OXYGEN RETENTION IN D-ION-IRRADIATED B4C AND BORON-DOPED GRAPHITES

Atmospheric oxygen sorption in the variety of boronized graphites and boron carbide B4C has been studied. The samples were irradiated with D-ions at the energy of 1 and 3 keV, fluence between 1 x 10(16) and 1 x 10(19) D/cm(2) at room temperature and then were exposed to air. After the irradiation with fluence, at which the deuterium reemission flux appeared, oxygen accumulation in the subsurface layer with D-ion mean range thickness was observed. The sorbed oxygen amount increased linearly with D-ion energy and boron content in the material. It is supposed that the open porosity develops under the D-ion irradiation. This porosity is responsible for air penetration into the zone of deuterium implantation. The formation of B2O3, as a result of water vapor interaction with B4C precipitates, is thought to be the main mechanism of oxygen accumulation.