Influence of surface corrugation on the sputtering of carbon materials under high-fluence ion bombardment

Abstract

The results of experimental and computer-based studies of the sputtering and erosion of carbonmaterial surfaces under high-fluence irradiation with 30-keV Ar⁺ ions at various angles of ion incidence are given. The irradiation of highly oriented pyrolytic graphite (HOPG) and polyacrylonitrile fibers of carbon–carbon composites, which are characterized by surface corrugation, is considered. A model is proposed for taking into account the influence of parameters of symmetric corrugation on the characteristics of sputtering of the irradiated materials. Calculation shows that taking experimental values of the corrugation slopes into account allows one to explain the angular dependence of the sputtering yield of HOPG. It is found that the pronounced (about two times) suppression of sputtering within the range of incidence angles of 60°–80° is connected with the rear (relative to the ion beam) faces of the corrugation being obscured. Unlike the case of the normal incidence of ions, the sputtering yield at large incidence angles decreases as the corrugation period increases due to blocking of the sputtering of the rear and neighboring faces of microrelief elements.