HTHP EA HomeIssue Contents

Plasma-induced silica-like protection layer formation on C/C–SiC heat-shield materials for re-entry vehicles
Kurt Hirsch, Bernhard Roth, Ingo Altmann, Karl-Ludwig Barth, Herbert Jentschke, Achim Lunk, Uwe Schumacher

The interaction of a plasma flow with a sample of heat-shield material such as C/C – SiC suitable for thermal protection simulates the main features during the re-entry phase of space vehicles. The formation characteristics of a ‘self’ protecting silica-like surface layer are studied in situ by short-time images of a video camera. Band pass filters discriminate the grey emission of the surface against plasma radiation. Formation speeds and times, respectively, as well as a threshold behaviour were determined for different heat loads. Simultaneously the emission of erosion products (Si I, C I) was spectrally resolved and their temporal development recorded. Additional infrared emission spectra of the sample clearly show the development of the silica phonon spectra indicating a growing layer thickness. An analysis of the temporal development of the erosion rate of these materials agrees with the other results and the hypothesis on this self protection behaviour.

Full Text (IP)