Reaction bonded silicon nitride (RBSN) has been fabricated from Si powder with cordierite as a sintering aid. A nitridation rate of more than 90% was obtained in each specimen. As the amount of cordierite was increased, the nitridation rates decreased. Both α-Si3N4 and β-Si3N4 were formed during the nitridation of silicon to Si3N4. There were more beta crystals in the specimens with a higher cordierite content. The relative densities increased when the amount of cordierite increased. A Fracture toughness of 3.59±0.28 MPa-m1/2 was obtained for the specimen containing 18 wt% cordierite sintered at 1800 οC for 3 hours.
Keywords: Pressureless-sintering, RBSN, Nitridation, Relative density, Fracture toughness.