Synthesis and Properties of MoSi2/SiC Processed by Low Pressure Plasma Co-Injection and Deposition

Low-pressure plasma deposition (LPPD) and co-injection has been used to fabricate a MoSi2 composite reinforced with 15 µm SiC particles. The microstructure and creep behavior of the LPPD processed composite are reported and discussed. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed the structure of the composite to be lamellar and energy dispersive X-ray analysis (EDAX) identified the phases present in the material as: MoSi2, Mo5Si3, SiO2, and SiC. Density characterization revealed a porosity of less than 1.0 vol. %, indicating a nearly fully dense material. A high concentration of SiO2 (∼8.0 vol. %) present in the MoSi2/SiC composite may be attributed to possible contamination of the starting powders before or during LPPD. Sublimation of SiC during co-injection led to a low volume fraction (< 2.0 vol. %) of reinforcement in the composite. The creep rate of the LPPD MoSi2/SiC was higher relative to that of MoSi2/SiC composites fabricated by powder metallurgy (PM) techniques. On the basis of the results of this study it has become evident that alternative processing methods such as LPPD insitu processing may be better suited for the fabrication of elevated volume fraction MoSi2/SiC composites.