Ion irradiation behaviour and chemical durability of simple borosilicate glasses

Simple alkali alumino-borosilicate glasses were doped with iron and/or molybdenum oxides. The chemical composition was then fully characterized before irradiation at room temperature with 255 keV Xe ions to fluence ranging from 1015 up to 1017 ions/cm2. After irradiation, glass samples were leached in deionised water at 90 deg. C for 7 days. Scanning electron microscopy, electron microprobe analysis and ion beam analysis have been used to characterize the investigated samples. Irradiation induces a strong anti-correlated migration of boron and sodium. Alternatively enriched/impoverished zones are formed in the centre (irradiated) as well as at the rim (unirradiated) of the glass samples. Silicon, calcium, iron and molybdenum do not exhibit any perturbations in both surface and volume distributions. Boron and sodium mobility is mainly due to the coupling of thermal, electrical and stress gradients during ion irradiation. Glasses pre-irradiated before leaching exhibit stronger Na and B release than unirradiated glasses. A higher aluminium and iron surface enrichment is observed; it is probably due to the highest reactivity of the irradiated glasses having lost part of B and Na from the damaged network