Ultra-high temperature ceramics developments for hypersonic applications
Ultra-High Temperature Ceramics are good candidates to fulfil the harsh requirements of hypersonic applications. For more than a decade, the Materials and Structures Department (DMAS) of ONERA has been actively involved in several programmes to develop such materials for different applications (hypersonic flights, propulsion systems...). In our laboratories, monolithic and composite materials have been investigated as well as several processing methods. In this paper, we present for example the ZrB2-SiC and HfB2-SiC compositions with TaSi2 or Y2O3 additions which have been especially studied in the European Projects ATLLAS and ATLLAS II. Assessments of several prototypes in realistic environment are also described. Furthermore, based on these material developments, a specific study on the oxidation behaviour of such monoliths from 1200 °C to 2400 °C with a dedicated test bench using a 2 kW CO2 laser has been carried out (oxidation under air and water vapour atmospheres). Recently, some work on the manufacturing of Ultra-High Temperature Ceramic Matrix Composites has been initiated using slurry infiltration and pyrolysis. The behaviour and properties of these materials are encouraging.