Liquid phase sintered silicon carbide (LPS-SiC) ceramics having remarkably high oxidation resistance in wet air

Numerous studies on the oxidation characteristics of common silicon carbide ceramics have revealed very good oxidation resistance in dry atmospheres, provided that the oxygen partial pressure is sufficiently high. On the contrary, as other SiO2-passivated ceramics, SiC shows poor oxidation resistance in moist atmospheres. In this contribution, the oxidation behaviour at 1400 °C of fully dense SiC samples with Lu2O3–AlN and Lu2O3–Ho2O3 sintering additives is investigated. Similar to results recently reported for a novel Si3N4 material, it is demonstrated that Lu2O3 yields greatly improved oxidation behaviour as compared to other liquid phase sintered SiC materials. In particular, the Lu2O3–Ho2O3 additive leads to passive oxidation under a 0.01 MPa partial pressure of water.