Ion-induced modification of glassy carbon structure and morphology

The temperature dependences of ion-induced electron emission yield gamma (T) under 10-30 key 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 v 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 <= 100 degrees C) and to ordering till polycrystalline graphite structure at elevated temperatures (T >= 250 degrees C) The amorphization at room temperature is started at the mean radiation damage level < v > similar to 50 dpa and finished at < v > approximate to 75 dpa. The graphitization at T > 250 degrees C begins at < v > approximate to 75 dpa. (C) 2013 Elsevier B.V. All rights reserved.