Passive/active oxidation transition for CMC structural materials designed for the IXV vehicle re-entry phase

This paper reports the experimental results of oxidation studies for the determination of the transition between passive and active oxidation of two silicon carbide-based materials produced by Herakles-Safran (France) and MT Aerospace (Germany) with also the study of the oxidation kinetics in the active zone for the highest heating conditions of the Intermediate eXperimental Vehicle (IXV) re-entry trajectory. The transition between active and passive oxidation is determined for both materials using two different plasma facilities - a low enthalpy one using the MESOX at PROMES-CNRS (Font-Romeu Odeillo, France) and a high enthalpy one using the Plasmatron at VKI (Rhode St Genèse, Belgium) - and the experimental results lead to the same transition law. Characterization by SEM of the oxidized samples (surface and cross-section) is shown. Mass loss rates in active oxidation conditions are reported for both Herakles and MTA materials.