Application of EPR spectroscopy method for comparative analysis of structural damage accumulation kinetics in two-phase lithium-containing ceramics

Abstract

The aim of this study is to determine the differences in the damaged layer degradation kinetics in two-phase lithium-containing ceramics based on Li₂ZrO₃ and Li₄SiO₄ compounds in the case of irradiation with protons and helium ions, simulating the gas swelling and blistering processes, as well as the accumulation of radiolysis products in the damaged layer. During the conducted studies it was established that in the case of proton irradiation, the dominant role at fluences of 10¹⁵–10¹⁷ cm⁻² is played by oxygen vacancies, the change in the concentration of which upon reaching critical values causes a decrease in the thermophysical properties, and disordering of the damaged layer. In this case, the accumulation of radiolysis products in the form of HC₂ – and Zr³⁺ -defects in the structure of the damaged layer is observed at fluences of 5 × 10¹⁷ cm⁻², while when irradiated with He²⁺ ions, the formation of these types of HC₂ – and Zr³⁺ -defects is observed at a fluence of 10¹⁷ cm⁻². Comparison of the concentration dependences of defects in the damaged layer on the atomic displacement value under irradiation with protons and He²⁺ ions revealed that the formation of oxygen vacancies under irradiation with He²⁺ ions is more intense than in the case of irradiation with protons, which in turn results in more pronounced processes of accumulation of radiolysis products in the case of high-dose irradiation.