Low Cost sic/Si3N4 Nanocomposites

A new perspective low cost route of SiC-Si3N4 nanocomposite processing is introduced. The method of preparation is based on formation of SiC nanograins by the carbothermal reduction of SiO2 by C in the Y2O3 - SiO2 system at the temperature of sintering. The room temperature hardness of the SiC/Si3N4 nanocomposite with the 5 wt% of SiC was 17.3 GPa, fracture toughness of the same composite was 6.2 MPa.m(1/2). These properties are lower compared to those prepared by addition of amorphous SiCN powder. High temperature creep resistance is between 10(-9) to 10(-7) s(-1) within the temperature interval from 1200 to 1400 degreesC.