Ion-Induced Corrugation and Surface Erosion of PAN-Based Carbon Fiber

The regularities of ion-induced corrugation of a VMN-4 carbon-fiber shell of the KUP-VM unidirectional composite under high-fluence irradiation with Ar+ ions at energies of 20 and 30 keV have been experimentally studied in the range from room temperature to 600 degrees C. A developed submicron corrugated structure of the carbon fiber surface at an ion path length of 20-40 nm in graphite is registered starting from temperatures around 200 degrees C. The corrugation period is a few hundred nanometers, weakly depends on the temperature of the irradiated carbon fiber, and decreases with a decrease in the ion energy or an increase in the incidence angle of the ion beam on the cylindrical fiber surface. The temperature of an irradiated fiber has a strong effect on the geometry and the fraction of corrugations in the fiber surface part irradiated with ions at normal incidence. For an ion energy of 20 keV in the temperature range of 350-500 degrees C, the apical part of the fiber is similar to the initial surface. A stronger effect of corrugation reduction for an argon-ion beam energy of 20 keV in comparison with an irradiation energy of 30 keV is explained by the competition between the processes of ion-induced corrugation under plastic deformation of the modified layer and the surface erosion at sputtering, which leads to the smoothing of the surface.