radiolysis products.