Ultrahigh temperature ceramics for thermal protection systems, propulsion and energy

Ultra high temperature ceramics (UHTCs) include borides and carbides of early transition metals and are presently considered a class of promising materials for application in the aerospace and energy sectors. As for TPS systems, crucial issues for use in severe environment are the low fracture toughness and thermal shock resistance of UHTCs. To overcome these limits, ISTEC activities have been recently concerned with fabrication of ZrB2-based ceramics containing short and long SiC and C fibers/preforms (UHTC-CMCs). Another part of ISTEC ongoing research is concerned with the development of ultra- refractory carbides for application as rocket nozzles (HfC, TaC). These are interesting compounds for the development of future generation thrusters that require the combination of more severe combustion conditions in terms of temperature and pressure. Ablation tests and propulsion tests of ceramic nozzles are in progress.