Improved high temperature properties of SiC-ceramics sintered with Lu2O3-containing additives

Liquid-phase (LPS) sintered silicon carbide ceramics with additive systems containing aluminium nitride and rare earth oxides in combination are candidate materials for good high temperature performance in terms of creep behaviour and oxidation resistance. In the present work, creep testing in four-point bending geometry and scanning electron microscopic observation of oxidized surfaces were performed on yttrium and lutetium sesquioxide containing materials, demonstrating that Lu2O3-containing sintering additives give rise to largely improved properties. In particular, strain rates of about 1 × 10−9 s−1 were measured at both 1400 °C/100 MPa and 1300 °C/300 MPa in air. Oxidation resistance of LPS-SiC sintered with Lu2O3 was measured in the temperature range 1200–1500 °C for 100 h and improved behaviour was observed as compared to other liquid phase sintered SiC with different additives.