SBIR Phase II: Net Shape, SiC-Toughened Molybdenum Disilicide Composites

该小型企业创新研究(SBIR)二期项目旨在进一步开发和优化创新技术，以经济高效地制造高密度碳化硅(SiC)纤维增强二硅化钼(MoSi2)复合材料，该复合材料的强度和韧性可提高到非常高的温度(1400摄氏度)。二硅化钼在涡轮发动机、燃烧器、热煤气过滤器、熔融金属喷枪和加热元件等应用中具有非常诱人的耐热、耐氧化和耐腐蚀性能，但结构较弱。具有机械性能优越的第二相材料的增强使MoSi2基复合材料成为此类应用的重要候选材料，如果该复合材料能够有效地加工成净形状成本的话。第一阶段项目证明了反应形成MoSi2基质的可行性，其中控制了碳化硅晶须或颗粒的数量，这些颗粒本身就是原位形成的。此外，还开发了几种碳化硅(F)/MoSi2复合材料，它们具有强度大、致密和抗虫害的特点。这些组合物是通过一步法开发的，该工艺结合了Mo、Si和C元素混合物的自蔓延高温合成(SHS)和伪热等静压(HIP)-电结合。第二阶段的研究将展示该工艺的近净成形能力以及生产坚固的MoSi2基复合材料的能力。根据涡轮发动机制造商的设计规范，该项目还将在第二阶段结束时制造用于测试的原型。碳化硅(F)增韧的MoSi2复合材料可以立即实现商业用途，用作加热元件、燃烧和燃烧器试验台以及熔融金属过滤器。未来的应用包括航空和燃气轮机发动机部件、热交换器、热气体过滤器和垃圾焚烧炉。其他先进的应用包括超级电容器等储能设备。

This Small Business Innovation Research (SBIR) Phase II project aims at further developing and optimizing the innovative technology for the cost-effective fabrication of dense silicon carbide (SiC) fiber-reinforced molybdenum disilicide (MoSi2) composites with enhanced strength and toughness up to very high temperatures (1400 degrees C). Molybdenum disilicide has very attractive thermal, oxidative, and corrosion resistance properties for applications in turbine engines, burner rigs, hot gas filters, molten metal lances, and heating elements, but is structurally weak. Reinforcement with a mechanically superior second phase material makes MoSi2-based composites serious candidates for such applications if the composites can be processed to net shape cost effectively. The Phase I project demonstrated the feasibility of reaction forming the MoSi2 matrix with controlled amounts of SiC whiskers or particles, which themselves are formed in-situ. Further, several SiC(f)/MoSi2 compositions were developed that are strong, dense, and resistant to pesting. These compositions were developed using a single step process that combines Self-Propagating High-Temperature Synthesis (SHS) of elemental mixtures of Mo, Si, and C with psuedo-Hot Isostatic Pressing (HIP) -- electroconsolidation. Phase II research will demonstrate the near-net shape capability of the process along with the ability to produce robust MoSi2-based composites. Based on design specifications from turbine engine manufacturers, the project will also fabricate prototypes for testing at the end of Phase II. Immediate commercial use of the SiC(f)-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, hot gas filters, and waste incinerators. Other advanced applications include energy storage devices such as ultracapacitors.