Ion-induced modification of glassy carbon structure and morphology

The temperature dependences of ion-induced electron emission yield γ (T) under 10–30keV Ar+ high-fluence ion irradiation of glassy carbon SU-2500 at normal ion incidence have been analyzed to trace the structure and morphology changes depending on the irradiation temperature and the level of radiation damage ν measured in dpa (displacements per atom). It has been found that high fluence ion irradiation can result in changes of pristine structure of glassy carbon to amorphous structure at relatively low temperatures (T⩽100oC) and to ordering till polycrystalline graphite structure at elevated temperatures (T⩾250oC) The amorphization at room temperature is started at the mean radiation damage level ∼50 dpa and finished at ≈75 dpa. The graphitization at T>250°C begins at ≈75 dpa.