Abstract : Improving the thermal efficiency of aircraft gas turbines and of thermal power generation systems is of great interest for industry. Despite the various studies performed to increase their heat-resistance, the use of nickel-based superalloys at temperatures beyond 1150°C will be difficult. For higher temperatures, new high temperature structural materials are required. In this context, ceramics offer many advantages compared to Ni-based superalloys: a lower density and a better resistance to oxidation and abrasion. Two kinds of ceramics are investigated at Onera: Si3N4 based materials for use up to 1500°C and directionally solidified eutectic (DSE) ceramics up to 1700°C. For both materials improving toughness is a challenge. This paper presents the processing techniques, the microstructural features and the mechanical properties.
