A dense and fine-grained SiC/Ti3Si(Al)C2 composite and its high-temperature oxidation behavior

A dense SiC/Ti3Si(Al)C-2 composite was synthesized by in situ hot pressing powders of Si, TiC and Al as a sintering additive at 1500 degrees C for 2 h under 30 MPa in Ar atmosphere. This composite has a fine-grained and homogeneous microstructure with grain sizes of 5 mu m for Ti3Si(Al)C-2 and of 1 mu m for SiC. The SiC/Ti3Si(Al)C-2 composite possesses an improved oxidation resistance, with parabolic rate constants of 4.57 x 10(-8) kg(2)/m(4)/s at 1200 degrees C and 1.31 x 10(-7) kg(2)/m(4)/s at 1300 degrees C. This study provides an experimental evidence to confirm the formation of amorphous phases in the oxide scale of the SiC/Ti3Si(Al)C-2 composite. Microstructure and phase composition of the SiC/Ti3Si(Al)C-2 composite and oxide scales were identified by X-ray diffractometry and scanning electron microscopy. The mechanism for the enhanced oxidation resistance has been discussed. (c) 2012 Elsevier Ltd. All rights reserved.