Abstract: MoSi compound composites were synthesized by in situ reaction hot pressing. Their microstructure and phase composition were analyzed by means of scanning electron microscope(SEM), electron probe microanalyzer(EPMA) and Xray diffractometer(XRD). The results indicate that the reaction products in MoSi system vary according to the order MoSi2→Mo5Si3→Mo3Si with increasing content of Mo in mixed powders. The sintered materials are nearly fully densified except the Mo3SiMo composite,exhibiting fine and homogeneous microstructures. Both MoSi2Si and MoSi2Mo5Si3 materials have an equivalent volume fraction and display an“infiltrationflow structure”. In Mo3SiMo composite, the excess Mo phase exists in “islandstructure”.

Key words: Mo-Si compounds, Reaction sintering, Microstructure