J. Phys. IV France 10 (2000) Pr9-713-Pr9-718
Experimental and theoretical simulation of material degradation caused by atomic oxygen impact in spaceT. Uchiyama, K. Satoh and T. Shioya
Department of Aeronautics and Astronautics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
The degradation of structural material exposed in space is a new problem, since various kinds of materials have been used for structures in low earth orbit (LEO). This study presents an experiment of degradation on the ground and a simulation by the molecular dynamics. In the experiment, atomic oxygen produced at a plasma torch is accelerated fluid dynamically with working gas. Graphite, C/C composite and Si-C.C. (: Silicon impregnated C/C composite) were used as the target materials. The mass loss per unit area is approximately proportional to the exposure time and depends strongly on the temperature of material surface. The eroded surfaces of materials were observed with SEM and EPMA. In case of C/C composite, the matrix region erodes substantially more than carbon fiber. The mass loss of Si-C.C. is less than that of corresponding C/C composite and only the C/C composite region erodes deeply with almost no erosion in Si and SiC regions. In order to investigate the degradation caused by high-energy atomic oxygen, numerical simulation was conducted for graphite using the molecular dynamics method. The simulation model explains the influence of exposure time on the degradation of material.
© EDP Sciences 2000