Oxidation and emissivity of Inconel 718 alloy as potential space debris during its atmospheric entry

摘要

In order to mitigate debris in orbit and to avoid dramatic collisions on Earth after atmospheric re-entry at its end of-life, the spacecraft missions have to take into account the influence of atmospheric re-entry conditions on the spacecraft survivability. In this way, oxidation in air plasma conditions was studied on Inconel 718 alloy in order to obtain degradation kinetic laws at high temperature for short time duration (few minutes). Moreover, measurements of the total emissivity at high temperature up to the melting point were carried out on the same alloy - in high vacuum to avoid oxidation - and on samples oxidized in standard or in air plasma conditions. An increase of the total emissivity for oxidized samples by a factor 3 to 4 is obtained compared to as-received samples. This effect can strongly influence the ablation during a trajectory and consequently the casualty area calculation. Experimental results on oxidation and emissivity are presented together with the microstructural characterization of the samples (surface and cross-section) using several techniques. (C). 2017 Elsevier Inc. All rights reserved.