Ultra-high temperature ceramics (UHTCs), particularly diborides and carbides of the transition metals like hafnium and zirconium, are currently accepted as potential candidates for a variety of high-temperature structural applications, including furnace elements, plasma-arc electrodes, or rocket engines and thermal protection structures for space vehicles with temperature capabilities at over 1800 ◦C.The growing interest in UHTCs stems from the opportunities they provide for designing a new generation of space vehicles with very sharp leading edges.4 This innovative class of materials has the potential to overturn an age-old tenet of aerodynamics, that only blunt-body spacecraft can survive the searing temperatures generated as the vehicle repeatedly tears through the terrestrial atmosphere during hypersonic flights. The expected highly localized heating loads in the areas particularly exposed to the interaction with the atmosphere during re-entry missions dictate the need for oxidation and ablation resistance, coupled with a low surface catalytic efficiency, and a capacity to conduct away or re-radiate excess energy.The introduction of SiC in matrices of zirconium and hafnium diborides improved the mechanical properties1,3,6 and oxidation resistance.
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