This Phase I Small Business Innovation Research (SBIR) project aims to tailor and develop (fiber)-reinforced MOSi2 composites with enhanced strength and toughness up to very high temperatures (~1400C). The MOSi2 matrix will be formed and reinforced with controlled amounts of SiC fibers (continuous or chopped), and the composite densified in one step. The SiC reinforcement will provide structural strength and toughness to the composite without adding to its weight. Densification will be accomplished in a single step process that combines SHS (combustion synthesis) of elemental mixtures of Mo, Si, and C with HIPing (electro-consolidation). In-situ reinforcement with continuous or chopped SiC fibers will take place through reaction of Si and C at or below the adiabatic temperatures of SHS reaction between Mo and Si. Near-net shape capability of the process is enhanced by the use of C fiber preforms for infiltration. Molybdenum disilicide (MOSi2) has attractive thermal, oxidation, and corrosion resistance properties but is weak structurally. Reinforcement with a mechanically superior second phase material makes MoSi2-based composites serious candidates for useful applications, if the composites can be processed to net shape and economically. Immediate commercial use of the SiC-toughened MOSi2 composites can be realized as heating elements, combustion and burner rigs, and molten metal filters. Future applications include uses for aviation and gas turbine engine components, heat exchangers, waste incinerators, and hot gas filters. Other advanced applications include energy storage devices such as ultracapacitors.
