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

摘要

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 SiO_2-passivated ceramics, SiC shows poor oxidation resistance in moist atmospheres. In this contribution, the oxidation behaviour at 1400 deg C of fully dense SiC samples with Lu_2O_3-AlN and Lu_2O_3-Ho_2O_3 sintering additives is investigated. Similar to results recently reported for a novel Si_3N_4 material, it is demonstrated that Lu_2O_3 yields greatly improved oxidation behaviour as compared to other liquid phase sintered SiC materials. In particular, the Lu_2O_3-Ho_2O_3 additive leads to passive oxidation under a 0.01 MPa partial pressure of water.