Ultra-high temperature ceramic matrix composite

Ultra-high temperature ceramic matrix composites (UHTCMC) are a class of refractory <a href="/facts/Ceramic_matrix_composites/zvty2Svr">ceramic matrix composites</a> (CMCs) with melting points significantly higher than that of typical CMCs. Among other applications, they are the subject of extensive research in the aerospace engineering field for their ability to withstand extreme heat for extended periods of time, a crucial property in applications such as <a href="/facts/Space_Shuttle_thermal_protection_system/1rHI1w6q">thermal protection systems</a> (TPS) for high heat fluxes (> 10 MW/m2) and <a href="/facts/Rocket_engine_nozzle/K4kHCmFX">rocket nozzles</a>. <a href="/facts/Reinforced_carbon%25E2%2580%2593carbon/hDRQD3W2">Carbon fiber-reinforced carbon</a> (C/C) maintains its structural integrity up to 2000 °C; however, C/C is mainly used as an <a href="/facts/Ablation/tTSHH09G">ablative</a> material, designed to purposefully erode under extreme temperatures in order to dissipate energy. Carbon fiber reinforced silicon carbide matrix composites (<a href="/facts/Reinforced_carbon%25E2%2580%2593carbon/hDRQD3W2">C/SiC</a>) and Silicon carbide fiber reinforced silicon carbide matrix composites (<a href="/facts/Ceramic_matrix_composite/zvty2Svr">SiC/SiC</a>) are considered reusable materials because silicon carbide is a hard material with a low erosion and it forms a <a href="/facts/Fused_quartz/avtX1fy3">silica glass</a> layer during oxidation which prevents further oxidation of inner material. However, above a certain temperature (which depends on the environmental conditions, such as the partial pressure of oxygen), the active oxidation of the silicon carbide matrix begins, resulting in the formation of gaseous silicon monoxide (SiO(g)). This leads to a loss of protection against further oxidation, causing the material to undergo uncontrolled and rapid erosion. For this reason C/SiC and SiC/SiC are used in the range of temperature between 1200 °C - 1400 °C. The oxidation resistance and the thermo-mechanical properties of these materials can be improved by incorporating a fraction of about 20-30% of UHTC phases, e.g., <a href="/facts/Zirconium_diboride/PRQSefK0">ZrB2</a>, into the matrix.
On the one hand <a href="/facts/Ceramic_matrix_composite/zvty2Svr">CMCs</a> are lightweight materials with high strength-to-weight ratio even at high temperature, high thermal shock resistance and toughness but suffer of erosion during service. On the other side bulk ceramics made of <a href="/facts/Ultra-high_temperature_ceramic/oTkLhdab">ultra-high temperature ceramics</a> (e.g. ZrB2, HfB2, or their composites) are hard materials which show low erosion even above 2000 °C but are heavy and suffer of catastrophic fracture and low thermal shock resistance compared to CMCs. Failure is easily under mechanical or thermo-mechanical loads because of cracks initiated by small defects or scratches. current research is focused on combining several reinforcing elements (e.g short carbon fibers, PAN or pitch based continuous carbon fibers, ceramic fibers, graphite sheets, etc) with <a href="/facts/Ultra-high_temperature_ceramic/oTkLhdab">UHTC</a> phases to reduce the brittleness of these materials.
The European Commission funded a research project, C3HARME, under the NMP-19-2015 call of Framework Programmes for Research and Technological Development in 2016-2020 for the design, manufacturing and testing of a new class of ultra-refractory ceramic matrix composites reinforced with carbon fibers suitable for applications in severe aerospace environments as possible near-zero ablation thermal protection system (TPS) materials (e.g. <a href="/facts/Heat_shield/YvRhkzAz">heat shield</a>) and for propulsion (e.g. rocket nozzle). The demand for reusable advanced materials with temperature capability over 2000 °C has been growing. Recently carbon fiber reinforced zirconium boride-based composites obtained by powder slurry impregnation (SI) and sintering has been investigated. With these promising properties, these materials can be also considered for other applications including as friction materials for braking systems.

Ultra-high temperature ceramic matrix composite open-in-new

Ultra-high temperature ceramic matrix composite