MICROSTRUCTURE AND PROPERTIES OF mosi2-Si3N4 COMPOSITES

Si3N4-composites materials containing different amounts of MoSi2 were produced by hot-pressing. MoSi2 particles (mean size 0.8 µm) were homogeneously dispersed within a nanostructured Si3N4 matrix (mean grain size < 0.2 µm). The influence of MoSi2 inclusions on microstructure and electrical and mechanical properties of the composites was discussed and compared to the properties of monolithic Si3N4. As a result of both the refined microstructure of the matrix and presence of ductile inclusions, these materials possess outstanding mechanical properties, with bending strength up to 1130 MPa (RT) and 880 MPa (1000°C) and fracture toughness up to 8 MPa·m ½. Electrical resistivity is ~10-3 Ohm·cm.