Abstract:
The paper presents the results of a study on the application of Raman and UV spectroscopy methods to determine
the structural damage kinetics in the near-surface layer of BeO ceramics caused by high-dose irradiation with
He2+ ions. Interest in this type of ceramics is due to the combination of its structural and thermophysical pa
rameters, making these ceramics one of the promising classes of materials for microelectronics and structural
materials for nuclear reactors, with the possibility of operation in conditions of heightened radiation background.
According to the conducted studies, it was established that with the irradiation fluence growth, changes in the
nature of deformation structural distortions associated with the accumulation of residual mechanical stresses of
tensile and compressive types are observed. At irradiation fluences of 1016–5 × 1016 Не2+/cm2
, tensile stresses
play a dominant role in structural distortions, while the value of compressive stresses at fluence growth makes up
a small share in the overall nature of the deformations. Moreover, an elevation in the irradiation fluence above 5
× 1016 He2+/cm2 leads to a rise in the concentration of defects caused by the formation of oxygen vacancies, as
well as He-VO type complexes, the presence of which is indicated by the halo intensity growth in the Raman
spectra, as well as a change in the intensity of the absorption bands. Analysis of changes in thermophysical
parameters revealed that a rise in structural distortions associated with the accumulation of complex defects
results in thermal conductivity reduction and a deterioration in heat transfer processes associated with partial
amorphization of the damaged layer. Moreover, the established direct relationship between the value of residual
mechanical stresses and the degradation of thermal conductivity indicates the cumulative effect of destructive
changes caused by irradiation, as well as the influence of diffusion mechanisms on the damaged layer thickness
growth.
