Pressureless sintering of internally synthesized SiC-TiB2 composites with improved fracture strength

Abstract

SiC-TiB2 particulate composites were fabricated by converting TiO2 to TiB2 through the reaction between TiO2, B4C and C. The presence of initially very fine, in-situ created, TiB2 particles increased driving force for sintering and enabled fabrication of a dense composite utilizing pressureless sintering and the liquid phase created between Al2O3 and Y2O3 additives. The effect of volume fraction of the in-situ formed TiB2 on density, microstructure and flexural strength was discussed. It was found that the presence of TiB2 particles suppressed the growth of SiC grains and enhanced fracture strength. The fracture strength of samples containing 12 vol% TiB2 was more than 30% higher than that of the monolithic SIC. The effect of SIC grain size on fracture strength was also analyzed. (C) 2010 Elsevier B.V. All rights reserved.