Multilayer SiC for thermal protection system of space vehicles: Manufacturing and testing under simulated re-entry conditions

Self passivating behavior of multilayer SiC under simulated atmospheric re-entry conditions

“…[12][13][14] Since 1990 Clegg showed that the SiC-based multilayer displays improved toughness over monolithic SiC when weak layers (due to different composition or enhanced porosity degree) are integrated within the laminate architecture. [15][16][17] The weakness of some layers and of interlayer bonds as well as the residual stresses are believed to promote crack deflection phenomena, which result in the increase of the fracture work.…”

Multilayer SiC for thermal protection system of space vehicles with decreased thermal conductivity through the thickness

“…33,34,38,39 The processing method involved several steps: slurry preparation, tape casting, solvent evaporation, layer stacking, debinding and sintering. The slurry was obtained by dispersing SiC powder (grade UF 15 produced by Starck, particle size 0.55 m and specific surface area 14-16 m 2 /g), with boron powder (grade I produced by Starck, particle size 1-2 m and specific surface area >10 m 2 /g) and graphite powder (flake 7-10 m produced by Alfa Aesar) as sintering aids, together with dispersant (fish oil) in a mixture of organic solvents (ethanol, butanol and tetrachloroethylene in approximate weight percent rates of 23, 36 and 41).…”

“…In a previous paper, 34 we already proposed SiC-based laminate containing porous layers (prepared by tape casting, debinding and sintering) as a promising material to be employed for TPS of space vehicles and we described the behaviour of this material when submitted to thermal re-entry tests under test conditions representing the trajectory of the HERMES vehicle. 35 Owing to the promising thermal performance of this material, the presence of porous layers in the architecture of SiC-based laminates was further investigated in this paper.…”

Oxidation Resistance of Multilayer SiC for Space Vehicle Thermal Protection Systems

“…The final sintering treatment was performed under an argon atmosphere (pressure 500-600 mbar) at 2 200 8C for 30 min. More details about this processing method have been reported in a previous paper [20] .…”

“…In addition, after 100 re-entry cycles this kind of multilayer ceramic retained a significant fraction of its original strength and stiffness, thus proving its effectiveness as external component of a re-usable TPS. [20] Multilayer SiC can be easily produced by exploiting tape-casting technology, which is suitable for obtaining flexible ceramic sheets of rather large size (e.g., 2 Â 10 m in industrial tape-casting equipment). These sheets can be stacked on a mould, thus obtaining flat or curved panels with tailored shapes and thickness.…”