Characterization Of Emissivity And Surface Catalycity Of Ultra High Temperature Ceramics And C/SIC Composites For Space Applications
- Paper number
IAC-07-C2.4.05
- Author
Dr. Luigi Scatteia, CIRA Italian Aerospace Research Centre, Italy
- Coauthor
Dr. Davide Alfano, CIRA Italian Aerospace Research Centre, Italy
- Coauthor
Dr. Marianne Balat Pichelin, France
- Coauthor
Dr. Karin Handrick, MAN Technologie AG, Germany
- Coauthor
Prof. Raffaele Savino, University of Naples "Federico II", Italy
- Year
2007
- Abstract
Surface catalycity and emissivity are key parameters for the eligibility of ceramic materials in hot structures manufacturing. Reliable experimental evaluations of these parameters are required to feed aero-convective heating computations (that, in absence of experimental data, have to rely on extremely conservative theoretical values), and extrapolate the structure performance in real re-entry conditions from on-ground test data obtained in arc-jet facilities. In this paper the results of an experimental campaign dedicated to characterize the surface catalycity and the emissivity of UHTC materials and of coated C/SiC composites are presented. The campaign was jointly conducted by CIRA and PROMES-CNRS on two UHTC material compositions based upon ZrB2 and HfB2 produced by CNR-ISTEC and on the C/SiC “Keraman” produced by MT Aerospace. These materials are currently under evaluation within the Sharp Hot Structure (SHS) technological project led by CIRA, The UHTC samples tested was produced by hot pressing, and then machined into samples for measurement by using alternatively diamond tooling (DT) and electrical discharge machining (EDM): this was done in order to investigate the effect of EDM machining on the surface properties of the samples. The recombination coefficient for atomic oxygen and the total hemispherical emissivity in the range 1000-1800 K were measured, under vacuum and under low pressure subsonic air flow. The characterization campaign was conducted using the MEDIASE and MESOX facilities developed at the PROMES-CNRS laboratory. Microstructural analysis prior and after the high temperature exposure into the MEDIASE and MESOX apparati were also performed. Additional tests were performed using a different experimental set-up based upon the use of a plasma torch plant. This allowed to reach test temperature up to 2300K. The obtained results were compared and discussed.
- Abstract document
- Manuscript document
IAC-07-C2.4.05.pdf (🔒 authorized access only).
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