High temperature strength of silicon carbide sintered with 1 wt.% aluminum nitride and lutetium oxide

A heat-resistant SiC ceramic was developed from submicron p-sic powders using a small amount (1 wt.%) of AlN-Lu2O3 additives at a molar ratio of 60:40. Observation of the ceramic using high-resolution transmission electron microscopy (HRTEM) showed a lack of amorphous films in both homophase (SiC-SiC) boundaries and junction areas. The junction phase consisted of Lu-Si-O elements, and the homophase boundaries contained Lu, Al, O, and N atoms as segregates. The ceramic maintained its room temperature (RT) strength up to 1600 degrees C. The flexural strength of the ceramic was 630 MPa and 633 MPa at RT and 1600 degrees C, respectively. (C) 2012 Elsevier Ltd. All rights reserved.