Silicon nitride/silicon carbide nanocomposite obtained by nitridation of SiC: fabrication and high temperature mechanical properties

Si3N4/SiC nanocomposites have been successfully synthesized according to a novel technique consisting in the nitridation of silicon carbide raw materials followed by their sintering in the presence of appropriate sintering aids. Depending on the kind of additive used, the microstructure of the final nanocomposite can be tailored from elongated silicon nitride matrix grains with silicon carbide nanoparticles dispersed into them, through completely nano-sized composites consisting of equiaxed silicon carbide and silicon nitride grains. Thermomechanical properties are related to those microstructural features and to the secondary phase composition and its subsequent crystallisation.