Concentrated Solar Energy as a Diagnostic Tool to Study Materials Under Extreme Conditions

Abstract

This paper deals with the material testing under extreme conditions, mainly around space programs, using the French CNRS (Centre National de la Recherche Scientifique) solar facilities for planetary entry (Earth, Mars), solar corona in situ exploration, and cryogenic propulsion. For these purposes, different facilities were developed around the various solar concentrators: MESOX (Moyen d’Essai Solaire d’OXydation), for the study of the atomic oxygen recombination at the surface of heated materials and the oxidation kinetics of ceramics under plasma atmospheres up to 2300 K. (Some results are given for several materials.); MEDIASE (Moyen d’Essai et de DIagnostic en Ambiance Spatiale Extre^me), for the thermophysical characterization of thermal shield materials up to 2400°K under high vacuum: mass-loss kinetics, mass spectrometry (neutral and ionic species) and thermo-radiative properties (total or spectral directional emissivity). (Results are presented for various carbon/carbon composite materials.); and DISCO (DISpositif de Caracte´risation Optique), for the measurement of changes in the reflectivity of materials at temperatures up to 2500°K and its correlation with the surface behavior (aging, ablation and oxidation). Results concerning a copper alloy used for the combustion chamber of cryogenic motors are given.

Hafnium and tantalum carbides for high temperature solar receivers

“…High-temperature characterization has been carried out using the MEDIASE (Moyen d'Essai et de Diagnostic en Ambiance Spatiale Extrême) set-up of the MegaWatt Solar Furnace [15][16][17] in Font Romeu (France). MEDIASE is composed by a high-vacuum chamber (ultimate pressure limit of 10 À6 mbar), equipped with a hemispherical silica glass window of 35 cm diameter.…”

Emissivity and catalycity measurements on SiC-coated carbon fibre reinforced silicon carbide composite

“…Total hemispherical emissivity ε ∩ (T) as a function of temperature T has been measured in the range 700-1600 • C using a direct method 41 with the MEDIASE set-up developed at PROMES-CNRS laboratory [42][43][44] under the Solar Facilities for Europe (SOLFACE) program (6th Framework Program-European Community). Although the temperature values reached by different parts of a TPS during the re-entry phase in Earth's atmosphere depends on the geometry of the spacecraft and on the specific re-entry trajectory, the chosen temperature range (700-1600 • C) to perform emissivity and catalycity measurements is relevant to describe the typical reentry conditions of a blunt-body winged re-entry vehicle (e.g.…”

Surface Properties and Oxidation Behaviour of Ultra High Temperature Ceramics for Sharp Leading Edges

“…The device, depicted in Fig. 3, is described in details elsewhere [9,10]. Emissivity experiments have been carried out in air at 200 Pa and at 10 -3 Pa.…”