Study of the structural degradation kinetics of the near-surface layer of ZrO2 ceramics exposed to low-energy Не2+ ion irradiation

Abstract

The effects of radiation damage accumulation in the near-surface layer of ZrO₂ ceramics arising under high-dose irradiation with low-energy Не²⁺ ions alongside the determination of the influence of irradiation temperature on the thickness of the damaged layer in ceramics, the change of which is caused by the effects of ion diffusion into the depth of the material, are considered in this work. To determine the effects of radiation damage, and to determine the kinetics of changes depending on the variation of external factors, the method of Raman piezospectroscopy of lateral chips of ceramics was used, which made it possible to obtain data on changes in the values of residual stresses and FWHM along the trajectory of ion movement in the material, as well as at a depth exceeding the depth of ion penetration into the material. According to the conducted studies, it was established that the main type of deformation distortions arising as a result of irradiation and, as a consequence, the accumulation of structural changes caused by irradiation, is associated with the formation of residual mechanical tensile stresses in the structure. Moreover, a change in the irradiation conditions, in particular, an increase in the irradiation temperature, leads to an increase in the values of residual mechanical stresses in the structure of the damaged layer, and an increase in the thickness of the damaged layer is also observed, the change of which is due to the effects of ion diffusion deep into the target material. Analysis of alterations in the FWHM value indicates that at low irradiation fluences (below 10¹⁷ ion/cm²), the main changes in the structural features of the damaged layer are due to the effects of accumulation of structural distortions as a result of deformation stresses, while at high-dose irradiation, the formation of amorphous-like inclusions, the presence of which is associated with helium agglomeration, as well as the formation of gas-filled inclusions in the damaged layer, contribute to the destructive disordering of the damaged layer.