Properties of Si3N4-MoSi2 composites with nanostructured matrix

Si3N4-composite materials containing different amounts of MoSi2 were produced by hot pressing. MoSi2 particles (mean grain 0.8 ?m) were homogeneously dispersed within a nanostructured Si3N4 matrix (mean grain size 0.2 ?m). The influence of MoSi2 inclusions on microstructure and electrical and mechanical properties of the composites is discussed. As a result of both refined microstructure of the matrix and presence of ductile inclusions, these materials possess good mechanical properties, with bending strength up to 1130 MPa (RT) and 880 MPa (1000°C) and a fracture toughness up to 6 MPa m^0.5. Electrical resistivity drops to about 10^(-3) Ohm cm.