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

这个小型企业创新研究（SBIR）二期项目旨在进一步开发和优化创新技术，以经济高效地制造致密碳化硅（SiC）纤维增强二硅化钼（MoSi2）复合材料，增强强度和韧性，可达到极高的温度（1400摄氏度）。二硅化钼在涡轮发动机、燃烧器、热气体过滤器、熔融金属喷枪和加热元件中具有非常有吸引力的耐热、抗氧化和耐腐蚀性能，但其结构较弱。如果mosi2基复合材料能够经济有效地加工成净形状，那么机械性能优越的第二相材料将使其成为此类应用的重要候选材料。第一阶段的项目证明了用可控数量的SiC晶须或颗粒形成MoSi2基体的可行性，这些晶须或颗粒本身是原位形成的。此外，还开发了几种强度高、密度大、抗虫害的SiC(f)/MoSi2组合物。这些成分是通过单步工艺开发的，该工艺结合了Mo， Si和C元素混合物的自传播高温合成（SHS）和伪热等静压(HIP) -电固合。第二阶段的研究将展示该工艺的近净形状能力，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原型进行测试。SiC(f)增韧MoSi2复合材料的直接商业用途可以实现作为加热元件，燃烧和燃烧器平台，以及熔融金属过滤器。未来的应用包括航空和燃气涡轮发动机部件、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能量存储设备，如超级电容器。

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.