Control of structural parameters and thermal conductivity of BeO ceramics using heavy ion irradiation and post-radiation annealing

Abstract

Abstract The paper presents the results of research on changes in structural properties of BeO ceramics under heavy ion irradiation and post-radiation annealing. Irradiation was carried out on heavy ion accelerator DC-60 using Ni12+ ions with an energy of 100 MeV and irradiation fluence of 1013-1014 ions/cm2. According to X-ray diffraction analysis, it was found that a decrease of diffraction peaks intensity and their shift to small-angles region indicate an increase in interplanar distances and crystal lattice parameters, the change of which is caused by defects migration and their implantation into interstitial lattice site. For annealed samples an increased intensity of diffraction peaks, comparable in magnitude with original sample intensities, is observed. The increasing fluence of irradiation leads to a sharp decrease in crystallinity degree and the formation of more than 6.5% amorphous inclusions. Meanwhile, post-radiation annealing allows reducing amorphous inclusions concentration by 3%, which leads to a decrease in defects and vacancies in the structure. Reduction of deformations and amorphous inclusions as well as conservation of thermal conductivity coefficient indicate a potential applicability of post-radiation annealing of BeO ceramics as a method to control radiation defects accumulation and subsequent structure amorphization.