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

该小型企业创新研究（SBIR）第二阶段项目旨在进一步开发和优化具有成本效益的致密碳化硅（SiC）纤维增强二硅化钼（MoSi 2）复合材料的制造创新技术，该复合材料具有增强的强度和韧性，可达到非常高的温度（1400摄氏度）。 二硅化钼对于涡轮机发动机、燃烧器装置、热气过滤器、熔融金属喷枪和加热元件中的应用具有非常有吸引力的耐热性、抗氧化性和抗腐蚀性，但是其结构较弱。 如果复合材料可以被有效地加工成净形状，则具有机械上优异的上级第二相材料的增强使得基于MoSi 2的复合材料成为此类应用的重要候选者。 第一阶段项目证明了反应形成具有可控量的SiC晶须或颗粒的MoSi 2基质的可行性，SiC晶须或颗粒本身是原位形成的。 此外，开发了几种强度、密度和抗虫害的SiC（f）/MoSi 2组合物。 这些组合物是使用将Mo、Si和C的元素混合物的自蒸发高温合成（SHS）与准热等静压（HIP）-电固结相结合的单步工艺开发的。 第二阶段的研究将证明该工艺沿着的近净成形能力以及生产坚固的MoSi 2基复合材料的能力。 根据涡轮机发动机制造商的设计规范，该项目还将制造原型，以便在第二阶段结束时进行测试。SiC（f）增韧的MoSi 2复合材料可作为加热元件、燃烧和燃烧器装置以及熔融金属过滤器实现直接商业用途。 未来的应用包括用于航空和燃气涡轮机发动机部件、热交换器、热气过滤器和废物焚烧炉。 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.