Plasma-induced silica-like protection layer formation on C/C - SiC heat-shield materials for re-entry vehicles

High-enthalpy test environments, flow modeling and in situ diagnostics for characterizing ultra-high temperature ceramics

“…Hirsch et al, 52 Altman et al, 53 and Jentschke et al 54 have monitored Si atom densities in front of C/C-SiC composites exposed to nitrogen-oxygen plasma flows, using high-resolution spectroscopy of Si I multiplet emissions in the 250-253-nm range. Herdrich et al 55 observed Si emission near 252 nm and 288 nm while testing SiC specimens in oxygen-nitrogen plasmas, and also captured emission from SiO 2 molecules near 423 nm.…”

“…This suggests that FTIR emission spectroscopy might be used as an in situ monitor for changing surface compositions during high-enthalpy testing. Measurements of this type were made by Hirsch et al 52 for characterizing the oxidation behavior of carbon/carbon and carbon/silicon carbide composites in the ICP wind tunnels. However, this concept has never been explored as an in situ diagnostic for UHTC materials systems.…”