LEAPS-MPS: Exploring Centrifugal Jet Spinning of Ultra-High-Temperature Ceramic Nanofibers

该奖项全部或部分由2021年美国救援计划法案（公法117-2）资助。非技术描述：该研究项目包括一种新颖的方法来制造微米和纳米尺寸的陶瓷纤维，可以承受数千摄氏度而不熔化。将金属盐和聚合物溶解以制成粘性溶液，随后将其纺成纤维。然后对纤维进行热处理，使金属与聚合物中的碳反应，形成超高温陶瓷纤维。研究了高温和氧气对纤维微观结构的影响。这项研究使得有可能在低温下大量制造纤维形式无法获得的化合物的陶瓷衬垫。这些超高温陶瓷纤维垫可用于热保护系统，使飞机、导弹和火箭能够以高超音速更快、更长时间地飞行。来自一个少数民族服务机构的两名本科生和两名研究生正在获得陶瓷制造和测试方面的实验室经验。另有8至16名本科生从事陶瓷材料表征设备的设计、制造和测试。毕业生通常在高科技行业就业或继续攻读研究生学位。技术难题：过渡金属碳化物纳米晶纳米颗粒、纳米棒、纳米粉末和纳米线的合成方法有很多种，但是，利用规模化技术大规模生产长且连续的超高温过渡金属碳化物纳米纤维仍然是一个巨大的挑战。在这个项目中，新型的过渡金属碳化物纳米纤维是通过碳热还原离心喷射纺丝制造的聚合物前体纳米纤维。离心喷射纺丝利用离心力从溶液中生产纤维，其速度和成本与熔喷和玻璃纤维方法相似，并且在该项目中用于利用节能聚合物前体合成方法，其附加优点是易于大规模生产。研究了纤维的氧化行为。从该项目中获得的知识可以用于大批量制造其他陶瓷纤维。此外，这项研究为代表性不足的群体的本科生和研究生提供了获得材料科学和工程实践经验的机会。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).NON-TECHNICAL DESCRIPTION: This research project consists of a novel method to fabricate micro- and nano-sized ceramic fibers that can withstand several thousand degrees Celsius without melting. A metal salt and a polymer are dissolved to make a viscous solution that is subsequently spun into fibers. The fibers are then heat treated to react the metal with the carbon in the polymer and form the ultra-high-temperature ceramic fiber. The effects of high temperatures and oxygen in the atmosphere on the fibers’ microstructure are also studied. This research makes it possible to fabricate, in large quantities and at low temperature, ceramic nanofiber mats of compounds not available in fiber form. These ultra-high temperature ceramic fiber mats can contribute to thermal protection systems that allow aircraft, missiles, and rockets to travel faster and for a longer period at hypersonic speed. Two undergraduate students and two graduate students from a minority-serving institution are obtaining laboratory experience in ceramic manufacturing and testing. Another 8 to 16 undergraduate students are engaged in designing, fabricating, and testing equipment for ceramic materials characterization. Graduates typically find employment in the high-tech industry or further pursue graduate degrees.TECHNICAL DETAILS: Several synthesis methods exist for the fabrication of transition metal carbide nanocrystalline nanoparticles, nanorods, nano-powders, and nanowires; however, it is still a great challenge to fabricate long and continuous ultra-high-temperature transition metal carbide nanofibers using scalable techniques for mass production. In this project, novel transition-metal carbide nanofibers are fabricated by the carbothermal reduction of polymer precursor nanofibers manufactured by centrifugal jet spinning. Centrifugal jet spinning uses centrifugal forces to produce fibers from solutions at speeds and costs similar to melt-blown and glass fiber methods and is used in this project to leverage the energy-efficient polymer precursor synthesis method with the added benefit of being easily scalable for mass production. The oxidation behavior of the fibers is also investigated. The knowledge obtained from this project can be useful to fabricate other ceramic fibers in large quantities. In addition, this research provides opportunities for undergraduate and graduate students of underrepresented groups to obtain hands-on experience in materials science and engineering.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.