The regularities of surface corrugation of polyacrylonitrile based carbon fibers under high-fluence ion irradiation

摘要

The regularities of surface corrugation of polyacrylonitrile based carbon fibers reinforcing composite KUP-VM has been studied experimentally after high-fluence 30 keV Ne~+, 20 and 30 keV Ar~+, 30 keV N_2~+ ion irradiation at target temperatures ranging from 100 to 600℃. It was found that periodic corrugated structure parameters, such as the angles of the inclination β of the corrugations and their fraction on the fiber surface have strong temperature dependences. The periodicity of corrugations for all used ions slightly decreases with increasing temperature and is of the order of hundreds of nanometers. For neon and argon ions the corrugation inclination angles and the fraction in contrary of nitrogen ions show minima at the temperatures near 400 ℃ which corresponds to the minimum of radiation-induced dimensional changes in carbon materials. The depth of the minima at 400℃ depends on the competition of the processes of ion-induced plastic deformation of carbon materials and ion bombardment sputtering. For nitrogen ions the inclination angles increase with temperature so that at temperature ～ 270℃ they reach maximum values ～ 40°, staying at this level at subsequent temperature elevation up to 600℃. The qualitative difference in the temperature dependences of fiber corrugation for noble gas ions and nitrogen ones is connected to nitrogen chemical activity and the creation of C—N bonds under nitrogen ion implantation.