Erosion of carbon fiber composites under high-fluence heavy ion irradiation

The ion-induced erosion, determining by sputtering yield Y and surface evolution including structure and morphology changes of the modified surface layers, of two commercial carbon fiber composites (CFC) with different reinforcement – KUP-VM (1D) and Desna 4 (4D) have been studied under 30 keV Ar+ high fluence (φt ∼ 1018–1020 ion/cm2) irradiation in the temperature range from room temperature to 400 °C. Ion-induced erosion results in the changes of carbon fiber structure which depend on temperature and ion fluence. Monitoring of ion-induced structural changes using the temperature dependence of ion-induced electron emission yield has shown that for Desna 4 and KUP-VM at dynamic annealing temperature Та ≈ 170 °С the transition takes place from disordering at T < Ta to recrystallization at T > Ta. The annealing temperature Та is close to the one for polycrystalline graphites. Microscopy analysis has shown that at temperatures Т < Ta the etching of the fibers results in a formation of trough-like longitudinal cavities and hillocks. Irradiation at temperatures T > Ta leads to a crimped structure with the ribs perpendicular to fiber axis. After further sputtering of the crimps the fiber morphology is transformed to an isotropic globular structure. As a result the sputtering yield decreases for Desna 4 more than twice. This value is almost equal to that for KUP-VM, Desna 4, polycrystalline graphites and glassy carbons at room temperature.