Catalytic and Radiative Behaviors of ZrB2-SiC Ultrahigh Temperature Ceramic Composites

Material property requirements for analysis and design of UHTC components in hypersonic applications

“…Direct measurements of hemispherical emissivity at elevated temperatures are difficult, and few such data are available in the literature for UHTC materials. The measurements of Scatteia et al 58,59 for ZrB 2 -15SiC-2MoSi 2 , ZrB 2 -15SiC, and ZrB 2 -15SiC-10HfB 2 composites are a notable exception. Emissivity values ranged from 0.49 to 0.81, depending on material composition, temperature, machining method, and ambient oxygen environment.…”

“…Emissivity values ranged from 0.49 to 0.81, depending on material composition, temperature, machining method, and ambient oxygen environment. Scatteia et al 58,59 assign errors of ±5% to their measurements.…”

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

“…Both values of emittance are reasonable estimates for oxidized ZrB 2 -SiC composites. 14,17,43 Without an in situ method for determining the high-temperature emittance during testing, such a level of uncertainty (∼15%) in emittance is unavoidable. Note that the hot wall heat fluxes are only about half of the corresponding cold wall heat fluxes, which suggests that the surface catalytic efficiencies of the oxidized UHTC surface must be low.…”

“…The emittance measurements of Scatteia et al on various UHTC composites (ZrB 2 -15SiC, ZrB 2 -15SiC-2MoSi 2 , and ZrB 2 -15SiC-10HfB 2 ) are notable in this regard. 43 Because it may be difficult to reproduce oxidized UHTC surfaces in the laboratory that are the same as those formed in the low-pressure, highly dissociated-oxygen environments of arc-jet and ICP flows, in situ measurements would be preferred.…”

Advances in Ultra High Temperature Ceramics for Hot Structures

“…The total hemispherical emissivity and the atomic oxygen recombination coefficient were measured using the MEDIASE and MESOX facilities located at PROMES-CNRS, France 33) . Both the UHTC composition A and B, were tested, in samples machined by diamond loaded tools (DLT) or by electrical discharge machining (EDM) in order to evaluate the effect of the surface finish on those properties 33), 34) .…”